Patent Publication Number: US-9895527-B2

Title: Fluid delivery system, fluid path set, and pressure isolation mechanism with hemodynamic pressure dampening correction

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of application Ser. No. 12/975,531, filed on Dec. 22, 2010, now U.S. Pat. No. 8,992,489, which was a division of application Ser. No. 11/551,027, filed on Oct. 19, 2006, now abandoned, which is a continuation-in-part of application Ser. No. 11/004,670, filed on Dec. 3, 2004, now U.S. Pat. No. 8,540,698, which is a continuation-in-part of application Ser. No. 10/826,149, filed on Apr. 16, 2004, now U.S. Pat. No. 7,611,503, the disclosures of which are incorporated herein by reference. 
     RELATED APPLICATIONS 
     This application may contain subject matter that is related to that disclosed in the following co-pending applications: (1) application Ser. No. 10/818,748, filed on Apr. 6, 2004, now U.S. Pat. No. 7,326,186; (2) application Ser. No. 10/818,477, filed on Apr. 5, 2004, now U.S. Pat. No. 7,563,249; (3) application Ser. No. 10/326,582, filed on Dec. 20, 2002, now U.S. Pat. No. 7,549,977; (4) application Ser. No. 10/237,139, filed on Sep. 6, 2002, now U.S. Pat. No. 6,866,654; and (5) application Ser. No. 09/982,518, filed on Oct. 18, 2001, now U.S. Pat. No. 7,094,216, the disclosures of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates generally to fluid delivery systems for supplying fluids during medical diagnostic and therapeutic procedures, further, to fluid transfer sets and flow controlling and regulating devices associated therewith used with fluid delivery systems for conducting and regulating fluids flows. 
     Description of Related Art 
     In many medical diagnostic and therapeutic procedures, a physician or other person injects a patient with a fluid. In recent years, a number of injector-actuated syringes and powered injectors for pressurized injection of fluids, such as contrast media, have been developed for use in procedures such as angiography, computed tomography, ultrasound, and NMR/MRI. In general, these powered injectors are designed to deliver a preset amount of contrast media at a preset flow rate. 
     Angiography is used generally in the detection and treatment of abnormalities or restrictions in blood vessels. In an angiographic procedure, a radiographic image of vascular structure is obtained through the use of a radiographic contrast medium, sometimes referred to simply as contrast, injected through a catheter. The vascular structures in fluid connection with the vein or artery in which the contrast is injected are filled with contrast. X-rays passing through the region of interest are absorbed by the contrast, causing a radiographic outline or image of blood vessels containing the contrast. The resulting images can be displayed on, for example, a monitor and recorded. 
     In a typical angiographic procedure, a physician places a cardiac catheter into a vein or artery. The catheter is connected to either a manual or to an automatic contrast injection mechanism. A typical manual contrast injection mechanism, as illustrated, for example, in  FIG. 1 , includes a syringe in fluid connection with a catheter connection. The fluid path also includes, for example, a source of contrast fluid, a source of saline, and a pressure transducer P to measure patient blood pressure. In a typical system, the source of contrast is connected to the fluid path via a valve V 1 , for example, a three-way stopcock. The source of saline and pressure transducer P may also be connected to the fluid path via additional valves V 2  and V 3 , respectively. The operator of the manual system of  FIG. 1 , manually controls the syringe and each of the valves V 1  and V 2  to draw saline or contrast into the syringe and to inject the saline or contrast into the patient through the catheter connection. The pressure transducers used in such procedures are extremely sensitive to even moderately high pressures generated during activation of the syringe, so the operator must close valve V 3  to isolate pressure transducer P from the fluid path when the syringe is activated to prevent damage to pressure transducer P. While the syringe is not activated, valve V 3  is usually open to monitor patient blood pressure. 
     The operator of the syringe of  FIG. 1  may adjust the flow rate and volume of injection by altering the force applied to the plunger of the syringe. Manual sources of fluid pressure and flow used in medical applications such as syringes and manifolds thus typically require operator effort that provides feedback of the fluid pressure/flow generated to the operator. The feedback is desirable, but the operator effort often leads to fatigue. Thus, fluid pressure and flow may vary depending on the operator&#39;s strength and technique. 
     Automatic contrast injection mechanisms typically include a syringe connected to a powered injector having, for example, a powered linear actuator. Typically, an operator enters settings into an electronic control system of the powered injector for a fixed volume of contrast material and a fixed rate of injection. In many systems, there is no interactive control between the operator and the powered injector, except to start or stop the injection. A change in flow rate in such systems occurs by stopping the machine and resetting the parameters. Automation of angiographic procedures using powered injectors is discussed, for example, in U.S. Pat. Nos. 5,460,609, 5,573,515 and 5,800,397. 
     U.S. Pat. No. 5,800,397 discloses an angiographic injector system having high pressure and low pressure systems. The high pressure system includes a motor-driven injector pump to deliver radiographic contrast material under high pressure to a catheter. The low pressure system includes, among other things, a pressure transducer to measure blood pressure and a pump to deliver a saline solution to the patient as well as to aspirate waste fluid. A manifold is connected to the syringe pump, the low pressure system, and the patient catheter. A flow valve associated with the manifold is normally maintained in a first state connecting the low pressure system to the catheter through the manifold, and disconnecting the high pressure system from the catheter and the low pressure system. When pressure from the syringe pump reaches a predetermined and set level, the valve switches to a second state connecting the high pressure system/syringe pump to the catheter, while disconnecting the low pressure system from the catheter and from the high pressure system. In this manner, the pressure transducer is protected from high pressures, (see column 3, lines 20-37 of U.S. Pat. No. 5,800,397). However, compliance in the system components, for example, expansion of the syringe, tubing, and other components under pressure, using such a manifold system can lead to a less than optimal injection bolus. Moreover, the arrangement of the system components of U.S. Pat. No. 5,800,397 results in relatively large amounts of wasted contrast and/or undesirable injection of an excessive amount of contrast when the low pressure, typical saline system, is used. The injector system of U.S. Pat. No. 5,800,397 also includes a handheld remote control connected to a console. The control includes saline push button switches and a flow rate control lever or trigger. By progressive squeezing of the control trigger, the user provides a command signal to the console to provide a continuously variable injection rate corresponding to the degree of depression of the control trigger. 
     U.S. Pat. No. 5,916,165 discloses a handheld pneumatic controller for producing a variable control signal to control a rate of fluid dispersion to the patient in an angiographic system. U.S. Pat. No. 5,515,851 discloses an angiographic system with a finger activated control pad to regulate the injection of fluids. 
     Unlike manual injection systems, however, there is little if any feedback to the operator of system pressure in the systems disclosed in the U.S. Patents identified previously. There are potential advantages to such feedback. In the use of a manual syringe, for example, excessive back pressure on the syringe plunger can provide evidence of occlusion of the fluid path. 
     U.S. Pat. No. 5,840,026 discloses, an injection system in which an electronic control system is connected to the contrast delivery system and a tactile feedback control unit. In one embodiment, the tactile feedback control unit includes a disposable syringe that is located within a durable/reusable cradle and is in fluid connection with the fluid being delivered to the patient. The cradle is electrically connected to the electronic control system and is physically connected to a sliding potentiometer that is driven by the plunger of a disposable syringe. During use of the injection system of U.S. Pat. No. 5,840,026, the operator holds the cradle and syringe and, as the operator depresses the sliding potentiometer/syringe piston assembly, the plunger is moved forward, displacing fluid toward the patient and creating a pressure in the syringe. A sliding potentiometer tracks the position of the syringe plunger. The electronic control system controls the contrast delivery system to inject an amount of fluid into the patient based on the change in position of the plunger. As the fluid is injected, the pressure the operator feels in his or her hand is proportional to the actual pressure produced by the contrast delivery system. The force required to move the piston provides the operator with tactile feedback on the pressure in the system. The operator is able to use this feedback to ensure the safety of the injection procedure. Unlike the case of a manual injection system, the injection system of U.S. Pat. No. 5,840,026 does not require the operator to develop the system pressure and flow rate. The operator develops a smaller, manually applied pressure that corresponds to or is proportional to the system pressure. The required manual power output (that is, pressure×flow rate) is decreased as compared to manual systems, whereas the tactile feedback associated therewith is retained. 
     While manual and automated injectors are known in the medical field, a need generally exists for improved fluid delivery systems adapted for use in medical diagnostic and therapeutic procedures where fluids are supplied to a patient during the procedure. A specific need generally exists for an improved fluid delivery system for use in fluid injection procedures, such as angiography. Additionally, a need generally exists for fluid transfer sets and flow controlling and regulating devices associated therewith that may be used with fluid delivery systems for conducting and regulating fluids flows. Moreover, a continuing need exists in the medical field to generally improve upon known medical devices and systems used to supply fluids to patients during medical procedures such as angiography, computed tomography, ultrasound, and NMR/MRI. 
     SUMMARY OF THE INVENTION 
     The present invention provides an injector system including a powered injector, a pressurizing chamber in operative connection with the powered injector, a fluid path in fluid connection with the pressurizing chamber, and a manual control in fluid connection with the fluid path. The manual control includes at least one actuator for controlling the injector through application of force by an operator. The actuator provides tactile feedback of pressure in the fluid path to the operator via direct or indirect operative or fluid connection with the fluid path (i.e., pressure in the fluid path transfers a corresponding or a proportional force to the operator). In one embodiment, the actuator is adapted to stop an injection procedure if no force is applied to the actuator. The manual control may, for example, include a chamber in fluid connection with the fluid path. The actuator may be a button or a plunger in operative connection with a piston disposed within the chamber. The actuator may be biased in an off position. 
     In another aspect, the manual control includes a first actuator for controlling the injector in a low pressure mode through application of force by an operator. The first actuator provides tactile feedback of pressure in the fluid path to the operator via fluid connection with the fluid path as described previously. The first actuator also provides control of flow rate by changing the force thereon. The manual control also may include a second actuator having an on state and an off state. The second actuator causes the injector to enter into a preprogrammed high-pressure injection mode when placed in the on state. The manual control may also include a third actuator for controlling flow of saline in the fluid path. 
     In another aspect of the present invention, the actuator provides tactile feedback of fluid pressure and is also in operative connection with an audible feedback unit that provides audible feedback of fluid pressure and/or fluid flow to the operator. The manual controls of the present invention may be purged of air before injection via, for example, a purge valve. 
     The present invention also provides a system for injection of fluid into a patient including a multi-patient reusable section and a per-patient disposable section. The multi-patient reusable section and the per-patient disposable section are removably connectable via a connector or connectors, for example, via a high-pressure connector. The multi-patient reusable section includes a powered injector in fluid connection with a source of a first injection fluid and a first fluid path connecting the injector and a high-pressure connector. The per-patient disposable section includes a second fluid path adapted to connect the high-pressure connector and the patient in fluid connection. The per-patient disposable section further includes a manual control as described above including a connector to place the manual control in fluid connection with the second fluid path. The multi-patient reusable section may further include a valve mechanism connecting the injector, first fluid source, and the first fluid path. 
     In one embodiment, the multi-patient reusable section further includes a source of a second injection fluid and a pumping mechanism in fluid connection with the second fluid source for pressurizing the second fluid. The pumping mechanism is preferably in fluid connection with the valve mechanism. 
     In one aspect, the manual control includes a first actuator providing control of flow rate of the first fluid by changing the force on the first actuator and a second actuator, the second actuator causing the injector to enter into a preprogrammed high pressure injection mode when placed in an on state. The system may further include a pressure sensor in fluid communication with the second fluid path via a pressure-activated isolator that isolates the pressure sensor from pressures in the second fluid path above a set pressure. In one embodiment, the per-patient disposable section may include a check valve in the second fluid path separating components of the per-patient disposable section from the multi-patient reusable section to reduce or eliminate flow of contaminated fluid into the multi-patient reusable section. 
     The present invention further provides a method of injecting a fluid into a patient including the steps of: removably connecting a multi-patient reusable section to a per-patient disposable section via a high-pressure connector, the multi-patient reusable section including a powered injector in fluid connection with a source of a first injection fluid and a first fluid path connecting the injector and the high-pressure connector, the per-patient disposable section including a second fluid path adapted to connect the high-pressure connector and the patient in fluid connection; connecting a manual control including a connector to the second fluid path to place the manual control in fluid connection with the second fluid path, the manual control including at least one actuator for controlling the powered injector through application of force by an operator, the actuator being adapted to provide tactile feedback of pressure in the second fluid path to the operator via fluid connection with the second fluid path; and injecting a fluid into a patient. 
     The method may further include the step of connecting a pressure sensor in fluid communication with the second fluid path via a pressure activated isolator that isolates the pressure sensor from pressures in the second fluid path above a set pressure. 
     Still further, the present invention provides a per-patient disposable set for use in an injection procedure including a fluid path adapted to form a fluid connection between a high-pressure connector and the patient, and a manual control in fluid connection with the fluid path. The manual control includes at least one actuator for controlling the powered injector through application of force by an operator. The actuator is adapted to provide tactile feedback of pressure in the fluid path to the operator via fluid connection with the fluid path. The per-patient disposable set further includes a pressure sensor in fluid connection with the fluid path via a pressure activated isolator adapted to isolate the pressure sensor from pressures in the fluid path above a set pressure. 
     The manual, for example, handheld controllers of the present invention provide a number of advantages including, but not limited to the following: tactile feedback of actual fluid path pressure via fluid communication with the fluid path, compact size and small priming volume; dead man switch capability; ergonomic design for control of both contrast and saline; injection pressure feedback linked to variable flow and audible feedback; rigid material construction; actuator control providing a progressively increasing flow rate as the actuator is pushed or depressed through its range of motion; and high-pressure injections that are greater in pressure than could be generated or tolerated by an operator&#39;s hand. 
     In another aspect, the present invention provides an injection system for use in angiography including a powered injector in fluid connection with a source of injection fluid and a pressure sensor in fluid connection with the powered injector via a pressure activated isolator adapted to isolate the pressure sensor from pressures in the fluid path above a set pressure. The pressure sensor elevation is independent of or independently variable of the position of the remainder of the injection system, including the position or elevation of the powered injector. 
     In a further aspect, the present invention provides an angiographic injection system for injecting an injection fluid into a patient including a pressurizing device for supplying injection fluid under pressure; a low pressure fluid delivery system; and a pressure isolation mechanism having a first port for connection to the pressurizing device, a second port for connection to the patient, and a third port for connection to the low pressure fluid delivery system. The pressure isolation mechanism includes a valve having a first state and a second state different from the first state. Preferably, the first state and the second state are mutually exclusive of each other. The first state occurs when the second and third ports are connected and the first and third ports are connected. The second state occurs when the first and second ports are connected and the first and third ports are disconnected. The valve is normally biased to the first state via, for example, a spring, and is switchable to the second state when fluid pressure from the syringe pump reaches a predetermined pressure level. The first and second ports remain connected in the first state and in the second state. 
     The system preferably further includes a valve in line between the pressurizing device and the first port of the pressure isolation mechanism to control flow of the injection fluid. Preferably, the valve is an automated valve. The valve is preferably operable to minimize or eliminate the effects of compliance of the pressurizing device and related tubing. 
     The low pressure delivery system may include a source of saline or other suitable flushing medium, a drip chamber in fluid connection with the source of saline, and a detector to sense the amount of saline in the source of saline. The system may further include a saline control valve and an air detector in line between the saline drip chamber and the pressure isolation mechanism. 
     The pressurizing device may be in fluid connection with a source of injection fluid via an injection fluid drip chamber. The system may further include a detector to sense the amount of injection fluid in the source of injection fluid. Likewise, the system may also include an injection fluid control valve and an air detector in line between the injection fluid drip chamber and the pressure isolation mechanism. 
     In one embodiment, the system further includes a handheld controller to control injection of injection fluid and injection of saline. The handheld controller may include a first control having a first mode to control injection of injection fluid in a low pressure mode, the flow rate of the injection corresponding to, for example, being proportional to, the distance the first control is depressed. Preferably, the low pressure injection is ceased if the first control is released while in the first mode. The first control may, for example, have a second mode to control injection of injection fluid in a high pressure mode. The high pressure mode injection is preferably ceased if the first control is released while in the second mode. The hand controller may further include at least a second control to control injection of saline. Preferably, the injection of saline is ceased if the second control is released during injection of saline. 
     The system preferably further includes a pressure transducer in fluid connection with the third port of the pressure isolation mechanism. 
     In still a further aspect, the present invention provides an injection system for use in angiography including a source of saline, a pump in fluid connection with the source of saline to pressurize the saline, a saline valve in fluid connection via a first port thereof with an outlet of the pump, a first connector in fluid connection with a second port of the saline valve, a source of contrast, a contrast valve in fluid connection with the source of contrast via a first port of the contrast valve, a powered injector in fluid connection with a second port of the contrast valve, a second connector in fluid connection with a third port of the contrast valve, and a pressure isolation mechanism. 
     The pressure isolation mechanism has a lumen having a first port in fluid connection with the second connector and a second port in fluid connection with a patient catheter. The isolation mechanism further has a third port in fluid connection with the first connector and with the lumen. The pressure isolation mechanism further includes a valve having a first state and a preferably mutually exclusive second state—the first state occurring when the lumen and the third port are connected, and the second state occurring when the lumen and the third port are disconnected. The valve is preferably normally biased to the first state and is switchable to the second state when fluid pressure from the powered injector reaches a predetermined pressure level. The first and second ports of the lumen preferably remain connected whether in the first state or in the second state. The system further includes a pressure transducer in fluid connection with the third port of the pressure isolation mechanism. 
     The system may also include a first air or air column detector in fluid connection between the saline valve and the first connector and a second air detector in fluid connection between the contrast valve and the second connector. 
     The system may also include a first drip chamber in fluid connection between the source of saline and the pump and a detector in operative connection with the first drip chamber to sense the amount of saline in the source of saline. Likewise, the system may include a second drip chamber in fluid connection between the source of contrast and the contrast valve and a detector in operative connection with the second drip chamber to sense the amount of injection fluid in the source of injection fluid. One advantage of a drip chamber is to reduce likelihood of introduction of air into the system once the system has been initially purged of air or primed. 
     In another aspect, the present invention provides a pressure isolation mechanism for use in a medical procedure. The pressure isolation mechanism or pressure isolator includes a lumen, an isolation port in fluid connection with lumen, and a valve having a first state and a second state. The first state occurs when the lumen and the isolation port are connected. The second state occurs when the lumen and the isolation port are disconnected. The lumen remains open for flow of fluid therethrough in the first state and in the second state. The valve is normally in the first state and is switchable to the second state when fluid pressure in the lumen reaches a predetermined pressure level. The valve may, for example, be biased to the first state, for example, via a spring or other mechanism suitable to apply a biasing force as known in the art. A pressure sensor or transducer can be in fluid connection with the isolation port of the pressure isolation mechanism as described previously. 
     The valve may be switched between the first state and the second state by the force of the fluid pressure. Alternatively, an electromechanical actuator in operative connection with a pressure sensor may control the state of the valve as a function of the fluid pressure. The pressure sensor may, for example, be a pressure transducer in fluid connection with the isolation port as described previously. 
     In general, the pressure isolation mechanism is useful in any medical procedure in which is it desirable to isolate a fluid pathway or fluid path component from fluid flow above a certain fluid pressure. The fluid pathway or fluid path component is placed in fluid connection with the isolation port of the pressure isolation mechanism. For example, a pressure transducer may be placed in connection with the isolation port to protect the pressure transducer form damage as a result of exposure to excess fluid pressure. 
     In a further aspect, the present invention provides a fluid delivery system including a manually operated syringe and a pressure isolation mechanism as described above. 
     The present invention provides in another aspect a method of adding a patient pressure transducer to a fluid path used in a medical procedure to deliver fluid to a patient. The method includes the step of placing a lumen of a pressure isolation mechanism as described above in the fluid path via, for example, a first port and a second port of the lumen. The method also includes the steps of connecting a pressure transducer to the third or isolation port of the pressure isolation mechanism. The method is useful, for example, in adding a patient pressure transducer to an angiographic fluid delivery system including a manual syringe. 
     The present invention is further directed to a fluid path set for use generally in a fluid delivery system. The fluid path set generally includes a first section generally adapted for association with a pressurizing device such as a syringe, and a second section adapted for removable fluid communication with the first section. The first section may be a multi-patient section of the fluid path set, and the second section may be a single or per-patient section of the fluid path set and be disposable after use with a single patient. The multi-patient section may be disposable after a preset number of uses with the fluid delivery system. Additionally, the multi-patient section may be provided as a single patent set or section, disposed of after use with a single patient or injection procedure. Further, it is within the scope of the present invention to provide the first and second sections of the fluid path set as multi-use components that may be re-sterilized after each use or injection procedure. The first section may be adapted for connection to a source of fluid to be loaded into a pressurizing device. The first section may comprise a multi-position valve adapted to selectively isolate the fluid source and the second section. 
     Another aspect of the present invention is directed to a connector for use in a fluid delivery or transfer system or arrangement, and generally adapted to reduce the likelihood of contamination at connection points in the fluid path set when changing components in the fluid path set. The connector may be used with the fluid path set for providing removable fluid communication between the first section and the second section. The connector is configured to reduce contamination when connecting one or more typically disposable second sections with a typically multiple-patient first section in the fluid path set. The connector generally includes a first connector member and a second connector member, which are generally adapted to removably connect with one another. The first and second connector members may be associated with either the first section or the second section. Thus, if the first connector member is associated with the first section, the second connector member is associated with the second section, and vice versa. The first connector member includes an outer housing and a first threaded member disposed in the outer housing. The second connector member includes a second threaded member. The first threaded member and second threaded member cooperate to securely and releasably connect the first member to the second member, when the first connector member is connected to the second connector member. The connection of the first connector member with the second connector member generally establishes the removable fluid communication between the first section and the second section, when the connector is used therewith. The second threaded member is preferably received in the outer housing of the first connector member when the first connector member is connected to the second connector member. 
     The first threaded member may be recessed within the outer housing. The first threaded member may be formed as an externally-threaded luer, which may be recessed within the outer housing. The second member may include a luer disposed in the second threaded member and adapted to cooperate with the first threaded member. The luer may be recessed within the second threaded member. 
     The first threaded member may be formed as an externally-threaded female luer, and the second member may include a male luer disposed in the second threaded member, such that the male luer cooperates with the female luer when the first connector member is connected to the second connector member. One or both of the female luer and the male luer may be recessed within the outer housing and the second threaded member, respectively. 
     The first threaded member may be externally-threaded and the second threaded member may be internally-threaded. The second threaded member may include at least one circumferentially-extending raised structure on an external surface thereof. The raised structure may define a tortuous path with an inner wall of the outer housing for inhibiting liquid flow between the outer housing and the second threaded member when the first connector member is connected to the second connector member. The raised structure may define a chamber with the inner wall of the outer housing and the first threaded member when the first connector member is connected to the second connector member. 
     Protective caps may be associated with the first connector member and the second connector member, respectively, prior to connecting the first connector member and the second connector member. The first and second connector members may each include a raised tab adapted to cooperate with a corresponding groove defined internally in the protective caps, for securing removable engagement between the first and second connector members and the respective protective caps. The protective caps may be disposable or reusable items. 
     An additional aspect of the present invention is directed to a pressure isolation mechanism that may be used, for example, with the fluid path set. For example, the second section of the fluid path set may include the pressure isolation mechanism. The pressure isolation mechanism generally comprises a lumen, a pressure isolation port, and a valve member. The valve member includes a biasing portion biasing the valve member to a normally open position permitting fluid communication between the lumen and the pressure isolation port. The valve member is movable to a closed position when fluid pressure in the lumen reaches a predetermined pressure level sufficient to overcome the biasing force of the biasing portion of the valve member. 
     The pressure isolation mechanism may have a housing that defines the lumen and the pressure isolation port. A pressure transducer may be associated with the pressure isolation port. The valve member may comprise a seat member and a base portion engaged with the seat member. The biasing portion of the valve member may be a generally cone-shaped portion of the seat member. The generally cone-shaped portion preferably has a predetermined spring force. The seat member may be adapted to engage a housing of the pressure isolation mechanism in the closed position of the valve member. The seat member may define an aperture and the base portion may be formed with a projection engaged with the aperture for connecting the base portion to the seat member. The base portion may be joined to the seat member by mechanical connection therewith or bonded to the seat member, for example with an adhesive. 
     The pressure isolation mechanism may have a multi-piece housing, such as a two-piece housing including a first portion cooperating with a second portion. The first portion may be in an interference fit engagement with the second portion. The first portion and second portion may be formed to define a tortuous or shear interface therebetween to enhance strength. 
     A still further aspect of the present invention is directed to an improved drip chamber that may be used as part of the fluid path set. For example, one or more drip chambers may be used with the first section, or the second section. In one embodiment, the first section includes an intervening drip chamber between the primary fluid source and the syringe. The drip chamber generally comprises a projection useful for determining a level of fluid in the drip chamber. The projection is preferably raised from the body of the drip chamber, and may extend longitudinally or laterally along the body of the drip chamber. 
     Additionally, the first section may be adapted for connection to a secondary source of fluid to be delivered to a patient, such as saline. An intervening drip chamber may also be associated with the secondary fluid source and the first section. The drip chamber associated with the secondary fluid source preferably also has a projection for determining a level of fluid in the drip chamber, which is also preferably raised from the body of the drip chamber. The second section may be further adapted for removable fluid communication with the first section, such that the secondary fluid source is in fluid communication with the pressure isolation port. The intervening drip chamber associated with the secondary fluid source may be located between the secondary fluid source and the pressure isolation port. 
     The present invention is further directed as a method of preparing a fluid delivery system for association with a patient. The method generally includes providing the fluid delivery system including an injector, associating a syringe with the injector, and providing the fluid path set comprising the first section and the second section. The first section may be connected with the syringe, and the second section connected to the first section to provide removable fluid communication therebetween. 
     The first section may be removably connected to the second section with the connector described previously. The second section is generally placed in removable fluid communication with the first section by connecting the first connector member and the second connector member of the connector. The second threaded member of the second connector is received in the outer housing of the first connector member when the first connector member and second connector member are connected. 
     Additionally, the present invention is a method of delivering fluid to a patient, generally providing a fluid delivery system including an injector, associating a syringe with the injector, and providing the fluid path set comprising the first section and the second section. The first section may be connected with the syringe, and the second section connected to the first section to provide removable fluid communication therebetween. The second section may then be connected to the patient and the injector actuated to deliver fluid to the patient. When the fluid delivery procedure is complete, the injector may be deactivated to terminate delivery of fluid to the patient, and the second section of the fluid path set may be disconnected from the patient. 
     The first section may be removably connected to the second section with the connector described previously. The second section is generally placed in removable fluid communication with the first section by connecting the first connector member and the second connector member of the connector. The second threaded member of the second connector is received in the outer housing of the first connector member when the first connector member and second connector member are connected. 
     The method of delivering fluid to the patient may further include disconnecting the second section from the first section and providing a new second section. The new second section may be connected to the existing first section to provide removable fluid communication therebetween. The new second section may be connected to the same patient or a new patient, and the injector may be actuated to deliver fluid to the patient. The present invention is additionally directed to an injection system including a source of injection fluid, a pump device, and a fluid path set, summarized previously, disposed between the source of injection fluid and the pump device. The first and second sections of the fluid path set may be connected using one or more of the connectors discussed previously. 
     The present invention is also an injector system that generally includes a source of injection fluid, a pump device, a fluid path set disposed between the source of injection fluid and the pump device, and a fluid control device. The fluid path set includes a multi-position valve. The fluid control device is operatively associated with the fluid path set and includes a valve actuator adapted to operate the multi-position valve. The valve actuator is adapted to close the multi-position valve to isolate the pump device from a patient and stop flow of the injection fluid to the patient at substantially any pressure or flow rate generated by the pump device for delivering a sharp bolus of the injection fluid to the patient. The valve actuator may be further adapted to selectively place the pump device in fluid communication with the source of injection fluid for supplying the injection fluid to the pump device. 
     The valve actuator may include a position indicator indicating a position of the multi-position valve. The valve actuator may include a sensor indicating presence of the multi-position valve in the valve actuator. The valve actuator may include a retainer for removably supporting the multi-position valve. 
     The fluid path set may include a drip chamber and the fluid control device may include a fluid level sensing mechanism operatively associated with the drip chamber for sensing the injection fluid level in the drip chamber. An air column detector may be operatively associated with the fluid path set. The pump device of the injector system may be a powered injector. 
     A source of medical fluid may be associated with the fluid path set, and a pump operatively associated with the source of medical fluid for supplying the medical fluid to the patient via the fluid path set. The fluid path set may include a drip chamber and the fluid control device may include a fluid level sensing mechanism operatively associated with the drip chamber for sensing the medical fluid level in the drip chamber. A shut-off valve may be associated with the pump for stopping flow of the medical fluid to the patient. The shut-off may be an automated pinch valve. The pump may be a peristaltic pump. The fluid control device may further include guides for securing the fluid path set in association with the pump. A hand held control device may be associated with the pump device or the fluid control device for controlling the flow rate of the injection fluid from the pump device. 
     The injector system may further include a drip chamber having a body with a projection, and a fluid level sensing mechanism. The fluid level sensing mechanism may include a drip chamber support for supporting the drip chamber body, and a fluid level sensor associated with the drip chamber support. The drip chamber support is generally adapted to support the drip chamber body such that the projection is operatively associated with at least one fluid level sensor. The fluid level sensor may be an ultrasonic or optical fluid level sensor. The drip chamber support may be adapted to support the drip chamber body such that the projection is in contact with the fluid level sensor. The injector system may further include an indicator light associated with the fluid level sensor for illuminating the drip chamber. The fluid level sensing mechanism is adapted to cause the indicator light to intermittently operate if a fluid level in the drip chamber is at an unsafe level. 
     The present invention further encompasses an air detector assembly for the fluid control device comprising. The air detector assembly includes an air column detector adapted to detect the presence of air in medical tubing, and a retaining device for securing the medical tubing in operative association with the air column detector. The retaining device generally includes a base adapted for association with the air column detector, and a closure member connected to the base and adapted to secure the medical tubing in operative association with the air column detector. 
     The closure member is generally movable from a closed position wherein the closure member secures the medical tubing in operative association with the air column detector, to an open position allowing the medical tubing to be disassociated from the air column detector. The closure member is preferably biased to the open position and secured in the closed position by a releasable locking mechanism. The closure member may be secured in the closed position by a releasable locking mechanism. The closure member may be formed of substantially clear plastic material to permit viewing of the medical tubing. 
     The present invention is also a fluid control device for connecting a pump device to a source of injection fluid. The fluid control device includes a fluid path set comprising a multi-position valve adapted to associate a patient and the source of injection fluid with the pump device, and a valve actuator adapted to operate the multi-position valve to selectively isolate the pump device from the patient, and place the pump device in fluid communication with the source of injection fluid for supplying the injection fluid to the pump device. 
     The present invention is a method of preparing the fluid delivery system to deliver an injection fluid to a patient, generally including providing a pump device for supplying the injection fluid to the patient under pressure, providing a fluid control device, associating a fluid path set with the fluid control device, and connecting the pump device with the source of the injection fluid via the fluid path set. The pump device may be a syringe actuated by a powered injector. 
     The step of associating the fluid path set with the fluid control device may include associating a multi-patient set or section with the fluid control device and removably connecting a per-patient set or section with the multi-patient set or section. The multi-patient set and per-patient set may be removably connected by at least one connector. The step of associating the multi-patient set with the fluid control device may include associating a multi-position valve associated with the multi-patient set with a valve actuator associated with the fluid control device. The pump device may be connected with the source of the injection fluid via the multi-patient set. 
     The method may further include connecting the fluid path set to a source of medical fluid, associating the fluid path set with a pump adapted to deliver the medical fluid to the patient, and actuating the pump to purge air from the portion of the fluid path set associated with the source of medical fluid. The method may further include connecting the fluid path set to a patient catheter. 
     A hand held control device may be associated with the pump device for controlling the pump device as part of the method. 
     Additionally, the method may include actuating the fluid control device to permit fluid communication between the pump device and the source of injection fluid, actuating the pump device to draw injection fluid from the source of injection fluid into the pump device, and actuating the pump device to purge air from the fluid path set into the source of injection fluid. The fluid control device and pump device may be controlled according to instructions programmed in a control unit operatively connected to the fluid control device and the pump device. The control device may be a graphical interface display. The first step or act of actuating the pump device includes moving a syringe plunger in a proximal direction within the syringe to draw injection fluid into the syringe from the source of injection fluid. The second step or act of actuating the pump device may include reversing the direction of the syringe plunger in the syringe to purge air from the fluid path set. 
     The fluid control device may be in the form of a valve actuator adapted to actuate a multi-position valve associated with the fluid path set. The method may include deactivating the pump device and actuating the fluid control device to isolate the pump device from the source of injection fluid. 
     In another embodiment, the present invention is a method of delivering an injection fluid to a patient, generally including providing a fluid delivery system comprising a source of injection fluid, a pump device, and a fluid path set comprising a fluid control device disposed between the source of injection fluid and the pump device; actuating the fluid control device to prevent fluid communication between the pump device and the source of injection fluid, and to permit fluid communication between the pump device and the patient; actuating the pump device to deliver pressurized injection fluid to the patient; and monitoring a level of injection fluid in a container associated with the fluid path set and in fluid communication with the source of injection fluid. The method may additionally include continuously monitoring the fluid path set for presence of air during the delivery of the pressurized injection fluid. 
     The method may further include actuating the fluid control device to stop fluid communication between the pump device and the patient at substantially any pressure or flow rate generated by the pump device. The pump device may be a syringe or a peristaltic pump. The step or act of actuating the pump device may include moving a syringe plunger in a distal direction within the syringe to force fluid out of the syringe and into the patient via the fluid path set. The fluid control device may be an automated multi-position valve. The pump device may be actuated by a hand held control device operatively connected to the pump device. 
     The fluid control device and pump device may be controlled according to instructions programmed in a control unit operatively connected to the fluid control device and the pump device. 
     The method may further include connecting the fluid path set to a source of medical fluid, and delivering the medical fluid to the patient associating with a pump associated with the fluid control device. 
     The pump device may be a syringe and the method may further include actuating the fluid control device to permit fluid communication between the syringe and the source of injection fluid, and refilling the syringe with injection fluid from the source of injection fluid. The method may further include actuating the fluid control device to close fluid communication between the pump device and the source of injection fluid and to permit fluid communication between the pump device and the patient, and actuating the pump device to again deliver pressurized injection fluid to the patient. The method may include monitoring a level of injection fluid in a container associated with the fluid path set and in fluid communication with the source of injection fluid. 
     Furthermore, the pump device may be a syringe, and the method may include actuating the fluid control device to isolate the syringe from the source of injection fluid and the patient, and retracting a syringe plunger in the syringe to reduce fluid pressure in the syringe. 
     The present invention is also directed to a fluid delivery system comprising a fluid path set including a first section and a second section adapted for removable fluid communication with the first section. At least one connector provides the removable fluid communication between the first section and the second section. The connector includes a first connector member defining a lumen for fluid flow through the first connector member. The first connector member comprises a first luer member and a first annular member disposed coaxially about the first luer member. The first luer member may be recessed within the first annular member. The connector further includes a second connector member defining a lumen for fluid through the second connector member. The second connector member comprises a second luer member and a second annular member disposed coaxially about the second luer member. The second luer member may be recessed within the second annular member. A check valve arrangement may be disposed in the lumen of one of the first and second connector members for limiting fluid flow to one direction through the medical connector. The first and second annular members may be adapted to operably engage to securely and releasably connect the first and second connector members. The engagement of the first and second annular members causes engagement between the first and second luer members to provide fluid communication between the lumens in the first and second connector members. The first annular member may be rotatably associated with the first connector member to rotate about the first luer member. 
     The first annular member may be adapted to coaxially receive the second annular member. The first annular member may be internally threaded and the second annular member may be externally threaded such that first and second annular members threadably engage to securely and releasably connect the first and second connector members. One of the first and second luer members may be formed as a male luer and the other may be formed as a female luer. The first annular member and first luer member may define an annular cavity therebetween such that the second annular member is at least partially received in the annular cavity when the first and second annular members are in operative engagement. When the second annular member is at least partially received in the annular cavity, the annular cavity may form a liquid-trapping chamber for inhibiting leakage of liquid between the first and second connector members. 
     The check valve arrangement comprises a stopper element disposed in the lumen in one of the first and second connector members for limiting fluid flow to one direction through the connector. The stopper element is adapted to seat against an internal shoulder in the lumen to prevent fluid flow therethrough until sufficient fluid pressure is present within the lumen to unseat the stopper element from the internal shoulder. The internal shoulder may be formed by a structure inserted in the lumen and which forms one end of a receiving cavity accommodating the stopper element. At least one septum may be provided in the lumen, dividing the lumen into at least two channels. The at least one septum may form the other end of the receiving cavity. Longitudinal grooves may be defined in the wall of the receiving cavity for fluid flow through the cavity when sufficient fluid pressure is present within the lumen to unseat the stopper element from the internal shoulder. The inserted structure may be a retaining sleeve and the stopper element may seat against the retaining sleeve until sufficient fluid pressure is present within a central bore in the retaining sleeve to unseat the stopper element from the retaining sleeve. 
     The stopper element may be formed of a resiliently deformable material, such that the stopper element deforms at least axially once sufficient fluid pressure is present in the lumen, thereby unseating from the internal shoulder and permitting fluid flow through the lumen. The first section may be adapted for connection to a pressuring device and to a source of fluid to be loaded into the pressurizing device. The first section may comprise an intervening drip chamber between the fluid source and the pressurizing device. The second section may comprise a pressure isolation mechanism in accordance with the description of the pressure isolation mechanism provided previously. 
     Other details and advantages of the present invention will become clear when reading the following detailed description in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an embodiment of a known manual injector system. 
         FIG. 2  illustrates one embodiment of an injection system of the present invention. 
         FIG. 3  illustrates an embodiment of a pressure activated isolator assembly of the present invention. 
         FIG. 4  illustrates an embodiment of a handheld controller or hand piece of the present invention. 
         FIG. 5  illustrates another embodiment of a handheld controller of the present invention in which the handheld controller is connected to the fluid path via a “T” connection. 
         FIG. 6A  illustrates another embodiment of a handheld controller of the present invention including a control switch for pressure feedback in low pressure injection, a switch for high pressure injection, and a switch for saline injection. 
         FIG. 6B  illustrates another embodiment of a handheld controller of the present invention, which is wearable on a finger of the user. 
         FIG. 7A  illustrates a schematic representation of another embodiment of an injection system of the present invention. 
         FIG. 7B  illustrates a side view of an embodiment of a portion of the injection system of  FIG. 7A  in which a pressure transducer is in the fluid path. 
         FIG. 7C  illustrates a side view of an embodiment of a portion of the injection system of  FIG. 7A  in which a pressure transducer is separated from the fluid path by a T-connector and a length of tubing. 
         FIG. 7D  illustrates a side cross-sectional view of an embodiment of a pressure isolation valve of the present invention in which the valve is in a first, “open” state. 
         FIG. 7E  illustrates a side cross-sectional view of the pressure isolation valve of  FIG. 7D  in which the valve is in a second, “closed” state. 
         FIG. 7F  illustrates a perspective view of the pressure isolation valve of  FIGS. 7D and 7E . 
         FIG. 7G  illustrates a front view of the injection system of  FIG. 7A . 
         FIG. 7H  illustrates a front view of the handheld controller of the injection system of  FIG. 7A . 
         FIG. 8A  illustrates an angiographic injection system of the present invention including a manual syringe and a pressure isolation mechanism or valve of the present invention, in which the pressure isolation mechanism is closed to isolate a pressure transducer from the fluid path. 
         FIG. 8B  illustrates the angiographic injection system of  FIG. 8A  in which the pressure isolation mechanism is open to place the pressure transducer in operative communication with the fluid path. 
         FIG. 9A  is a perspective view of a fluid delivery or injection system in accordance with another embodiment of and including generally analogous components to the system of  FIG. 7G . 
         FIG. 9B  is a perspective view of another embodiment of the fluid delivery or injection system including priming bulbs as part of the fluid path. 
         FIG. 10A  is a side and partially perspective view of a fluid path set used with the fluid delivery system of  FIG. 9A . 
         FIG. 10B  is a side and partially perspective view of a fluid path set used with the fluid delivery system of  FIG. 9B . 
         FIG. 11A  is a perspective view of a drip chamber in accordance with the present invention and adapted for use in the fluid path of  FIG. 10A . 
         FIG. 11B  is a perspective view of another embodiment of the drip chamber adapted for use in the fluid path set of  FIG. 10A . 
         FIG. 12  is a perspective view of another embodiment of the pressure isolation mechanism or valve of the present invention and provided in the fluid path set of  FIG. 10A . 
         FIG. 13  is a cross section view taken along lines  13 - 13  in  FIG. 12 . 
         FIG. 14  is an exploded perspective view of the pressure isolation mechanism of  FIG. 12 . 
         FIG. 15  is a perspective view of a biasing valve member used in the pressure isolation mechanism of  FIG. 12 . 
         FIG. 16  is a perspective view of a connector in accordance with the present invention and adapted for use in the fluid path set of  FIG. 10A , and showing first and second connector members of the connector disconnected from one another. 
         FIG. 17  is a longitudinal cross sectional view of the connector of  FIG. 16 , showing the first and second connector members connected together. 
         FIG. 18  is a longitudinal cross sectional view of the first connector member of the connector of  FIGS. 16 and 17 . 
         FIG. 19  is a longitudinal cross sectional view of the second connector member of the connector of  FIGS. 16 and 17 . 
         FIG. 20  is a perspective view of a fluid control module or device in accordance with the present invention. 
         FIG. 21  is a second perspective view of the fluid control module or device shown in  FIG. 20 . 
         FIG. 22  is a longitudinal cross sectional view of a valve actuator of the fluid control module or device shown in  FIGS. 20 and 21 . 
         FIG. 23  is an exploded perspective view of the valve actuator of  FIG. 22 ; 
         FIG. 24A  is a perspective view of a fluid level sensing mechanism of the fluid control module or device shown in  FIGS. 20 and 21  and adapted to interface with the drip chamber shown in  FIG. 11A . 
         FIG. 24B  is a perspective view of the fluid level sensing mechanism adapted to interface with the drip chamber shown in  FIG. 11B . 
         FIG. 25A  is an exploded perspective view of the fluid level sensing mechanism of  FIG. 24A . 
         FIG. 25B  is an exploded perspective view of the fluid level sensing mechanism of  FIG. 24B . 
         FIG. 26A  is a transverse cross sectional view of the fluid level sensing mechanism of  FIG. 24A . 
         FIG. 26B  is a transverse cross sectional view of the fluid level sensing mechanism of  FIG. 24B . 
         FIG. 27  is an exploded perspective view of a peristaltic pump of the fluid control module or device shown in  FIGS. 20 and 21 . 
         FIG. 28  is an exploded perspective view of a pinch valve assembly of the fluid control module or device shown in  FIGS. 20 and 21 . 
         FIG. 29  is a perspective view of an air detector assembly of the fluid control module or device shown in  FIGS. 20 and 21 . 
         FIG. 30  is a longitudinal cross sectional view of the air detector assembly of  FIG. 29 . 
         FIG. 31  is an exploded perspective view of the air detector assembly of  FIGS. 29 and 30 . 
         FIG. 32  is an elevational view of the fluid delivery or injection system of  FIG. 9  associated with a hospital examination table. 
         FIG. 33  is a top perspective view of the fluid delivery or injection system of  FIG. 32 . 
         FIGS. 34-36  are respective graphical user interface displays of a setup wizard control system used to control the fluid delivery or injection system of the present invention, 
         FIG. 37  is an exploded perspective view of an embodiment of the first connector member for an alternative connector used in the fluid path set of  FIGS. 10A-10B , showing the first connector member incorporating a check valve arrangement in accordance with the present invention. 
         FIG. 38  is a longitudinal cross sectional view of the first connector member of  FIG. 37 . 
         FIG. 39A  is a longitudinal cross sectional view of another embodiment of the second connector member for the alternative connector used in the fluid path set of  FIG. 10 ; 
         FIG. 39B  is a cross sectional view showing the second connector member of  FIG. 39A  with a flow interrupter. 
         FIG. 40A  is a longitudinal cross sectional view showing the first and second connector members of  FIGS. 38 and 39A  connected together and forming the alternative embodiment of the connector for use in the fluid path set of  FIGS. 10A-10B . 
         FIG. 40B  is a longitudinal cross sectional view showing the first and second connector members of  FIGS. 38 and 39B  connected together and the check valve arrangement omitted from the first connector member. 
         FIG. 41  is a longitudinal cross sectional view of the first connector member of  FIG. 37  in the form of a swivel-type first connector member. 
         FIG. 42  is an exploded perspective view of the swiveling first connector member of  FIG. 41 . 
         FIG. 43  is a cross sectional view take along line  43 - 43  in  FIG. 38 . 
         FIG. 44  is a longitudinal cross sectional view of the first connector member of  FIG. 38  having the check valve arrangement removed. 
         FIG. 45  is a longitudinal cross sectional view showing the first and second connector members connected as depicted in  FIG. 40A  and showing the results of fluid pressure acting on the check valve arrangement. 
         FIG. 46  is a cross sectional view take along line  46 - 46  in  FIG. 45 . 
         FIG. 47  is a longitudinal cross sectional view showing the first and second connector members connected as depicted in  FIG. 40  and showing alternative variations of the first and second connector members in accordance with the present invention. 
         FIG. 48  is a perspective view of another embodiment of the pressure isolation mechanism including a valve arrangement adapted to provide hemodynamic pressure dampening correction. 
         FIG. 49  is a partial cross sectional view of the pressure isolation mechanism of  FIG. 48  illustrating the valve arrangement. 
         FIGS. 50A-50C  are perspective views of respective embodiments of an elastomeric disk valve associated with the valve arrangement of  FIG. 49 . 
         FIG. 51  is a perspective view of a sleeve adaptor used to associate the elastomeric disk valve with the pressure isolation mechanism. 
         FIG. 52  is perspective view of a distal end of the sleeve adaptor of  FIG. 51 . 
         FIG. 53  is a cross sectional view of a first alternative embodiment of the valve arrangement shown in  FIG. 49 . 
         FIG. 54  is a cross sectional view of a second alternative embodiment of the valve arrangement shown in  FIG. 49 . 
         FIG. 55  is a cross sectional view of a third alternative embodiment of the valve arrangement shown in  FIG. 49 . 
         FIG. 56  is a cross-sectional view of a fourth alternative embodiment of the valve arrangement shown in  FIG. 49 . 
         FIG. 57  is a cross-sectional view of a fifth alternative embodiment of the valve arrangement shown in  FIG. 49 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In one aspect, the present invention provides an energy/signal source to generate fluid pressure/flow while also providing to the user tactile and/or audible feedback of the fluid pressure generated, allowing the user to modulate the fluid pressure/flow. The powered injection system of the present invention is capable of providing, for example, both precise low-flow/low-pressure fluid delivery for powered coronary injections and high-flow/high-pressure fluid delivery for ventricle injections. 
       FIG. 2  illustrates one embodiment of the present invention in which injector system  10  is preferably divided into two sections: a multi-patient section or set A and a per-patient disposable section or set B. Section or set A and section or set B are preferably separated and removably coupled into fluid connection by a high-pressure connector or by a high-pressure, “aseptic” connector  20  such as the septum connector disclosed in U.S. Pat. No. 6,096,011, assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. The aseptic coupler or connector of U.S. Pat. No. 6,096,011 is suitable for repeated use (coupling and uncoupling) at relatively high pressures. Aseptic connector  20  preferably maintains a leak-proof seal at high pressures after many such uses and can, for example, include a surface that can be disinfected (for example, between patients) by wiping with a suitable disinfectant. Another high-pressure aseptic connector suitable for use in the present invention is disclosed in U.S. patent application Ser. No. 09/553,822, filed on Apr. 21, 2000, assigned to the assignee of the present invention, the disclosure of which is incorporated herein by reference. 
     Multi-patient set A preferably includes a powered injector  30  which is typically an electromechanical drive system for generating fluid pressure/flow via, for example, a pressurizing chamber such as a syringe  40  as known in the art. Suitable powered injectors and syringes for use in the present invention are disclosed, for example, in PCT Publication No. WO 97/07841 and U.S. Pat. No. 4,677,980, assigned to the assignee of the present invention, the disclosures of which are incorporated herein by reference. 
     In general, the injector drive is an electromechanical device that creates linear motion acting on a syringe plunger (not shown in  FIG. 2 ) to provide the generation of fluid pressure/flow. A source of injection media  60 , for example, a contrast bottle, is in fluid connection with the syringe via, for example, an electromechanical valve actuator assembly  50  for controlling and directing fluid flow by acting upon preferably disposable valves  52  and  54 . Valves  52  and  54  are preferably multi-position valves that are fluid wetted. Valves  52  and  54  can alternatively or additionally be manually operated. Contrast bottle or container  60  can be prepackaged contrast media, often distributed in a glass or plastic container with a rubber septum for allowing connections via IV spikes. An interim container or reservoir  70  is preferably placed between contrast bottle  60  and electromechanical valve assembly  50  to provide an air gap in the fluid path to enable purging of air from the system and to allow level detection of contrast source  60  which helps to prevent reintroduction of air once purged. Interim reservoir  70  can operate in conjunction with a contrast level detection system as described in further detail below. A contrast level detector  80  can, for example, include one or more electrical, optical, ultrasound, or mechanical sensors that detect the presence of fluid at a certain level in interim reservoir  70 . 
     Further protection against injection of air into a patient can be provided by variety of mechanisms for detection of air in the fluid path or stream. For example, ultrasonic bubble detection can be used to detect the presence of air in the fluid path. Likewise, backlighting can facilitate air bubble detection by the operator. In the backlighting method of bubble detection, the injector side of the fluid path is illuminated to increase visualization of the fluid path, fluid presence and air presence. 
     At least one source  90  of another fluid, typically saline or other suitable medium, can also be provided. Additional fluid sources, such as therapeutic fluids, can also be provided. Additional fluid sources such as saline supply  90  are preferably in operative or fluid connection with a pressurizing mechanism such as a powered injector or a peristaltic pump  100 . In  FIG. 2 , peristaltic pump  100  in operative connection with the saline source  90  is in fluid connection with the fluid path of injector  30  via electromechanical valve actuator assembly  50 . 
     A controller unit  200  provides power to injector  30  and to peristaltic pump  100  in a controlled manner. Controller unit  200  provides communication between the various system components. A graphical user interface display  210  is preferably provided in connection with controller unit  200  to display information to the user and to enable the user to set and adjust device parameters. An audible feedback source  220  can be provided, for example, to provide feedback to the user of the rate of flow provided by injector  30 . For example, a sound can increase in pitch, volume and/or frequency as flow rate is increased. 
     Per-patient disposable set B includes fluid wetted components of the fluid delivery path. Per-patient disposable set B preferably includes a waste port  310 , for example through which patient blood can be drawn, a pressure measurement port  320 , and an interface  330  to a catheter  340 , for example, a connector such as a standard luer connector. Waste port  310  can, for example, include a manually activated or automated valve to allow discharge of unwanted fluid and connection of, for example, manually operated syringes. Moreover, a powered aspiration mechanism, for example a peristaltic pump  314  connected via tubing to a waste bag  316 , can be connected to waste port  310  via, for example, a standard connector  312 , to aspirate fluid from the system as well as to draw blood from the patient. Drawing fluid from the system and blood from the patient into a waste bag  316  assists in eliminating air from the fluid delivery system. 
     Pressure port  320  preferably includes a pressure-activated isolator  350  for pressure transducer isolation as, for example, illustrated in  FIG. 3 . Pressure-activated isolator  350  is a fluid activated assembly that is located in line with the injection flow. In the embodiment of  FIG. 3 , a valve  352  within the assembly isolates pressure transducer  360  by shutting off during high-pressure injections. A biasing member or mechanism such as a spring  354  returns valve  352  to its original open position when the injector system is not injecting at high pressure, thus opening the fluid path to pressure transducer  360 . In the embodiment of  FIGS. 2 and 3 , pressure-activated isolator  350  transitions to a closed position to isolate only pressure transducer  360 , which is not in fluid connection with contrast source  60  or saline source  90  other than through pressure-activated isolator  350 . Pressure transducer  360  can, for example, be located near the patient to substantially reduce or remove pressure signal dampening resulting from intervening tubing, fluid and system components and thereby improve accuracy as compared to other pressure measurement systems currently used in angiographic procedures. Preferably, pressure transducer  360  is separated by a minimum, for example by no more than approximately three feet, of tubing from the patient/catheter connector. Because of the multi-patient nature of set A, the pressure transducer assembly and the remainder of per-patient disposable set B are preferably located downstream of a double check valve  370  to provide continuous measurements. As such, a pressure isolation mechanism such as described above is required to isolate pressure transducer  360  from high pressure during power injection. 
     The system also includes a manually operated, for example, a handheld or hand operated, control  400  that can, for example, generate or process a control signal that is electrical, mechanical, pneumatic, optical, radio frequency, audible or any combination thereof to effect control of injector  30  and preferably to also effect control of peristaltic pump  100 . Handheld control  400  also preferably provides feedback, for example, tactile, visual, audible, etc., of the injected fluid pressure and flow to the operator. Handheld control  400  preferably provides at least one type of feedback, for example, tactile feedback. In the embodiments of  FIGS. 2, 4 and 5 , the handheld control or hand piece is in operative communication with the fluid flow and allows the user to feel the pressure in the fluid path line. Preferably, an electrical switch allows the user to turn on/off and modulate the fluid/flow pressure of the system for low-pressure/low-flow coronary injections only. High-pressure injection is activated, for example, using either display  210  or a separate, second control on the handheld control. The handheld control thus provides pressure feedback to the user while controlling the low-pressure/low-flow coronary injections. 
     The handheld controls of the present invention can, for example, include a fluid path containment chamber in which a movable element is able to travel a pre-determined distance. The moveable element is preferably in direct contact with the fluid path and is affected by fluid flow and pressure. The movable element incorporates a mechanism to process a signal, which can be used to control the fluid pressure/flow source remotely. The handheld device is capable of being used with a signal processor related to the movement of the moveable element as known in the art. 
     In one embodiment of the present invention, a handheld control device  500  incorporates a moveable piston  510  slidably disposed within a chamber  520  in a direction generally perpendicular to the direction of fluid flow as illustrated in  FIG. 4 . Chamber  520  and piston  510  can be directly in the fluid path or can be spaced from the fluid path by a length of tubing (see, for example,  FIG. 5 ). Handheld device  500  allows moveable piston  510  to be positioned under one finger while device  500  is held in the hand. Piston  510  preferably incorporates a switch  530 , that when compressed, controls the fluid flow generated by an external fluid pressure/flow source, for example, injector  30 . Upon generation of the pressure, piston  510  is displaced by increased pressure, which is detectable by the operator. Further compression of piston  510  by the operator preferably increases the signal to the fluid flow/pressure generator, resulting in an increase in the pressure/flow and an increased pressure on piston  510 , which is felt by the operator. Backpressure or tubing occlusion causes increased pressure in the system, upward movement of piston  510  and tactile feedback to the operator, thereby alerting the operator to potential problems in the injection procedure. The system can also provide audible and/or visual feedback of the flow rate via, for example, user display  210  that is preferably controlled by the position of piston  510 . 
     As illustrated in  FIG. 5 , a handheld control  500 ′ can be connected in a “T”  550 ′ off of the main line for more flexibility. A purge valve  540 ′ can be located at the end of handheld control  500 ′ for air elimination during system purge. Air can also be purged from the handheld control  500 ′ before it is connected to the fluid path.  FIG. 5  also illustrates a second switch  560 ′ for initiation of a high pressure injection. An additional switch or switches can also be provided to, for example, control delivery of saline. 
       FIGS. 6A and 6B  illustrate other, ergonomic handheld controls. Handheld control  600  of  FIG. 6A  includes a chamber  620  that can be in fluid connection with the injection system fluid path as described above. A low pressure control switch  610  similar in operation to piston  510  is slidably disposed within chamber  620  to control low-pressure injections of contrast. Chamber  620  can, for example, be formed to conform to the hand of the user. A switch  630  to begin a high pressure injection via injector  30  is provided on handheld control  600 . Also, a switch  640  to control delivery of saline is provided on handheld control  600 . 
       FIG. 6B  illustrates an embodiment of a finger-wearable handheld control  700 . In that regard, a finger of the user&#39;s hand passes through passage  710  in control  700  while control  700  is held in the user&#39;s hand. A rotating switch  720  controls low-pressure injection. A high pressure injection switch  730  and a saline switch  740  are also provided. 
     System  10  ( FIG. 2 ) can also include a manually operated foot controller  420  including one or more actuators  430  in communication with controller  200 . Foot controller  420  can, for example, be used to control flow through system  10  in conjunction with or independently of handheld controller  400 . 
     Another embodiment of an injector system  800  is illustrated in  FIGS. 7A through 7H . In this embodiment, referring primarily to  FIGS. 7A and 7G , a fluid control module  810  is in operative connection with a powered injector  830  to which a syringe  840  is connected as described above. Syringe  840  is in fluid connection with an automated valve  852  of fluid control module  810 , which is also in fluid connection with a source of contrast  860  via an intermediate drip chamber  870  (see  FIG. 7A ). Drip chamber  870  preferably includes a fluid level sensing mechanism  880 . A preferably automated valve/stopcock  852  such as known in the art is also in fluid connection with a first, inlet port of a lumen  954  of a pressure isolation valve  950  (see, for example,  FIGS. 7D through 7F ). Valve  852  prevents saline and/or contaminated fluids from entering syringe  840  and enables the operator to stop flow of injection fluid (for example, contrast) from syringe  840  quickly at any pressure or flow rate. This ability to substantially immediately stop flow of injection fluid at any pressure and flow rate substantially removes the effects of system compliance and enables delivery of a “sharp” bolus. An air column detector  856  can be placed in line between stopcock  852  and pressure isolation valve  950 . 
     Fluid control module  810  further includes a source of saline  890  in fluid connection with a peristaltic pump  900  via an intervening drip chamber  910 . Drip chamber  910  preferably includes a fluid level sensing mechanism  920 . Peristaltic pump  900  is in fluid connection with a preferably automated valve/stopcock  854 , which is in fluid connection with pressure isolation valve  950 . In addition to controlling flow of saline, valve  854  prevents contaminated fluids from reaching peristaltic pump  900  and saline source  890 . An air column detector  858  can be placed in line between stopcock  854  and pressure isolation valve  950 . 
     A controller  970  and a display  974  (see  FIG. 7A ) are also in operative connection with injector  830  as described above. Furthermore, handheld controller  1000  is in operative connection with injector  830  and thereby with fluid control module  810 . In the embodiment of  FIGS. 7A through 7C  and  FIG. 7G , handheld controller  1000  does not provide tactile feedback of system pressure to the operator. However, a handheld controller providing such tactile feedback (for example, handheld controller  600 ) can readily be used in connection with system  800 . Moreover, a foot controller as described above can also be provided. 
     In general, the preferably per-patient disposable portion or set of system  800  is illustrated within dashed lines in  FIGS. 7A, 7B, and 7C . Two connectors  990   a  and  990   b  (which are preferably aseptic connectors as described above) are used to connect the multi-patient fluid path set with the per-patient fluid path set. Use of two separate/parallel fluid lines and two separate connectors to connect the multi-patient set with the per-patient disposable set affords a number of benefits over current angiographic injection systems including decreased contrast waste and avoidance of injecting potentially hazardous amounts of contrast into the patient during saline purges. Moreover, system  800  facilitates close placement of pressure transducer  980  to the patient, improving measurement accuracy as compared to currently available systems. Although handheld controller  1000  in the embodiments of  FIGS. 7A through 7H  is not in direct connection with the fluid path, it is preferably disposable because of contamination with bodily fluids that typically occurs from operator handling thereof. 
     Lumen  954 , via a second, outlet port thereof, of pressure isolation valve  950  is preferably in fluid connection with an automated or manual valve/stopcock  994 , which preferably includes a waste port  996  as described above. Catheter  1100  is preferably connected via a rotating luer connection  998 . 
       FIG. 7B  illustrates a portion of a fluid path set for use in system  800  of  FIG. 7A  in which a pressure transducer  980  is directly in the saline fluid path.  FIG. 7C  illustrates a fluid path set for use in system  800  of  FIG. 7A  in which pressure transducer  980  is separated from the saline fluid path by a “T” connector  982  and a length of tubing  984 . In the embodiments of  FIGS. 7B and 7C , spikes  976   a  and  976   b  are used to connect to contrast source  860  and saline source  890 , respectively. In general, standard luer connections are used to connect most of the components of system  800 . In  FIGS. 7B and 7C  several of these luer connections are illustrated in a disconnected state. Alternatively, one or more of the illustrated connections can, for example, be non-luer or bonded connections. 
     One embodiment of a pressure isolation valve  950  is illustrated in  FIGS. 7D through 7F . Pressure isolation valve  950  includes a housing  952  with a high pressure lumen  954 , through which fluid passes under pressure. Pressure isolation valve  950  also includes a port  956  to which pressure transducer  980  and saline source  890  are connected. A piston  958  acts to isolate pressure transducer  980  once a given pressure is reached in lumen  954  of pressure isolation valve  950 . In an “open” or rest state, as shown in  FIG. 7D , there is hydraulic or fluid communication between lumen  954 , including catheter  1100  and injector  840  connected thereto, and isolation port  956 , including pressure transducer  980  and the saline fluid path connected thereto. 
     Preferably, the clearances and apertures within pressure isolation valve  950  are sufficiently generous to transmit changes in pressure that normally occur during normal heart function quickly, as to not damp or attenuate the signal. The pressure effect on piston  958  of the flow of injection fluid from syringe  840  through lumen  954  is illustrated with dashed arrows in  FIG. 7D  while the flow of saline through pressure isolation mechanism  950  is illustrated with solid arrows. When the pressure within lumen  954  increases during an injection, piston  958  responds by moving to the right in the orientation of  FIGS. 7D and 7E , compressing a spring  960  until a seal portion  962  at the left end of piston  958  contacts a sealing seat  964  as illustrated in  FIG. 7E . At this point, lumen or port  956  is isolated from lumen  954  and any additional increase in pressure acts to increase or improve the effectiveness of the seal  962 . When the pressure within lumen  954  subsides, spring  960  reopens pressure isolation valve  950  by pushing piston  958  to the left. In one embodiment, fluid does not flow through port  956 . In this embodiment, pressure isolation valve  950  only isolates the tubing and devices distal to port  956  from high pressure and does not control flow. 
     Pressure isolation valve  950  of the present invention is suited for use in any medical fluid path in which it is desirable to automatically isolate a pressure sensitive fluid path component, for example, a pressure transducer or other fluid path component or fluid pathway from pressures above a certain predetermined pressure. The pressure at which pressure isolation valve  950  isolates port  956  from lumen  954  can be readily and easily adjusted through variation of a number of variables as known to those skilled in the art, including, for example, various valve dimensions and the properties of spring  960 , for example, the force constant thereof. Connection of pressure isolation valve  950  into any fluid path is quite simple. In that regard, lumen  954  is simply placed in the fluid path via connection of ports  954   a  and  954   b  to disconnected or open ends of the fluid path without any other change to the fluid path or to pressure isolation valve  950 . Standard connections such as luer connections as known in the medical arts can be used to connect lumen  954  to the fluid path. Valve  950  can also be incorporated into or embedded within other devices such as a manifold, a pressure transducer or a connector. 
     In an alternative to mechanical operation of valve piston  958  as described above, valve piston  958  can also be controlled via an electromechanical mechanism. For example, a pressure sensor such as pressure sensor or transducer  980  (see, for example,  FIG. 7B ) can send a signal to an actuator, for example, in the operative position of and functioning in a similar manner to spring  960  as known in the control art to control the position of valve piston  958  and thereby control fluid flow through port  956 . 
       FIGS. 8A and 8B  illustrate use of pressure isolation valve  950  to automatically isolate a pressure transducer P from increased pressures in a manual injection system such as set forth in  FIG. 1 . Valve V 3 , used for manual isolation of a pressure transducer as described previously, can be removed from the fluid path or retained therein. As illustrated in  FIG. 8A , application of a force F to the syringe plunger extension causes pressurized fluid to flow from the syringe into the fluid path. The elevated pressure causes pressure within lumen  954  to increase. As discussed previously in connection with  FIGS. 7D and 7E , piston  958  responds by moving to the right in the orientation of  FIGS. 8A and 8B , compressing spring  960  until seal portion  962  contacts sealing seat  964  as illustrated in  FIG. 8A . At this point, port  956  and pressure transducer P are isolated from lumen  954  and the remainder of the fluid path. As illustrated in  FIG. 8B , when the syringe in inactivated, the pressure within lumen  954  subsides, and spring  960  reopens pressure isolation valve  950  by pushing piston  958  to the left. 
     Incorporation of pressure isolation valve  950  into the fluid path of  FIGS. 8A and 8B  provides a substantial improvement compared to the injection system of  FIG. 1 . For example, it is taxing and difficult for a physician or other operator using the system of  FIG. 1  to operate each of valves V 1 , V 2  and V 3 . Operators often either forget to close valve V 3  during injections, thereby resulting in damaged pressure transducers or fail to reopen the valves post-injection preventing proper or timely patient monitoring. Injection procedures are greatly facilitated in the system of  FIGS. 8A and 8B  by automation of the isolation of pressure transducer P at elevated pressures. 
     As discussed above, saline is used occasionally during routine catheterization procedures. For example, controls  1020   a  or  1020   b  on handheld control  1000  can send a signal to control the flow of saline. For patient safety, it is desirable to introduce the saline close to the proximal end of catheter  1000  so the amount of contrast purged ahead of the saline is minimized during a saline injection. Once again, the parallel line configuration of the contrast delivery and saline deliver fluid paths of present invention assist in preventing such undesirable injections. 
     Since the required saline flow rates are low and the viscosity of saline is much lower than the viscosity of contrast, the pressures required to force saline through catheter  1100  are much less than that of contrast. By protecting the saline line from the high pressures required for contrast injection, additional system compliance is avoided and the saline line does not need to be made of the same high-pressure line as the contrast. Protection of the saline line from high pressure is accomplished by connecting the saline line to port  956  of pressure isolation valve  950  to introduce the saline flow as illustrated with solid arrows in  FIG. 7D . In this embodiment, port  956  is normally open, permitting the flow of saline therethrough, when required, as well as the monitoring of the patient blood pressure. During a high-pressure injection, pressure isolation valve  950  functions as described above and protects pressure transducer  980  and the low-pressure saline line from the high contrast injection pressures. 
     The elevation of catheter  1100  often changes during the course of an injection procedure, for example, as the patient is raised or lowered. Such changes in elevation of catheter  1100  can result in erroneous blood pressure readings by pressure transducer  980 . Therefore, pressure transducer  980  is preferably positioned such that it changes elevation with catheter  1100  and is not dependent upon the position of the injection system, including the position of injector  830 . 
     In one embodiment illustrated in  FIGS. 7G and 7H , handheld controller  1000  included a plunger or stem control  1010  that, when in a first/low pressure mode, is depressed by the operator to control the flow of contrast from syringe  840 . The farther plunger  1010  is depressed, the greater the flow rate via, for example, a potentiometer such as a linear potentiometer within housing  1020  of controller  1000 . In this embodiment, the operator can use graphical user interface display  974  to change the mode of plunger  1010  to a second mode in which it causes injector  830  to initiate a high pressure injection as preprogrammed by the operator. In this second/high pressure mode, the operator maintains plunger  1010  in a depressed state to continue the injection. Preferably, if plunger  1010  is released, the high-pressure injection is terminated substantially immediately, for example, by control of valve  852 . Handheld controller  1000  also includes at least one switch to control saline flow in system  800 . In the embodiment of  FIG. 7H , handheld controller  1000  includes two saline switches  1030   a  and  1030   b  on either side of plunger  1010  for ease of access by the operator. In this embodiment, switches  1030   a  and  1030   b  include resilient cantilevered members  1032   a  and  1032   b , respectively, which are depressed by the operator to deliver saline through system  800 . Preferably, one of switches  1030   a  or  1030   b  must be maintained in a depressed state by the operator to continue delivery of saline. If the depressed switch is released, saline flow is preferably stopped substantially immediately, for example, via control of valve  854 . 
     As illustrated in  FIG. 7G , many of the components of system  800  can be supported on a mobile stand  805 . Injector  830  is preferably rotatable about stand  805  as indicated by the arrow of  FIG. 7G . In one embodiment of system  800  of  FIGS. 7G and 7H : stopcocks were obtained from Medical Associates Network, Inc., a distributor for Elcam Plastic, under product number 565302; spikes were obtained from Qosina under product numbers 23202 and 23207, tubing was obtained from Merit Medical under product numbers DCT-100 and DCT-148; connectors were obtained from Merit Medical under product number 102101003, a rotating hub was obtained from Medical Associates Network, Inc., a distributor for Elcam Plastic, under product number 565310; a peristaltic pump from Watson-Marlow was obtained having a product number of 133.4451.THF; and fluid level sensor from Omron were obtained under product number EESPX613. 
     The following describes a typical use scenario of injection systems of the present invention and assumes that all fluid path components are assembled/connected and located in their proper position, including contrast and saline containers. 
     Typically, the first step in an injection procedure is replacing air in the fluid path with fluid. By operator initiation and machine control, the powered injector causes the syringe plunger to move rearward toward the powered injector, thereby creating a negative pressure at the connection point to a control valve in proximity to the contrast interim container. The control valve is positioned to allow fluid flow from the contrast bottle, into the interim container and into the syringe. Upon drawing a predetermined amount of contrast into the syringe, the injector drive preferably reverses direction creating a positive pressure and fluid movement in the direction of the contrast container or the catheter, which is not connected to a patient, to drive any entrapped air out of the fluid path into an “air gap” established in the interim container or through the catheter. Air is further preferably initially purged from the system during start-up by, for example, distributing a fluid such as saline through the fluid path, sometimes referred to as “priming”. The system is preferably maintained air-free during an injection procedure. Priming is preferably done once per patient or once per multi-patient, depending on disposable fluid path configuration. 
     The system can include, for example, “contrast low” level (need for refill) and “stop filling” limit sensors on the interim reservoir as described above to help ensure that air is not aspirated into the contrast syringe during a fill cycle. An ultrasonic air column sensor or sensors and/or other types of sensors can also be included downstream of the injector to detect air gaps within the line as a secondary safety sensor. 
     By operator initiation and machine control, a second fluid pump connected to a bulk source of saline, typically a prefilled bag, provides fluid flow in the direction of patient catheter. Enough saline is preferably pumped throughout disposable set to achieve elimination of all visible air during priming. Using the saline priming feature, a handheld controller that is in fluid connection with the fluid path to provide tactile feedback as described previously can, for example, be purged of air by opening an integral bleed valve. After priming is complete the bleed valve is closed. 
     Once the system is properly set up and primed, it can be connected to the patient via the catheter. The system preferably has a range of parameters for flow, pressure, variable flow, alarms and performance limits as known in the art. 
     To deliver contrast at low flow and low pressure, for example, to the coronary arteries, depressing a first button, piston or other controller on the handheld controller initiates flow of contrast and in some embodiments provides feedback, for example, tactile and/or audible feedback. Further depressing the button on the hand controller preferably increases the flow rate of contrast. If at any time the button is released, the fluid flow preferably stops and any feedback ends. This “dead-man” operability can be provided, for example, by biasing, for example spring loading, the first control or actuator toward the off position. The minimum and maximum flows are preferably established by the parameters set using a graphical user interface on the display. 
     To deliver contrast at high flow and high pressure, for example, to the left ventricle, a separate switch or second actuator/controller on the hand control is preferably depressed. Alternatively, a second mode of the first actuator/controller can be entered to control high pressure flow. In embodiments in which the handheld control provides tactile feedback during low-pressure injection, preferably no such tactile feedback is provided during high pressure flow. However, other feedback such as an audible tone feedback different than any audible tone provided during the low-pressure mode can be provided. The high-pressure/high-flow function is preferably first input/selected from the parameters input/set using the graphical user interface on the display. The high-flow and high-pressure injection is preferably preprogrammed and the flow cannot be varied. As discussed above, any direct, tactile feedback is preferably eliminated, as the pressure is often over 1000 psi. If at any time the second button is released, the injection preferably stops. 
     To deliver saline, a second or third switch, controller or actuator on the hand controller is preferably selected, causing saline flow at a pre-selected flow rate. Alternatively, a single controller or actuator having three different control modes can be used. As with the other actuators or actuator modes on the handheld controller, if at any time the third button is released, the saline flow preferably stops. 
     A pressure sensor is preferably connected to a pressure isolation valve as described above. Patient pressure monitoring can be determined at any time except when an injection of fluid exceeds the pressure set by the pressure isolation valve. 
     A multi-patient set can be designed so that at least some portions thereof can safely be reused for multiple patients. In such a design, for example, the syringe and interface to contrast/saline components, disposable valves and related tubing, and a multi-use high-pressure, aseptic connector can preferably be reused for multiple patients. 
     Handheld controllers, whether or not in fluid connection with the fluid path, and related tubing and check valves are preferably replaced for each patient. Likewise, any waste port, pressure port, and the interface to catheter are preferably replaced for each patient. Aseptic connectors of a multi-patient set can, for example, be wiped clean before connecting a disposable set for each new patient. Reusable or multi-patient sets preferably have a limited numbers of reuses and preferably are not used for longer than a set period of time, for example, an 8-hour period. 
     Another embodiment of a fluid injector or delivery system  1200  is illustrated generally in  FIGS. 9A-9B . In this embodiment, an injector  1300  is operatively associated with a fluid control module  1400 . The details of the injector  1300  are set forth in U.S. Pat. Nos. 7,549,977 and 7,563,249, which are each incorporated herein by reference in their entirety. The injector  1300  is adapted to support and actuate a syringe, as described in the foregoing applications. The fluid control module  1400  is associated with the injector  1300  for controlling fluid flows delivered by the injector  1300 . The fluid control module  1400  is generally adapted to support and control a fluid path set  1700  used to connect a syringe associated with the injector  1300  to a catheter (not shown) to be associated with a patient. 
     The fluid delivery system  1200  further includes a support assembly  1600  adapted to support the injector  1300  and the fluid control module  1400 , as discussed further herein. The support assembly  1600  may be configured as a movable platform or base so that the fluid delivery system  1200  is generally transportable, or for connection to a standard hospital bed or examination table on which a patient will be located during an injection procedure. Additionally, the fluid delivery system  1200  preferably further includes a user-input control section or device  1800  for interfacing with computer hardware/software (i.e., electronic memory) of the fluid control module  1400  and/or the injector  1300 . While the details of the fluid control module  1400  are set forth in detail hereinafter, the fluid control module  1400  generally includes a housing  1402 , a valve actuator  1404  for controlling a fluid control valve, a fluid level sensing mechanism  1406 , a peristaltic pump  1408 , an automatic shut-off or pinch valve  1410 , and an air detector assembly  1412 . The details of the control section  1800  are also set forth hereinafter in this disclosure. 
     As indicated, the fluid control module  1400  is generally adapted to support and control the fluid path set  1700  used to connect a syringe associated with the injector  1300  to a catheter (not shown). Referring now to  FIGS. 9A-9B and 10A-10B , the fluid path set  1700  is shown in greater detail in  FIGS. 10A-10B . The fluid path set  1700  may be considered to include a syringe  1702  that is to be associated with the injector  1300 . The fluid path set  1700  is generally used to associate the syringe  1702  with a first or primary source of injection fluid  1704 , also referred to herein as a primary fluid container, which will be loaded into the syringe  1702  for an injection procedure. The primary fluid container  1704  may be contrast media in the case of an angiographic procedure, as an example. The fluid path set  1700  is further adapted to associate the fluid control module  1400  with a secondary or additional source of fluid  1706 , also referred to herein as a secondary fluid container, to be supplied or delivered to the patient via the catheter. In a typical angiographic procedure, saline is used as a secondary flushing fluid which is supplied to the patient between injections of contrast media. 
     In a general injection procedure involving the fluid delivery system  1200 , the injector  1300  is filled with fluid from the primary fluid container  1704  and delivers the fluid via the fluid path set  1700  to the catheter and, ultimately, the patient. The fluid control module  1400  generally controls or manages the delivery of the injection through a valve associated with the fluid path set  1700 , which is controlled or actuated by the valve actuator  1404  on the fluid control module  1400 . The fluid control module  1400  is further adapted to deliver the fluid from the secondary fluid container  1706  under pressure via the peristaltic pump  1408  on the fluid control module  1400 . 
     The fluid path set  1700 , as illustrated in  FIGS. 10A-10B , generally comprises a first section or set  1710  and a second section or set  1720 . The first section  1710  is generally adapted to connect the syringe  1702  to the primary fluid container  1704 , and to connect the second section  1720  to the secondary fluid container  1706 . The first section  1710  is preferably multi-patient section or set disposed after a preset number of injection procedures are accomplished with the fluid delivery system  1200 . Thus, the first section  1710  may be used for a preset number of injection procedures involving one or more with patients and may then be discarded. Optionally, the first section  1710  may be adapted to be re-sterilized for reuse. The first section  1710  is preferably provided as a sterile set, preferably in a sterile package. The second section  1720  is a per-patient section or set, which is preferably disposed of after each injection procedure involving the fluid delivery system  1200 . The fluid path set  1700  is generally similar to the fluid path set illustrated in  FIG. 7B , discussed previously, but includes the structures discussed hereinafter. The first section  1710  and second section  1720  are placed in fluid communication by one or more connectors  1708 , the details of which are also set forth hereinafter. 
     The first section  1710  includes a multi-position valve  1712 , for example a 3-position stopcock valve, which is adapted to be automatically controlled or actuated by the valve actuator  1404  on the fluid control module  1400 . The multi-position valve  1712  is adapted to selectively isolate the syringe  1702 , the primary fluid container  1704 , and the second section  1720  to selectively allow the injector  1300  to fill the syringe  1702  with fluid from the primary fluid container  1704 , deliver the fluid loaded into the syringe  1702  to the second section  1720 , or isolate the syringe  1702  from the primary fluid container  1704  and the second section  1720 . The multi-position valve  1712  is connected to the syringe  1702  by a luer connection  1714 , which may be a standard luer connection known in the art. 
     The first section  1710  further includes intervening drip chambers  1716  associated with the primary fluid container  1704  and the secondary fluid container  1706 . In  FIGS. 9B and 10B , drip chambers  1716  are replaced by priming bulbs P in the fluid path set  1700 , and the fluid level sensing mechanism  1406  is altered to interface with the priming bulbs P and/or medical tubing associated with the priming bulbs P as discussed further herein in connection with  FIGS. 24-26 . The drip chambers  1716  are adapted to be associated with primary and secondary fluid containers  1704 ,  1706  with conventional spike members  1717 . The fluid level sensing mechanism  1406  on the fluid control module  1400  is used to sense fluid levels in the drip chambers  1716  when the fluid path set  1700  is associated with the injector  1300  and the fluid control module  1400 . Generally, operation of the fluid delivery system  1200  includes filling, loading, or “priming” the syringe  1702  with fluid from the primary fluid container  1704 , which passes to the syringe  1702  via the drip chamber  1716  associated with the primary fluid container  1704 . Similarly, during operation of the fluid delivery system  1200 , fluid such as saline, from the secondary fluid container  1706  is supplied to the second section  1720  via the drip chamber  1716  associated with the secondary fluid container  1706 . The drip chambers  1716  are generally adapted to permit fluid level sensors associated with the fluid level sensing mechanism  1406  to detect the level of fluid in the drip chambers  1716 , for example by using optical or ultrasonic methods. Respective output lines  1718  made, for example, of conventional low pressure medical tubing, are associated with the drip chambers  1716  for connecting the drip chambers  1716  to the multi-position valve  1712  and the second section  1720 . The outlet of the multi-position valve  1712  is connected to an output line  1719 , which is used to connect the multi-position valve  1712  and syringe  1702  to the second section  1720 . Due to the high injection pressures typically generated by the injector  1300  during an injection procedure such as angiography, the output line  1719  is preferably constructed of high pressure medical tubing. An inlet to the multi-position valve  1712  is connected via an inlet line  1721  to the syringe  1702 , and is preferably also constructed of high pressure medical tubing. 
     The second section  1720  generally includes a pressure isolation mechanism or valve  1722 . The pressure isolation mechanism  1722  is connected by respective input lines  1724 ,  1726  and the connectors  1708  to the first section  1710 . The first input line  1724  is preferably formed of conventional medical tubing and connects the pressure isolation mechanism  1722  with the drip chamber  1716  associated with the secondary fluid container  1706 . The second input line  1726  is preferably formed of high pressure medical tubing and connects the pressure isolation mechanism  1722  with the output line  1719  connected to the multi-position valve  1712  and, ultimately, the syringe  1702  and primary fluid container  1704 . The tubing used for the second input line  1726  is preferably high pressure medical tubing. 
     An output line  1728  is associated with the pressure isolation mechanism  1722  for connecting the pressure isolation mechanism  1722  with the catheter. A second multi-position valve  1730 , for example in the form of a stopcock valve, may be provided in the output line  1728 , as a shut-off feature. As shown in  FIGS. 10A-10B , the multi-position valve  1730  may be provided as a simple shut-off valve to isolate the catheter from the first section  1710  of the fluid path set  1700 . The output line  1728  may further include a catheter connection  1732  for associating the fluid path set  1700  with a catheter to be used in a fluid injection procedure involving the fluid delivery system  1200 . 
     Referring briefly to  FIG. 11A , one of the drip chambers  1716  used in the fluid path set  1700  is shown in enlarged detail. The drip chamber  1716  shown in  FIG. 11A  generally has an elongated body  1734  with a top end  1736  and a bottom end  1738 . The body  1734  is formed with a projection  1740 , which generally extends longitudinally along the body  1734 , or in any configuration on the body  1734  of the drip chamber  1716 , and may even be in the form of a handle with an opening such as those found on plastic bottles. The projection  1740  is generally provided to interact with the fluid level sensing mechanism  1406  on the fluid control module  1400 , and may be referred to as a “back” window because the projection  1740  will generally face the fluid level sensors in the fluid level sensing mechanism  1406  when the drip chamber  1716  is associated with the fluid level sensing mechanism  1406 .  FIG. 11B  illustrates an alternative drip chamber  1716 ′ which has a tapered or domed upper end  1741  which limits the accumulation of air bubbles in drip chamber  1716 ′ and, further, facilitates easy expulsion of air bubbles during priming of the drip chamber  1716 ′ during operational set-up of fluid path set  1700 , which is discussed in detail herein. The use of alternative drip chamber  1716 ′ is identical to that of drip chamber  1716  and each are shown associated with fluid level sensing mechanism  1406  in  FIGS. 24-26  discussed herein. 
     The body  1734  is preferably formed of a plastic material and, more particularly, a resiliently deformable medical-grade plastic material to allow in-place “priming” of the drip chamber  1716 , when the drip chamber  1716  is associated with the fluid level sensing mechanism  1406 . The fluid level sensing mechanism  1406  is generally adapted to support and secure the drip chambers  1716 , as shown in  FIG. 9A . The projection  1740  further permits the drip chamber  1716  to be primed in place in the fluid level sensing mechanism  1406 . The plastic material comprising the body  1734  may be substantially clear or slightly opaque, but the projection  1740  is preferably clear to allow an optical fluid level sensor in the fluid level sensing mechanism  1406  to detect the fluid level in the drip chamber  1716 . The projection  1740  is preferably raised from the body  1734  of the drip chamber  1716  to allow priming of the drip chamber  1716 . Generally, the body  1734  of the drip chamber  1716  is sufficiently clear to allow light transmission from lighting associated with the fluid level sensing mechanism  1406 . The body  1734  of the drip chamber  1716  will generally act as a light conduit or “light pipe” that will illuminate the fluid flow path in the medical tubing forming the output lines  1718  associated with the drip chambers  1716  connected to the primary and second fluid containers  1704 ,  1706 . 
     Referring to  FIGS. 12-15 , the pressure isolation mechanism  1722  is shown in greater detail. The pressure isolation mechanism  1722  includes a housing  1742 . The housing  1742  may be a unitary housing or, preferably, a multi-piece housing as shown in  FIG. 13 . Preferably, the housing  1742  is a two-piece housing including a first portion  1744  and a second portion  1746 , which are adapted to connect together to form the housing  1742 . The first and second portions  1744 ,  1746  are preferably formed for interference engagement with each other. 
     The interference engagement is formed by engagement of a depending annular flange  1748  formed on the first portion  1744  of the housing  1742  with a corresponding recess or groove  1749 , for example, a circular recess or groove, formed or defined in the second portion  1746  of the housing  1742 . The recess  1749  is purposely made slightly smaller in width than the thickness of the annular flange  1748 , so that when the first and second portions  1744 ,  1746  of the housing  1742  are joined together there is interference engagement between the annular flange  1748  and the recess  1749 . The second portion  1746  of the housing  1742  may include a raised annular flange  1750  that engages or cooperates with a corresponding recess or groove  1751  defined in the first portion  1744 . The raised annular flange  1750  may engage with the recess  1751  in a similar friction fit manner as the annular flange  1748  and recess  1749  discussed previously. The combination of the annular flanges  1748 ,  1750  and recesses  1749 ,  1751  generally define a shear interface  1752  between the first and second portions  1744 ,  1746  of the housing  1742 , which increases their assembly strength. An adhesive or ultrasonic weld may be used along the shear interface  1752  to secure the first and second portions  1744 ,  1746  together. The connection between the flanges  1748 ,  1750  and the recesses  1749 ,  1751  generally define a tortuous path along this connection line. 
     The first portion  1744  of the housing  1742  defines a primary or high pressure lumen  1754 , which forms a high pressure side of the pressure isolation mechanism  1722 . An inlet  1755  to the high pressure or primary lumen  1754  is in fluid communication with the second input line  1726 , which is the high pressure line connecting the pressure isolation mechanism  1722  with the output line  1719  associated with the multi-position valve  1712  and, ultimately, the syringe  1702  and the primary fluid container  1704 . An outlet  1756  of the primary lumen  1754  is connected to the second multi-position valve  1730 , which may be provided in the output line  1728  as discussed previously. 
     The second portion  1746  of the housing  1742  defines a secondary or low pressure lumen  1758 , which generally forms a low pressure side of the pressure isolation mechanism  1722 . The secondary lumen  1758  has an inlet  1759  that is in fluid communication with the first input line  1724 , which is the low pressure line that connects the pressure isolation mechanism  1722  to the secondary fluid container  1706  via the peristaltic pump  1408  on the fluid control module  1400  and drip chamber  1716 . The second portion  1746  of the housing  1742  includes a vent hole  1760  provided for proper operation of the pressure isolation mechanism  1722 . The second portion  1746  of the housing  1742  further includes a pressure isolation port  1761  to which a pressure transducer (See  FIGS. 7B through 7F ) may be connected. The structure forming the pressure isolation port  1761  may terminate in a luer connector for connecting a pressure transducer to the pressure isolation port  1761 . 
     The first and second portions  1744 ,  1746  of the housing  1742  may define an internal chamber  1762 , generally in fluid communication with the primary lumen  1754  and the secondary lumen  1758 . The first portion  1744  of the housing  1742  may include a depending retaining member  1763  extending into the internal chamber  1762 . An internal valve member  1764  is located in the internal chamber  1762  and is used to isolate the pressure isolation port  1761  when the pressure isolation mechanism  1722  is associated with the syringe  1702 , (i.e., in fluid communication with an operating syringe  1702 ). The valve member  1764  is generally engaged by the retaining member  1763  depending or extending from the first portion  1744  of the housing  1742  to maintain a preload of the valve member  1764 . The valve member  1764  is generally adapted to bias the pressure isolation mechanism  1722  to a normally open position, wherein the primary lumen  1754  is in fluid communication with the secondary lumen  1758  and the pressure isolation port  1761  through the internal chamber  1762 . The valve member  1764  is generally further adapted to isolate the pressure isolation port  1761  once fluid pressure in the primary lumen  1754  reaches a preset pressure, as described further herein. 
     The valve member  1764  is preferably a two-piece structure comprising a seat member  1766  and a base portion  1767 . The seat member  1766  is generally adapted to seat against a seal ring  1768  formed on the second portion  1746  of the housing  1742  in the closed position of the valve member  1764 , thereby isolating the primary lumen  1754  from the secondary lumen  1758  and the pressure isolation port  1761 . The seat member  1766  includes an integral biasing portion  1770 . The biasing portion  1770  is a generally conical shaped portion of the seat member  1766  that is hollow and preferably has a pre-established or preset spring force tension. The base portion  1767  is generally engaged by the retaining member  1763  depending or extending from the first portion  1744  of the housing  1742  to maintain a preload of the conical shaped biasing portion  1770  and form a seal with the body of the second portion  1746  of the housing  1742 , thereby preventing fluid from leaking or exiting via the vent hole  1760 . The vent hole  1760  allows for proper operation of the valve member  1764  by allowing air to vent from the conical shaped biasing portion  1770  during operation of the valve member  1764 . When the pressure within primary lumen  1754  increases during an injection procedure, the biasing portion  1770  of the seat member  1764  responds by deforming within the internal chamber  1762  until the seat member  1766  of the valve member  1764  seats against the seal ring  1768  formed on the second portion  1746  of the housing  1742 . Once the seat member  1766  seats against the seal ring  1768 , the valve member  1764  is in a closed position. The pre-established or preset spring force tension is preferably selected to prevent damage to the pressure transducer, saline line, or other pressure sensitive devices typically connected to the pressure isolation port  1761  and may be pre-selected such that the valve member  1764  is in the closed position when the fluid pressure in the primary lumen  1754  is less than 70 psi. In the closed position of the valve member  1764 , the primary lumen  1754  is isolated from the secondary lumen  1758  and the pressure isolation port  1761 . 
     As  FIG. 14  shows, the seat member  1766  may define an opening  1772  for receiving a tab or projection  1773  on the base portion  1767  for connecting the base portion  1767  to the seat member  1766 . The seat member  1766  and base portion  1767  may be secured together by mechanical devices (i.e., fasteners), adhesively secured together, or bonded together when the valve member  1764  is formed. For example, the seat member  1766  and the base portion  1767  may be formed of different polymeric materials that will adhere to one another, for example, when elevated heat or pressure re applied. For example, the seat member  1766  may be made of a thermoplastic elastomer and the base portion  1767  formed of a polypropylene that will adhere to the thermoplastic elastomer when the seat member  1766  and the base portion  1767  are molded together. 
       FIGS. 48-52  illustrate a further aspect of pressure isolation mechanism  1722 . As will be clear from the foregoing, pressure isolation mechanism  1722  is the merge point for contrast and saline for delivery to a patient during a fluid injection or delivery procedure. One aspect of pressure isolation mechanism  1722  relates to using a pressure transducer associated with pressure isolation port  1761  to take hemodynamic blood pressure signal readings and obtain other relevant information associated with the fluid delivery procedure involving the delivery of contrast and/or saline to the patient. As is known from the foregoing, valve member  1764  provides automatic overpressure protection to this transducer during delivery of contrast at high pressure to the pressure isolation mechanism. 
     The pressure isolation mechanism  1722  as configured and explained previously provides accurate undamped hemodynamic pressure readings when saline is present between the patient and the pressure transducer associated with pressure isolation port  1761 . However, it is also desirable to provide an undamped signal when contrast is present between the patient and the pressure transducer. Generally, hemodynamic pressure signals are damped by the presence of air bubbles, thicker fluid media such as contrast, medical tubing lengths, internal diameters, and overall system and tubing compliance. The variation of pressure isolation mechanism  1722  illustrated in  FIGS. 48-52  significantly reduces the dampening of the hemodynamic pressure signals when contrast is present by substantially isolating the compliant tubing associated with the saline, low pressure “side” of the pressure isolation mechanism  1722  from the pressure transducer associated with the pressure isolation port  1761 . This is accomplished in one variation by substantially isolating the compliant tubing and other upstream elements associated with low pressure or secondary lumen  1758  with a valve arrangement  2100  disposed in this lumen. The valve arrangement  2100 , as will be clear from the following description, allows fluid flow in two directions (bilaterally) in the secondary lumen  1758  carrying saline but fluid flow does not start until pressures are above any blood pressure readings. 
     In general, in the pressure isolation mechanism  1722 , outlet port  1756  of primary lumen  1754  is associated with a patient, inlet port of primary lumen  1755  is associated with syringe  1702  and high pressure fluid injector  1300 , and inlet port  1759  of secondary lumen  1758  is associated with the low pressure saline delivery system including peristaltic pump  1408 . Valve arrangement  2100  is generally associated with inlet port  1759  of secondary lumen  1758  and isolates the “compliant” system components of the low pressure saline fluid delivery system from hemodynamic blood pressure signals from the patient. As a result, these readings are substantially undamped and accurate reading may be taken via a pressure transducer (See  FIG. 7C ) associated with pressure isolation port  1761 . 
     The valve arrangement  2100  comprises an adaptor sleeve  2110  which is sized for mating engagement with the inlet portion or port  1759  of secondary lumen  1758 . Adaptor sleeve  2110  may be an injection molded structure and defines a lumen  2112  therethrough adapted to accept the medical tubing forming first input line  1724 , which may be adhesively secured in lumen  2112 . A stop  2114  is formed in lumen  2112  to limit insertion of first input line  1724  in adaptor sleeve  2110 . Adaptor sleeve  2110  secures a disk valve  2116  in place within inlet port  1759  and across secondary lumen  1758 . Disk valve  2116  regulates fluid flow bi-laterally through secondary lumen  1758  and desirably comprises a stamped disk valve member  2118  made from a flexible thermoplastic material that has one or more slits or openings  2120  through the body of the disk valve member  2118 . The number of slits  2120  and length of the slits  2120  control the pressure necessary to achieve flow in both directions (bilaterally). Slit disk valves achieve flow control by changing one or more of several design factors as is well-known in the art. For example, slit or passageway opening pressure may be affected by choice of material for the disk valve member  2118 , number of slits  2120 , length of slits  2120 , freedom of deflection/deformation permitted in secondary lumen  1758  and/or inlet port  1759 , and diameter of the secondary lumen  1758  and inlet port  1759 . 
     In operation, disk valve  2116  allows fluid flow in both directions and stop  2114  is typically spaced a short distance away from the disk valve member  2118  to provide sufficient spacing or room to allow the disk valve member  2118  to deflect or deform under fluid pressure whereby slits  2120  open and allow fluid flow therethrough. On the opposite side of the disk valve  2116 , the secondary lumen  1758  may be formed with a shoulder  2122  to restrain the movement or deflection of the disk valve member  2118  in the secondary lumen  1758 . While the sandwiched arrangement of disk valve member  2118  between shoulder  2122  and stop  2114  may be sufficient to fix the location of the disk valve  2116  in port  1759 , it is desirable to use a medical grade adhesive around the periphery of disk valve member  2118  to secure the disk valve member  2118  in inlet port  1759  and across secondary lumen  1758 . If desired, a small in-line porous filter valve  2119  may be provided in secondary lumen  1758  to add back pressure to limit on pulsatile flow of peristaltic pump  1408  and slow down the initial burst of air and fluid when the disk valve  2116  initially operates or opens.  FIGS. 50A-50C  illustrate disk valve member  2118  with one, two, and three slits  2120 , respectively, allow for the changing of opening pressure for valve arrangement  2100 . Stop  2114  is generally tapered to allow for the deflecting/deforming movement of disk valve member  2118  in lumen  2112  during operation of disk valve  2118 . Disk valve  2118  generally forms a “second” valve structure in pressure isolation mechanism  1722  in addition to the “first” valve structure in pressure isolation mechanism  1722  in the form of valve member  1764 . 
     As shown in  FIGS. 51-52 , sleeve adaptor  2110  is formed with a tubular body portion  2124  that defines lumen  2112  and an integral annular collar  2126  which extends along the outer side of the tubular body portion  2124 . Annular collar  2126  engages or receives the tubular portion of the lower or second portion  1746  of valve housing  1742  which defines the secondary lumen  1758  and inlet port  1759 . Annular collar  2126  defines an annular space  2128  for receiving the inlet port  1759  defined by the tubular portion of the second portion  1746  of valve housing  1742 . Inlet port  1759  may be secured in annular space  2128  via medical grade adhesive and/or frictional engagement. As revealed by  FIGS. 51-52  and  FIG. 49 , disk valve member  2118  may be formed with a continuous (or alternatively interrupted) recess or groove  2130  adapted to receive a single continuous tab member  2132  (or multiple, discrete tab members  2132 ) provided on a distal end  2134  of the tubular body portion  2124  of the sleeve adaptor  2110 . This inter-engagement between the tab member  2232  and the recess or groove  2130  in the disk valve member  2118  helps to secure the engagement between disk valve  2116  and sleeve adaptor  2110  in inlet port  1759 . The inter-engagement between the tab member  2232  and the recess or groove  2130  in disk valve member  2118  may be supplemented with a medical grade adhesive if desired. 
       FIGS. 53-57  illustrate various additional embodiments of valve arrangement  2100 . In  FIG. 53 , sleeve adaptor  2110  just comprises a tubular body portion  2124  which is inserted and secured entirely within inlet port  1759 . Disk valve  2116  is secured to the distal end  2134  of tubular body portion  2124  of sleeve adaptor  2110  in the same manner as described previously. In this embodiment, it is possible for the disk valve  2116  and tubular body portion  2124  to be integrally formed as a unitary element. The tubular body portion  2124  of sleeve adaptor  2110  serves as a limit or stop limiting the insertion of first input line  1724  in inlet port  1759 . In  FIG. 53 , inlet port  1759  exhibits a stepped configuration in the vicinity of the distal end  2134  of tubular body portion  2124  and the tubular body portion  2124  defines a corresponding stepped shape to provide inter-fitting engagement or cooperation between these structures. 
       FIG. 54  illustrates an embodiment of valve arrangement  2100  which is similar to the valve arrangement  2100  of  FIG. 49  but the sleeve adaptor  2110  lacks annular collar  2126 . In this embodiment, a portion or length of the tubular body portion  2124  at distal end  2134  is secured in inlet port  1759  via medical grade adhesive and/or frictional engagement. The remainder of tubular body portion  2124  extends outward from inlet port  1759  and forms the portion of pressure isolation mechanism  1722  which accepts first input line  1724 . As  FIG. 54  further illustrates, lumen  2112  may be tapered toward first input line  1724  to minimize the production of air bubbles as fluid flows through sleeve adaptor  2110  and otherwise maintain laminar flow through the sleeve adaptor  2110  during fluid flow. The valve arrangement  2100  of  FIG. 55  is generally similar to that shown in  FIG. 54  but an elongated adaptor structure  2136  is associated with the sleeve adaptor  2110  and is inserted in inlet port  1759  to form the fluid connection between the valve arrangement  2100  and inlet port  1759  defined by the tubular portion of the second portion  1746  of valve housing  1742 . Elongated adaptor structure or member  2136  may be secured in inlet port  1759  via grade adhesive and/or frictional engagement. 
       FIG. 56  illustrates an embodiment of valve arrangement  2100  which is similar to the valve arrangement of  FIG. 53  but the tubular body portion  2124  of sleeve adaptor  2110  is truncated in overall length when compared to the tubular body portion  2124  of the sleeve adaptor  2110  of  FIG. 53 . Additionally, inlet port  1759  and the distal end  2134  of tubular body portion  2134  do not exhibit the inter-fitting stepped engagement provided between these structures in the valve arrangement  2100  depicted in  FIG. 53 . In  FIG. 56 , disk valve member  2118  is secured in inlet port  1759  on one side by shoulder  2122  defined in inlet port  1759  and the other side by adhesive engagement between tubular body portion  2124  of sleeve adaptor  2110  and the inlet port  1759  and, more clearly, the tubular portion of the second portion  1746  of valve housing  1742  which defines the inlet port  1759 . As shown in  FIG. 56 , an entire length L 1  of the tubular body portion  2124  may be secured within inlet port  1759 .  FIG. 57  illustrates a further embodiment of valve arrangement  2100  wherein sleeve adaptor  2110  and disk valve  2116  are formed integrally as a unitary structure which is position and secured in place in inlet port  1759  or, as illustrated, in secondary lumen  1758  via medical grade adhesive and/or frictional engagement. In a similar manner to that shown in  FIG. 56 , an entire length L 2  of the tubular body portion  2124  may be secured within secondary lumen  1758 , typically by adhesive. While for foregoing discussion of valve arrangement  2100  is provided in the context of pressure isolation mechanism  1722 , valve arrangement  2100  may useful in any fluid delivery setting wherein it is desired to substantially isolate compliant “upstream” system elements from affecting a downstream parameter such as blood pressure signals in the foregoing example. 
       FIGS. 16-19  illustrate the reduced or anti-contamination connector  1708  used to connect the first section  1710  and second section  1720  in the fluid path set  1700  shown in  FIGS. 10A-10B  in greater detail. As shown in  FIGS. 10A-10B  discussed previously, one connector  1708  connects the high pressure, second input line  1726  associated with the pressure isolation mechanism  1722  with the high pressure output line  1719  from the multi-position valve  1712  associated with controlling fluid flow from the syringe  1702 . A second connector  1708  connects the low pressure, first input line  1724  associated with the pressure isolation mechanism  1722  to the output line  1718  associated with the drip chamber  1716  connected to the secondary fluid container  1706 . 
     The connector  1708  generally includes a first connector member  1774  that is adapted for removable connection to a second connector member  1776 . The first and second connector members  1774 ,  1776  are designed or structured to reduce the possibility of contaminating the internal elements of the first and second connector members  1774 ,  1776  when they are handled by a user of the connector  1708 . The first and second connector members  1774 ,  1776  are preferably unitary structures that are integrally formed from plastic material, such as a medical-grade plastic material capable of resisting pressures generated during injection procedures such as angiography. The first and second connector members  1774 ,  1776  are preferably formed with external wings  1775  for grasping by a user of the connector  1708  while manipulating the first and second connector members  1774 ,  1776 , particularly when connecting the first and second connector members  1774 ,  1776  together. As discussed herein, the first and second connector members  1774 ,  1776  preferably include structures that provide a removable threaded engagement between the first and second threaded members  1774 ,  1776 . The wings  1775  generally provide the mechanical advantage necessary to tighten the preferred threaded engagement between the first and second connector members  1774 ,  1776 . The first connector member  1774  defines a central lumen  1777  that extends entirely through the first connector member  1774 . Likewise, the second connector member  1776  defines a central lumen  1778  extending entirely through the second connector member  1776 , so that when the first and second connector members  1774 ,  1776  are connected, fluid communication is established therebetween via lumens  1777 ,  1778 . 
     The first connector member  1774  includes an outer housing  1780 . The outer housing  1780  is generally a cylindrical shaped hollow structure and may have a smooth or textured outer surface  1781 . The first connector member  1774  further includes a first threaded member  1782  located within the outer housing  1780 . The first threaded member  1782  may be coaxially located within the outer housing  1780 . As shown in  FIG. 17 , the lumen  1777  in the first connector member  1774  extends through the first threaded member  1782 . The first threaded member  1782  is preferably externally threaded and may be in the form of an externally threaded female luer fitting. The first threaded member  1782  is recessed within the outer housing  1780  by a recessed distance R 1 , as shown in  FIG. 18 . The recessed distance R 1  is preferably sufficient to prevent contact with the end or tip of the first threaded member  1782  when a person touches the end or tip of the first connector member  1774 . The recessed distance R 1  thereby reduces the possibility of contaminating the first threaded member  1774 , when the first connector member  1774  is manipulated by a user of the connector  1708 . In particular, the recessed distance R 1  is of sufficient distance that human skin on a person&#39;s finger or thumb will not penetrate to the depth of the first threaded member  1782  and come into contact with the end or tip of the first threaded member  1782 . 
     The second connector member  1776  includes a second threaded member  1784 , which generally forms the connecting portion or structure of the second connector member  1776 . The second threaded member  1784  is preferably internally threaded to receive the externally threaded first threaded member  1782  for connecting the first and second connector members  1774 ,  1776  together in removable engagement. The first threaded member  1782  may be in the form of an externally-threaded female luer. The second connector member  1776  further includes a luer fitting  1786  located in the second threaded member  1784 . The luer fitting  1786  is preferably in the form of a male luer adapted to cooperate with the first threaded member  1782  when the first connector member  1774  is connected to the second connector member  1776 . The luer fitting  1786  is preferably coaxially disposed in the second threaded member  1784 . The lumen  1778  in the second connector member  1776  extends entirely through the luer fitting  1786 . The luer fitting  1786  is recessed within the second threaded member  1784  by a recessed distance R 2 , in a similar manner to how the first threaded member  1782  is recessed within the outer housing  1780 . The second threaded member  1784  further includes one or more circumferentially-extended raised structures  1788 , such as rings, on an outer surface  1789  thereof. 
       FIG. 17  shows the connection between the first and second connector members  1774 ,  1776  forming the connector  1708 . In the connected arrangement of the first and second connector members  1774 ,  1776 , the first threaded member  1774  is secured to the second connector member  1776  by removable threaded engagement between the externally threaded first threaded member  1782  and the internally threaded second threaded member  1784 . The luer fitting  1786  recessed within the second threaded member  1784  cooperates with the first threaded member  1782  to provide fluid communication between the first and second connector members  1774 ,  1776 . The present invention is not intended to be limited to the specific connection arrangement shown in  FIG. 17 , and the locations of the first threaded member  1782  and the second threaded member  1784  may be reversed in accordance with the present invention. Thus, the first threaded member  1782  may be provided on the second connector member  1776  and the second threaded member  1784  may be provided on the first connector member  1774 . 
     In the connected arrangement between the first and second connector members  1774 ,  1776 , the first threaded member  1782  and the second threaded member  1784  are threadably engaged and coaxially overlap one another. The outer housing  1780  of the first connector member  1774  generally encompasses the connection between the first and second threaded members  1782 ,  1784 . In particular, the outer housing  1780  generally coaxially encompasses the overall connection between the first and second threaded members  1782 ,  1784 . The outer housing  1780  has an internal wall or surface  1790  located opposite from the outer surface  1789  of the second threaded member  1784 , when the first and second threaded members  1782 ,  1784  are threadably engaged. As  FIG. 18  illustrates, the inner wall or surface  1790  of the outer housing  1780  and the first threaded member  1782  generally define an annular cavity  1791  about the first threaded member  1782 , in which the second threaded member  1784  is generally received when the first and second threaded members  1782 ,  1784  are threadably engaged. The distance between the inner wall or surface  1790  of the outer housing  1780  and the first threaded member  1782  in the annular cavity  1791  is preferably sufficient to receive at least the overall wall thickness of the second threaded member  1784 , including the raised structures  1788  on the outer surface  1789  of the second threaded member  1784  as generally depicted in  FIG. 17 . 
     In the connected arrangement of the first and second connector members  1774 ,  1776 , the annular cavity  1791  is substantially enclosed by the second threaded member  1784  to form a substantially enclosed chamber  1792 . The chamber  1792  is generally bounded by the body of the first threaded member  1782 , the inner wall or surface  1790  of the outer housing  1780 , and the end or tip of the second threaded member  1784 . The chamber  1792  is generally adapted to trap liquids, such as blood or contrast media, therein that may spill or leak from the first and second threaded members  1774 ,  1776 , when they are connected or disconnected to connect or disconnect the first and second sections  1710 ,  1720  of the fluid path set  1700 , for example during or after an angiography procedure. 
     The first connector member  1774  and second connector member  1776  define respective conduit-receiving cavities  1794 ,  1793  at the ends of the first and second connector members  1774 ,  1776  opposite from the first threaded member  1782  and the second threaded member  1784 , respectively. The conduit-receiving cavities  1794 ,  1793  are generally adapted to receive medical tubing to be associated with the first and second connector members  1774 ,  1776 . The medical tubing may be secured in the conduit-receiving cavities  1793 ,  1794  through the use of an appropriate medical-grade adhesive. The primary and secondary lumens  1754 ,  1758  may be formed with similar conduit-receiving cavities for receiving medical tubing used to connect the pressure isolation mechanism  1722  to other components in the fluid path set  1700 . A suitable medical-grade adhesive may be used in such cavities to secure the medical tubing. Similar structures and connections may also be provided in the inlet and outlet ports of the drip chambers  1716 . 
     As indicated previously, in the connected arrangement of the first and second connector members  1774 ,  1776 , the liquid-trapping chamber  1792  is formed, and is generally used to trap liquids that may spill or leak from the first and second connector members  1774 ,  1776 , when they are connected or disconnected during or after an injection procedure involving the fluid path set  1700 . The raised structures  1788  on the outer surface  1789  of the second connector member  1784  are adapted to form a tortuous path  1795  for inhibiting liquid flow out of or into the liquid-trapping chamber  1792 . Thus, liquid-trapping generally means inhibiting liquid flow rather than fully containing liquid. The tortuous path  1795  will generally cause liquids present or leaking into the chamber  1792  to remain in the chamber  1792 , and will further inhibit outside liquid from migrating into the sterile connection between the first threaded member  1782  and the second threaded member  1784 . By maintaining contaminated liquids in the chamber  1792  or generally between the inner surface  1790  of the outer housing  1780  and the outer surface of  1780  of the second threaded member  1784 , the sterility of the connection between the luer fitting  1786  and the first threaded member  1782  is generally maintained. Additionally, even when the first connector member  1774  is disconnected from the second connector member  1776 , the annular cavity  1791  about the first threaded member  1782  will act to maintain any contaminated liquids generally within the outer housing  1780 , and maintain the sterility of the luer fitting  1786  within the second threaded member  1784 . Thus, the second connector member  1776  may be re-used in a connection arrangement involving a different first connector member  1774 . 
     Referring to  FIGS. 18 and 19 , the first and second connector members  1774 ,  1776  may be formed with circumferentially-extending raised ribs  1796  adapted to secure removable protector caps  1798  on the first and second connector members  1774 ,  1776  prior to connecting the first and second connector members  1774 ,  1776 .  FIGS. 18 and 19  show the protector caps  1798  engaged with the first and second connector members  1774 ,  1776 . The protector caps  1798  define circumferentially-extending internal grooves or recesses  1799  for receiving the raised ribs  1796  on the first and second connector members  1774 ,  1776 . The raised rib  1796  on the first and second connector members  1774 ,  1776  are preferably adapted to frictionally engage the grooves or recesses  1799  formed in the protector caps  1798  to maintain the protector caps  1798  on the first and second connector members  1774 ,  1776 . The protector caps  1798  generally maintain the sterility of the first and second threaded members  1782 ,  1784  prior to connecting the first and second connector members  1774 ,  1776  together. 
     Referring further to  FIG. 19 , the protector caps  1798  may be used to cover the first and second connector members  1774 ,  1776  of the connectors  1708  in the fluid path set  1700  before and after injection procedures involving the fluid path set  1700 . Thus, the first and second sections  1710 ,  1720  of the fluid path set  1700  may be kept disconnected prior to an injection procedure when the fluid delivery system  1200  is being readied to carry out an injection procedure. Moreover, when an injection procedure is complete, additional, sterile protector caps  1798  may be used to cover the first or second connector members  1774 ,  1776  in the connectors  1708  associated with the first section  1710  of the fluid path set  1700 , so that this portion of the fluid path set  1700  may be reused. 
     As the connector  1708  of the present invention generally includes a male-threaded first connector member  1774  and a female-threaded second connector member  1776 , the male-threaded/female-threaded orientation of the first and second connector members  1774 ,  1776  may be used as a tactile, physical indicator to prevent the high pressure primary input line  1726  to the pressure isolation mechanism  1722  from being incorrectly connected to the output line  1718  associated with the secondary fluid container  1706 . Similarly, and more importantly, this feature may be used to prevent the low pressure, second input line  1724  to the pressure isolation mechanism  1722  from being incorrectly connected to the high pressure output line  1719  associated with multi-position valve  1712  controlling flow rate from the syringe  1702 . As  FIGS. 10A-10B  illustrate, the locations of the first and second connector members  1774 ,  1776  are reversed in the connectors  1708  used in the fluid path set  1700 , which will prevent inadvertent, incorrect cross-connections between the first and second sections  1710 ,  1720  in the fluid path set  1700 . 
     Referring further to  FIGS. 37-47 , another embodiment of the connectors  1708 ′ used to connect the first and second sections  1710 ,  1720  in the fluid path set  1700  depicted in  FIGS. 10A-10B  are shown. The connectors  1708 ′ includes first and second connector members  1774 ′,  1776 ′, which are now configured slightly differently from the connector members  1774 ,  1776  discussed previously. These differences will be discussed with reference to  FIGS. 37-47  and  FIGS. 10A-10B and 16-19  discussed previously. 
     The first connector member  1774 ′ is now formed with an internally-threaded outer housing  1780 ′ in comparison to the outer housing  1780  of the previous embodiment of the connector  1708 , which is essentially smooth-bored. The inner wall or surface  1790 ′ of the outer housing  1780 ′ defines internal threads  2000 . The outer surface  1781 ′ of the outer housing  1780 ′ may have a smooth texture as illustrated in  FIG. 37 , or include longitudinally-extending raised ribs  2002  as illustrated in  FIG. 42  to be discussed herein. 
     An additional difference between the first connector member  1774  of the connector  1708  discussed previously and the present embodiment of the connector  1708 ′ relates to the configuration of the first threaded member  1782 ′. The first connector member  1774 ′ does not include external threads on this component. The “first member”  1782 ′ without external threads is formed substantially as a conventional female luer fitting, but is still recessed a distance R 1  within outer housing  1780 ′ in accordance with the description of the first threaded member  1782  hereinabove. Accordingly, this element will be referred to herein as the “first luer member  1782 ′”. The first luer member  1782 ′ and outer housing  1780 ′ define an annular cavity  1791 ′ therebetween for receiving the second threaded member  1784 ′ of the second connector member  1776 ′ in the manner discussed previously. As the outer housing  1780 ′ is disposed coaxially and concentrically about the first luer member  1782 ′, the outer housing  1780 ′ may be referred to as the “first annular member  1780 ′” and this denotation will be used hereinafter. 
     With specific reference to  FIGS. 41 and 42 , the outer housing or first annular member  1780 ′ may be adapted to rotate or “swivel” relative to the first luer member  1782 ′ in the first connector member  1774 ′ so that the connector  1708 ′ may be a “swiveling” connector. As shown in these two figures, the first annular member  1780 ′ includes an annular flange  2004  that cooperates or engages a circumferentially extending recess  2006  defined adjacent the first luer member  1782 ′. The flange  2004  may rotationally slide in recess  2006  so that the first annular member  1780 ′ may rotate or swivel relative to the first luer member  1782 ′. 
     As discussed previously, the fluid path set  1700  includes two connectors  1708 ′ for connecting the first and second sections  1710 ,  1720  in the fluid path set  1700 . The rotational or swiveling feature of the first annular member  1780 ′ allows the first connector member  1774 ′ in each of the connectors  1708 ′ to be joined to the second connector member  1776 ′ in each of the connectors  1708 ′ without disturbing or altering the orientation of the respective input/output lines  1718 ,  1724  and  1719 ,  1726  associated with the connectors  1708 ′ (see  FIGS. 10A-10B ). For example, the connector  1708 ′ associated with the high pressure input/output lines  1719 ,  1726  connected to the syringe  1702  may be joined with the “swivel” connector  1708 ′ so that the orientation of the downstream pressure isolation mechanism  1722  is undisturbed. Thus, once the downstream orientation of the pressure isolation mechanism  1722  is set to a desired orientation by an operator of the fluid delivery system  1200 , the swiveling feature of the first connector member  1774 ′ may be used as a way of ensuring that this desired orientation is maintained. Without this swivel feature, it is possible that rotational force may be applied to the pressure isolation mechanism  1722  when the first and second connector members  1774 ′,  1776 ′ are joined in the two connectors  1708 ′ used in the fluid path set  1700 , causing the pressure isolation mechanism  1722  to be rotated to an undesirable position. For example, an operator of the fluid delivery system  1200  may elect to have the pressure isolation port  1761  of the pressure isolation mechanism  1722  to be positioned to point toward the operator, as is the orientation of this component in  FIGS. 10A-10B . Due to the swiveling feature of the first annular member  1780 ′ of the first connector member  1774 ′ in the two connectors  1708 ′ used in the fluid path set  1700 , the operator can ensure that a desired orientation of the pressure isolation mechanism  1722  may be maintained when the respective pairs of input/output lines  1718 ,  1724  and  1719 ,  1726  are joined by the connectors  1708 ′. The swiveling feature ensures that rotational force is not substantially applied to the pressure isolation mechanism  1722  thereby altering its orientation when the first and second section sections  1710 ,  1720  of the fluid path set  1700  are connected. 
     As was the case with the connectors  1708  illustrated in  FIGS. 10A-10B  discussed previously, the connectors  1708 ′ used in the fluid path set  1700  may reverse locations for the first and second connector members  1774 ′,  1776 ′ so that the “high” pressure side of the first section  1710  of the fluid path set  1700  is not inadvertently connected to the “low” pressure side of the second section  1720  of the fluid path set  1700  and vice versa. The raised longitudinal ribs  2002  on the outer housing  1780 ′ further improve the ability of the operator to make the connection between the first and second connector members  1774 ′,  1776 ′ by improving the frictional engagement between an operator&#39;s fingertips and the outer housing or first annular member  1780 ′ when rotating the first annular member  1780 ′ to threadably engage the second threaded member  1784 ′ associated with the second connector member  1776 ′. 
     Referring further to  FIGS. 37-47 , the second connector member  1776 ′ is now specifically adapted to threadably engage the internal threads  2000  provided on the inner surface  1790 ′ of the outer housing or first annular member  1780 ′. The second threaded member  1784 ′, which may be referred to as “second annular member  1784 ′” in an analogous manner to the first annular member  1780 ′, is now formed with external threads  2004  on the external surface  1789 ′ of the second annular member  1784 ′ for engaging the internal threads  2000  within the first annular member  1780 ′ of the first connector member  1774 ′. The external threads  2004  functionally take the place of the internal threads in the second threaded member  1776  in the previous embodiment of the connector  1708 . In the previous embodiment, the internally threaded second threaded member  1784  threadably engages the externally threaded first threaded member  1782  to connect the first and second connector members  1774 ,  1776 . The external threads  2004  in the present embodiment are formed in place of the raised structures  1788  in the previous embodiment, and now threadably engage the internal threads  2000  within the first annular member  1780 ′ to connect the first and second connector members  1774 ′,  1776 ′. 
     In addition to securing the threaded engagement between the first and second connector members  1774 ′,  1776 ′, the external threads  2004  generally perform the function as the raised structures  1788 , namely forming a tortuous path (not shown) or tortuous barrier for inhibiting or substantially preventing liquid flow out of or into liquid-trapping chamber  1792 ′. The tortuous path formed by the external threads  2004  now acts to substantially prevent liquid flow rather than just inhibiting liquid flow as was the case in the previous embodiment of the connector  1708 . This is because the engagement between the internal and external threads  2000 ,  2004  substantially closes off the liquid-trapping chamber  1792 ′ in a substantially liquid tight manner, whereas the raised structures  1788  in the previous embodiment of the connector  1708  define a tortuous path  1795  that substantially inhibits liquid flow into and out of chamber  1792 , rather than substantially sealing off chamber  1792  as is substantially the case in the present embodiment. 
     The second connector member  1776 ′ also includes a recessed luer fitting or member  1786 ′, for example a male luer fitting, that is adapted to engage the first luer member  1782 ′ which, as indicated previously, may be formed as a female luer fitting. This “second” luer member  1786 ′ is recessed within the second annular member  1784 ′ by a distance R 2  in a similar manner to the previously discussed embodiment of the connector  1708 . The first and second connector members  1774 ′,  1776 ′ are each adapted to receive a protector cap  1798  (see  FIGS. 18 and 19 ) in the manner discussed previously. 
     As shown in  FIG. 47 , the first and second luer members  1782 ′,  1786 ′ are not required to be recessed within the first and second annular member  1780 ′,  1784 ′ and may extend substantially flush with the first and second annular members  1780 ′,  1784 ′. Additionally, it may be advantageous for only one of the first and second luer members  1782 ′,  1786 ′ to be recessed within the first and second annular members  1780 ′,  1784 ′. For example,  FIG. 47  shows the first luer member  1782 ′ extended to be substantially flush with the first annular member  1780 ′ for increased positive locking engagement (i.e., increased surface area of engagement) with the second luer member  1786 ′. The first annular member  1780 ′ provides a gripping surface for an operator&#39;s fingertips and will help ensure that contact is not made with the first luer member  1782 ′. In this situation, the second luer member  1786 ′ may be recessed as indicated previously. However, the second luer member  1786 ′ may be extended to be flush with the second annular member  1786  as shown in phantom lines in  FIG. 47 . In view of the foregoing, the first and second luer members  1782 ′,  1786 ′ may both be recessed or substantially flush with respect to the first and second annular members  1780 ′,  1784 ′, or only one of the first and second luer members  1782 ′,  1786 ′ may be recessed within the first and second annular members  1780 ′,  1784 ′ while the other is substantially flush with the first and second annular members  1780 ′,  1784 ′. These same optional combinations may be applied in an analogous manner to the connector  1708  discussed previously. 
     To join the first and second connector members  1774 ′,  1776 ′ together, the user inserts the second annular member  1784 ′ partially into first annular member  1780 ′ of the first connector member  1774 ′ until the external threads  2004  on the second annular member  1784 ′ contact and begin to engage the internal threads  2000  provided on the inner surface  1790 ′ of the first annular member  1780 ′. Once in position, the user may begin rotating the first annular member  1780 ′ so that the opposing external and internal threads  2004 ,  2000  associated with the second annular member  1784 ′ and first annular member  1780 ′, respectively, engage and draw the first and second connector members  1774 ′,  1776 ′ into threaded engagement. As the first and second connector members  1774 ′,  1776 ′ are drawn together, the second luer member  1786 ′ typically recessed within the second annular member  1784 ′ is received in the first luer member  1782 ′, thereby completing the fluid connection between lumens  1777 ′,  1778 ′. It will be understood that the present invention is intended to include a reversed configuration for the “male” second luer member  1786 ′ and “female” first luer member  1782 ′. In such a reversed configuration, the male second luer member  1786 ′ may be formed as a female luer fitting, and the first luer member  1782 ′ may be formed as a male luer fitting. 
     The connectors  1708 ′ used in the fluid path set  1700  may further include a check valve arrangement  2010  for limiting flow through the connectors  1708 ′. The check valve arrangement  2010  may be disposed within lumen  1777 ′ of the first connector member  1774 ′, or lumen  1778 ′ in the second connector member  1776 ′ depending on which direction through the connector  1708 ′ it is desired to limit flow. 
     The check valve arrangement  2010  is provided in one or both of the connectors  1708 ′ used to connect the first section  1710  to the second section  1720  of the fluid path set  1700  to isolate the first section  1710  from the second section  1720  unless pressure is present in the lines of the first section  1710 . More particularly, the check valve arrangement  2010  in the connectors  1708 ′ isolates one or both output lines  1724 ,  1726  (see  FIGS. 10A-10B ) from one or both corresponding input lines  1718 ,  1719  associated with the connectors  1708 ′ when pressure is not present in input lines  1718 ,  1719 . In this disclosure, it will be assumed that the check valve arrangement  2010  is provided in both connectors  1708 ′ in the fluid path set  1700 . 
     The check valve arrangement  2010  associated with the connectors  1708 ′ is normally closed until fluid pressure in the connectors  1708 ′ is sufficient to open the respective check valve arrangements  2010  permitting flow through the connectors  1708 ′. Such pressure is supplied by the peristaltic pump  1408 , discussed herein connection with  FIG. 27 , associated with input line  1718  and the syringe  1702  associated with input line  1719 . For example, the connector  1708 ′ associated with input line  1718  may be configured such that the first connector member  1774 ′ of the connector  1708 ′ is associated with input line  1718 . Input line  1718  is, in turn, connected to the drip container  1716  containing a secondary injection fluid. The check valve arrangement  2010  may be provided in the first connector member  1774 ′ to prevent secondary injection fluid from passing through the connector  1708 ′ until sufficient pressure is present in input line  1718  to open the normally closed check valve arrangement  2010 . As indicated, sufficient fluid pressure to open the check valve arrangement  2010  would be supplied by the peristaltic pump  1408 , and may be in the range of about 8-20 psi. 
     A check valve arrangement  2010  may be provided in the connector  1708 ′ connecting input line  1719  with output line  1726  on the “high” pressure side of the fluid path set  1700  associated with the syringe  1702 . In this situation, the check valve arrangement  2010  may be provided in lumen  1778 ′ in the second connector member  1776 ′. As indicated previously, in order to avoid an inadvertent cross connection between input line  1719  and output line  1724  and, further, a corresponding inadvertent cross connection between input line  1718  and output line  1726 , the locations for the first and second connector members  1774 ′,  1776 ′ may be reversed in the connectors  1708 ′ connecting the respective input lines  1718 ,  1719  and output lines  1724 ,  1726 . Accordingly, if the check valve assembly  2010  is provided in the first connector member  1774 ′ of the connector  1708 ′ associated with input line  1718 , the other connector  1708 ′ associated with input line  1719  will have the check valve assembly  2010  provided in the second connector member  1776 ′ rather than the first connector member  1774 ′. The check valve assembly  2010  disposed in the second connector member  1776  will open under the fluid pressure supplied by the syringe  1702 , as indicated previously. 
     The check valve assembly  2010  will generally be discussed as it is situated within the first connector member  1774 ′ of the connector  1708 ′ used to connect input line  1718  with output line  1724 , but the following discussion is equally applicable to the situation where the check valve assembly  2010  could be associated with the second connector member  1776 ′. The check valve assembly  2010  is generally comprised of a retaining sleeve  2012  and check valve stopper element  2014 . The sleeve  2012  is disposed (i.e., inserted) within lumen  1777 ′ and held therein by a friction fit. The lumen  1777 ′ in the present embodiment of the connector  1708 ′ includes an extended length conduit receiving cavity  1794 ′, wherein the sleeve  2012  is positioned. The conduit receiving cavity  1794 ′ defines an internal shoulder  2016 . The sleeve  2012  is disposed within the conduit receiving cavity  1794 ′ of lumen  1777  so that the sleeve  2012  abuts the shoulder  2016 . As will be appreciated, flow though the lumen  1777 ′ will be in the direction of arrow  2018  when the connector  1708 ′ is associated with input line  1718 . Accordingly, flow through the lumen  1777 ′ will pass centrally through central bore  2020  in sleeve  2012 . 
     The first luer member  1782 ′ of the first connector member  1774 ′ defines a central opening or aperture  2022  connected to lumen  1777 ′. The first connector member  1774 ′ further includes at least one septum  2024  in the central opening  2022  which divides the central opening  2022  into two or more output channels  2026 . In the present embodiment, the first connector member  1774 ′ is illustrated with only one septum  2024  for clarity. The septum  2024  and a distal end  2028  of the sleeve  2012  define opposing ends of a cavity  2030  adapted to receive the stopper element  2014  (hereinafter “stopper  2014 ”). The cavity  2030  is bounded circumferentially or perimetrically by the wall of lumen  1777 ′. 
     As shown most clearly in  FIG. 39A , the second connector member  1776 ′ may be may have a similar configuration to the first connector member  1774 ′ with respect to lumen  1778 ′ to receive the check valve arrangement  2010 . As shown in  FIGS. 40, 45, and 47 , the supporting septum  2024  for the check valve arrangement  2010  may be omitted from the second connector member  1776 ′ in the connector  1708 ′, if desired. The distal end  2028  of the sleeve  2012  forms an internal shoulder in lumen  1777  against which the stopper seats  2014  to prevent flow through the lumen  1777  in the normally closed condition of the check valve arrangement  2010 . 
     Referring to  FIGS. 39B and 40B , in one variation of connector  1708 ′, a flow interrupter F is provided on the male second luer member  1786 ′. Flow interrupter F operates to affect the flow of fluid entering the female first luer member  1782 ′ from the male second luer member  1786 ′, as shown in  FIG. 40B , wherein flow direction is indicated by arrow  2018  and is now from the male second luer member  1786 ′ to the female first luer member  1782 ′. In operation, flow interrupter F induces turbulent flow in the fluid flow exiting the male second luer member  1786 ′ and entering an interface area A defined by or between the male second luer member  1786 ′ and the female first luer member  1782 ′ which advantageously has the effect of removing or “flushing” away trapped air (if any) in this interface area A. While flow interrupter F is shown associated with the male second luer member  1786 ′ as in  FIG. 39B , this structure may also be associated with the female first luer member  1782 ′ by placing the flow interrupter F in lumen  1777 ′. Typically, in accordance with this disclosure, the flow interrupter F is provided in the luer lumen (either  1777 ′,  1778 ′) which dispenses fluid into the interface area A between luer members  1782 ′,  1786 ′ (i.e., the upstream lumen). Flow interrupter F may also be applied to connector  1708  illustrated in  FIGS. 16-19  in generally the same manner as the foregoing. 
     In the normally closed condition of the check valve arrangement  2010 , the stopper  2014  extends between the opposing ends of the cavity  2030  and seals the central bore  2020  by engaging the internal shoulder formed by the distal end  2028  of the sleeve  2012 , thereby preventing flow from passing through the first connector member  1774 ′ and into the second connector member  1776 ′. The stopper  2014  may be formed of a resiliently deformable material such as, a polyethylene thermoplastic elastomer, which deforms when fluid pressure is present in central bore  2020 . Preferably, the resilient material chosen for the stopper  2014  has sufficient resiliency to maintain the closure of the central bore  2020  until a predetermined pressure is reached in the central bore  2020  and, hence, lumen  1777 ′. As this predetermined “lift” or deformation pressure is reached, the stopper  2014  deforms axially a sufficient amount in cavity  2030  to allow flow to pass from central bore  2020  into the cavity  2030 . As the stopper  2014  deforms axially it will unseat from the distal end  2028  of the sleeve  2012 , thereby allowing flow to exit from the central bore  2020 . As the stopper  2014  deforms axially it will simultaneously expand radially. In order to allow fluid to freely pass through cavity  2030  and into channels  2026 , longitudinal grooves or recesses  2032  are defined in the wall of cavity  2030  to permit liquid flow around the stopper  2014  and through the cavity  2030 . The liquid may then flow through channels  2026  to enter the second connector member  1776 ′ and the lumen  1778 ′ therethrough. Once the fluid pressure is discontinued, for example, by the peristaltic pump  1408  shutting-off, the stopper  2014  will expand axially and again seal against the distal end  2028  of the sleeve  2012  to seal the central bore  2020  and prevent fluid flow through the connector  1708 ′. The distal end  2028  may define a circumferential recess  2034  that will accept the stopper  2014  to improve the seal between the stopper  2014  and sleeve  2012 . Since the stopper  2014  is formed of a resiliently deformable material, the stopper  2014  may deform or “mold” into this recess  2034  when the pressure in lumen  1777 ′ and central bore  2020  drops to a level sufficient to cause enough axial deformation of the stopper  2014  to cause the stopper  2014  to unseat from the distal end  2028  of the sleeve  2012 . The check valve arrangement  2010  when used in the connector  1708 ′ connecting input line  1718  with output line  1724  in the “secondary” side of the fluid path set  1700  may take the place of the pinch valve  1410  discussed hereinafter. This is because the check valve arrangement  2010  in the first connector member  1774 ′ will perform substantially the same function as the pinch valve  1410 , and may be used in combination with the pinch valve  1410  or as a replacement to the pinch valve  1410 . 
     Referring to  FIGS. 9-10 and 20-21  the fluid control module  1400  is shown in greater detail. The fluid control module or device  1400 , as indicated previously, generally includes a housing  1402 , a valve actuator  1404 , a fluid level sensing mechanism  1406 , a peristaltic pump  1408 , an automatic shut-off or pinch valve  1410 , and an air detector assembly  1412 . The various components comprising the fluid control module or device  1400  will be discussed in detail herein. 
     The housing  1402  generally defines a port  1420  for associating the injector  1300  with the fluid control module  1400 . In particular, the injector  1300  is generally mounted to the fluid control module  1400  to be pivotal relative to the fluid control module  1400 . The port  1420  includes a mating structure  1422  for connecting the injector  1300  to the fluid control module  1400  and providing for the pivotal connection between the injector  1300  and the fluid control module  1400 . The port  1420  defines an opening  1424  for passing electrical conduits (not shown) therethrough to operatively connect computer hardware provided in the injector  1300  with computer hardware in the fluid control module  1400 , so that the injector  1300  and fluid control module  1400  are electrically connected. While the port  1420  is shown on the side of the fluid control module  1400 , this configuration is just an exemplary arrangement for the pivotal connection between the injector  1300  and fluid control module  1400  and other configurations are possible in accordance with the present invention such as mounting the injector at the top of the fluid control module  1400 . 
     The housing  1402  may be a multi-piece structure comprised of opposing sides or portions  1426 ,  1428  that are secured together by conventional mechanical fasteners or similar fastening methods. The fluid control module  1400  is generally adapted to support an IV pole  1430  used to support containers of fluids, for example the primary fluid container  1704  (i.e., contrast media) and the secondary fluid container  1706  (i.e., saline), the contents of which are supplied to a patient via the fluid delivery system  1200 . In particular, the rear side or portion  1428  of the housing  1402  is adapted to support the IV pole  1430 . A hand controller support  1432  may be connected to the front side or portion of the housing  1402  for supporting a hand controller used to operate the fluid delivery system  1200 , as discussed further herein. Additionally, the fluid control module  1400  preferably includes a connector  1433  adapted to operatively associate a hand controller with the fluid control module  1400 . 
     Referring further to  FIGS. 22 and 23 , the valve actuator  1404  is shown in greater detail. Generally, the valve actuator  1404  is adapted to support and actuate the multi-position valve  1712  associated with the primary section  1710  of the fluid path set  1700 . The multi-position valve  1712 , as indicated previously, may be a three-position stopcock valve. The valve actuator  1404  is generally adapted to selectively move or actuate the multi-position valve  1712  between three set positions of the multi-position valve  1712 , as will be discussed further herein. Generally, the valve actuator  1404  is adapted to place the multi-position valve  1712  in one of three distinct positions, including (1) an inject or open position, (2) a fill position, and (3) a closed or isolation position. In the inject position, the syringe  1702  of the fluid path set  1700  is in fluid communication with the secondary section  1720  of the fluid path set  1700 . In the fill position, the syringe  1702  is in fluid communication with the primary fluid container  1704  via the drip chamber  1716  associated with the primary fluid container  1704 . Finally, in the closed position, the syringe  1702  is isolated from the primary fluid container  1704  and the second section  1720  of the fluid path set  1700 . The specific components of the valve actuator  1404  adapted to place the multi-position valve  1712  in the foregoing positions or states will be discussed further herein. 
     As  FIGS. 22 and 23  generally illustrate, the valve actuator  1404  is a multi-piece apparatus adapted to accept, support, and actuate the multi-position valve  1712 . The valve actuator  1404  includes a base support member  1440  which is generally used to support the various components of the valve actuator  1404 . The base support member  1440  may be a machined part, for example, a machined aluminum part. A stepper motor  1442  is secured by mechanical fasteners  1443  to one side of the base support member  1440 . The stepper motor  1442  includes an output shaft  1444  that provides the motive forces for operating the valve actuator  1404 . A shaft interface  1446  is disposed on the other side of base support member  1440  from the stepper motor  1442 , and is in operative engagement with the output shaft  1444 . The shaft interface  1446  is associated with the output shaft  1444  to transfer the motor torque provided by the stepper motor  1442  to other components of the valve actuator  1404 , as discussed herein. The shaft interface  1446  may be secured to the base support member  1440  using the same mechanical fasteners  1443  used to secure the stepper motor  1442  to the base support member  1440 . 
     The valve actuator  1404  further includes a photosensor assembly or array  1448  that includes, preferably, two photosensor position sensors  1450  for indicating the position of the handle of the multi-position valve  1712  when associated with the valve actuator  1404 , and a third photosensor  1451  for indicating the presence of the multi-position valve  1712  in the valve actuator  1404 . The various photosensors  1450 ,  1451  are carried or supported on two plates  1452  joined by a connecting member  1453 . The plates  1452  are secured to the base support member  1440  by mechanical fasteners  1454 , such that the photosensor assembly  1448  is associated with the shaft interface  1446 . In particular, the shaft interface  1446  includes two semi-circular structures or rings  1456 , only one of which is shown in  FIGS. 22 and 23 , that interface with the position sensors  1450  to indicate the position of the stepper motor  1442 . The position of the stepper motor  1442  may be correlated to the position of the handle of the multi-position valve  1712  and, thus, reflect the operational position of the multi-position valve  1712  (i.e., inject, fill, isolate). In particular, the semi-circular structures  1456  may define windows  1457  that correlate to the three possible operational positions of the handle of the multi-position valve  1712 . The shaft interface  1446  further provides a hard stop that interfaces with the base support member  1440  to prevent over-rotation of the handle of the multi-position valve  1712  during operation of the valve actuator  1404 . 
     The shaft interface  1446  defines one or more slots  1458  for guiding an actuating member or pin  1460  into operational association with the valve present sensor  1451 . Thus, the actuating member or pin  1460  is generally used to indicate the presence of the multi-position valve  1712  in the valve actuator  1404 . The actuating member  1460  includes a plurality of spokes  1461  that cooperate with the slots  1458  in the shaft interface  1446 . The actuating member  1460  further includes a distal structure  1462  adapted to coact with the body of the multi-position valve  1712 . The engagement of the body of the multi-position valve  1712  with the distal structure  1462  of the actuating member  1460  generally causes the actuating member  1460  to move proximally toward the base support member  1440  and shaft interface  1446  and into operational engagement with the valve present sensor  1451 , which preferably initiates a signal to the computer hardware/software associated with the fluid control module  1400  and/or in the injector  1300  indicating the presence of the multi-position valve  1712  in the valve actuator  1404 . The proximal movement of the actuating member  1460  causes the spokes  1461  to move into further engagement with the slots  1458  defined in the shaft interface  1446 , which allows for the general proximal movement of the actuating member  1460  into the shaft interface  1446 . 
     The distal structure  1462  of the actuating member  1460  cooperates with an adaptor  1464  that is formed to interface with the handle of the multi-position valve  1712 . The adaptor  1464  is generally formed to mate with the handle of multi-position valve  1712  and transfer the motor torque from the stepper motor  1442  to the handle to move the handle between the inject, fill, and isolate positions indicated previously. The second multi-position valve  1730  depicted in  FIGS. 10A-10B , discussed previously, shows a conventional stopcock valve with a handle, and is the general type of valve that the valve actuator  1404  is intended to operate in accordance with the present invention. The adaptor  1464  defines a side opening  1465  for receiving the handle of the multi-position valve  1712 . 
     The adaptor  1464  coaxially associates with the distal structure  1462  of the actuating member  1460 . Additionally, the adaptor  1464  is adapted to coact with a distal portion  1466  of the shaft interface  1446 . The distal portion  1466  of the shaft interface  1446  defines the slots  1458  for receiving the spokes  1461  of the actuating member  1460 . The shaft interface  1446  is generally used to transfer the motor torque from the output shaft  1444  to the adaptor  1464  to cause the rotation of the handle of the multi-position valve  1712  to place the multi-position valve  1712  in the respective inject, fill, and isolate positions discussed previously. As shown in  FIG. 22 , the output shaft  1444  cooperates with a proximal portion  1467  of the shaft interface  1446 , and the adaptor  1464  is operationally associated with the output shaft  1444  via the distal portion  1466  of the shaft interface  1446 . The shaft interface  1446  is generally adapted to transmit the rotary movement of the output shaft  1444  to the adaptor  1464  via the operational engagement between the distal portion  1466  of the shaft interface  1446  and the adaptor  1464 . Thus, the rotary motion of the output shaft  1444  is used to rotate the adaptor  1464  to one of the three operational positions of the multi-position valve  1712  when the stepper motor  1442  is activated. The position signals from the position sensors  1450  may be used to control the operation of the stepper motor  1442  to selectively place the multi-position valve  1712  in one of the three operational positions. In particular, the computer hardware/software associated with the fluid control module  1400  and/or injector  1300  may use the position signals from the position sensors  1450  as input signals and control operation of the stepper motor  1442  based on the information contained in the position signals (i.e., select a desired operational state for the multi-position valve  1712 ). 
     The valve actuator  1404  further includes a support assembly  1468  for supporting the multi-position valve  1712  in the valve actuator  1404 . The support assembly includes a valve retainer  1469  and a housing  1470  for enclosing and supporting the valve retainer  1469 . The valve retainer  1469  includes three snap positions or mounts  1471  adapted to engage the body of the multi-position valve  1712  to secure the multi-position valve  1712  in the valve actuator  1404 . The valve retainer  1469  may be formed of a plastic material and the housing  1470  may be formed of a more robust material for protecting the multi-position valve  1712  and may be provided, for example, as a machined aluminum part. 
     The adaptor  1464  generally extends through a central opening  1472  in the valve retainer  1469  to engage the body of the multi-position valve  1712  and, in particular, receive the handle of the multi-position valve  1712  in the side opening  1465 , to operatively associate the multi-position valve  1712  with the actuating components of the valve actuator  1404 . The valve retainer  1469  has a proximal engagement structure  1473  that defines the central opening  1472 . The engagement structure  1473  coacts with a mating circumferentially-extending edge  1474  on the actuator  1464  so that the axial force associated with inserting the body of the multi-position valve  1712  into the snap positions  1471  is transmitted via the actuator  1464  to the body of the shaft interface  1446  and the base support member  1440 . The axial movement associated with inserting the multi-position valve  1712  into the valve retainer  1469  causes the body of the multi-position valve  1712  to contact and engage the distal structure  1462  of the actuating member  1460 , thereby causing the actuating member  1460  to move proximally and operatively associate with the valve present sensor  1451 . The valve present sensor  1451 , once activated, initiates the valve present signal to the fluid control module  1400  and/or injector  1300 . 
     The housing  1470  of the support assembly  1468  may be secured to the shaft interface  1446  and the base support member  1440  using the same mechanical fasteners  1443  used to secure the stepper motor  1442  to the base support member  1440 . The housing  1470  preferably defines multiple semi-circular cut-outs or recesses  1475  for accommodating the body of the multi-position valve  1712 , and generally corresponding to the snap positions or mounts  1471  formed in the valve retainer  1469 . The cut-outs or recesses  1475  provide hard stops for the body of the multi-position valve  1712 , which are provided to prevent the snap positions or mounts  1471  from becoming over-stressed due to repeated insertions and removals of multi-position valves  1712  into and out of the valve actuator  1404 . The valve actuator  1404 , after being assembled to include all of the various components discussed hereinabove, may be installed as a unit in the fluid control module  1400 . 
     Generally, when the body of the multi-position valve  1712  is inserted into the valve retainer  1469  and engaged with the snap mounts  1471 , the handle of the multi-position valve  1712  is received in the adaptor  1464 . The axial force associated with placing the multi-position valve  1712  in the valve retainer  1469  is transmitted via the mating engagement between the engagement structure  1473  on the valve retainer  1469  and the circumferential edge  1474  on the adaptor  1464  to the shaft interface  1446  and the base support member  1440 . As the body of the multi-position valve is inserted into the valve retainer  1469 , the body engages the distal structure  1462  of the actuating member  1460 , causing the actuating member  1460  to move proximally into the shaft interface  1446 , with the spokes  1461  of the actuating member  1460  depressing or moving into further engagement with the slots  1458  in the distal portion  1466  of the shaft interface  1446 . The axial proximal movement imparted to the actuating member  1460  causes the actuating member  1460  to operatively associate with the valve present sensor  1451 , which initiates a valve present signal to the fluid control module and or injector  1300 . As shown in  FIG. 22 , the actuating member  1460  is preferably biased to a non-operative position relative to the valve present sensor  1451  by a biasing member or device such as a spring  1476 , so that upon removal of the multi-position valve  1712  from the valve retainer  1469 , the actuating member  1460  is moved automatically out of operative association with the valve present sensor  1451 . 
     Referring further to  FIGS. 24A-26B and 24B-26B , the fluid level sensing mechanism  1406  (hereinafter “fluid level sensor  1406 ”) provided on the fluid control module  1400  is shown in greater detail. The fluid level sensor  1406  generally interfaces with the drip chambers  1716  (or drip chambers  1716 ′) associated with the primary and secondary fluid containers  1704 ,  1706 . The fluid level sensor  1406  is provided to indicate to the operator of the fluid delivery system  1200  that sufficient injection fluid, either primary contrast media or secondary saline, is available for an injection or flushing procedure. The fluid level sensor  1406  is generally adapted to indicate to warn the operator when the fluid level in the drip chambers  1716  is below a level sufficient to conduct an injection procedure. The fluid level sensor  1406  is provided as a safety feature to ensure that air is not introduced into the fluid path set  1700  during an injection procedure or flushing procedure involving the fluid delivery system  1200 . 
     The fluid level sensor  1406  generally includes a support plate  1480 , a drip chamber support  1482 , and one or more fluid level sensors  1484  (“hereinafter fluid sensors  1484 ”) which are adapted for association with the drip chambers  1716  connected to the primary and secondary fluid containers  1704 ,  1706 . The support plate  1480  generally supports the various components of the fluid level sensor  1406 . The drip chamber support  1482  is generally secured to the support plate  1480  by suitable mechanical fasteners  1485  or another suitable attachment or mounting scheme. The drip chamber support  1482  is preferably a unitary structure that is integrally molded of plastic material, and includes a plurality of attachment or support locations  1486  adapted to support the drip chambers  1716 . In particular, the drip chamber support  1482  includes snap mounts or positions  1488  for securing the bodies  1734  of the drip chambers  1716  in the fluid level sensor  1406 , and operatively associated with the fluid sensors  1484 . The snap mounts  1488  may be adapted to engage inlet and outlet ports of the drip chambers  1716 , as shown in  FIG. 26A . 
     The drip chamber support  1482  defines respective openings  1490  for receiving the fluid sensors  1484 , and associating the fluid sensors  1484  with the drip chambers  1716 . The openings  1490  are positioned to allow the fluid sensors  1484  to be operatively associated with the projection  1740  formed on the bodies  1734  of the respective drip chambers  1716 . As shown in  FIG. 26A , the fluid sensors  1484  may physically contact the projections  1740  on the drip chambers  1716 , when the drip chambers  1716  are secured in the support locations  1486  on the drip chamber support  1482 . The fluid sensors  1484  may be optical or ultrasonic sensors. A suitable ultrasonic sensor for the fluid sensors  1484  is manufactured by Omron. A gasket  1492  may be provided between the drip chamber support  1482  and the support plate  1480  to prevent fluid intrusion between the drip chamber support  1482  and the support plate  1480 , which could damage the fluid sensors  1484 . Indicator lights  1494  may be associated with the support locations  1486  to illuminate the drip chambers  1716 . The indicator lights  1494  are further adapted to visually indicate when the fluid level in the drip chambers  1716  drops to an unsafe level during operation of the fluid delivery system  1200 , for example by changing modes to an intermittent mode and blinking to indicate to the operator that insufficient fluid is available for an injection procedure. The indicator lights  1494  provide “back-lighting” for not only the drip chambers  1716  but also the medical tubing associated with the drip chambers  1716 , and light the medical tubing and drip chambers  1716  in such a manner that the medical tubing and the drip chambers  1716  form a “light pipe” that illuminates at least part if not all of the first section  1710  of the fluid path set  1700 . The back lighting allows the operator of the fluid delivery system  1200  to easily visually inspect the drip chambers  1716  to check the fluid level present in the drip chambers  1716 . 
     The fluid sensors  1484  are generally adapted to provide fluid level signals to the computer hardware/software associated with the fluid control module  1400  and/or injector  1300  to indicate the fluid levels in the drip chambers  1716 . The fluid sensors  1484  may be further adapted to initiate an alarm signal to the computer hardware/software associated with the fluid control module  1400  and/or the injector  1300  when the fluid level in the drip chambers  1716  falls to an unsafe level. The computer hardware/software associated with the fluid control module  1400  and/or the injector  1300  may be adapted to respond to the alarm signal by halting the on-going injection procedure. 
     As  FIG. 26A  illustrates, the fluid sensors  1484  are tilted or angled at a slight or small angle relative to a vertical axis generally parallel to the face of the support plate  1480 . The slight angle, for example 3°, is selected to complement the projection  1740  on the bodies  1734  of the drip chambers  1716 . The projection  1740  on the bodies of the drip chambers  1716  is preferably tapered at a small angle, such as 3°. The projection  1740  on the bodies  1734  of the drip chambers  1716  is preferably tapered inward at a small angle from the top end  1736  to the bottom end  1738  on the drip chambers  1716 , as illustrated in  FIG. 26A . The fluid sensors  1784  are positioned in the openings  1490  to compliment the tapered projections  1740  on the respective drip chambers  1716 , and preferably physically contact the projections  1740  as indicated previously. 
     In  FIG. 9B , fluid level sensor  1406  is configured in a manner to interface with the tubing forming output lines  1718  above priming bulbs P, the priming volume defined by priming bulbs P, or fluid entry tubing/tubing connections C with output lines  1718  used to connect the priming bulbs P with the output lines  1718 . In the illustrated embodiment, snap mounts  1488  are eliminated in favor of the fluid sensors  1484  providing physical support for the fluid entry tubing/tubing connections C connecting the priming bulbs P with the output lines  1718  and, thereby, the priming bulbs P themselves. Fluid sensors  1484  are operable, depending of the sensed location, to determine the presence or absence of fluid in output lines  1718 , the priming bulbs P themselves, or the fluid entry tubing/tubing connections C connecting the priming bulbs P with the output lines  1718  and, thus, the presence or absence of fluid in the priming bulbs P. Priming bulbs P shown in  FIGS. 9B and 10B  are operable in a conventional manner to displace air bubbles from the medical tubing forming output lines  1718  and desirably displace a volume greater than the volume between the priming bulbs P and spikes  1717 . 
     As shown in  FIGS. 9A-9B , the fluid control module  1400  includes a peristaltic pump  1408  that is associated with the secondary fluid container  1706 . The peristaltic pump  1408 , or an equivalent device, is used to deliver fluid from the secondary fluid container  1706  to a patient typically between fluid injections from the primary fluid container  1704 , which are delivered via the syringe  1702  and the injector  1300 . The peristaltic pump  1408  is generally adapted to deliver a set flow rate of the secondary fluid, for example saline, to the patient via the second section  1720  of the fluid path set  1700 . The peristaltic pump  1408  may be a conventional pump known in the art. 
     The details of the peristaltic pump  1408  are shown in  FIGS. 9A-9B, 27, and 28 . Generally, the peristaltic pump  1408  includes a pump head  1496 , a base plate  1497  for mounting the pump head  1496  to the front portion or side  1426  of the housing  1402 , and an enclosure or door structure  1498  for enclosing the pump head  1496 . Mechanical fasteners  1499  may be used to secure the pump head  1496  to the base plate  1497 , and may further be used to secure the base plate  1497  to the front side  1426  of the housing  1402 . 
     As shown in  FIGS. 20 and 21 , the front side  1426  of the housing  1402  preferably includes opposing guides  1500 ,  1502  located above and below the peristaltic pump  1408  for securing medical tubing generally used to connect the secondary fluid container  1706  to the second section  1720  of the fluid path set  1700  via the peristaltic pump  1408 . In particular, with particular reference to  FIGS. 10A-10B , the output line  1718  from the drip chamber  1716  associated with the secondary fluid container  1706  is associated with the peristaltic pump  1408 , and may be secured in operative engagement with the peristaltic pump  1408  using the opposing guides  1500 ,  1502 . The guides  1500 ,  1502  may be integrally formed with the front side or portion  1426  of the housing  1402  and generally define L-shaped slots  1503 , which are generally adapted to receive the medical tubing forming the output line  1718 .  FIGS. 9A-9B  illustrate the use of the guides  1500 ,  1502 , with the medical tubing extending from the secondary fluid container  1706  and associated with peristaltic pump  1408  received in the guides  1500 ,  1502  in accordance with the present invention. The door structure  1498  of the peristaltic pump  1408  may be adapted to prevent gravity flow from the secondary fluid container  1706  when the peristaltic pump  1408  is not in operation, and further secures the output line  1718  in operative association with the pump head  1496 , as is conventional in the art. 
     Referring further to  FIG. 28 , the shut-off or pinch valve  1410  of the fluid control module  1400  is shown. The pinch valve  1410  is provided downstream of the peristaltic pump  1408  and is used as back-up fluid shut-off mechanism to discontinue fluid flow to the second section  1720  of the fluid path set  1700  when the peristaltic pump  1408  ceases operation. The pinch valve  1410  is adapted to open for fluid flow during operation of the peristaltic pump  1408 , and is further adapted to automatically close when the peristaltic pump  1408  ceases operation to prevent air from being introduced into the second section  1720  of the fluid path set  1700 . The pinch valve  1410  generally prevents gravity flow to the second section  1720  of the fluid path set  1700  when the peristaltic pump  1408  is not in operation, and is generally provided as a back-up shut-off mechanism to the peristaltic pump  1408 . The pinch valve  1410  may be a conventional pinch valve, such as that manufactured by Acro Associates. The pinch valve  1410  is mounted to the front side or portion  1426  of the housing  1402  by a bracket  1504  and mechanical fasteners  1505 . A gasket  1506  may be used to seal the connection between the pinch valve  1410  and the front side or portion  1426  of the housing  1402 . 
     Referring further to  FIGS. 29-31 , the air detector assembly  1412  of the fluid control module  1400  is shown in greater detail. The air detector assembly  1412  is adapted to detect gross air columns that may be present in the output line  1718  connected to the drip chamber  1716  associated with the secondary fluid container  1706 , and the output line  1719  associated with the multi-position valve  1712 . The air detector assembly  1412  is generally adapted to initiate a signal to the computer hardware/software associated with the fluid control module  1400  and/or injector  1300 , if gross air is detected in the medical tubing forming the output line  1719  associated with the multi-position valve  1712  or in the medical tubing forming the output line  1718  and further associated with the peristaltic pump  1408 . The fluid control module  1400  and injector  1300  are preferably adapted to discontinue any on-going fluid injection procedures if the air detector assembly  1412  detects gross air in the output line  1718  or the output line  1719 . 
     The air detector assembly  1412  generally includes a sensor section  1508  and a retaining device  1510  for securing the medical tubing forming the output line  1718  and output line  1719 . The sensor section  1508  generally includes two air column detectors  1512  adapted to detect the presence of gross air in the medical tubing secured by the retaining device  1510 . The air column detectors  1512  may be conventional air detectors such as those manufactured by Zevex. The sensor section  1508  may be secured to the retaining device  1510  with mechanical fasteners  1513 . 
     The retaining device  1510  is generally adapted to secure the medical tubing forming the output line  1718  and output line  1719  in operative association with the air column detectors  1512 . The retaining device  1510  generally includes a base  1514  and a closure assembly  1516  associated with the base  1514 . The sensor section  1508  is secured to the base  1514  with the mechanical fasteners  1513 . The base  1514  defines two front openings  1518  for receiving the air column detectors  1512  and associating the air column detectors  1512  with the medical tubing. The air column detectors  1512  each define a recess  1520  for receiving the medical tubing, as shown in  FIG. 30 . 
     The closure assembly  1516  is generally adapted to secure the engagement of the medical tubing in the recesses  1520  in the air column detectors  1512 . The closure assembly  1516  is formed by two closure members or doors  1522 , which are generally adapted to move from a closed position securing the medical tubing in the recesses  1520 , to an open position permitting removal or disengagement of the medical tubing from the recesses  1520 . The closure members  1522  are pivotally connected to the base  1514  by pins  1524 , and are preferably biased to the open position by respective torsion springs  1526  associated with the pins  1524 . The closure members  1522  may include projections  1528  that cooperate at least partially with the recesses  1520  in the air column detectors  1512  to secure the medical tubing in the recesses  1520  when the closure members  1522  are in the closed position. The closure members  1522  are preferably formed of a substantially clear plastic material to permit viewing of the medical tubing in the recesses  1520  when the closure members  1522  are in the closed position. 
     A releasable locking mechanism or device  1530  may be associated with the retaining device  1510  for securing the closure members  1522  in the closed position. The locking mechanism  1530  is provided to counteract the biasing force of the torsion springs  1526 . The locking mechanism  1530  includes two sliders  1532  that are spring-loaded by a spring  1533 . The closure members  1522  generally engage the sliders  1532 , as shown in  FIG. 30 , and push against the spring-force to allow the closure members  1522  to move past the sliders  1532 , and then allow the sliders  1532  to engage the closure members  1522  to hold the closure members  1522  in the closed position. The sliders  1532  may be retracted against the spring-force by two buttons  1534  located on opposing sides of the base  1514 . By depressing the buttons  1534 , the sliders  1532  are retracted, which allows the closure members  1522  to spring open under the biasing force of the torsion springs  1526 . A cover plate  1535  may enclose the sliders  1532  of the locking mechanism  1530 . 
     The base  1514  may include recessed structures  1536  located below the front openings  1518  that are adapted to engage the first and second connector members  1774 ,  1776  of the connectors  1708  in the fluid path set  1700  when the closure members  1522  are in the closed position. In particular, the closure members  1522  generally secure the first and second connector members  1774 ,  1776  to the recessed structures  1536  when the closure members  1522  are in the closed position, thereby preventing their movement when the first and second connector members  1774 ,  1776  being joined and allowing one-handed connection of these parts. The recessed structures  1536  are adapted to engage the bodies of the first and second connector members  1774 ,  1776 , so that first and second connector members  1774 ,  1776  in the connectors  1708  of the fluid path set  1700  may be joined or connected with a one-handed operation. Thus, the recessed structures  1536  are generally adapted to prevent rotation of the first and second connector members  1774 ,  1776  when engaged with the recessed structures  1536 , so that the corresponding mating components to be connected to the “engaged” first or second connector member  1774 ,  1776  may be joined to the engaged first or second connector member  1774 ,  1776  without having to use two hands to manipulate the opposing connecting members. 
     The installation and operation of the fluid delivery system  1200  will now be discussed. Prior to turning on the fluid delivery system  1200 , a source of power, such as 110 or 220 volts of electricity sent through a line cord from a wall socket (not shown) is provided to the fluid delivery system  1200 . Thereafter, the operator turns on a master power switch (not shown), preferably situated on either the fluid control module  1400  or the injector  1300  of the fluid delivery system  1200 . The fluid delivery system  1200  responds through visual indicia, such as the illumination of a green light (not shown) on the fluid control module  1400  or the injector  1300 , to indicate that the fluid delivery system  1200  is in a powered-up state. The operator then turns on the user display  210  (See  FIG. 2 ) via a user display switch (not shown). It is to be understood that the user display  210  may be turned on prior to the fluid delivery system  1200 . After power has been supplied to the user display  210 , the fluid delivery system  1200  responds by undergoing various self-diagnostic checks to determine if the fluid delivery system  1200  exhibits any faults or conditions that would prevent proper operation of the fluid delivery system  1200 . If any of the self-diagnostic checks fail and/or a fault is detected in the fluid delivery system  1200 , a critical error window or screen is displayed on the user display  210 , which may instruct the operator to contact service personnel to remedy the fault or instruct the operator on how to remedy the fault himself or herself. Additionally, the fluid delivery system  1200  will not allow an operator to proceed with an injection if any of the self-diagnostic checks have failed. However, if all self-diagnostic checks are passed, the fluid delivery system  1200  proceeds to display a main control screen on the user display  210 . 
     The main control screen includes various on-screen controls, such as buttons, that may be accessed by the operator via the touch-screen of the user display  210 . The on-screen controls may include, but are not limited to, selectable options, menus, sub-menus, input fields, virtual keyboards, etc. The operator may therefore utilize the touch-screen of the user display  210  to program one or more injection cycles of the fluid delivery system  1200 , and to display performance parameters. It is to be understood that input to the user display  210  may also be accomplished by providing an on-screen cursor and external pointing device, such as a trackball or mouse, that is operatively associated with the on-screen cursor. It is to be understood that the operator may stop any automatic functions of the fluid delivery system  1200  by touching an “Abort” button or anywhere on the user display  210 . 
     Desirably, the main control screen includes a “New Case Setup” button, that when touched, initiates a “New Case Setup” screen to be displayed on the user display  210 . In a practical sense, a “new case” is representative of one or more injections for a specific patient and, therefore, having specific parameters inputted and associated therewith. The operator touches the “New Case Setup” button and, subsequently, the resultant “New Case Setup” screen displays a “Multi-Patient Syringe” button. After touching the “Multi-Patient Syringe” button, the operator is presented with a screen displaying a “Retract” button and an “Engage Plunger” button displayed thereon. The operator touches the “Retract” button and the fluid delivery system  1200  retracts the piston associated with the injector  1300 . The operator may then remove the syringe  1702  from its package, orient the syringe  1702  to fit the pressure jacket assembly of the injector  1300 , and place the syringe  1702  into the pressure jacket of the pressure jacket assembly. During the course of the syringe installation, the “Multi-Patient Syringe” screen remains on the user display  210 . Thus, after loading the syringe  1702  properly in the pressure jacket assembly, the operator touches the “Engage Plunger” button, which causes the injector piston to move forward. The fluid delivery system  1200  continues to move the injector piston forward until the injector piston engages the syringe plunger in the syringe  1702 , and mechanically locks thereto. An audible clicking noise is produced to indicate a secure coupling between the injector piston and the syringe plunger. Thereafter, the syringe plunger travels the length of the syringe  1702  to the distal end of the syringe  1702 . The fluid delivery system  1200  may provide visual feedback of this action to the operator via the user display  210 . Thereafter, the operator rotates the injector head of the injector  1300  into an upright position to allow any air to collect at the distal end of the syringe  1702  when the syringe  1702  is subsequently filled. The user display  210  then reverts to the “New Case Setup” screen. 
     The fluid delivery system  1200  is now ready to accept the installation of the first section  1710  of the fluid path set  1700 . Specifically, the operator removes the first section  1710  from its package. The first section  1710  is preferably provided in a sterile condition in the package. The operator then touches a “Multi-Patient Section” button, which causes the user display  210  to show an image of the fluid control module  1400 , bottle holders (i.e., primary and secondary fluid containers  1704 ,  1706 ), and injector  1300 , with an overview of the first section  1710  highlighted in relation to these components. Additionally, the user display  210  also displays an “Install Saline” and an “Install Contrast” button. The operator touches the “Install Saline” button, which causes an enumerated list of actions corresponding to enumerated sections of the image relating to the first section  1710  of the fluid path set  1700 , and connecting the first section  1710  to the secondary fluid container  1706 , which typically contains saline. This enumerated list may include, but is not limited, to actions such as (1) Install saline tubing (which is depicted as a button); (2) Spike saline; (3) Fill drip chamber; and (4) Finish with saline. Thereafter, the fluid control module  1400  opens the pinch valve  1410 . Next, the operator installs the saline container (i.e., secondary fluid container  1706 ). The operator now installs the drip chamber  1716  associated with the secondary fluid container  1706  into place, and then opens the peristaltic pump  1408 . The operator then routes the medical tubing forming the output line  1718  from the drip chamber  1716  through the peristaltic pump  1408  into the pinch valve  1410  and into the air detector assembly  1412 . Then, the operator closes the peristaltic pump  1408 . The text on the “Close Saline Tubing” button changes to read “Install Saline Tubing.” Then, the operator spikes the secondary fluid container  1706  with spike  1717 , fills the drip chamber  1716  by squeezing or “priming” it, and touches a “Complete” button. The fluid control module  1400  now closes the pinch valve  1410 . The user display  210  may provide visual indicia, such as a darkening of the saline portion, to indicate that the saline installation is completed successfully. Then, the operator touches the “Install Contrast” button, which causes an enumerated list of actions corresponding to enumerated sections of the image relating to the contrast to be displayed. This enumerated list may include, but is not limited to actions such as: (1) Install contrast (which is depicted as a button); (2) Attach high pressure line (i.e., input line  1721 ) to syringe; (3) Spike contrast; (4) Fill drip chamber; and (5) Finish with contrast. Accordingly, the operator hangs the contrast bottle (i.e., primary fluid container  1704 ) and touches the “Install Contrast” button. Thereafter, the fluid control module  1400  turns the valve actuator  1404  to the inject position. The operator now installs the drip chamber  1716  associated with the primary fluid container  1706  in place in the fluid level sensing mechanism  1406 , the multi-position valve  1712  in the valve retainer  1469  in the housing  1470 , and the output line  1718  in the air detector assembly  1412 . Then, the operator closes the air detector assembly  1412 . Thereafter, the operator attaches the high pressure input line  1721  to the multi-position valve to the syringe  1702 . Next, the operator spikes the primary fluid container  1704 , fills the drip chamber  1716  by squeezing or “priming” it, and touches a “Complete” button. The user display  210  may provide visual indicia, such as a darkening of the contrast portion, to indicate that the contrast installation is completed. It is to be understood that the installation of the “contrast portion” and “saline portion” of the first section  1710  may be performed in parallel instead of serially. Furthermore, the order of installation between the contrast portion and the saline portion of the first section  1710  may be reversed. Moreover, the internal sequence for installing the contrast portion and the saline portion may vary in numerous ways in accordance with the present invention. 
     The syringe  1702  may now be initially filled with contrast media from the primary fluid container  1706 . Specifically, the operator touches a “Fill Contrast” button on the user display  210 , which causes the fluid delivery system  1200  to enter an auto-fill mode, and to place the multi-position valve  1712  in the fill position. After verifying that there is sufficient contrast media in the contrast drip chamber  1716  to initiate the fill process, the fluid delivery system  1200  moves the injector piston proximally at a controlled rate, such as 3 mL/s, which causes contrast media to be drawn from the primary fluid container  1704 . The fluid delivery system  1200  may provide visual feedback of this action to the operator via the user display  210 . Thus, the fluid delivery system  1200  may display on the user display  210  the current volume in the syringe  1702  based upon the position of the injector piston. The fluid delivery system  1200  proceeds to draw contrast until a predetermined event occurs, such as the total remaining volume in the syringe  1702  reaches a preset or pre-chosen amount or the contrast media volume in the primary fluid container  1706  is depleted completely. The multi-position valve  1712  is then turned to the closed or isolate position by the fluid delivery system  1200 . 
     The fluid delivery system  1200  is now configured to undergo a purge of any air in the tubing of the first section  1710  of the fluid path set  1700 . Specifically, the operator removes the protective caps  1798  from the first section  1710 . Thereafter, the operator touches a “Purge Contrast” button on the “New Case Setup” screen, which causes the fluid delivery system  1200  to move the multi-position valve  1712  to the inject position. Then, the fluid delivery system  1200  moves the injector piston forward at a predetermined rate, such as 1.0 to 1.5 mL/s, which causes any gas or liquid to be discharged from the syringe  1702 , and the first section  1710 . The operator ensures that the discharged fluid is caught manually in a suitable container. After the operator is satisfied that all or most of the visible air is discharged, the operator touches the “Purge Contrast” button again to stop the purge. However, if the operator does not manually stop the purge, the fluid delivery system  1200  may stop the purge automatically, for example, once 5 mL of liquid or air is purged, based upon the relative injector piston movement. The operator may facilitate the removal of any remaining trapped air by tapping the body of the pressure jacket, joints, valves, and medical tubing in the first section  1710 . It is to be understood that the purging operation may be repeated as necessary to ensure that all air is expelled from the syringe  1702  and the first section  1710 . Thereafter, the operator touches a “Complete” button, which causes the multi-position valve  1712  to move to the closed or isolate position, thereby stopping the flow of contrast media. The fluid delivery system  1200  then causes the user display  210  to return to the “New Case Setup” screen. The operator may now install a new set of protector caps  1798  to the exposed ends of the first section  1710 . 
     The fluid delivery system  1200  now may undergo a purge of any air in the saline portion of the first section  1710 . Specifically, the operator touches a “Purge Saline” button on the “New Case Setup” screen, which causes the fluid delivery system  1200  to open the pinch valve  1410 , and turn on the peristaltic pump  1408 . Saline from the secondary fluid container  1706  begins to flow at a predetermined flow rate, such as 1.25 mL/s, which causes any gas or liquid to be discharged from the first section  1710 . The operator ensures that the discharged fluid is caught manually in a suitable container. After the operator is satisfied that all or most of the visible air is discharged, the operator touches the “Purge Saline” button again to stop the purge. However, if the operator does not manually stop the purge, the fluid delivery system  1200  may stop the purge automatically after, for example, 5 seconds have passed since the initiation of the purge. The operator may facilitate the removal of any remaining trapped air by manually tapping the joints, valves, and tubing in the first section  1710 . It is to be understood that the purging operation may be repeated as necessary to ensure that substantially all air, particularly gross air, is expelled from the first section  1710 . Thereafter, the operator touches a “Complete” button, which causes the user display  210  to return to the “New Case Setup” screen. It is to be understood that the order of purging the contrast and saline portions of the first section  1710  may be reversed. 
     At this point, the fluid delivery system  1200  is ready to accept the installation of the second section  1720  of the fluid path set  1700 . Specifically, the operator removes the protector caps  1798  from the first section  1710  and removes the second section  1720  from its package. Then, the operator may secure the patient end of the second section  1720  to an imaging table or other securing point. The operator then removes the protector caps  1798  from the second section  1720 . Thereafter, the operator connects the connectors  1708  associated with the first and second sections  1710 ,  1720  to fluidly connect these sets or sections. In particular, the operator attaches the male connector of the low-pressure saline tubing to the female connector of the first section  1710  and attaches the female contrast connector of the high-pressure contrast tubing to the male connector of the first section  1710 . It is to be understood that the order of connecting the low pressure saline tubing and the high pressure contrast tubing to their respective connectors  1708  may be reversed. The operator may now optionally place a sterile cover (not shown) on the user display  210  to maintain a sterile environment. 
     The fluid delivery system  1200  is now configured to undergo a purge of any air in both the contrast portion (i.e., contrast lines), and saline portion, (i.e., saline lines), of the first section  1710  and the second section  1720 . To purge the air in the contrast portion, the operator removes a cap (not shown) on the pressure isolation port  1761 . The operator then touches the “Purge Contrast” button on the user display  210 , which causes the fluid delivery system  1200  to move the multi-position valve  1712  to the inject position. The contrast begins to flow through the contrast tubing, to fill the pressure isolation mechanism  1722 , and then to flow out of the pressure isolation port  1761 . The operator then touches the “Purge Contrast” button again to stop the purge. However, if the operator does not manually stop the purge, the fluid delivery system  1200  may stop the purge automatically, once a predetermined amount, for example 5 mL, of fluid or air is purged, based upon the relative piston movement. When the purge is complete, the fluid delivery system  1200  moves the multi-position valve  1712  to the closed position. The operator then attaches a pressure transducer (See  FIGS. 7B-7F ) or line to the pressure isolation port  1761 . The operator initiates a contrast purging by touching the “Purge Contrast” button on the user display  210 , which causes the fluid delivery system  1200  to move the multi-position valve  1712  to the inject position. The contrast begins to flow through the pressure isolation port  1761  and pressure transducer. Subsequently, the operator turns the transducer multi-position valve  1712  to the inject position. The fluid delivery system  1200  then moves the injector piston forward at a predetermined rate, such as 1.0 to 1.5 mL/s, which causes any gas or liquid to be discharged from the syringe  1702 , first section  1710 , and the second section  1720 . The operator ensures that the discharged fluid is caught manually in a suitable container. After the operator is satisfied that all or most of the visible gross air is discharged, the operator touches the “Purge Contrast” button again to stop the purge. However, if the operator does not manually stop the purge, the fluid delivery system  1200  may stop the purge automatically, once a predetermined amount, for example 5 mL, of fluid or air is purged, based upon the relative piston movement. When the purge is complete, the fluid delivery system  1200  moves the multi-position valve  1712  to the closed position. The operator may facilitate the removal of any remaining trapped air by manually tapping the pressure isolation mechanism  1722 , connectors, valves, and tubing in both the first section  1710  and the second section  1720 , and adjusting the second multi-position valve  1730  as necessary. It is to be understood that the purging operation may be repeated as necessary to ensure that all gross air has been expelled from the fluid path set  1700 . 
     To purge the air in the saline portion, the operator touches the “Purge Saline” button, which causes the fluid delivery system  1200  to open the pinch valve  1410  and turn on the peristaltic pump  1408 . Saline from the secondary fluid container  1706  begins to drip at a predetermined flow rate, such as 1.25 mL/s, which causes any air in the saline portion of the fluid path set  1700  to be expelled. The operator ensures that the discharged saline is manually caught in a suitable container. After the operator is satisfied that all or most of the visible air is discharged, the operator touches the “Purge Saline” button again to stop the purge. However, if the operator does not manually stop the purge, the fluid delivery system  1200  may stop the purge automatically after, for example, 5 seconds have passed since the initiation of the purge. The operator may facilitate the removal of any remaining trapped air by manually tapping the various components of the fluid path set  1700  in the manner discussed previously. It is to be understood that the purging operation may be repeated as necessary to ensure that all air is expelled from the fluid path set  1700 . Thereafter, the operator touches the “Complete” button, which causes the display to return to the “New Case Setup” screen. It is to be understood that the order of purging the contrast portion and then the saline portion of the fluid path set  1700 , may be reversed. 
     The fluid delivery system  1200  may be configured to allow an operator to purge the contrast and saline portions of the fluid path set  1700  line by utilizing the hand controller  400  as opposed to solely utilizing the on-screen controls. Furthermore, it is to be understood that the hand controller  400  may be connected to the fluid control module  1400  at any time during the installation of the fluid delivery system  1200 . Specifically, the connector end of the hand controller connector secures to the hand controller plug of the fluid control module  1400 . Connection of the hand controller  400  may cause an icon representing the connected hand controller  400  to be displayed on the user display  210 . A preferred embodiment of the hand controller  400  is disclosed in U.S. Patent Application Publication No. 2005/0273056, the contents of which are incorporated herein by reference in its entirety. 
     With reference to  FIG. 34-36 , the operator may utilize a setup wizard interface  1801  to aid in the installation and operation of the fluid delivery system  1200 . Specifically, the setup wizard interface  1801  allows the operator of the fluid delivery system  1200  to follow graphical representations and textual instructions concerning the installation of various components and steps to be followed in ensuring proper operation of the fluid delivery system  1200 . The exemplary setup wizard interface  1801  is accessed from the main control screen and is displayed on the user display  210 . The setup wizard interface  1801  may be divided into distinct portions, such as a graphical portion  1802 , an instructional portion  1804 , and an individual component and process setup portion  1806 . The individual component and process setup portion  1806  may include a series of on-screen buttons such as a “Multi-Patient Syringe” button, a “Multi-Patient Section” button, and a “Single Patient Section” button, relating to respective components of the fluid delivery system. Additionally, the individual component setup and process setup portion  1806  may include another series of buttons such as a “Fill Syringe” button, a “Purge Contrast” button, and a “Purge Saline” button, relating to respective processes of the fluid delivery system  1200 . Desirably, each of these buttons maintains a series of corresponding instructions associated therewith, that display within the instructional portion  1804  of the setup wizard when the respective button is selected. The instructions displayed within the instructional portion  1804  may also reference related portions of the fluid delivery system  1200 , or parts thereof that are graphically depicted within the graphical portion  1802 . Furthermore, the instructions of the instructional portion  1804  may also contain embedded buttons associated with other instructions for components or installation procedures related thereto. When these additional buttons are selected, the instructions associated therewith are then displayed in the same instructional portion  1804 . For example, if the operator selects an “Install Saline Tubing”  1808  button, as shown in  FIG. 35 , the instructions associated therewith, namely: (1) Install drip chamber; (2) Open pump door; (3) Install saline line; (4) Close pump door; (5) Spike saline bag; and, (6) Fill drip chamber, appear within the instructional portion  1804 , as shown in  FIG. 36 . The instructional portion  1804  may also display related tips, warnings, or advisements. For example, a message informing the operator that the patient must be disconnected prior to engagement of the plunger, displays beneath the “Engage plunger” instruction, as shown in  FIG. 34 . 
     As shown in  FIGS. 34-36 , the setup wizard interface  1801  is laid out such that certain instructional portions  1804  of the pre-injection setup sequence may be bypassed depending upon the operator&#39;s familiarity with the setup of the fluid delivery system  1200 . Thus, the operator need not follow the instructions provided by the setup wizard interface  1801  in a linear fashion. For example, a novice operator may want to proceed linearly with the instructions for setup, whereas a more skilled operator may want to view only instructions regarding setup of specific components and installation steps of the fluid delivery system  1200 . The setup wizard interface  1801 , therefore, efficiently conveys the requisite information for proper setup of the fluid delivery system  1200  to operators of various degrees of familiarity and knowledge of the fluid delivery system  1200 . 
     Once the necessary components of the fluid delivery system are properly installed, the operator of the fluid delivery system  1200  may administer either a fixed rate injection or a variable rate injection in conjunction with a saline flush delivery. The user display allows the operator to input various data relating to each type of injection to be administered. Additionally, the user display  210  preferably provides visual and/or audio feedback during the delivery of the contrast in the injection cycle including, but not limited to, values corresponding to the flow rate, volume, and pressure limit relating to that particular injection cycle. It is to be understood that values displayed on the display  210  unit may be dynamic, such that with each varying plunger depression of the hand controller  400 , new values for the flow rate, volume, and pressure limit may be displayed on the user display. 
     The fluid delivery system  1200  provides for various modes of refilling the syringe once the fluid delivery system  1200  determines that there is insufficient contrast media to perform an injection. A full automatic type refill is defined as a refill that occurs after the initial filling of the syringe  1702 . The full automatic type of refill automatically fills the syringe  1702  with a maximum volume of contrast media that the syringe  1702  may hold, for example, 150 mL. Thus, in a full automatic type refill, refill commands are automatically given from the user display  210  without any operator intervention. A predetermined automatic type of refill fills the syringe  1702  with a predetermined operator specified volume, for example 25, 50, 75, or 100 mL. Thus, if there is insufficient contrast in the syringe  1702  to complete the next injection, the operator is prompted for permission by the user display as to whether or not the fluid delivery system should be allowed to initiate a refill to the predetermined volume. A manual type of fill allows the operator to fill the syringe  1702  by utilizing the on-screen controls, whenever the operator deems a refill to be necessary. Thus, a manual type fill includes a start and stop refill function associated therewith. However, the manual fill is still subject to programming of the fluid delivery system  1200  and the operator, in the manual fill mode, will be selecting from a menu of fill levels rather than an independently chosen level. Prior to each injection, the operator may indicate to the fluid delivery system  1200  which refill type is to be used when additional contrast is required to finish an injection. Once a refill type is selected, the refill type remains in place until changed by the operator. In an exemplary embodiment, the operator may touch a “Protocol” button on the main control screen to display a protocol screen with an “Options” button displayed thereon. The operator touches the “Options” button, which causes a list of options to appear, such as a “Refill Type” button. After touching the “Refill Type” button, the operator is typically presented with three refill types, namely (1) Full Automatic, for example to 150 mL; (2) Predetermined, for example 25, 50, 75, or 100 mL; and, (3) Manual. If the operator selects the full automatic refill, then a pop-up window confirming the automatic refill request may appear. If the operator selects the predetermined refill, a list of fill volumes appears, which requires the operator to choose from one of the fill volumes. Desirably, the fill volumes are listed in manageable 25 mL increments, as an example. If the operator selects the manual refill, then a pop-up window confirming the manual refill request may appear. Once the operator is satisfied with using a particular refill type for the instant injection cycle, the operator may then confirm the use of this refill type by touching another confirmation button, such as an “OK” button. 
     The fluid delivery system  1200  may maintain pre-programmed fluid delivery programs, (i.e., protocols), stored therein. Thus, instead of manually entering the desired flow rate, volume, pressure limit, rise time, and optionally delay for each injection cycle, the operator may program and store protocols, and recall previously stored protocols corresponding to injection elements, such as the desired flow rate, volume, pressure limit, rise time, and optionally delay. In an exemplary embodiment, a protocol is programmed and recalled via the on-screen controls of the user display  210 . Specifically, the operator navigates to the protocol screen by touching, for example, the “Protocol” button, if not there already. Thereafter, the operator touches a “Fixed Flow” or “Variable Flow” mode button, which indicates whether a protocol relating to a fixed or variable flow injection, respectively, will be programmed. It is to be understood that not all injection elements may be changed by the operator when entering values relating to the variable flow injection. 
     A pop-up window confirming the request to enter into programming mode may appear, which requires the operator to confirm the request. The operator then touches a flow rate button. Visual indicia, such as inversing the color of the button, may indicate that indeed this or any button was touched by the operator. A parameter range for the allowable flow rate is displayed, along with the virtual numeric keyboard for entering the flow rate. The operator enters the desired flow rate and may touch a confirmation button, such as “Enter” to confirm the entered flow rate. Next, the operator touches a volume button. A parameter range for the allowable volume is displayed, along with the virtual numeric keyboard for entering the volume. The operator enters the desired volume and may confirm the volume by touching the “Enter” button. Then, the operator touches a pressure limit button. A parameter range for the allowable pressure range is displayed, along with the virtual numeric keyboard for entering the pressure. The operator enters the desired pressure and may confirm the pressure by touching the “Enter” button. Then, the operator touches a “Rise” button. A parameter range for the allowable rise time is then displayed, along with the virtual numeric keyboard for entering the rise time. The operator enters the rise time and may confirm the rise time by touching the “Enter” button. It is to be understood that any of the above values be entered in varying orders. The fluid delivery system  1200  is programmed to alert the operator if a requested command or entered value is outside the predefined parameters. This alert may be accomplished through either audio or visual indicia, such as a beep or an on-screen alert message, respectively. 
     After entering the appropriate values for a protocol, the operator may store the protocol into any available memory position of the fluid delivery system  1200  for future use of the protocol in other injection cycles with other patients. Specifically, the operator touches a “Store” button. The virtual alphanumeric keyboard for entering a name for the corresponding protocol is displayed. The operator may enter an appropriate name and confirm the name by touching the “Enter” button. 
     The operator may recall any previously stored protocol from the memory of the fluid delivery system  1200 . For example, the operator may navigate to the protocol screen by touching a “Protocol” button, if not already there. Thereafter, the operator touches a “Recall” button. The fluid delivery system displays a screen showing all available, saved, preprogrammed protocols. The operator may recall, or select any of the protocols by touching the corresponding button of the protocol. Accordingly, the fluid delivery system displays the values associated with that particular protocol, as previously stored in memory. If the operator is satisfied with using this protocol for the instant injection cycle, the operator may confirm the use of this protocol by touching another confirmation button, such as an “OK” button. 
     Once the appropriate protocol is selected and is initiated with the fluid delivery system  1200 , the corresponding fixed rate injection or a variable rate injection may be performed. It is to be understood that either the fixed rate or the variable rate injections may be performed by the hand controller  400 . Alternatively, injections may be performed directly through the on-screen controls of the user display  210 , bypassing the need for the hand controller  400  or the foot pedal. 
     In an exemplary embodiment, the fixed rate injection is initiated by the operator by depressing the plunger on the hand controller  400 . Subsequently, the air detector assembly  1412  turns on and begins to monitor for any air within the lines. The multi-position valve  1712  rotates to the inject position. The injector piston accelerates to a programmed rate in the rise time allotted. The contrast media flows until either the operator releases the plunger or the programmed volume, as specified by the protocol, is delivered. After any of these conditions has been met, the injector piston ceases forward movement. Then the multi-position valve  1712  rotates to a closed or isolate position preferably after a set period of time to allow residual contrast media to exit the syringe  1702 , and the air detector assembly  1412  enters into a sleep-mode. 
     In an exemplary embodiment, the variable rate injection is initiated by the operator by depressing the plunger on the hand controller  400 . Subsequently, the air detector mechanism  1412  turns on to monitor for any air within the lines. The multi-position valve  1712  rotates to the inject position. The injector piston moves forward corresponding to a percentage of an acceleration rate as determined by the position of the plunger of the hand controller  400 . The contrast flows until either the operator releases the plunger or the programmed volume, as specified by the protocol, is delivered. After any of these conditions is met, the injector piston ceases forward movement. Thereafter, the multi-position valve  1712  preferably remains open for a preset or predetermined amount of time, to allow residual contrast media to exit the syringe  1702 . Then, the multi-position valve  1712  rotates to a closed position. If the entire programmed volume is delivered in a variable flow rate mode, then the injector  1300  rearms. If the operator releases the hand controller actuating member or assembly before the entire programmed volume is delivered, the multi-position valve  1712  remains open for the predetermined amount of time and then closes. It is to be understood that at the end of each variable rate injection, the fluid delivery system  1200  creates a sharp bolus within the contrast tubing downstream of the multi-position valve  1712 , by suppressing the delivery of contrast media that is not delivered at the programmed flow rate. A sharp bolus of contrast media may be defined as a distinct or defined column of liquid having well-defined opposing ends or boundaries. However, the creation of the sharp bolus results in pressure buildup upstream of the multi-position valve  1712 . To remove the excess pressure, the multi-position valve  1712  may have a simple vent for expelling liquid and relieving the excess pressure. Alternatively, the injector piston may be moved slowly backward or proximally in a controlled manner, so that no vacuum is created in the contrast tubing, and so that no audible sound, such as a whizzing sound, is produced. Desirably, this result is accomplished by having the fluid delivery system  1200  turning the voltage applied to the injector head motor on and off in short increments, thereby creating a controlled sequence of release/stop movements of the injector piston until the pressure in the syringe  1702  is equalized. After the pressure drops to the system friction of the fluid delivery system  1200 , which is mostly comprised of the static friction between the syringe plunger and the syringe  1702  and the internal mechanical components of the injector head of the injector  1300 , the fluid delivery system  1200  is ready for another injection. This process is repeated until the programmed volume has been delivered. Thereafter, the air detector assembly  1412  enters into a sleep-mode. 
     The saline flush delivery or injection may be performed at any time during the injection cycle, except when contrast is flowing. In an exemplary embodiment, initiating the saline injection requires the operator to depress the saline actuator or saline button of the hand controller  400 . Subsequently, the air detector assembly  1412  of the fluid control module  1400  turns on to monitor for any air in the medical tubing associated with the saline portion of the fluid path set  1700 . The pinch valve  1410  retracts to allow for the flow of saline from the secondary fluid container  1706 . The fluid delivery system  1200  may be configured to permit the flow of saline until the operator releases the saline button on the hand controller  400 , presses the saline button again, or until a predetermined amount of time lapses from the initiation of the flow of saline. The saline flow stops once movement in the peristaltic pump  1408  ceases. Thereafter, the pinch valve  1410  moves to a closed position and the air detector assembly  1412  enters into a sleep-mode. 
     During either the fixed rate injection cycle or the variable rate injection cycle, the fluid delivery system  1200  may display an instantaneous average value for a corresponding flow rate, fluid pressure, volume delivered for the most recent individual injection within the injection cycle, and a cumulative volume delivered to the patient, up to and including, the most recent injection. At the conclusion of the delivery, the fluid delivery system  1200  may display a peak flow rate, a peak fluid pressure, a volume delivered for the most recent individual injection within the injection cycle, and a cumulative volume delivered to the patient during the entire delivery. 
     It is to be understood that the fluid delivery system may exist in either an armed or unarmed state, which corresponds respectively to whether or not the operator is allowed to perform an injection. The fluid delivery system  1200  may enter a disarmed or safe state when certain conditions are met including, but not limited to, failure of a self-diagnostic check, detection of air in either the contrast or saline portions of the fluid path set  1700 , absence of some of the requisite components, and the reaching of a pressure limit that is deemed to be unsafe for the patient. The converse of these conditions and/or other factors must be present for the fluid delivery system  1200  to enter the armed state. The fluid delivery system  1200  may provide various visual and/or audible alarms to the operator to identify specific conditions that arise during the functioning of the fluid delivery system  1200 . Such conditions may include, but are not limited to the arming/disarming of the fluid delivery system  1200  and the state thereof, the detection of air in the fluid path, the insufficiency or unavailability of fluid in the fluid delivery path or fluid supply to perform an injection, and the reaching of a pressure disarm limit. 
     With reference to  FIGS. 32 and 33  and with continuing reference to  FIG. 9 , the support assembly  1600  of the fluid delivery system  1200  includes a support arm  1602  for supporting the control section  1800  and the user display  210  in particular. A second support arm  1604  extends from a support column  1606  that generally supports the injector and fluid control module  1400 . The support arms  1602 ,  1604  are associated with a rail interface  1608  which is generally adapted to attach the fluid delivery system  1200  to a hospital bed or examination table  1610 . The support column  1606  may include a pedestal interface  1612  for attaching the fluid delivery system  1200  to a movable pedestal  1614 . As shown in  FIG. 32 , the fluid delivery system may either be attached to the examination table  1610  or the movable pedestal  1614  to provide the maximum amount of flexibility and ease in utilizing the fluid delivery system  1200 . Thus, when the fluid delivery system  1200  is mounted to the examination table  1610 , a rail mount  1616  is attached to a rail  1618  of the examination table  1610 . This allows the rail interface  1608  to be removably attached to the rail mount  1616 . Thus, the rail mount  1616  indirectly supports the user display  210 , the injector  1300 , and the fluid control module  1400 . In an alternative embodiment, as shown in  FIG. 33 , only the injector  1300  and the fluid control module  1400  are indirectly supported by the rail mount  1616 , and an additional rail mount  1616  may be utilized to independently support the user display  210  at a different location on the rail  1618  of the examination table  1610 . Returning to  FIG. 32 , the movable pedestal  1614  provides mobility to the fluid delivery system  1200  and height adjustability features. The movable pedestal  1614  includes a pedestal interface mount  1620  extending therefrom, for attaching the pedestal interface  1612  to the movable pedestal  1614 . The pedestal interface mount  1620  may be configured to interface with electrical connections from the pedestal interface  1612 . The movable pedestal  1614  further includes a base  1622  for holding loose components related to the fluid delivery system  1200  and the power cables associated therewith. A handle  1624  provides access to the interior of the base  1622 . The base  1622  may also include a power socket  1626  that interfaces with the power cables (not shown) within the base  1622 . Thus, a single external power cable (not shown) may be plugged directly into the power socket  1626  to provide sufficient power for operation of the entire fluid delivery system  1200 . The movable pedestal  1614  may also include a plurality of casters  1628  having lockable brakes  1630  and wheels  1632 . A handle  1634  may be attached to the movable pedestal  1614  to facilitate movement of the fluid delivery system  1200 . By aligning the rail interface  1608  over the rail mount  1616  and then lowering the height of the movable pedestal  1614 , the fluid delivery system  1200 , may easily be transferred from the pedestal  1614  and to the bed  1610 . It is to be understood that the aforementioned configurations are not to be considered as limiting the placement and positioning of the fluid delivery system  1200 . 
     Although the present invention has been described in detail in connection with the above embodiments and/or examples, it is to be understood that such detail is solely for that purpose and that variations can be made by those skilled in the art without departing from the invention. The scope of the invention is indicated by the following claims rather than by the foregoing description. All changes and variations that come within the meaning and range of equivalency of the claims are to be embraced within their scope.