Abstract:
The invention is a delivery catheter, e.g., a guide catheter, having an imaging element in proximity to the distal end of the catheter. Catheters of the invention are able to placement of the catheter in proximity to an ostium, thereby increasing the efficiency of contrast delivery while reducing the risk of ischemia due to blocked blood supply. The invention additionally assists in maintaining catheter position during delivery of a fluid from the catheter, resulting in better performance with less fluid. For example, a catheter of the invention can be used to produce improved fluoroscopic images with less overall contrast. This improvement reduces the risk of an allergic reaction to the contrast while decreasing the length of time for a procedure, i.e., because of a need to re-contrast.

Description:
RELATED APPLICATION 
       [0001]    The present invention claims the benefit of and priority to U.S. Provisional No. 61/783,110, filed Mar. 14, 2013, which is incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to delivery catheters, e.g., guide catheters, having imaging elements to facilitate placement of the catheter and to direct the flow of a delivered fluid. 
       BACKGROUND 
       [0003]    Catheters are tubes used to perform medical procedures, remove materials, and deliver Fluids. For example, catheters are often used in the performance of medical procedures such as coronary angiography for injecting dye, or the like, into the cardiovascular system for diagnosis. A variety of catheters are also used in various cardiovascular procedures to widen the lumen of an artery or vein which has become at least partially blocked by a stenotic lesion. 
         [0004]    In many intravascular procedures, the instruments used to perform the medical procedures are guided through the vasculature using contrast agents and real-time x-ray images, i.e., fluoroscopy. Often the contrast is introduced into the vasculature by placing a guide catheter through the heart and in proximity to an ostium (opening) leading to the coronary arteries, e.g., the left anterior descending coronary artery or the left circumflex coronary artery. In this configuration, contrast introduced via the guide catheter will be pushed through the coronary arteries with the natural pumping of the heart, thereby providing images of the arteries on the fluoroscope. 
         [0005]    Placement of the guide catheter near an ostium is a delicate task, however. If the guide catheter is too far away, flushing is less complete and less effective. This can increase the need to add more contrast and to increase the length of the flushes. This results in increased contrast loading and increased ischemic in the tissues oxygenated by the arteries. On the other hand, if the catheter completely blocks the ostium, the arteries past the ostium will also be blocked, resulting in ischemia in the tissues oxygenated by the arteries. A better method for placing guide catheters is needed. 
       SUMMARY 
       [0006]    The invention is a delivery catheter, e.g., a guide catheter, having an imaging element in proximity to the distal end of the catheter. Catheters of the invention are easier to place in proximity to an ostium, thereby increasing the efficiency of contrast delivery while reducing the risk of ischemia due to blocked blood supply. A particular benefit of the invention is that the imaging element provides visualization for initial placement of the catheter and during a procedure (including introducing flow contrast into the vessel and introduction of one or more interventional catheters through the guide catheter). The visualization allows an operator to ensure the catheter remains in a safe location during the procedure, thereby reducing risk of ischemia due to catheter placement. Because the placement of the guide catheter is visualized, an operator is better equipped to direct the flow of a fluid from the catheter, resulting in better performance with less fluid. For example, a catheter of the invention can be used to produce improved fluoroscopic images with less overall contrast. This improvement reduces the risk of an allergic reaction to the contrast while decreasing the length of time for a procedure, i.e., because of a need to re-contrast. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a generalized depiction of a catheter having distal ports for use in delivering agents, e.g., contrast agents, or guiding interventional catheters. 
           [0008]      FIG. 2  depicts a rapid-exchange configuration of a delivery catheter according to certain embodiments. 
           [0009]      FIG. 3  illustrates deployment of a guide catheter of the invention at an ostium. 
           [0010]      FIGS. 4A-4C  illustrate an alternative use of a delivery catheter of the invention in a biological lumen. 
           [0011]      FIG. 5  depicts a system for use with catheters of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    The invention is a delivery catheter having imaging elements that facilitate visualization of the vasculature and catheter placement. The visualization provided by the delivery catheter of the invention helps to direct the flow of a fluid delivered or guide an interventional catheter to a treatment site. The design of the delivery catheter is especially-suited to be used with guide catheters, such as the type used to deliver contrast agents or place interventional catheters during endovascular procedures. The imaging element is located at or near the distal end of the delivery catheter. The imaging element is a part of an imaging assembly, such an IVUS or photoacoustic imaging assembly. In certain embodiments, the imaging element is an ultrasound transducer, a piezoelectric micromachined ultrasound transducer, a capacitive micromachined ultrasound transducer, and a photoacoustic ultrasound transducer. 
         [0013]    Catheters having the described imaging elements can be any type of catheter. Catheters include any elongated intraluminal device that comprises a tube or shaft that is configured to enter a body lumen. Many catheters for endovascular procedures are around 200 cm in total length and are administered via a cannula (introducer) that has been placed in an artery (e.g., the femoral, brachial, or radial artery). Catheters can be shorter, however, e.g., between 100 and 200 cm, or longer, e.g., between 200 and 400 cm. Often a vascular catheter is delivered along a guidewire. The catheter may have a lumen running the length of the catheter to accept a guidewire (over the rail) or only a portion of catheter, typically the distal tip  410 , will have a guidewire lumen (rapid exchange). An inner lumen diameter of catheters of the invention (including over the wire and rapid exchange configurations) may be configured to receive one or more interventional catheters. 
         [0014]    In some instances, the catheters are placed with a guidewire. Access guidewires (generally “guidewires” herein) are known medical devices used in the vasculature or other anatomical passageway to act as a guide for other devices, e.g., a catheter. Typically, the guidewire is inserted into an artery or vein and guided through the vasculature under fluoroscopy (real time x-ray imaging) to the location of interest. In some procedures one or more devices are delivered over the guide wire to diagnose, image, or treat the condition. Guidewires typically have diameters of 0.010″ to 0.035″, with 0.014″ being the most common. Guidewires (and other intravascular objects) are also sized in units of French, each French being ⅓ of a mm or 0.013″. Guidewire lengths vary up to 400 cm, depending on the anatomy and work flow. The ends of the guidewire are denoted as distal (far from the user, i.e., inside the body) and proximal (near the user, i.e., outside the body). Often a guidewire has a flexible distal tip portion about 3 cm long and a slightly less flexible portion about 30 to 50 cm long leading up to the tip with the remainder of the guidewire being stiffer to assist in maneuvering the guidewire through tortuous vasculature, etc. The tip of a guidewire typically has a stop or a hook to prevent a guided device, e.g., a catheter from passing beyond the distal tip. In some embodiments, the tip can be deformed by a user to produce a desired shape. 
         [0015]    In some instances, the catheter comprises a resilient inner coil, making it possible to shape the catheter and deliver it to targeted anatomy, e.g., the heart. Such catheters are generally known as guide catheters and are often used to deliver fluids, e.g., contrast agents to critical areas, or to deliver the catheter to tortuous locations, such as vasculature or the heart. Because the catheters are rather narrow, e.g., typically 8 French or less, it is also possible to guide a second catheter, for example, an imaging or therapeutic along the guide catheter to a desired location along the guide catheter. 
         [0016]    An embodiment of a catheter system  10  for use with the invention is shown in  FIG. 1 .  FIG. 1  is merely exemplary, as many other configurations of the catheter system  10  are possible to achieve the principles of the invention. The catheter system  10  includes a guide catheter  12  having a catheter body  14  with a proximal end  16  and a distal end  18 . A luminal opening at the distal end  18  allows a fluid to be delivered to a patient or an interventional catheter to be placed at a target location. Catheter body  14  is flexible and defines a catheter axis  15 , and may include multiple lumens, such as a guidewire lumen, an inflation lumen, and a fluid delivery lumen. Catheter  12  includes an imaging element  19 , proximal to the distal end  18 , and a housing  29  adjacent proximal hub  16 . Typically, the imaging element  19  is placed on the external surface of the catheter body  14 . Although, the imaging element  19  may also be placed, for example, within catheter body  14 . In certain embodiments, the imaging element  19  is placed in a ring array around the catheter body  14 . In this manner, the imaging element surrounds one or more lumens of the catheter body. Preferably, the imaging element  19  is located right next to the distal end of  18 . Ideally, the distal end  18  is less than 1 cm from the imaging element, preferably now more than a few millimeters. Minimal distance d between the imaging element  19  and the distal end  18  allows the imaging element to image luminal surfaces and other objects that are substantially flush with the distal end  18 . Additional lumens may be provided for other treatments, such as irrigation, aspiration, perfusion, or delivery of a device, e.g., a stent. 
         [0017]    According to certain embodiments, the imaging element  19  is coupled to one or more signal lines  17 . The signal lines  17  couple to the imaging element  19  and run along an inner lumen of the catheter body. In certain embodiments, the signal lines  17  are bonded of laminated into a wall of the inner lumen. The signal lines  117  run along the inner wall towards proximal hub  16 . At proximal hub  16 , the single lines  17  are incorporated into an external cable. As shown the signal lines  17  (as enclosed in an external cable) extend through an external housing  29  coupled to the proximal hub  16  and attached to a patient interface module (PIM) connector  31 . The PIM connector may couple to an imaging system (such as the imaging system  400  shown in  FIG. 5 ). The imaging system  400  is configured to control treatment, send and receive imaging data, and process imaging data. The imaging system is described in more detail hereinafter. 
         [0018]    In an embodiment, housing  29  includes a first connector  26  in communication with the guidewire lumen and optionally a second connector  28  in communication with e.g. a delivery lumen. The catheter  10  may be ridden over a guidewire running through the guidewire lumen to a position of interest. The guidewire lumen may be configured to receive a guidewire and an interventional catheter, which may also be riding over the guidewire. The interventional catheter may be for ablation, stent placement, angioplasty, imaging, pressure sensing, ect. Both first and second connectors  26 ,  28  may optionally comprise standard connectors, such as Luer-Loc™ connectors. 
         [0019]    In certain embodiments, the guide catheter  10  further includes a balloon  22  or other expandable member. In addition to the imaging element, the expandable members  22  can be used effectively and reliably place the distal tip  18  of the catheter inside an ostium  310  of an artery  330  (as shown in  FIG. 3 ). This placement assures that the length d of the guide catheter inside the ostium is appropriate for the procedure. In some embodiments, the guide catheter will have markers distal to the balloon  22 , allowing a surgeon to modify the length of the distance d as needed for the procedure. An additional benefit of the balloons is that fluids flushed from the catheter will be directed distally away from the tip. 
         [0020]    Housing  29  additionally provides a connection to a pump  38  coupled to a fluid source, e.g., saline or contrast. The pump  38  may be any pump suitable to deliver sufficient pressure to push the fluid. through the delivery lumen to be administered via the distal opening. In some embodiments, the pump  38  will be designed to give an initial burst of pressure to inflate a balloon  22 . The pump  38  may be a peristaltic pump, or the pump  38  may be a syringe. The reservoir  40  is any suitable reservoir to hold the fluid prior to delivery to the patient. The reservoir  40  may comprise pressure and temperature controls to maintain the fluid in optimum condition. In simple embodiments, both the pump  38  and the reservoir  40  take the form of a single syringe. In advanced embodiments, as shown in  FIG. 1 , the pump  38  and the particle reservoir  40  may be controlled by a controller  42  that is interfaced with patient monitoring equipment, e.g., a blood oxygen sensor, or a pressure sensor. 
         [0021]    The controller  42  may include a processor, or is coupled to a processor, used to control flow of fluid into the catheter. In certain embodiments, the controller  42  is a computer. The controller may be included in imaging system  400 . For example, the controller  42  may be computer  449 . In such aspect, one computer may be used to control image collection and related processes and control fluid flow through the catheter  12 . 
         [0022]    As shown in  FIG. 1 , the catheter  1  is an over-the-wire guide catheter. Over-the-wire guide catheters have a functional lumen that extends the entire length of the shaft, from the distal end to a proximal hub. Devices, such as interventional catheters, introduced into the guide catheter are placed into the proximal end of the guide catheter, which is extending out of the patients body. The devices are pushed guided through the length of the guidewire. 
         [0023]    In addition to the over-the-wire guidewire configuration, catheters of the invention may alternatively have a rapid exchange configuration. Rapid exchange catheters are characterized by the distal catheter shaft being from about 10 cm to about 40 cm long. The catheter does not require that another device, such an interventional catheter, be pushed through the entire length of the catheter. Rather, an interventional catheter may ride along a guidewire, and enter the guide catheter through a catheter entry port located at a proximal end of the distal shaft. The rapid exchange guidewire allows one to more easily exchange varying interventional catheters into the delivery catheter. In addition, rapid exchange delivery catheters are compatible with virtually any length interventional catheter. 
         [0024]      FIG. 2  depicts a catheter of the invention having a rapid exchange configuration. The catheter  300  has a distal shaft  50  defining a lumen  54 . The distal shaft is about 10 cm to about 40 cm in length. However, it is contemplated that the distal shaft  50  may be shorter or longer depending on the application. The distal shaft  50  includes an imaging element  119  located at or near the distal end  18 . Like the catheter of  FIG. 1 , the distance between the imaging element  19  and the distal end  18  is preferably minimized such that the imaging plane is substantially flush with the absolute end of the catheter  300 . The distal shaft  50  includes proximal end  52 . The proximal end  52  terminates in a soft, atraumatic catheter port  53  leading to lumen  53 . Typically, the imaging element  19  is placed on the external surface of the distal shaft  50 . Although, the imaging element  19  may also be placed, for example, within distal shaft  50 . In certain embodiments, the imaging element  19  is placed in a ring array around the distal shaft  50 . The rapid exchange configuration may also include a balloon or expandable element. 
         [0025]    A push rod  21  is coupled to the proximal end  52 . The push rod  21  may be made of any suitable material. Typically, the push rod  21  is made of stainless steel, such as 304 ss. The push rod  21  may be attached to the proximal end  52  via adhesive or thermal bonding. The push rod terminates at a proximal hub  83 . The proximal hub  83  may be used to control movement of the catheter  80 . Alternatively, a handle separate from the proximal hub  83  may be used to manipulate and control movement of the guide catheter. 
         [0026]    According to certain embodiments, the imaging element  19  is coupled to one or more signal lines  17 . The signal lines  17  couple to the imaging element  19  and run along an inner lumen of the distal shaft  50 . In certain embodiments, the signal lines  17  are bonded of laminated into a wall of the distal shaft  50 . At the distal shaft, the signal lines  17  may transition to a sleeve  93 . The sleeve  93  may run next to a parallel to the push rod  21 . Preferably, the sleeve  93  is coupled to the push rod  21 . The signal lines  17  run within sleeve  93  towards proximal hub  83 . At proximal hub  83 , the single lines  17  are incorporated into an external cable. As shown, the signal lines  17  (as enclosed in an external cable) are attached to a patient interface module (PIM) connector  31 . The PIM connector  31  may couple to an imaging system (such as the imaging system  400  shown in  FIG. 5 ). The imaging system  400  is configured to control treatment, send and receive imaging data, and process imaging data. The imaging system is described in more detail hereinafter. 
         [0027]    As shown in  FIG. 3 , the guide catheter having imaging element  19  can be used to effectively and reliably place the distal tip  18  of the catheter inside an ostium  310  of an artery  330 . This visualization assures the guide catheter is appropriately placed inside the ostium for the procedure. 
         [0028]      FIG. 4A-4C  further depicts a guide catheter of the invention in use. In this embodiment, the catheter  200  has been placed in a lumen  280 , which may be an artery or vein on the order of the same size as the catheter  200 . The catheter  200  includes an imaging element  210 , a catheter body  230 , a distal tip  235 , a fluid delivery lumen  250 , and optionally a balloon  212 . The imaging element is able to send and receive imaging data so that an operator can visualize the vessel during the procedure. This allows the delivery catheter to be appropriately placed and remain in the appropriate place during the procedure. Fluid contrast for external imaging is delivered, and then an interventional catheter is introduced through the delivery catheter. The interventional catheter may be used to ablate or morcellate tissue at a treatment site in the artery, for example. 
         [0029]    The sequence of insertion, fluid delivery, and interventional catheter introduction is shown in  FIGS. 4A-4C , respectively. As shown in  FIG. 4A , prior to fluid delivery, the imaging element  210 , positioned near the distal tip  235 , is placed within a biological lumen  280 . The imaging element  210  allows one to maintain, through visualization, the proper positioning of the catheter  200  during a procedure. Once the catheter  200  is in place with the guidance of the imaging element  210 , a balloon  212  can be inflated in order to assist in maintaining the positioning of the guide catheter  200 . With the balloon  212  expanded, a fluid introduced via the distal end  235  can only travel to the distal side of balloon  212 . When used with a contrast agent, the inflated balloon  210  will result in sharp line on the fluoroscope detailing the exact location of the catheter end. This method will also be useful if the catheter is inserted against the normal flow of fluid in the lumen, e.g., blood flow. An interventional catheter  290  may then be introduced, as shown in  FIG. 4C , while being imaged by an external modality. In addition, intraluminal images can be obtained with the imaging element  210  to ensure positioning of the delivery catheter throughout the procedure. 
         [0030]    The methods of the invention can also be used with various interventional devices, such as catheters. Various interventional catheters are described in U.S. Pat. Nos. 8,187,267, 7,993,333, 7,981,151, 8,080,800, and 6,544,217. 
         [0031]    As discussed, imaging elements of the invention may be placed on an outer catheter body/shaft or within a catheter body/shaft. The imaging element may have any suitable configuration for imaging a vessel surface. In certain embodiments, the imaging element is a ring transducer array wrapped around a distal end of the catheter shaft. This configuration allows one to image a cross-section of the vessel without having to rotate the catheter shaft. 
         [0032]    In certain embodiments, the imaging elements of the array are transducers, such as ultrasound transducers, piezoelectric micromachined ultrasound transducers, capacitive micromachined ultrasound transducers, and photo-acoustic transducers. Each imaging elements of the array may include a signal transmitter and a signal collector (or image collector). The signal transducer and the signal collector may be the same or different. For example, a piezoelectric element that is used to transmit a signal may also be used to receive a signal. Ultrasound transducers produce ultrasound energy and receive echoes from which real time ultrasound images of a thin section of the blood vessel are produced. The transducers in the array may be constructed from piezoelectric components that produce sound energy at 20-50 MHz. 
         [0033]    In yet another embodiment, the imaging element is an optical acoustic imaging element. Optical-acoustic imaging elements include at least one acoustic-to-optical transducer. In certain embodiments, the acoustic-to-optical transducer is a Fiber Bragg Grating within an optical fiber. The imaging element may one or more optical fibers with Fiber Bragg Gratings placed longitudinally along a length of the catheter shaft. For example, the imaging element may include two or more optical fibers aligned next to each other, and each with a plurality of Fiber Bragg Gratings. In another embodiment, an optical fiber having several Fiber Bragg Gratings may be wrapped around the distal end of the catheter. In some embodiments, the imaging elements may include an optical fiber with one or more Fiber Bragg Gratings (acoustic-to-optical transducer) and one or more other transducers. The at least one other transducer may be used to generate the acoustic energy for imaging. Acoustic generating transducers can be electric-to-acoustic transducers or optical-to-acoustic transducers. 
         [0034]    Fiber Bragg Gratings for imaging provides a means for measuring the interference between two paths taken by an optical beam. A partially-reflecting Fiber Bragg Grating is used to split the incident beam of light into two parts, in which one part of the beam travels along a path that is kept constant (constant path) and another part travels a path for detecting a change (change path). The paths are then combined to detect any interferences in the beam. If the paths are identical, then the two paths combine to form the original beam. If the paths are different, then the two parts will add or subtract from each other and form an interference. The Fiber Bragg Grating elements are thus able to sense a change wavelength between the constant path and the change path based on received ultrasound or acoustic energy. The detected optical signal interferences can be used to generate an image using any conventional means. 
         [0035]    Exemplary optical-acoustic imaging elements are disclosed in more detail in U.S. Pat. Nos. 6,659,957 and 7,527,594, 7,245.789, 7447,388, 7,660,492, 8,059,923 and in U.S. Patent Publication Nos. 2008/0119739, 2010/0087732 and 2012/0108943. 
         [0036]    In another embodiment, the imaging element of the invention is a capacitive micromachined ultrasound transducer array (CMUT). CMUT elements generally include at least a pair of electrodes separated by a uniform air or vacuum gap, with the upper electrode suspended on a flexible membrane. Impinging acoustic signals cause the membrane to deflect, resulting in capacitive changes between the electrodes, which produce electronic signals usable for ultrasonic imaging. Exemplary CMUT arrays are described in more detail in U.S. Pat. Nos. 8,309,428 and 6,328,696, and U.S. Publication No. 2007/0161896. 
         [0037]    In another embodiment, the imaging element of the invention is a piezoelectric micromachined ultrasound transducer array (PMUT). In PMUTs the sound-radiating element is a micromachined multi-layer membrane that is activated by a piezoactive layer (such as a PZT thin film). The PZT thin film is poled in the thickness direction. Application of an electric field across the thickness direction causes a strain in the film and induces membrane bending, thereby propagating a sound wave. reflected sound waves are received on the membrane, which causes a detectable charge displacement in the electrode PZT. PMUT arrays are described in more detail in U.S. Pat. No. 8,148,877, U.S. Publication No. 2003/0085635, and Akasheh, Firas, et al. “Development of piezoelectric micromachined ultrasonic transducers.” Sensors and Actuators A: Physical 111.2 (2004): 275-287. 
         [0038]    While the invention is described as delivering fluids, e.g., contrast, to the vasculature and or delivering interventional catheters, it is understood that similar methods could be used to deliver fluids to a number of tissues that are accessible via the various lumen of the body, including, but not limited to vasculature of the lymphatic and nervous systems, various structures of the gastrointestinal tract including lumen of the small intestine, large intestine, stomach, esophagus, colon, pancreatic duct, bile duct, hepatic duct, lumen of the reproductive tract including the vas deferens, uterus and fallopian tubes, structures of the urinary tract including urinary collecting ducts, renal tubules, urethra, and bladder, and structures of the head and neck and pulmonary system including sinuses, parotid, trachea, bronchi, and lungs. 
         [0039]    In some embodiments, a catheter of the invention includes imaging element that sends and receives imaging data through the operation of IVUS, or other imaging hardware. In some embodiments, a catheter of the invention is coupled to a processing device. A processing device of the invention is a computer device such as a laptop, desktop, or tablet computer, and obtains a three-dimensional data set by retrieving it from a tangible storage medium, such as a disk drive on a server using a network or as an email attachment. 
         [0040]    Methods of the invention can be performed using software, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions can also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations (e.g., imaging apparatus in one room and host workstation in another, or in separate buildings, for example, with wireless or wired connections). 
         [0041]    In some embodiments, a user interacts with a visual interface to view images from the imaging system. Input from a user (e.g., parameters or a selection) are received by a processor in an electronic device (such as a computer  449 ). The selection can be rendered into a visible display. An exemplary imaging system is illustrated in  FIG. 5 . As shown in  FIG. 5 , an imaging engine  859  of the imaging assembly communicates with host workstation  433  as well as optionally server  413  over network  409 . The data acquisition element  855  (DAQ) of the imaging engine receives imaging data from one or more imaging element. In some embodiments, an operator uses computer  449  or terminal  467  to control system  400  or to receive images. An image may be displayed using an I/O  454 ,  437 , or  471 , which may include a monitor. Any I/O may include a keyboard, mouse or touchscreen to communicate with any of processor  421 ,  459 ,  441 , or  475 , for example, to cause data to be stored in any tangible, nontransitory memory  463 ,  445 ,  479 , or  429 . Server  413  generally includes an interface module  425  to effectuate communication over network  409  or write data to data file  417 . 
         [0042]    Processors suitable for the execution of computer program include, by way of example, both general and special purpose microprocessors, and any one or more processor of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Information carriers suitable for embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, (e.g., EPROM, EEPROM, solid state drive (SSD), and flash memory devices); magnetic disks, (e.g., internal hard disks or removable disks); magneto-optical disks; and optical disks (e.g., CD and DVD disks). The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry. 
         [0043]    To provide for interaction with a user, the subject matter described herein can be implemented on a computer having an I/O device, e.g., a CRT, LCD, LED, or projection device for displaying information to the user and an input or output device such as a keyboard and a pointing device, (e.g., a mouse or a trackball), by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well. For example, feedback provided to the user can be any form of sensory feedback, (e.g., visual feedback, auditory feedback, or tactile feedback), and input from the user can be received in any form, including acoustic, speech, or tactile input. 
         [0044]    The subject matter described herein can be implemented in a computing system that includes a back-end component (e.g., a data server  413 ), a middleware component (e.g., an application server), or a front-end component (e.g., a client computer  449  having a graphical user interface  454  or a web browser through which a user can interact with an implementation of the subject matter described herein), or any combination of such back-end, middleware, and front-end components. The components of the system can be interconnected through network  409  by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include cell network (e.g., 3G or 4G), a local area network (LAN), and a wide area network (WAN), e.g., the Internet. 
         [0045]    The subject matter described herein can be implemented as one or more computer program products, such as one or more computer programs tangibly embodied in an information carrier (e.g., in a non-transitory computer-readable medium) for execution by, or to control the operation of, data processing apparatus (e.g., a programmable processor, a computer, or multiple computers). A computer program (also known as a program, software, software application, app, macro, or code) can be written in any form of programming language, including compiled or interpreted languages (e.g., C, C++, Perl), and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. Systems and methods of the invention can include instructions written in any suitable programming language known in the art, including, without limitation, C, C++, Perl, Java, ActiveX, HTML5, Visual Basic, or JavaScript. 
         [0046]    A computer program does not necessarily correspond to a file. A program can be stored in a portion of file  417  that holds other programs or data, in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub-programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network. 
         [0047]    A file can be a digital file, for example, stored on a hard drive, SSD, CD, or other tangible, non-transitory medium. A file can be sent from one device to another over network  409  (e.g., as packets being sent from a server to a client, for example, through a Network Interface Card, modem, wireless card, or similar). 
         [0048]    Writing a file according to the invention involves transforming a tangible, non-transitory computer-readable medium, for example, by adding, removing, or rearranging particles (e.g., with a net charge or dipole moment into patterns of magnetization by read/write heads), the patterns then representing new collocations of information about objective physical phenomena desired by, and useful to, the user. In some embodiments, writing involves a physical transformation of material in tangible, non-transitory computer readable media (e.g., with certain optical properties so that optical read/write devices can then read the new and useful collocation of information, e.g., burning a CD-ROM). In some embodiments, writing a file includes transforming a physical flash memory apparatus such as NAND flash memory device and storing information by transforming physical elements in an array of memory cells made from floating-gate transistors. Methods of writing a file are well-known in the art and, for example, can be invoked manually or automatically by a program or by a save command from software or a write command from a programming language. 
       INCORPORATION BY REFERENCE 
       [0049]    References and citations to other documents, such as patents, patent applications, patent publications, journals, books, papers, web contents, have been made throughout this disclosure. All such documents are hereby incorporated herein by reference in their entirety for all purposes. 
       EQUIVALENTS 
       [0050]    The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting on the invention described herein. Scope of the invention is thus indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein