Abstract:
A diagnostic catheter and method of use for analyzing tissue is provided. A method for analyzing tissue in accordance with one embodiment of the present invention includes inserting a catheter having a sensor at its distal end into the body of a patient, applying suction through the catheter to secure the tissue to the catheter and then analyzing the tissue with the sensor. An apparatus for analyzing tissue within the body of a patient in accordance with an alternative embodiment of the present invention is also provided. This alternative embodiment includes a catheter having a first end and a second end, the first end having an orifice and a sensor, the catheter also having a lumen.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 09/513,076, which was filed on Feb. 25, 2000, and which is herein incorporated, in its entirety, by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention is directed to the analysis of internal tissue of a patient. More particularly the present invention regards the use of a vacuum within a patient&#39;s body to secure tissue near a diagnostic sensor. 
       BACKGROUND OF THE INVENTION 
       [0003]    Diagnostic procedures to analyze and diagnose a patient are a common component of modern medical care. There are numerous diagnostic procedures that can be performed on a patient. Some of these diagnostic procedures, such as x-ray and Magnetic Resonance Imaging, are performed completely outside of the body while others, such as tissue biopsies and in situ analysis, require entry into the body and more direct contact with the suspect body part. Those procedures that require more direct tissue contact may be performed through the esophagus and other existing orifices in the patient or through incisions, both small and large, made in the body of the patient. 
         [0004]    Whether the diagnostic procedure is performed through an existing orifice or through an incision in the body of the patient, the tissue to be analyzed may often be out of the direct reach of the practitioner. In these situations, in order to reach and analyze the tissue, the practitioner will often employ an instrument having sensors at its distal end. When an instrument is employed the practitioner must manipulate and guide the instrument from outside the body in order to position the sensors, located at its distal end, next to the suspect tissue. This manipulation and steering of the instrument is often a time-consuming and cumbersome process. 
         [0005]    For example, when tissue is analyzed during an endoluminal procedure, the practitioner must manipulate the medical instrument containing the sensor within the tight quarters of the endoscope. Once the sensor is properly positioned by the practitioner, it must then be maintained adjacent to the tissue in order to receive satisfactory results. In some circumstances the practitioner may not be able to satisfactorily manipulate the sensor in order to position it near the tissue to be analyzed. Similarly they may not be able to satisfactorily maintain the contact between the tissue and the instrument during the analysis. To resolve both of these problems, a second instrument, having a hook at its distal end, has been employed. This second instrument is inserted down into the endoscope in order to hook the tissue, move it next to the sensor, and hold the tissue in place during the testing. The application of this second instrument, although frequently used, is disfavored as its use is time consuming and can injure and permanently damage the tissue being tested. 
         [0006]    In another example, when diagnostic testing is performed without an endoscope, directly through an incision into the patient&#39;s body, the practitioner must also position the sensor adjacent to the suspect tissue and may also be required to hold the tissue in direct contact with the catheter in order to perform the analysis. Here, too, positioning the catheter and maintaining its direct contact with the tissue is an arduous and tedious process. A second instrument, such as the hook described above, is often used to grab the tissue, tug it to the sensor and anchor the tissue in direct contact with the catheter. As in the endoluminal procedure, the use of this second instrument, the hook, prolongs the procedure and increases the risk of injury to the tissue. 
         [0007]    As is evident, what is needed is a method and an apparatus that provides for the diagnosis of suspect and diseased tissue within the body of a patient without the cumbersome, time-consuming, and risky procedures that have been employed in the past. 
       SUMMARY OF THE INVENTION 
       [0008]    In accordance with the present invention a diagnostic catheter using a vacuum for tissue positioning is provided. A method for analyzing tissue in accordance with one embodiment of the present invention includes inserting a catheter having a sensor at its distal end into the body of a patient, applying suction through the catheter to secure the tissue to the catheter and then analyzing the tissue with the sensor. 
         [0009]    An apparatus for analyzing tissue within the body of a patient in accordance with an alternative embodiment of the present invention is also provided. This alternative embodiment includes a catheter having a first end and a second end, the first end having an orifice and a sensor, the catheter also having a lumen. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a catheter in accordance with a first embodiment of the present invention. 
           [0011]      FIG. 2  is a cross-sectional view along line  2 - 2  of  FIG. 1 . 
           [0012]      FIG. 3  is an enlarged view of the catheter from  FIG. 1  after being placed next to tissue to be analyzed. 
           [0013]      FIG. 4  is an enlarged view of the catheter from  FIG. 1  wherein a vacuum force has been used to draw tissue down and in contact with the catheter. 
           [0014]      FIG. 5  is the distal end of an endoscope containing a catheter in accordance with a second embodiment of the present invention. 
           [0015]      FIG. 6  is a catheter employing a syringe to create a vacuum force in accordance with a third embodiment of the present invention. 
           [0016]      FIG. 7  is a cross-sectional view of the distal end of a catheter in accordance with a fourth embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 1  illustrates a catheter  10  in accordance with a first embodiment of the present invention. This catheter  10 , which may be tube-shaped and may have a 2-3 mm external diameter, contains a hollow cylindrical distal tip  120  as well as a hollow cylindrical catheter body  190  and a hollow cylindrical tube  185 . The distal tip  120  contains four equally sized orifices  100  along its surface. These orifices  100 , which may be 0.5 mm in diameter, penetrate completely through one of the walls of the catheter&#39;s  10  hollow cylindrical distal tip  120  and may be spaced a diameter apart from one another. The hollow cylindrical distal tip  120  also contains three sensors  110  affixed to its surface and equally located between the four orifices  100 . These sensors  110  may be numerous types of sensors including electrical sensors that test the voltage drop across the tissue being tested, ultrasound sensors, such as the Boston Scientific/SCIMED UltraCross® TX200 transducers, which employ sound waves to analyze the tissue, and optical sensors, which employ visible or non visible light to sense the properties of the tissue being analyzed. These sensors  110  are connected to sensor line  195  which is located within the distal tip  120 , the catheter body  190 , and the coupler  180 . This sensor line  195  connects the sensors  110  with the sensor communication cable  130 . The sensor communication cable  130  is in turn connected to a sensor output device (not shown) such as a cathode ray tube. Dependent upon the type of sensors  110  employed the sensor line  195  and the sensor communication cable  130  may be electrical wires, optical fibers, or some other communication link. 
         [0018]    As can be seen, a vacuum hose  160  is also connected to the coupler  180 . In addition to being connected to the coupler  180  on one end, the vacuum hose  160  is also connected to a vacuum pump, which is not shown, at the other end. This vacuum pump, although not illustrated, may be a 1180 Gomco suction unit, capable of creating a vacuum between 0 and 22 in. Hg and having a bottle coupled to it to prevent solids and liquids from entering the pump. This vacuum pump is used to create an inward suction force through the orifices  100  located at the distal tip  120  of the catheter  10 . This inward vacuum force generated by the vacuum travels from the vacuum pump through the vacuum hose  160 , through the first vacuum channel  165  located in the coupler  180  and the tube  185 , through the suction adjustment valve  175 , back through the tube  185 , this time in the second vacuum channel  155 , which is located within the tube  185 , through the coupler  180 , the catheter body  190 , and the distal tip  120 , such that the vacuum force is in fluid communication with the orifices  100 . 
         [0019]    A suction adjustment knob  170  is rotationally connected to the suction adjustment valve  175 . This suction adjustment valve  175  regulates the amount of suction from the vacuum pump (not shown) that will be transferred from the first vacuum channel  165  to the second vacuum channel  155  and eventually to the orifices  100  located in the distal tip  120  of the catheter  10 . By turning the suction adjustment knob  170  the suction adjustment valve  175  is opened or closed and the amount of suction drawn through the orifices  100  at the distal tip  120  of the catheter  10  is either concomitantly increased or decreased. 
         [0020]    In practice a practitioner utilizing the catheter  10  of  FIG. 1  may insert the catheter  10  into the body of the patient through an existing orifice or through an incision made specifically for the procedure. The practitioner would then position the distal tip  120  of the catheter  10 , which is made from a flexible polymer, allowing the practitioner to bend and flex the catheter next to the tissue to be diagnosed. Then, once the catheter&#39;s  10  distal tip  120  is in its desired position, the practitioner would then turn the vacuum pump on and adjust the amount of vacuum that will be drawn through the orifices  100  at the distal tip  120  of the catheter  10  by turning the suction adjustment knob  170 . As the practitioner rotates the suction adjustment knob  170  and increases the vacuum drawn through the four orifices  100 , the tissue to be analyzed is drawn towards the orifices  100  and, consequently, towards the sensors  110 . Once the suspect tissue has been repositioned and comes in contact with the sensors  110  the strength of the vacuum force may be maintained or it may be reduced by the practitioner to a level sufficient to maintain the contact between the tissue and the sensors  110 . By reducing the vacuum force holding the tissue to the sensors  110  the concentrated forces on the tissues are reduced. The distal tip  120  of the catheter  10  and the sensors  110  will remain in contact with the tissue for the duration of the analysis. 
         [0021]    Once the requisite analysis and diagnosis has been completed the vacuum may be reduced by turning the suction adjustment knob  170  or by turning the vacuum off, and the tissue will be free to revert back to its original resting position within the body. Once the tissue is released from the orifices  100  the catheter  10  can be removed from the patient or the procedure can be repeated again, as many times as required, for different sections of tissue. 
         [0022]      FIG. 2  is a cross-sectional view taken along line  2 - 2  of  FIG. 1 . As can be seen the distal tip  120  of the catheter  10  has a circular cross-section and the orifice  100  penetrates through the surface and the inner wall  200  of the distal tip  120 . The sensor line  195  as well as the second vacuum channel  155  are also evident in  FIG. 2 . 
         [0023]      FIG. 3  is an enlarged view of the distal tip  120  of the catheter  10  after it has been positioned near a tissue  330  within the body of the patient. Inward force arrows  320  are clearly shown. The inward force arrows  320  highlight the position of the downward force created through the plurality of orifices  100  by the vacuum being drawn through the second vacuum channel  155 . The direction of the vacuum force communicated from the vacuum pump through the catheter to the second vacuum channel  155  is illustrated by arrow  360 . 
         [0024]    In practice, and as discussed above, as the amount of vacuum is increased the tissue  330  is drawn down to the orifices  100  until the tissue  330  meets the sensors  110 . The sensors  110 , now touching the tissue, analyze the tissue and output their results to sensor electronics, including the cathode ray tube discussed above. Once the requisite data is obtained the vacuum is reduced, the tissue  330  is released, and the catheter may be removed or the procedure can be repeated again on a different area of tissue. 
         [0025]      FIG. 4  illustrates the distal tip  120  of the catheter after the suction being drawn down the second vacuum channel  155  has been increased, as shown by arrow  400 , the suction now drawing the tissue  330  down and in contact with the sensors  110 . The contact points between the sensors  110  and the tissue  330  are highlighted by arrows  410 . 
         [0026]      FIG. 5  illustrates the distal end  595  of a second embodiment of the present invention wherein a catheter  565  is inserted into the internal working channel  570  of an endoscope  510 . As can be seen, a light tip  520  of a light pipe  580  is located at the distal end  595  of the endoscope  510 . This light tip  520  is connected the light pipe  580  which is connected to a light source located at the proximate end of the endoscope (not shown). Also located at the distal end  595  of the endoscope  510  is an optical sensor  530 . The optical sensor  530  is connected to a communication line  590  which links the optical sensor  530  to the proximate end of the endoscope  510  (not shown) and allows the images gathered by the optical sensor  530  to be viewed by the practitioner on a nearby display screen. This optical sensor  530  may be used to assist the practitioner in navigating the distal end  595  of the endoscope  510  to the tissue to be analyzed or alternatively it may be utilized to inspect tissue being analyzed by the sensors  550  located on the distal tip  560  of the catheter  565 . 
         [0027]    As is evident, the catheter  565  is located within the internal working channel  570  of the endoscope  510 . The distal tip  560  of the catheter  565  extends from the distal end  595  of the endoscope  510  in this illustration. As in the previous embodiments, the distal tip  560  contains several orifices  540 , three in this embodiment, as compared to the four orifices utilized in the embodiment described above. The distal tip  560  also contains two sensors  550  as compared to the three employed in the first embodiment. 
         [0028]    A practitioner using this second embodiment would first insert the catheter  565  into the internal working channel  570  at the proximate end (not shown) of the endoscope  510 . The catheter  565  would only partially be inserted into the internal working channel of the endoscope  510  such that the distal tip  560  of the catheter  565  would not emerge from the distal end of the endoscope  510  at the beginning of the procedure. Next, the endoscope  510  may be inserted into the body of the patient through an opening, such as the mouth, or through an incision made in the body specifically to accommodate the diagnostic procedure. The endoscope  510  would then be guided into position from outside the body of the patient by the practitioner. If necessary the practitioner may turn the light tip  520  on and use the optical sensor  530  to assist in guiding the distal end  595  of the endoscope  510  down into its desired resting location. Then, once the distal end  595  of the endoscope  510  was positioned near the tissue to be analyzed the practitioner would extend the catheter&#39;s  565  distal tip  560  out from inside the internal working channel  570 . The practitioner would then position the distal tip  560  to be adjacent to the tissue to be analyzed, the orifices  540 , located on the distal tip  560 , facing the tissue to be tested. Similar to the positioning of the endoscope, the practitioner may also illuminate the light tip  520  and utilize the optical sensor  530  to aid in properly positioning the distal tip  560  of the catheter  565 . Once the distal tip  560  of the catheter  565  is properly positioned, the practitioner would turn on the vacuum source in order to draw the tissue towards the orifices  540 . Once the sensors  550  began to adequately sense the tissue, the practitioner could then adjust the vacuum being drawn through the orifices, either at the source of the vacuum or at the catheter  565  through an adjustment valve (illustrated above), so that only the requisite amount of force was utilized to maintain contact between the sensors  550  and the tissue being analyzed. 
         [0029]    Now coupled to the distal tip  560  of the catheter, the tissue, in addition to being analyzed by the sensors  550 , may also be manipulated by the practitioner by moving the catheter at its proximate end (not shown). As required, the tissue may be manipulated within the view of the optical sensor  530 . Once the required data was obtained by the sensors  550 , the vacuum would be reduced until the tissue would be released from the orifices  540 . If additional tissue testing was required, the procedure would be repeated. Once the requisite testing was completed the distal tip  560  of the catheter  565  would be withdrawn back into the endoscope  510  so that it no longer extended outside of the endoscope  510 . The endoscope  510  would then be removed from the body. 
         [0030]    While a light  520  and an optical sensor  530  are shown at the end of the endoscope  510  other diagnostic components can also be placed at the end of the endoscope  510  to assist the practitioner. For example, the same electrical and ultrasonic sensors placed on the surface of the distal tip  560  of the catheter may also be placed on the distal end  595  of the endoscope  510  to provide additional sources of data to the practitioner during the diagnosis. 
         [0031]      FIG. 6  illustrates a catheter  60  in accordance with a third embodiment of the present invention. In  FIG. 6  the catheter  60  has a catheter body  690  containing a sensor line  695 . The catheter body  690  is rigidly connected to a coupler  680 . The coupler  680  has a sensor communication cable  630  and a vacuum hose  660  protruding from the coupler&#39;s  680  lower side. The vacuum hose  660  has a connection hose  625  sealably connected to the vacuum hose  660 . The connection hose  625  is sized to fit to the connection hose  625  on one side and to a syringe  615  on the other. The syringe  615  is in fluid communication with the orifices  630  via the connection hose  625 , the vacuum hose  660 , the coupler  680 , and the catheter body  690 . The syringe  615  contains a plunger  605 . When the plunger  605  is drawn out, in the direction of the arrow, it creates a vacuum force that is ultimately transferred to the orifices  600  at the distal tip  620  of the catheter  60 . This syringe  615  is, therefore, an alternative to the vacuum pump described in the previous embodiments. When the syringe  615  is used, the vacuum adjustment valve  675  would be rotated until it was completely open so that the practitioner would be controlling the amount of vacuum force generated at the orifices  600  of the catheter  60  by sliding and holding the plunger  605  of the syringe  615 . 
         [0032]    Alternatively, as illustrated in  FIG. 7 , which is a cross-sectional view through the distal end of a fourth embodiment of the present invention, the sensors  710  and the orifices  700  do not need to be in line with one another along the outside surface of the catheter. Instead, they may also be placed at different locations of the distal tip  720  of the catheter. For example, as is evident in  FIG. 7  the orifice  700  penetrates through the top of the outside surface of the distal tip  720  of the catheter while the sensor  710  is positioned along a side of the outside surface of the distal tip  720  of the catheter. Similarly, while the sensors are illustrated on the surface of the catheter they may instead be formed in the catheter or placed on the inside wall  755  of the distal tip  720  of the catheter. Also, while an endoscope is described in the embodiments above, a flexible tube creating a pathway may, instead, be used in its place. Therefore, as will be evident to one of skill in the art, the above embodiments are merely illustrative of the invention disclosed herein and other embodiments may be employed without departing from the spirit and scope of the present invention.