Abstract:
Fluid jet tubes having operative openings and cell traps for cell cluster, tissue and debris harvesting and collecting are used with an endoscope such that the fluid jets draw-in, stabilize and hold in-vivo target specimens at a distal end. While the catheter grips the tissue by suction, blasts of high pressure solution strip from the tissue and suspend clusters of cells which are ready for analysis. The clusters are entrained in the solution and are recovered in a cell collection trap at the proximal end. Traps are removed, replaced or rotated out of and into alignment with a trap connector to accommodate new target specimens. A switch controls fluid flow, intensity and frequency of fluid jet blasts of the solution. The fluid jet catheter paired with a fiber optic system in an endoscope allows viewing of areas surrounding the distal end of the catheter.

Description:
BACKGROUND OF THE INVENTION 
     Colorectal carcinoma is a leading cause of morbidity and mortality across the globe. Gastric carcinoma also is a leading concern worldwide. Colonoscopy is the most accurate screening tool for colorectal cancer, and an esophagogastroduodenoscopy is the preferred method for gastric screening. The means by which a diagnosis is made during endoscopy is in question, however. Many techniques of mucosal sampling have been utilized since Hemmeter in 1889 described an abrasive instrument for diagnosing gastric carcinoma. For example, pinch, snare, brush, suction, salvage and fine needle aspiration (FNA) are established sampling techniques for gastrointestinal endoscopy. Lavage cytology is now considered obsolete, but was the technique that cultivated major advances in gastrointestinal cytology. Brush, suction, salvage, and FNA deliver samples appropriate for cyto-analysis and their interpretation rest upon cytology data gleaned for over 100 years. Their practical use, however, is limited because of the time and effort required for completion. Histology samples delivered by pinch and snare techniques, although the more commonly performed because of their rapid results are flawed techniques with lower diagnostic yields than brush, suction and salvage techniques. 
     Needs exist for a novel means used during endoscopy that dissects tissue into a cellular suspension capable of undergoing analytical cytology. 
     SUMMARY OF THE INVENTION 
     Fluid jet tubes having operative openings and cell traps for cell cluster, tissue and debris harvesting and collecting are used in diagnostics and therapeutics. Used with an endoscope the fluid jets draw-in, stabilize and hold in vivo target specimens at a distal end. While the catheter grips the tissue by suction, blasts of high pressure saline solution strip from the tissue and suspend clusters of cells which are ready for analysis. The clusters of cells are entrained in the saline solution and are recovered in a cell collection trap at the proximal end. Traps are removed and replaced or rotated out of and into alignment with a trap connector to accommodate new target specimens. 
     A foot switch controls fluid flow and intensity and frequency of the fluid jet blasts of the saline solution. The fluid jet catheter paired with a fiber optic system in an endoscope allows viewing of the area immediately surrounding the distal end of the catheter. 
     In diagnostics the tubes and traps are used with flexible and rigid endoscopes. In the therapeutics the tubes and trap are used with rigid endoscopes and in free standing applications to collect cell cluster, tissue and debris samples from arterial thrombectomy, external biopsy, wound debriedment, surgical incisions and surgical excisions. 
     In one embodiment the present invention uses a flexible endoscope which stabilizes and holds in vivo target specimens at a proximal end. While the endoscope grips the tissue by suction, blasts of high pressure saline solution strip the tissue samples and break the tissue into suspended cells which are ready for analysis. 
     A fluid-jet catheter of the invention unites the advantageous qualities of conventional techniques into one swift technique allowing for results while consuming fewer resources. 
     This invention provides a flexible fluid-jet catheter capable of dissecting tissue into a cellular suspension for undergoing analytical cytology. Analytical cytology is a practical and effective approach to medical diagnosis. 
     The fluid-jet catheter of the present invention uses high velocity saline jets to create a Bernoulli effect for entrapment, dissection and retrieval of tissue cells, providing a novel approach for the diagnosis and treatment of pathology through the flexible endoscope. It fosters new initiatives in tumor diagnosis and management of lesions found by flexible endoscopy. 
     In other embodiments of the invention cell traps are provided on return lines of abraiding and cutting fluid jets used for arterial thrombectomy, external and internal biopsies, wound debriedment and surgical incisions and excisions to collect cell clusters for further analyzing without further preparation. 
     High pressure fluid-jets have been successfully used in other medical devices. They have been used to create incisions during surgery, and to clean trauma wounds. The fluid-jet&#39;s application to flexible endoscopy, and specifically for the diagnosis and management of flexible endoscopic pathology has yet to be determined, however. 
     The fluid-jet dissects tissue into a cellular suspension capable of undergoing analytical cytology. Because of this, diagnostic rates are improved, and, unlike more commonly performed techniques, samples may be analyzed in-vitro with highly specific and sophisticated adjunctive techniques. A greater number of endoscopic lesions are capable of being diagnosed in cellular suspensions rather than permanently fixed in formalin. Eventually, such a rapid system for tissue sampling may stimulate improved techniques for point-of-care, on-site diagnosis. It may also stimulate new treatment modalities for endoscopic pathology in less invasive and more effective ways. It provides a novel means for less invasive treatment of conditions such as Polyposis coli and Barrett&#39;s esophagus. 
     The fluid-jet of the present invention is capable of being adjusted to various pulsation frequencies, pressures, patterns, fluid compositions, spray patterns and flow rates. In addition, the fluid-jet may be of any size. The fluid-jet provides means for retrieval of cell clusters from freshly dissected tissue. The retrieved tissue is immersed in a cytopreservative for transport of tissue freshly dissected by a fluid-jet. 
     Ideally, a limited range of fluid-jet settings would allow the dissection of many different tissue types into single cells, however, a wide variety of fluid-jet settings are available for dissecting different types of tissues. 
     The high pressure saline jet of a fluid-jet catheter may be of a single coherent stream, or may be of many geometric styles. Regardless of the pattern, the high velocity saline jet produces an immediate region of reduced pressure. Tissue is drawn into the path of the saline jet, and dissected free in the form of cell clusters. The cell clusters are then retrieved outside the flexible endoscope. The size of the fluid-jet orifice may also influence the effectiveness of the retrieval tube. The delivered cell clusters may then be re-suspended in a liquid based cytopreservative and prepared for analytical cytology. 
     Liquid-based analytical cytology is better than using fixed specimens because liquid-based cytology allows for conventional cyto-analysis of the cell clusters, thus allowing advanced adjunctive screening, such as flow cytometry and immunochemistry. Cell clusters may be examined with monoclonal or polyclonal antibodies to detect viral antigens of CMV, HSV and varicella zoster virus. In situ DNA or RNA hybridization using the polymerase chain reaction could also be used to detect the presence of viral DNA or RNA. These tests are rarely used in conventional sampling techniques because of the difficulty in obtaining an adequate sample. Once a sample is fixed in formalin, as are most endoscopic samples, analysis is limited. Current trends of endoscopic diagnosis seem primitive when compared to the tremendous data potentially gleaned from liquid-based cell suspensions. 
     Flexible endoscopes usually have at least one lumen employed for the management of endoscopic pathology. The fluid-jet catheter of the present invention uses the same lumen as do other techniques. Likewise, to sample an area of interest, the end piece of the fluid-jet catheter is positioned the same way as other techniques. With a foot switch, a high velocity saline jet is activated, and the corresponding cell clusters are delivered to a cell trap. The cell trap is removed, and the sample is re-suspended in a cytopreservative. The cell trap is replaced, but the fluid-jet catheter need not be removed from the endoscope port, unlike current techniques. The system is then ready for another session. The entire process should take less than ten seconds, a savings of over one minute per biopsy. This means the patient is under anesthesia up to fifteen-minutes less for ten biopsies taken during a procedure. 
     In addition to shorter biopsy times, there are several other therapeutic benefits to using fluid-jet catheters. Since a fluid-jet catheter could decrease the amount of time to remove diseased tissue, it may foster new initiatives in less invasive treatments. Conditions such as Polyposis coli, obstructive esophageal tumors, herniated disks, and gynecological tumors may take less time to treat using the fluid-jet endoscope catheter. 
     The dissected tissue may be captured in bridal crinoline, a 100% nylon fabric that is compatible with liquid-based cytology. The filtered cell clusters are then washed and re-suspended in a cytopreservative. Thin layer cytology slides are prepared using either an automated cell preparation station or a cyto-centrifuge, and are stained with Hematoxylin and Eosin. The slides may be visually inspected under a microscope. 
     A preferred embodiment of the fluid-jet catheter of the present invention is preferably at least five feet long, and less than 3.0 mm in outside diameter. The methods used to deliver the dissected tissue from the tip of the fluid-jet to the proximal end of the catheter involve either a positive pressure principle from the fluid-jet, or a negative pressure principle from wall suction. The fluid-jet is capable of exerting up to 20,000 psi. Ideally, the positive pressure generated from the high pressure fluid-jet will be such that the cell clusters are effectively pushed into and out of the retrieval tube. 
     Cytopreservatives are used to enhance the long term stability of cells dissected from tissue by fluid-jet. For example, hog intestinal mucosa remain well preserved in Cytorich red®, a slightly hemolytic cytopreservative, for several hours. Eventual, practical, widespread use of a fluid-jet endoscopic catheter will require the cell suspension to be stable for cytoanalysis for at least one week. Several commercially available cytopreservatives may be used and compared in their efficacy of preservation for up to one month. Fluid-jet dissection of tissue may have no untoward effects upon the cell suspension, or perhaps one cytopreservative is more effective than others. 
     These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-section view of the end piece of the fluid-jet catheter of the present invention. 
     FIG. 2 is a perspective view of the end piece of the fluid-jet catheter of the present invention. 
     FIG. 3 is a detail view of the chamber within the end piece of the fluid jet catheter. 
     FIG. 4 shows the fluid-jet catheter of the present invention dissecting a polyp inside an intestine. 
     FIG. 5A is a cross-section view of the distal end of the fluid-jet catheter of the present invention. 
     FIG. 5B is a cross-section view of the end piece of the fluid-jet catheter of the present invention. 
     FIG. 6 is a cross-section view of the distal end of an alternative embodiment of the fluid-jet catheter of the present invention in which a wide end piece tapers to attach to the catheter tube. 
     FIG. 7 is a cross-section view of the distal end of an alternative embodiment of the fluid-jet catheter of the present invention in which the pressure tube through which saline solution is pumped is concentric to the catheter tube. 
     FIG. 8 is a cross-section view of an alternative embodiment of the fluid-jet catheter of the present invention in which saline solution is pumped through an opening in an end piece to create a reduced pressure. 
     FIG. 9 is a schematic representation of the proximal end of the fluid-jet catheter of the present invention. 
     FIG. 10 shows a preferred catheter abraider or cutter tip. 
     FIG. 11 schematically shows the illuminated end of an endoscope with the catheter ready to extend and sample a tissue. 
     FIG. 12 schematically shows drawing a polyp into the operative opening and abraiding cell clusters from the polyp with fluid jets. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The fluid-jet catheter of the present invention uses high velocity saline jets to create a low pressure Bernoulli effect for tissue entrapment, dissection by high speed jets, and retrieval of targeted tissue cells, providing a novel approach for the diagnosis and treatment of pathology using a flexible catheter endoscope. 
     Flexible endoscopes usually have at least one lumen employed for the management of endoscopic pathology. The fluid-jet catheter of the present invention uses the same port as do other techniques, and extends from the proximal end to the distal end of the catheter within the lumen. To sample an area of interest, the end piece  2  of the fluid-jet catheter, shown in FIGS. 1-3, is positioned the same way as other techniques. 
     The fluid-jet provides means for retrieval of cell clusters from freshly dissected tissue. The retrieved tissue may be immersed in a cytopreservative for transporting tissue freshly dissected by a fluid-jet. The fluid-jet catheter of the present invention dissects tissue into a cellular suspension which is capable of undergoing analytical cytology. 
     The fluid-jet catheter of the present invention is preferably at least five feet long, and less than 3.0 mm in outside diameter. The methods used to deliver the dissected tissue from the distal end to the proximal end of the catheter involve either a positive pressure principle from the fluid-jet, or a negative pressure principle from wall suction. The fluid-jet is capable of exerting up to 20,000 psi. 
     FIG. 1 shows a cross-section view of an end piece  2  of a preferred embodiment of the fluid-jet catheter of the present invention. Preferably, the end piece  2  is constructed of stainless steel, but other materials may be used. In a preferred embodiment, the end piece  2  is cylindrical in shape with a domed top  6 . However, the end piece  2  may be of any shape. 
     The end piece  2  incorporates a hollow chamber  4  through which the saline solution fluid jet flows. Preferably, the chamber  4  is cylindrical in shape, however, the chamber may be of any geometry. The chamber  4  extends partially through the end piece  2 , interconnects outward flow tube and the return tube, and connects to a flow reverser  7  which redirects the flow of saline solution back towards the proximal end of the catheter. A lateral opening  8  is formed in an external side of the end piece  2 . As saline solution is jetted through the chamber toward the distal or proximal end of the fluid-jet catheter, negative pressure in the chamber and opening is caused by saline solution jetting through the chamber past the lateral opening  8 . Creating a Bernoulli effect causes suction, which allows targeted tissue to be drawn into the lateral opening  8  of the end piece  2 . The surface of the inward-drawn tissue is abraded by the jet stream of saline solution which strips clusters of cells from the tissue. The clusters of cells are entrained in the saline solution and flow through a cell trap recovery opening  12  which decreases diameter in a downstream direction toward the proximal end of the catheter. 
     FIG. 2 is a perspective view of the end piece  2  of the fluid-jet catheter of the present invention, showing the spatial relationships between the chamber  4 , the lateral opening  8  and the cell recovery opening  12 . The chamber  4  of the end piece  2  is shown in detail in FIG.  3 . 
     FIG. 4 shows a schematic view of the fluid-jet catheter of the present invention dissecting cells from a polyp  16  inside of a colon  18 . A targeted piece of the polyp  16  is drawn up into the lateral opening  8  of the end piece  2  due to suction created by a Bernoulli effect. As shown in FIGS. 5A and 5B, clusters  17  of cells are dissected from the polyp  16  by saline solution fluid jets pumped through the chamber  4  which extends through the end piece. Clusters of cells dissected from the tissue are then directed through a cell recovery opening and into a cell recovery tube which leads to a cell cluster trap. 
     FIGS. 5A and 5B are cross-section views of the dissecting distal end of the fluid-jet catheter of the present invention. FIG. 5A shows flexible tubing material  20  surrounding optical fibers  22  which are used for illuminating and conveying images of immediate surroundings of the fluid-jet end piece  2  to a viewing screen. The flexible tubing material  20  also surrounds a catheter tube  26  which houses a pressure tube  28  and a cell recovery return tube  14 . 
     FIG. 5B is a cross-section view of tissue from a polyp  16  being drawn into the lateral opening  8  of the end piece. The polyp  16  is abraded by saline jets which flow through a chamber  4 . The saline jets remove clusters of cells  17  from the targeted polyp  16 ; the clusters of cells  17  are entrained in the saline solution and are pushed through a cell recovery return tube  14  for collection at the proximal end of the catheter. 
     FIG. 6 shows one embodiment of the fluid-jet catheter of the present invention in which the curve  6  of the end piece  2  has a larger diameter than the catheter tube  26 , for smoothing flow and reducing pressure drop in the jetted fluid and allowing for dissection of large or irregularly shaped tissue samples. The end piece  2  tapers to attach to the catheter tube  26 . 
     FIG. 7 is a cross-section view of the dissecting, distal end of a preferred embodiment of the fluid-jet catheter of the present invention in which the pressure tube  28  through which saline solution is pumped into the chamber  4  extending through the end piece  2  is concentric with the catheter tube  26 . The catheter tube  26  and optical fibers  22  are surrounded by flexible tubing material  20 . A cell recovery tube  14  is housed within the catheter tube  26  for conveying dissected clusters of cells to the proximal end of the fluid-jet catheter of the present invention. 
     FIG. 8 shows an alternative embodiment of the fluid jet catheter of the present invention. In this embodiment, the pressure tube  28  through which saline is pumped leads to a chamber  4  within an end piece  2  incorporating a lateral opening  8 . The chamber  4  slopes toward the lateral opening  8 , causing a Venturi effect, resulting in suction. Tissue is drawn up into the opening  8  and is contacted by a saline solution fluid jet. The fluid jet dissects clusters of cells from the tissue, which are then pumped through a cell recovery opening  12  in the end piece  2  and into the cell recovery tube  14  for conveyance to the proximal end of the fluid-jet catheter. 
     FIG. 9 is a schematic representation of the proximal end of the fluid-jet catheter of the present invention. A catheter tube  26  and optical fibers  22  are surrounded by flexible tubing material  20 . Clusters of cells are passed through the cell recovery tube  14 , which is housed within the catheter tube  26 , and are deposited in a cell cluster trap  42  for storage and preservation. The cell cluster trap  42  is attached to the catheter tube by an attaching means  44  to facilitate removing and replacing the trap  42 . A pressure tube  28  for pumping saline solution is housed within the catheter tube  26  and is connected to a pump  40 . The pump is actuated by a controller  36 , which may be attached to a foot switch  38 . A power supply  34  supplies power to the controller  36  and to the pump  40 . 
     A foot switch  38  may be used to govern the actuation of the pump  40  for generating a high velocity saline jet by pumping saline through a pressure tube  28 . Targeted cell clusters contacted with the saline jet. The dissected targeted cells are then delivered to the proximal end of the fluid-jet catheter to a cell trap  42 . The cell trap  42  is removed, and the sample may be resuspended in a cytopreservative. The cell trap  42  must be replaced, but the fluid-jet catheter tube  26  need not be removed from the endoscope port, unlike current techniques. The system is then ready for another session. The process may be accomplished quickly and should take less than ten seconds, a savings of over one minute per biopsy. This time savings is beneficial because a patient is under anesthesia up to fifteen-minutes less for ten biopsies taken during a procedure. 
     Referring to FIG. 10, the fluid jet tip  50  used in diagnostics or therapeutics in conjunction with a cell trap. The tip  50  has a fluid jet lumen  52  which is curved to jet fluid from port  54  through operative opening  56  into receiver port  58  in the fluid return lumen  60 . The jet tip  50  may be constructed of two molded parts. A body portion  62  contains the two lumens  52  and  60  and the operative opening  56 . The end portion  64  contains the flow reversing curved portion  66  of high pressure lumen  52 . The lumens may be in tubes confined in the tip structure. Preferably the lumens ports and operative opening are formed in the structure during molding. 
     FIG. 11 shows an end  68  of a lighted endoscope  70 . Two fiber optic bundles  72  and  74  cast illumination  76  and  78  on internal targets within body organs and vessels through fibers in the bundles. The end  64  of the fluid jet tip  50  of a catheter may be fixed in the endoscope or more preferably may be slidable through the endoscope to make final adjustments for alignment of the tissue of interest with the operative opening in the tip  50 . 
     FIG. 12 shows the surface  82  of a polyp  80  being drawn into the operative opening  56  by negative pressure surrounding the jet  84  flowing across the opening from port  54  to port  58 . Cell clusters are abraided from the polyp surface  82  and are entrained with the jetted fluid in the return lumen  60 . 
     Flow through the tubes may be continuous, pulsed or intermittent. The return tube may have a larger diameter than the outward tube, to promote the jetting flow through the chamber. Suction, such as by aspiration, may be applied to the return tube downstream of the cell trap. The operator may, upon locating a polyp of interest, apply the aspiration or a lower outward flow or both to create a suction in the chamber. When observations through a screen attached to the fiber optic system, meters or alerts show that the tissue has been partially drawn into the chamber, the operator may further depress the pedal to increase or pulse the outward flow and maintain or increase the suction to abrade and collect cell clusters from the investigated polyp or tissue. The portion of the end is mapped. The flow is stopped, the cell trap is removed and marked to relate it to the mapped portion. 
     The distal end is moved to a new location while using the display screen. A new cell trap is inserted at the proximal end, and the cell cluster collection process is repeated. Many polyps or other tissue samples may be recovered without a lengthy process of withdrawing and reinserting a catheter. 
     A limited range of fluid-jet settings allows the dissection of many different tissue types into single cells or clusters of cells, however, a wide variety of fluid-jet settings are available for dissecting different types of tissues. The fluid-jet is capable of being adjusted to various pulsation frequencies, pressures, patterns, fluid compositions, spray patterns and flow rates. Preferably the fluid-jet is a saline solution fluid-jet. In addition, the fluid-jet may be of any size, as the size of the fluid-jet orifice may influence the effectiveness of dissection. 
     The high pressure saline jet of the fluid-jet catheter of the present invention may be of a single coherent stream, or may be of many geometric styles. Regardless of the pattern, the high velocity saline jet produces an immediate region of reduced pressure. Because of this region of reduced pressure, tissue is drawn into the path of the saline jet, and cell clusters are dissected free from the targeted tissue. The cell clusters are then retrieved outside the catheter. The delivered cell clusters may then be re-suspended in a liquid based cytopreservative and prepared for analytical cytology. 
     Liquid-based analytical cytology is better than using fixed specimens because liquid-based cytology allows for conventional cyto-analysis of the cell clusters, thus allowing advanced adjunctive screening, such as flow cytometry and immunochemistry. Cell clusters may be examined with monoclonal or polyclonal antibodies to detect viral antigens of CMV, HSV and varicella zoster virus. In situ DNA or RNA hybridization using the polymerase chain reaction could also be used to detect the presence of viral DNA or RNA. 
     The dissected clusters of cells collected in the cell cluster trap by the fluid-jet catheter of the present invention may be captured in bridal crinoline, a 100% nylon fabric that is compatible with liquid-based cytology. The filtered cell clusters may then be washed and re-suspended in a cytopreservative. Thin layer cytology slides may be prepared using either an automated cell preparation station or a cyto-centrifuge, and may be stained with Hematoxylin and Eosin or other prepared stains. The slides may be visually inspected under a microscope or subjected to other types of analysis. 
     Cytopreservatives may be used to enhance the long term stability of cells dissected from tissue by fluid-jet catheter of the present invention. For example, hog intestinal mucosa remain well preserved in Cytorich red®, a slightly hemolytic cytopreservative, for several hours. Eventual, practical, widespread use of a fluid-jet endoscopic catheter will require the cell suspension to be stable for cytoanalysis for at least one week. Several commercially available cytopreservatives may be used and compared in their efficacy of preservation of clusters of cells for up to one month. Fluid-jet dissection of tissue may have no untoward effects upon the cell suspension, or perhaps one cytopreservative is more effective than others. 
     While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention, which is defined in the following claims.