Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
  • A61B8/12—Diagnosis using ultrasonic, sonic or infrasonic waves in body cavities or body tracts, e.g. by using catheters

Definitions

• the present invention relates to a catheter for image acquisition.
• an imaging catheter that utilizes intravascular ultrasound (IVUS) is used as a medical device to obtain diagnostic images in order to observe the characteristics of these lesions or their condition after treatment (see Patent Document 1).
• IVUS intravascular ultrasound
• the tip end of the imaging sensor is formed by connecting a fusion tube made of thermoplastic resin or the like to a flange extending in the longitudinal direction on the tip side of the sensor, and fusing the fusion tube by heat fusion or the like. Therefore, the imaging catheter has a region at the tip where the fusion tube has melted and hardened (hard region) that is the length of the fusion tube.
• the tip end with the hard region is highly rigid and does not bend easily.
• an imaging catheter When an imaging catheter is inserted into a blood vessel, which is a body lumen, it advances to the target site along the shape of the blood vessel.
• the imaging catheter has a long hard region at its tip, when passing through a small blood vessel, this hard tip can get caught on the blood vessel wall, leaving room for improvement.
• the present invention was made based on the above problem, and specifically aims to provide an imaging catheter that can improve passability through biological lumens by shortening the longitudinal length of the hard region at the tip.
• the present invention can be achieved by any one of the means described below in (1) to (8).
• An imaging catheter for acquiring diagnostic ultrasonic tomographic images in a living body lumen, the imaging catheter comprising: an inner tube with a first lumen; a sensor section disposed at the tip of the inner tube, in which multiple transducers for transmitting and receiving ultrasonic waves in the living body lumen are arranged in a circumferential ring shape; an outer tube disposed to cover the inner tube at a position proximal to the sensor section so as to partition a second lumen; and a joint section that joins the sensor section to the inner tube and the outer tube, the sensor section being composed of a shaft section extending in the longitudinal direction, a reinforcing body having a tip support section disposed at the tip of the shaft section and having a diameter larger than the outer diameter of the shaft section, and a base support section disposed at the base end of the shaft section and having a diameter larger than the outer diameter of the shaft section; and a film sensor on whose outer surface the multiple transducers are arranged and wound around the reinforcing body, the joint section
• the joint has a tapered surface in which the outer diameter decreases from the tip support part of the sensor part toward the outer peripheral surface of the inner tube, and has a tip joint that joins the tip support part to the inner tube, a filling joint that fills the space between the shaft part of the reinforcement body and the wound film sensor, and a base joint that joins the base support part of the reinforcement body to the outer tube, and the tip joint, the filling joint, and the base joint are formed with the resin bonding agent.
• the imaging catheter uses a resin adhesive to form the joints, without using components such as fusion tubes, so that, for example, the longitudinal length of the tip joint that joins the inner tube and the tip support part of the reinforcement body can be shortened. This improves the passability of the imaging catheter through biological lumens such as blood vessels.
• FIG. 1 is a schematic configuration diagram of a medical system including an image acquisition catheter according to an embodiment.
• FIG. 2 is a diagram showing an image acquisition catheter according to an embodiment.
• FIG. 2 is a cross-sectional view of an imaging catheter according to an embodiment.
• 1 is a partial cross-sectional view of the vicinity of the tip of an imaging catheter according to an embodiment.
• FIG. 1 is a partial cross-sectional view of the vicinity of the tip of a conventional imaging catheter.
• 1A and 1B are diagrams showing a first form of a fixing reinforcement part of an imaging catheter according to an embodiment.
• 13A and 13B are diagrams showing a second form of the fixing reinforcement part of the imaging catheter according to the embodiment.
• 13A and 13B are diagrams showing a third form of the fixing reinforcement part of the imaging catheter according to the embodiment.
• the "longitudinal direction” is the direction along the central axis of the imaging catheter 100.
• the "radial direction” is the direction moving away from or approaching the central axis in an orthogonal cross section (transverse cross section) with the central axis of the imaging catheter 100 as the reference axis.
• the "circumferential direction” is the rotational direction with the central axis of the imaging catheter 100 as the reference axis.
• the side of the imaging catheter 100 where the proximal hub portion 60 is located is referred to as the "base end side.”
• the side of the imaging catheter 100 that is located opposite the base end side and that is introduced into the living body is referred to as the "tip side.”
• the "tip portion” refers to a portion that includes a certain range from the tip (the most distal end) toward the base end side
• the “base end portion” refers to a portion that includes a certain range from the base end (the most proximal end) toward the tip end side.
• the image acquisition catheter 100 is configured as an IVUS catheter that utilizes intravascular ultrasound (IVUS).
• IVUS intravascular ultrasound
• blood vessels are exemplified as a biological lumen to which the image acquisition catheter 100 is applied.
• the biological lumen to which the image acquisition catheter 100 is applied is not limited to blood vessels, and may be, for example, biological organs such as the bile duct, trachea, esophagus, other digestive tract, urethra, and ear and nose cavities.
• the medical system 1 includes an image acquisition catheter 100 and an external device 300.
• the medical system 1 inserts the image acquisition catheter 100 into a patient's blood vessel, delivers the sensor unit 30 to the lesion, and outputs images (such as cross-sectional images of the blood vessels) captured at and around the lesion to the external device 300 for use in diagnosing the characteristics of the lesion.
• the imaging catheter 100 has an inner tube 10, an outer tube 20, a sensor unit 30, a joint unit 40, a signal line 50, a proximal hub unit 60, and an imaging unit 70.
• the imaging catheter 100 is configured as a so-called "over-the-wire type catheter” in which a guidewire can be inserted and removed from the catheter base end through a first lumen 11 of the inner tube 10.
• the imaging catheter 100 may also be configured as a so-called "rapid exchange type catheter.”
• the inner tube 10 is a long tubular member having a first lumen 11 through which a guide wire can be inserted, the first lumen 11 extending from the distal end to the proximal end.
• the inner tube 10 has a distal end located at the distal end of the imaging catheter 100 and a proximal end located at the proximal end of the first port 61 of the proximal hub portion 60, and is configured to allow the guide wire to be inserted and removed.
• the material that makes up the inner tube 10 is a material that can be used in catheters, etc., and can be, for example, various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polyimide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based.
• various thermoplastic elastomers such as styrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polyimide-based, polybutadiene-based, trans-polyisoprene-based, fluororubber-based, and chlorinated polyethylene-based.
• the outer tube 20 is disposed so as to cover the inner tube 10 at a position proximal to the sensor unit 30, so as to define a second lumen 21, through which a plurality of signal lines 50 can be inserted, between the outer tube 20 and the inner tube 10.
• the proximal end of the outer tube 20 is located distal to the distal opening of the second port 62 inside the proximal hub portion 60. This allows the signal lines 50 to be inserted from the sensor unit 30 through the second lumen 21 and then led out of the second port 62.
• the outer tube 20 is disposed coaxially with the inner tube 10.
• the outer tube 20 can be made of, for example, the same material as the inner tube 10 exemplified above.
• the sensor unit 30 is disposed at the distal end of the inner tube 10, which is closer to the distal end than the outer tube 20.
• the sensor unit 30 is composed of a reinforcing body 31 and a film sensor 32.
• the sensor unit 30 transmits and receives ultrasonic waves within a biological lumen, and enables transmission of electrical signals between the sensor unit 300 and an external device 300 via signal lines 50 connected to each of the transducers 32a.
• the reinforcing body 31 has a cylindrical shaft portion 31a, a tip support portion 31b that is disposed at the tip of the shaft portion 31a and has a larger diameter than the outer diameter of the shaft portion 31a, and a base end support portion 31c that is disposed at the base end of the shaft portion 31a and has a larger diameter than the outer diameter of the shaft portion 31a.
• the reinforcing body 31 can be formed of a metal material.
• the reinforcing body 31 has a third lumen 31d formed therein through which the inner tube 10 can be inserted.
• the film sensor 32 is made of a flexible board with electronic components mounted on a form board, and an electronic circuit including multiple transducers 32a is formed on the outer surface.
• the film sensor 32 is wound around the tip support portion 31b and base support portion 31c of the reinforcement body 31.
• Each transducer 32a has an oscillator made of a piezoelectric material with piezoelectric properties, such as ceramics or quartz, capable of converting an electrical signal into ultrasonic vibrations.
• the transducers 32a form a phased array arranged in a ring shape along the circumferential direction of the reinforcing body 31 when the film sensor 32 is wrapped around the reinforcing body 31.
• the sensor unit 30 can acquire tomographic images of blood vessels over a wide range in the circumferential direction at once without rotating the sensor unit 30.
• the multiple transducers 32a have the function of transmitting ultrasonic waves based on an electric signal (pulse signal) into the body cavity and receiving ultrasonic waves reflected from the biological tissue in the body cavity.
• Each of the transducers 32a is disposed on the outer surface of the film sensor 32 and is connected to a multiplexer 32b.
• the multiplexer 32b is a combination circuit that selects one of the multiple input lines and connects it to a single output line.
• Each of the transducers 32a is connected to each of the multiple signal lines 50 via the multiplexer 32b.
• Each of the transducers 32a is configured so that the multiplexer 32b can sequentially switch between transmitting and receiving operations. In other words, the multiple transducers 32a sequentially receive each received signal and sequentially transmit the received signal via the multiplexer 32b.
• the multiplexer 32b is driven and controlled by a control IC 32c formed on the film sensor 32.
• the joint 40 joins the sensor unit 30 to the inner tube 10 and/or the outer tube 20.
• the joint 40 has a distal joint 41, a proximal joint 42, and a filling joint 43.
• the distal joint 41, the proximal joint 42, and the filling joint 43 are all formed of a resin bonding agent.
• the tip joint 41 is disposed on the tip side of the sensor unit 30 so as to be adjacent to the tip support portion 31b of the sensor unit 30 and to be in contact with the outer circumferential surface of the inner tube 10. This allows the sensor unit 30 to be firmly joined to the inner tube 10.
• the tip joint 41 has a tapered surface 41a whose outer diameter decreases from the tip support portion 31b of the sensor unit 30 toward the outer circumferential surface of the inner tube 10. Because the tip joint 41 has a tapered surface 41a, it is possible to improve the insertability of the imaging catheter 100.
• the base end joint 42 is disposed adjacent to the base end support portion 31c of the sensor unit 30 and between the tip end of the outer tube 20. This allows the sensor unit 30 to be firmly joined to the outer tube 20.
• the filling joint 43 is filled into the internal space 33 formed between the shaft portion 31a of the reinforcing body 31 and the wound film sensor 32. This allows the film sensor 32 to be firmly joined to the reinforcing body 31.
• the filling joint 43 can also be filled into the third lumen 31d. This allows the sensor portion 30 to be firmly joined to the inner tube 10. By filling the filling joint 43 into the third lumen 31d so as to connect between the tip joint 41 and the base joint 42, the joint strength of the entire joint 40 can be increased.
• the resin adhesive used as the joint 40 has a property of being fluid when applied and hardening due to a chemical change caused by a curing process after application.
• a UV-curable adhesive or a thermosetting adhesive (such as an epoxy-based adhesive) can be suitably used as the resin adhesive.
• the resin adhesive constituting the tip joint 41 partially penetrates into the interface between the reinforcement 31 and the film sensor 32 at the tip side of the sensor section 30.
• the resin adhesive constituting the base joint 42 partially penetrates into the interface between the reinforcement 31 and the film sensor 32 at the base side of the sensor section 30. This allows the imaging catheter 100 to firmly join the sensor section 30 to the inner tube 10 and the outer tube 20 using only the resin adhesive without using a fusion tube or the like, and simplifies the manufacturing process.
• the tip joint 41, base joint 42, and filling joint 43 constituting the joint 40 may be formed from the same resin adhesive or from multiple resin adhesives.
• the tip joint 41 can be formed only from a resin bonding agent, as shown in FIG. 4A.
• the tip joint 41 is formed so as to form a tapered surface 41a and to join the tip support part 31b and the outer circumferential surface of the inner tube 10.
• FIG. 4B shows the configuration around the tip of the conventional imaging catheter 500 for comparison.
• the tip 501 of the imaging catheter 500 is provided with a flange 520 extending toward the tip side of the sensor unit 510, and a fusion tube 540 is attached to this flange 520.
• the imaging catheter 500 is then bonded between the tip of the sensor unit 510 and the outer circumferential surface of the inner tube 530 by heat-sealing the fusion tube 540.
• the imaging catheter 500 has a joint 550 formed by bonding the tip of the sensor unit 510 and the inner tube 530 with the fusion tube 540.
• the tip joint 41 of the imaging catheter 100 of this embodiment has a longitudinal length L1 as shown in FIG. 4A.
• the longitudinal length L1 of the tip joint 41 corresponds to the longitudinal length of the hard region A1 at the tip of the imaging catheter 100 that can be formed by the tip joint 41.
• the joint 550 of the conventional imaging catheter 500 has a longitudinal length L2 as shown in FIG. 4B.
• the longitudinal length L2 of the joint 550 corresponds to the longitudinal length of the hard region A2 at the tip of the imaging catheter 500 that can be formed by the joint 550.
• the longitudinal length L1 of tip joint 41 is shorter than the longitudinal length L2 of joint 550 (L1 ⁇ L2).
• Tip joint 41 is formed only from a resin adhesive, whereas joint 550 is formed from fusion tube 540. Because tip joint 41 is formed from a resin adhesive, it is possible to adjust the longitudinal length to be shorter. In contrast, because joint 550 is connected to flange portion 520 and fusion tube 540 is disposed therein, it is necessarily longer in the longitudinal direction by the longitudinal length of fusion tube 540.
• the imaging catheter 100 has a tip joint 41 formed from a resin adhesive, and therefore has a shorter longitudinal length (L1 ⁇ L2) than the joint 550 formed from the fusion tube 540 of the conventional imaging catheter 500.
• the shorter the longitudinal length L1 of the tip joint 41 of the imaging catheter 100 the shorter the longitudinal length of the hard region A1 at the tip, improving blood vessel passage. Therefore, the imaging catheter 100 has improved maneuverability within blood vessels and can suppress blood vessel damage caused by contact with the inner blood vessel wall when advancing or retracting the catheter.
• the length L1 of the tip joint 41 in the longitudinal direction is 0.1 mm or more and 5 mm or less, and preferably 0.1 mm or more and 2 mm or less.
• the imaging catheter 100 can be configured with a fixing reinforcement section 80 that increases the fixing strength of the tip joint section 41 to the tip support section 31b of the reinforcement body 31.
• the fixing reinforcement section 80 can be formed on the tip support section 31b of the reinforcement body 31, as in the first form shown in Figure 5A, the second form shown in Figure 5B, and the third form shown in Figure 5C. The following forms can also be combined as appropriate.
• the fixing reinforcement part 80A according to the first embodiment is formed of an uneven part provided on the tip surface 31e of the tip support part 31b.
• the uneven shape of the fixing reinforcement part 80A can increase the contact area with the tip joint part 41.
• the fixing reinforcement part 80B is formed of one or more holes formed in the tip surface 31e of the tip support part 31b.
• the contact area of the fixing reinforcement part 80B with the tip joint part 41 can be increased by filling the holes with a resin adhesive.
• the fixing reinforcement part 80C is formed of a tapered step part formed on the outer peripheral surface of the outer edge of the tip of the tip support part 31b so as to reduce in diameter toward the inner tube 10.
• the tapered shape of the fixing reinforcement part 80C can increase the contact area with the tip joint part 41.
• the fixing strength of the tip joint part 41 to the tip support part 31b is increased, and peeling during operation can be prevented.
• the fixing reinforcement part 80C has a tapered shape toward the inner tube 10, it is easy to form the tapered surface 41a when forming the tip joint part 41 with a resin adhesive.
• the tapered step part has a length in the long axis direction of 0.1 mm or more and 2 mm or less. This allows the tip joint part 41 to be formed with a moderately tapered surface while shortening the length in the long axis direction.
• the signal lines 50 have wire portions 51 made of a metallic material having electrical conductivity and contrast properties, one end of which is connected to the sensor unit 30 and the other end of which is connected to the connector 110. Each of the signal lines 50 is connected to the multiplexer 32b or the control IC 32c by soldering or the like.
• the signal lines 50 are capable of transmitting and receiving electrical signals between the sensor unit 30 and the external device 300 by connecting the connector 110 to the connector 330 of the external device 300.
• the signal lines 50 are connected to the connector 110 in a state where the portions of the signal lines 50 exposed from the second port 62 of the proximal hub unit 60 on the base end side are bundled together to form a cable 120.
• the signal line 50 can be made up of multiple pieces of each, including a coated wire in which the wire portion 51 is coated with a fluororesin or the like, and a coaxial cable in which the outer conductor and inner conductor formed by the wire portion 51 are arranged at regular concentric intervals.
• the signal line 50 is a coaxial cable used as a dedicated receiving line, the transmission loss of the electrical signal (imaging data) acquired by the sensor unit 30 can be reduced.
• the signal line 50 can also be made up of a flexible cable in which multiple wire portions 51 are sandwiched between resin films or the like, or a flat cable in which multiple wire portions 51 covered with an insulating coating are arranged in parallel in a band shape.
• the proximal hub portion 60 has a first port 61 and a second port 62 , and is connected to the base ends of the inner tube 10 and the outer tube 20 .
• the proximal opening of the first port 61 of the hand hub section 60 is connected in communication with the first lumen 11 of the inner tube 10. This allows the hand hub section 60 to insert and remove a guide wire into and from the inner tube 10.
• the proximal opening of the second port 62 of the hand hub section 60 is connected in communication with the second lumen 21 of the outer tube 20. This allows the hand hub section 60 to lead out the proximal ends of multiple signal lines 50 from the second port 62.
• the hand hub portion 60 can be made of, for example, hard resin or metal materials that can be used in the medical field.
• the imaging section 70 is disposed near the tip of the inner tube 10.
• the imaging section 70 can be made of, for example, a known metal material that has X-ray contrast properties (X-ray opacity).
• the contrast imaging sections 70 can be placed at regular intervals along the longitudinal direction of the inner tube 10 so as to function as markers when measuring the distance of the sensor section 30 to the lesion in the blood vessel and the length of the lesion.
• the placement interval of the contrast imaging sections 70 can be set, for example, between 10 mm and 40 mm.
• the imaging section 70 can be a ring-shaped metal part with X-ray contrast that can be attached to the outer surface of the inner tube 10 by swaging or other processes.
• the imaging section 70 is not limited to being attached to the outer surface of the inner tube 10, but may also be partially or completely embedded inside the tube wall of the inner tube 10.
• the number, shape, spacing, etc. of the imaging sections 70 can be set appropriately according to the specifications of the imaging catheter 100.
• the external device 300 includes a control unit 310 , a display device 320 , and a connector 330 .
• the external device 300 is electrically connected to the imaging catheter 100 by connecting the connector 110 of the imaging catheter 100 to the connector 330. This allows the external device 300 to transmit and receive electrical signals to and from the sensor unit 30 of the imaging catheter 100.
• the control unit 310 is mainly composed of a CPU, memory, and input/output units, and is responsible for controlling the entire medical system 1.
• the control unit 310 outputs a control signal to the sensor unit 30 of the image acquisition catheter 100 to emit ultrasound, inputs a detection signal from the sensor unit 30, and performs predetermined signal processing based on the detection signal to acquire image data (tomographic image).
• the control unit 310 displays information (images) based on the acquired image data on the display device 320.
• the imaging catheter 100 is a device for acquiring diagnostic ultrasound tomographic images within a biological lumen, and comprises an inner tube 10 having a first lumen 11 through which a guidewire can be inserted, a sensor unit 30 arranged at the tip of the inner tube 10 and having a plurality of transducers 32a arranged in a circumferential ring shape for transmitting and receiving ultrasound within the biological lumen, a plurality of signal lines 50 connected to each of the transducers 32a and enabling transmission of electrical signals between the plurality of transducers 32a and an external device 300, and a catheter 300 arranged to cover the inner tube 10 at a position proximal to the sensor unit 30 so as to define a second lumen 21 through which the plurality of signal lines 50 can be inserted between the inner tube 10 and the sensor unit 30.
• the device has an outer tube 20 arranged as shown in FIG. 1, a proximal hub section 60 connected to the proximal end of the inner tube 10 and the proximal end of the outer tube 20 and equipped with a first port 61 through which a guide wire can be inserted and removed and a second port 62 through which multiple signal lines 50 are led out, a sensor section 30, and a joint section 40 that joins the inner tube 10 and the outer tube 20.
• the sensor section 30 is composed of a reinforcing body 31 having a shaft section 31a extending in the longitudinal direction, a tip support section 31b arranged at the tip of the shaft section 31a and having a larger diameter than the outer diameter of the shaft section 31a, and a base end support section 31c arranged at the base end of the shaft section 31a and having a larger diameter than the outer diameter of the shaft section 31a, and a film sensor 32 with multiple transducers 32a arranged on the outer surface and wound around the reinforcing body 31.
• the joint section 40 is formed of a resin adhesive.
• the tip of the conventional imaging catheter 500 is joined to the sensor section 510 using a fusion tube 540 as shown in FIG. 4B, and is therefore necessarily longer in the longitudinal direction by the longitudinal length of the fusion tube 540.
• the imaging catheter 100 uses a resin bonding agent to form the tip joint 41 that joins the inner tube 10 and the tip support section 31b of the reinforcement body 31 that constitute the joint 40, and therefore can have a shorter longitudinal length than the joint 550 (L1 ⁇ L2). Therefore, the imaging catheter 100 has improved operability within blood vessels (vascular passability) and can suppress blood vessel damage due to contact with the inner wall of the blood vessel during advancement and withdrawal operations.
• Medical system 10 inner tube, 11 first lumen, 20 outer tube, 21 second lumen, 30 sensor unit, 31 Reinforcement body (31a shaft portion, 31b tip support portion, 31c base end support portion, 31d third lumen, 31e tip surface of tip support portion), 32 film sensor (32a transducer, 32b multiplexer, 32c control IC), 33 interior space, 40 joint, 41 Tip joint, 42 proximal junction, 43 Filling joint, 50 signal line, 51 wire portion, 52 spiral part (52a loosely wound part, 52b, 54 closely wound part), 53 Extension part, 55 Blade portion, 60 Hand hub part, 61 first port, 62 second port, 70 Contrast department, 80 (80A to 80C) fixed reinforcement part, 100 Image acquisition catheter, 110 Connector of imaging catheter; 120 cable, 300 external device, 310 control unit, 320 display device, 330 External device connector.

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Citations (6)

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  • 2024-11-08 JP JP2025556467A patent/JPWO2025100517A1/ja active Pending
  • 2024-11-08 WO PCT/JP2024/039746 patent/WO2025100517A1/ja active Pending

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