Diagnostic imaging catheter

Abstract

This catheter for image diagnosis has: an outer tube; a drive shaft provided radially inside the outer tube; and an inner tube which is provided radially inside the outer tube and radially outside the drive shaft and can move axially relative to the outer tube and integrally with the drive shaft, wherein the inner tube has a notch by which a flow path inside the inner tube communicates with a flow path between the inner tube and the outer tube.

Description

Technical Field

[0001] The present disclosure relates to a catheter for image diagnosis.

Background Art

[0002] A catheter for image diagnosis generally has a pull-back mechanism at the hand-held part for changing the relative position between a sheath and a drive shaft in order to continuously observe a cross-section within a body cavity (see, for example, Patent Document 1). The pull-back mechanism includes an outer tube and an inner tube provided radially inside the outer tube and radially outside the drive shaft, and is axially movable relative to the outer tube and integrally with the drive shaft.

[0003] When using a catheter for image diagnosis, priming is performed to fill its lumen with a liquid. Priming is usually performed in the most retracted state where the inner tube is pulled out from the outer tube.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] During priming, when air is entrained when the priming liquid enters from the inner tube into the outer tube where the cross-sectional area of the flow path expands, the air may become bubbles and it may be difficult to escape from the pull-back mechanism.

[0006] Therefore, an object of the present disclosure is to provide a catheter for image diagnosis that can suppress the bubbling of air in the pull-back mechanism during priming and thus achieve good priming performance.

Means for Solving the Problems

[0007] A diagnostic imaging catheter in a first aspect of the present disclosure comprises an outer tube, a drive shaft provided radially inward from the outer tube, and an inner tube provided radially inward from the outer tube and radially outward from the drive shaft, and which is axially movable relative to the outer tube and integrally with the drive shaft, wherein the inner tube has a notch that connects a flow path within the inner tube to a flow path between the inner tube and the outer tube.

[0008] In one embodiment of the present disclosure, the imaging catheter includes a notch which provides a hole that connects the flow path within the inner tube to the flow path between the inner tube and the outer tube.

[0009] In one embodiment of the present disclosure, the imaging catheter has a hole through which the hole penetrates a recess provided on the outer surface of the inner tube, extending from the tip end to the proximal end of the inner tube.

[0010] In one embodiment of the present disclosure, the imaging catheter has an inner tube having a constricting portion that narrows the tip of the flow path within the inner tube.

[0011] A diagnostic imaging catheter in a second aspect of the present disclosure comprises an outer tube, a drive shaft provided radially inward of the outer tube, an inner tube provided radially inward of the outer tube and radially outward of the drive shaft, and movable axially relative to the outer tube and integrally with the drive shaft, and an elastic membrane facing the tip surface of the inner tube when the inner tube is fully retracted from the outer tube, wherein the elastic membrane has a hole that connects a flow path on the proximal end side of the elastic membrane to a flow path between the elastic membrane and the outer tube.

[0012] In one embodiment of the present disclosure, the imaging diagnostic catheter has an outer tube integrally with the elastic membrane.

[0013] In one embodiment of the present disclosure, the imaging diagnostic catheter has a support tube provided radially inward of the inner tube and radially outward of the drive shaft, and which is movable axially relative to the inner tube and integrally with the outer tube, wherein the support tube integrally includes the elastic membrane. [Effects of the Invention]

[0014] According to this disclosure, it is possible to provide an imaging diagnostic catheter that can suppress the formation of air bubbles within the pullback mechanism during priming, thereby achieving good priming performance. [Brief explanation of the drawing]

[0015] [Figure 1] This is a plan view showing an external device connected to an imaging diagnostic catheter as the first embodiment. [Figure 2A] Figure 1 is a side view showing the imaging catheter in its most forward position before the pullback operation. [Figure 2B] Figure 1 is a side view showing the imaging catheter in its fully retracted position after a pullback operation. [Figure 3] Figure 1 is a cross-sectional view showing the tip of the imaging catheter. [Figure 4] Figure 1 is a cross-sectional view showing the proximal end of the imaging diagnostic catheter. [Figure 5] Figure 1 is a cross-sectional view showing the pullback mechanism of an imaging catheter. [Figure 6] This is a cross-sectional view showing a magnified portion of the pullback mechanism shown in Figure 5. [Figure 7] This is a cross-sectional view AA in Figure 6. [Figure 8] Figure 6 is an external view showing the assembly of the tip of the inner tube. [Figure 9] This is a cross-sectional view showing a part of the pullback mechanism in the second embodiment. [Figure 10] Figure 9 is a cross-sectional view of BB.

Mode for Carrying Out the Invention

[0016] Hereinafter, with reference to the drawings, embodiments of the catheter for image diagnosis according to the present disclosure will be exemplified and described in detail.

[0017] The catheter 1 for image diagnosis according to the present embodiment shown in FIG. 1 is a dual type that uses both intravascular ultrasound diagnosis (IVUS) and optical coherence tomography (OCT). In the dual-type catheter 1 for image diagnosis, there are three modes: a mode in which a tomographic image is acquired only by IVUS, a mode in which a tomographic image is acquired only by OCT, and a mode in which a tomographic image is acquired by both IVUS and OCT, and these modes can be switched and used. As shown in FIG. 1, the catheter 1 for image diagnosis is connected to an external device 2 and driven. The catheter 1 for image diagnosis and the external device 2 constitute an image diagnostic apparatus 3.

[0018] As shown in FIGS. 1 to 5, the catheter 1 for image diagnosis includes a sheath 4 inserted into a body cavity such as a blood vessel (such as a coronary artery) of a living body, an outer tube 5 connected to the proximal end portion of the sheath 4, an inner tube 6 inserted into the outer tube 5 so as to be able to advance and retreat, a unit connector 7 that is continuous with the proximal end portion of the outer tube 5 and holds the inner tube 6 so as to be able to advance and retreat, and a hub 8 that is continuous with the proximal end portion of the inner tube 6. Further, the catheter 1 for image diagnosis has an imaging core 12 including a drive shaft 9, a housing 10 fixed to the tip of the drive shaft 9, and a signal transmission / reception unit 11 that is housed in the housing 10 and transmits and receives a signal that is ultrasonic waves and / or light. The imaging core 12 is inserted into the sheath 4, the outer tube 5, and the inner tube 6, and is axially movable forward and backward integrally with the inner tube 6 with respect to the sheath 4 and the outer tube 5.

[0019] In this specification, the tip refers to the end of the imaging catheter 1 that is inserted into a body cavity, the proximal end refers to the end of the imaging catheter 1 that is held outside a body cavity, the axial direction refers to the direction along the central axis O of the drive shaft 9 (i.e., the direction of extension of the drive shaft 9), the radial direction refers to the direction along a straight line perpendicular to the central axis O, and the circumferential direction refers to the direction around the central axis O.

[0020] As shown in Figure 2A, the drive shaft 9 extends through the sheath 4, outer tube 5, and inner tube 6 into the interior of the hub 8. The hub 8, inner tube 6, drive shaft 9, housing 10, and signal transmitting / receiving unit 11 are connected to each other so that they can move axially together with respect to the sheath 4 and outer tube 5. Therefore, for example, when the hub 8 is pushed toward the tip, i.e., when a push operation is performed, the inner tube 6 connected to the hub 8 is pushed into the outer tube 5 and the unit connector 7, and the drive shaft 9, housing 10, and signal transmitting / receiving unit 11, i.e., the imaging core 12, move forward inside the sheath 4, i.e., toward the tip. For example, when the hub 8 is pulled toward the base, i.e., when a pullback operation is performed, the inner tube 6 is pulled out from the outer tube 5 and the unit connector 7 as shown by arrow A1 in Figures 1 and 2B, and the imaging core 12 moves toward the base inside the sheath 4 as shown by arrow A2.

[0021] As shown in Figure 2A, when the inner tube 6 is pushed as far forward as possible, its tip reaches the vicinity of the relay connector 13. At this time, the signal transmitting / receiving unit 11 is located at the tip of the sheath 4 (near the tip surface of the inner lumen of the sheath 4). The relay connector 13 connects the sheath 4 and the outer tube 5.

[0022] As shown in Figure 2B, a locking portion 14 is provided at the tip of the inner tube 6 to prevent it from coming loose. The locking portion 14 prevents the inner tube 6 from coming out of the outer tube 5. The locking portion 14 is configured to catch on a predetermined position on the inner wall of the unit connector 7 when the hub 8 is pulled to its furthest back position, that is, when the inner tube 6 is pulled out as far as it will be from the outer tube 5 and the unit connector 7.

[0023] As shown in Figure 3, the drive shaft 9 is a long, hollow member, and inside it are arranged an electrical signal line (electrical cable) 15 and an optical signal line (optical fiber) 16 connected to the signal transmitting / receiving unit 11.

[0024] The drive shaft 9 is formed from a coil shaft. Although not shown in the diagram, the coil shaft can be formed from multiple layers of coils with different winding directions. Each coil is made of a metal such as stainless steel or Ni-Ti (nickel-titanium) alloy.

[0025] The signal transmitting / receiving unit 11 includes an ultrasonic transmitting / receiving unit 11a for transmitting and receiving ultrasonic waves, and an optical transmitting / receiving unit 11b for transmitting and receiving light. The ultrasonic transmitting / receiving unit 11a has a transducer that transmits ultrasonic waves based on pulse signals into a body cavity and receives ultrasonic waves reflected from biological tissue within the body cavity. The transducer is electrically connected to an electrical connector 15a (see Figure 4) via an electrical signal line 15. The transducer can be made of a piezoelectric material such as ceramics or quartz.

[0026] The optical transmitting / receiving unit 11b has an optical element that transmits light into the body cavity and receives light reflected from the biological tissue within the body cavity. The optical element is optically connected to the optical connector 16a (see Figure 4) via the optical signal line 16. The optical element can be formed by a lens, such as a ball lens.

[0027] The signal transmitting / receiving unit 11 is housed inside the housing 10. The base end of the housing 10 is fixed to the tip of the drive shaft 9. The housing 10 is formed from a cylindrical metal tube, and an opening 10a is provided on its circumferential surface so as not to obstruct the transmission and reception of signals by the signal transmitting / receiving unit 11. The housing 10 can be formed, for example, by laser processing. The housing 10 may also be formed by machining from a metal block or by MIM (metal injection molding).

[0028] A tip member 17 is provided at the tip of the housing 10. The tip member 17 has a substantially hemispherical outer shape, which suppresses friction and snagging with the inner surface of the sheath 4. However, a configuration without the tip member 17 is also possible.

[0029] The sheath 4 has a lumen 4a into which the drive shaft 9 is inserted so as to be able to move forward and backward. A tubular guidewire insertion member 18, through which a guidewire can be passed, is attached to the tip of the sheath 4, offset from the axis of the lumen of the sheath 4. The sheath 4 and the guidewire insertion member 18 are joined by welding or the like. The guidewire insertion member 18 is provided with an X-ray contrast-enhanced marker 19. The marker 19 is made of a highly radiopaque metal pipe such as Pt or Au.

[0030] A communication hole 20 is formed at the tip of the sheath 4, connecting the inside and outside of the lumen 4a. Furthermore, a reinforcing member 21, which is joined to the guidewire insertion member 18, is provided at the tip of the lumen 4a of the sheath 4. The reinforcing member 21 has a through hole that connects the lumen 4a, located on the proximal end side of the reinforcing member 21, to the communication hole 20. Note that the reinforcing member 21 is not required at the tip of the sheath 4.

[0031] The communication hole 20 is a priming fluid discharge hole for discharging the priming fluid. When using the imaging diagnostic catheter 1, during the priming process in which the priming fluid is filled into the sheath 4, the priming fluid can be discharged to the outside through the communication hole 20, and gases such as air can be discharged from inside the sheath 4 along with the priming fluid.

[0032] The tip portion of the sheath 4, which is the range in which the signal transmitting / receiving unit 11 moves in the axial direction of the sheath 4, forms a window portion with higher signal transmittance compared to other parts. The sheath 4, the guide wire insertion member 18, and the reinforcing member 21 are made of a flexible material, and the material is not particularly limited. Examples include 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 materials. One or more of these can also be used in combination (polymer alloy, polymer blend, laminate, etc.).

[0033] As shown in Figure 4, the hub 8 includes a hub body 8a that is tubular in shape coaxial with the inner tube 6 and detachably attached integrally to the external device 2, a port 8b that protrudes radially outward from the hub body 8a and communicates with the inside of the hub body 8a, a connecting pipe 8c that is integrally attached to the outer surface of the drive shaft 9, a bearing 8d that rotatably supports the connecting pipe 8c, a sealing member (first sealing member 8e) that prevents priming fluid from leaking from between the connecting pipe 8c and the bearing 8d toward the base end, and a connector part 8f that is equipped with an electrical connector 15a and an optical connector 16a and detachably attached integrally to the first drive unit 2a of the external device 2. The connector part 8f is rotatable integrally with the connecting pipe 8c and the drive shaft 9.

[0034] The base end of the inner tube 6 is integrally connected to the tip of the hub body 8a. The drive shaft 9 is drawn out from the inner tube 6 inside the hub body 8a.

[0035] As shown in Figure 1, an injection device 22 for injecting priming fluid during priming is connected to port 8b. The injection device 22 has a connector 22a connected to port 8b and a syringe (not shown) connected to the connector 22a via a tube 22b.

[0036] The external device 2 includes a first drive unit 2a for rotationally driving the drive shaft 9, and a second drive unit 2b for axially moving the drive shaft 9 (i.e., for push-in / pull-back operations). The first drive unit 2a can be configured as, for example, an electric motor. The second drive unit 2b can be configured as, for example, an electric motor and a linear motion conversion mechanism. The linear motion conversion mechanism can convert rotational motion into linear motion and can be configured as, for example, a ball screw or a rack and pinion mechanism.

[0037] The operation of the first drive unit 2a and the second drive unit 2b is controlled by a control device 2c electrically connected to them. The control device 2c includes a CPU (Central Processing Unit) and memory. The control device 2c is electrically connected to the display 2d.

[0038] The signal received by the ultrasonic transceiver 11a is transmitted to the control device 2c via the electrical connector 15a, where it undergoes predetermined processing and is displayed as an image on the display 2d. The signal received by the optical transceiver 11b is transmitted to the control device 2c via the optical connector 16a, where it undergoes predetermined processing and is displayed as an image on the display 2d.

[0039] During diagnosis, the sheath 4 is inserted into the body cavity, and the imaging core 12 is rotated at a constant speed of approximately 1,000 to 10,000 rpm by the first drive unit 2a of the external device 2. At the same time, the imaging core 12 retracts at a constant speed within the lumen 4a of the sheath 4 by a pullback operation performed by the second drive unit 2b of the external device 2. During this time, the control device 2c of the external device 2 transmits and receives signals at the signal transmission / reception unit 11. Based on the signals received through scanning by the rotation and retraction of these signals, the condition of the tissues surrounding the body cavity is displayed as an image on the display 2d.

[0040] Thus, the imaging catheter 1 has a pullback mechanism 23 at the proximal end that changes the relative position between the sheath 4 and the drive shaft 9 in order to continuously observe the cross-section of the body cavity. As shown in Figures 2A, 2B and 5, the pullback mechanism 23 includes an outer tube 5, an inner tube 6 provided radially inward of the outer tube 5 and radially outward of the drive shaft 9, which is movable axially relative to the outer tube 5 and integrally with the drive shaft 9, a support tube 24 provided radially inward of the inner tube 6 and radially outward of the drive shaft 9, a spacer 25 that integrally connects the outer tube 5 and the support tube 24, a relay connector 13, and a unit connector 7. As mentioned above, the relay connector 13 is integrally connected to the sheath 4, and the inner tube 6 is integrally connected to the hub 8. The unit connector 7 is provided with a sealing member (second sealing member 7a) that prevents priming fluid from leaking from between the unit connector 7 and the inner tube 6 toward the proximal end.

[0041] In the pullback mechanism 23, the outer tube 5, support tube 24, inner tube 6, and drive shaft 9 are arranged coaxially and share a common central axis O.

[0042] The relay connector 13 is cylindrical in shape and has a cylindrical base-side inner circumferential surface 13a and a cylindrical tip-side inner circumferential surface 13c that is connected to the tip of the base-side inner circumferential surface 13a via an annular stepped portion 13b. The outer circumferential surface of the base end of the sheath 4 is joined to the tip-side inner circumferential surface 13c by welding or the like. The outer circumferential surface of the tip of the outer tube 5 is joined to the base-side inner circumferential surface 13a by welding or the like.

[0043] The spacer 25 is cylindrical in shape, with its outer surface in contact with the inner surface of the tip of the outer tube 5, and its inner surface in contact with the outer surface of the tip of the support tube 24. Furthermore, the outer surface of the spacer 25 is joined to the inner surface of the tip of the outer tube 5 by welding or the like, and the inner surface of the spacer 25 is joined to the outer surface of the tip of the support tube 24 by welding or the like. The spacer 25 is made of, for example, synthetic resin or metal.

[0044] The support tube 24 can be formed, for example, as a single-layer or multi-layer coil or tube. The support tube 24 can be made of, for example, synthetic resin or metal. When the inner tube 6 and drive shaft 9 are advanced relative to the outer tube 5 by a pushing operation, the drive shaft 9 is supported from the radially outer side by the support tube 24, thereby preventing the drive shaft 9 from buckling inside the outer tube 5 and hindering its smooth advancement.

[0045] Priming is typically performed when the inner tube 6 is fully extended from the outer tube 5 (see Figures 1 and 5). During priming, the priming fluid introduced from port 8b passes through the inner tube 6 and branches into a flow path between the outer tube 5 and the support tube 24, and a flow path inside the support tube 24, and flows through the pullback mechanism 23 toward the tip.

[0046] The priming fluid flowing through the channel between the outer tube 5 and the support tube 24 passes through a connecting passage formed by a notch (not shown) provided at the tip of the support tube 24 or the spacer 25 or both, merges with the priming fluid flowing through the channel inside the support tube 24, and flows toward the tip.

[0047] In this embodiment, as shown in Figures 6 and 7, the inner tube 6 has a notch 26 that connects the flow path inside the inner tube 6 to the flow path between the outer circumferential surface of the inner tube 6 and the inner circumferential surface of the outer tube 5. The notch 26 consists of two holes 27 that connect the flow path inside the inner tube 6 to the flow path between the outer circumferential surface of the inner tube 6 and the inner circumferential surface of the outer tube 5, and two recesses 28 provided on the outer circumferential surface of the inner tube 6 so as to extend from the tip end to the base end of the inner tube 6. The two holes 27 are provided at positions opposite each other with respect to the central axis O, with one hole 27 passing through one recess 28 and the other hole 27 passing through the other recess 28. Each hole 27 extends along the radial direction. Each hole 27 has a circular cross-section.

[0048] Furthermore, the inner tube 6 has a constricted portion 29 that narrows the leading end of the flow path inside the inner tube 6. In other words, the inner circumferential surface of the inner tube 6 is reduced in diameter at the constricted portion 29.

[0049] A locking portion 14 is provided in the portion of the inner tube 6 behind the notch 26. The locking portion 14 is composed of an enlarged diameter portion on the outer surface of the inner tube 6, and the rear end surface of the locking portion 14 protrudes radially outward from the outer surface of the inner tube 6 and forms an annular shape with respect to the central axis O. The unit connector 7 has a stopper surface 7b that contacts the rear end surface of the locking portion 14 to restrict further retraction of the inner tube 6.

[0050] As shown in Figure 8, the inner tube 6 is composed of a cylindrical inner tube body 6a and a flow path adjustment member 6b that is joined to the tip of the inner tube body 6a by welding or the like. The flow path adjustment member 6b is cylindrical and has a notch 26 and a constricted portion 29. The base end portion of the flow path adjustment member 6b is provided with an insertion recess 6c formed by an inner circumferential surface that contacts the outer circumferential surface of the tip of the inner tube body 6a and an end surface that contacts the tip surface of the inner tube body 6a. The base end surface of the flow path adjustment member 6b constitutes the rear end surface of the locking portion 14.

[0051] The inner pipe 6 is not limited to being formed by joining the flow path adjustment member 6b to the inner pipe body 6a as described above, but may also be formed, for example, by melting the inner pipe body 6a and deforming it to the shape described above.

[0052] During priming, if air is entrained when the priming fluid enters the flow path in the outer tube 5, where the flow path cross-sectional area widens, the air may form bubbles that are difficult to escape from the pullback mechanism 23. However, in this embodiment, since the inner tube 6 has a notch 26, the priming fluid can flow out not only from the flow path along the inner circumferential surface of the inner tube 6, but also from the flow path between the outer circumferential surface of the inner tube 6 and the inner circumferential surface of the outer tube 5 through the notch 26, as shown by the white arrow in Figure 6, toward the tip. In other words, in this embodiment, the priming fluid flowing out from the inner tube 6 can flow to the radially outer portion of the outer tube 5. Therefore, the formation of air bubbles within the pullback mechanism 23 during priming can be suppressed.

[0053] Furthermore, since the inner tube 6 has a throttling section 29 as described above, the throttling section 29 suppresses the flow rate of the priming fluid flowing out from the flow path along the inner circumferential surface of the inner tube 6, thereby increasing the flow rate of the priming fluid flowing out from the flow path between the outer circumferential surface of the inner tube 6 and the inner circumferential surface of the outer tube 5 through the notch 26. Therefore, by providing the throttling section 29, the formation of air bubbles within the pullback mechanism 23 during priming can be suppressed more reliably.

[0054] As described above, according to this embodiment, the inner tube 6 has a notch 26 that connects the flow path inside the inner tube 6 to the flow path between the inner tube 6 and the outer tube 5, thereby suppressing the formation of air bubbles in the pullback mechanism 23 during priming and achieving good priming performance.

[0055] Furthermore, according to this embodiment, since the notch 26 includes two holes 27 that connect the flow path inside the inner tube 6 to the flow path between the inner tube 6 and the outer tube 5, the formation of air bubbles within the pullback mechanism 23 during priming can be more reliably suppressed, thereby achieving better priming performance with greater certainty.

[0056] Furthermore, according to this embodiment, since the two holes 27 pass through two recesses 28 provided on the outer surface of the inner tube 6 so as to extend from the tip to the base of the inner tube 6, the formation of air bubbles within the pullback mechanism 23 during priming can be more reliably suppressed, thereby achieving better priming performance with greater certainty. The number, arrangement, shape, orientation, etc., of the holes 27 and recesses 28 constituting the notch 26 can be set as appropriate.

[0057] Furthermore, according to this embodiment, since the inner tube 6 has a constricting portion 29 that narrows the tip of the flow path inside the inner tube 6, the formation of air bubbles within the pullback mechanism 23 during priming can be more reliably suppressed, thereby achieving better priming performance with greater certainty.

[0058] In order to suppress the formation of air bubbles within the pullback mechanism 23 during priming and thereby achieve good priming performance, in the first embodiment, the pullback mechanism 23 is configured such that the inner tube 6 has a notch 26. However, the same effect can be obtained by replacing the above configuration of the pullback mechanism 23 with a configuration like that of the second embodiment shown in Figures 9 to 10.

[0059] In the second embodiment, the inner cylinder 6 is cylindrical without a notch 26, and its inner diameter is constant in the axial direction. On the other hand, the outer tube 5 integrally has a convex elastic membrane 30 that protrudes toward the tip. The elastic membrane 30 can be integrally provided on the outer tube 5 by joining it to the inner circumferential surface of the outer tube 5, for example by welding. An opening 30a is provided at the tip of the elastic membrane 30 through which the drive shaft 9 and the support tube 24 pass. The elastic membrane 30 is configured to face the tip surface of the inner tube 6 when the inner tube 6 is in its most retracted state, and to be elastically deformed and penetrated by the inner tube 6 as the inner tube 6 moves forward from its retracted state. The elastic membrane 30 is made of, for example, synthetic resin or rubber.

[0060] The elastic membrane 30 has four holes 30b that connect the flow path on the proximal end side of the elastic membrane 30 to the flow path between the proximal end surface of the elastic membrane 30 and the inner circumferential surface of the outer tube 5. The four holes 30b are arranged at 90° intervals in the circumferential direction around the central axis O. Each hole 30b has a circular cross-section. The configuration other than the pullback mechanism 23 is the same as that of the first embodiment.

[0061] According to this embodiment, since the pullback mechanism 23 has an elastic membrane 30, the direction of the flow of the priming liquid that flows out from the flow path in the inner tube 6 to the flow path in the outer tube 5 can be bent radially outward through each of the holes 30b in the elastic membrane 30, as shown by the white arrows in Figure 9. In other words, in this embodiment as well, the priming liquid flowing out from the inner tube 6 can be directed to the radially outward portion of the outer tube 5. Therefore, the formation of air bubbles within the pullback mechanism 23 during priming can be suppressed, thereby achieving good priming performance. The number, arrangement, shape, etc., of the holes 30b provided in the elastic membrane 30 can be set as appropriate.

[0062] In the second embodiment, the outer tube 5 integrally includes the elastic membrane 30, but the invention is not limited to this configuration. For example, the support tube 24 may integrally include the elastic membrane 30. That is, the elastic membrane 30 may be integrally connected to the support tube 24 at the opening 30a and be provided separately from the outer tube 5. In this case, the elastic membrane 30 is configured to face the tip surface of the inner tube 6 when the inner tube 6 is in its most retracted state, and to be elastically deformed as the inner tube 6 advances from its retracted state, thereby entering the inner tube 6. The other configurations are the same as in the second embodiment. With this configuration as well, the priming liquid flowing out from the inner tube 6 can be flowed radially outward within the outer tube 5 through the four holes 30b of the elastic membrane 30, thereby suppressing the formation of air bubbles within the pullback mechanism 23 during priming and achieving good priming performance.

[0063] The embodiments described above are merely examples of the present disclosure, and various modifications are possible, for example, as described below.

[0064] The imaging diagnostic catheter 1 of the first embodiment includes an outer tube 5, a drive shaft 9 provided radially inward of the outer tube 5, and an inner tube 6 provided radially inward of the outer tube 5 and radially outward of the drive shaft 9, and which is movable axially relative to the outer tube 5 and integrally with the drive shaft 9. The inner tube 6 can be modified in various ways as long as it has a notch 26 that connects the flow path inside the inner tube 6 to the flow path between the inner tube 6 and the outer tube 5.

[0065] However, in the first embodiment of the diagnostic imaging catheter 1, it is preferable that the notch 26 includes a hole 27 that connects the flow path inside the inner tube 6 to the flow path between the inner tube 6 and the outer tube 5.

[0066] Furthermore, in the first embodiment of the diagnostic imaging catheter 1, it is preferable that the hole 27 penetrates a recess 28 provided on the outer surface of the inner tube 6 so as to extend from the tip end to the proximal end of the inner tube 6.

[0067] Furthermore, in the first embodiment of the diagnostic imaging catheter 1, it is preferable that the inner tube 6 has a constricting portion 29 that narrows the tip of the flow path inside the inner tube 6.

[0068] The imaging diagnostic catheter 1 of the second embodiment includes an outer tube 5, a drive shaft 9 provided radially inward of the outer tube 5, an inner tube 6 provided radially inward of the outer tube 5 and radially outward of the drive shaft 9, and which is axially movable relative to the outer tube 5 and integrally with the drive shaft 9, and an elastic membrane 30 facing the tip surface of the inner tube 6 when the inner tube 6 is fully retracted from the outer tube 5, and the elastic membrane 30 can be modified in various ways as long as it has a hole 30b that connects the flow path on the proximal end side of the elastic membrane 30 to the flow path between the elastic membrane 30 and the outer tube 5.

[0069] However, in the second embodiment of the diagnostic imaging catheter 1, it is preferable that the outer tube 5 integrally includes an elastic membrane 30.

[0070] Furthermore, the imaging diagnostic catheter 1 of the second embodiment has a support tube 24 that is provided radially inward from the inner tube 6 and radially outward from the drive shaft 9, and is movable axially relative to the inner tube 6 and integrally with the outer tube 5, and it is preferable that the support tube 24 integrally has an elastic membrane 30.

[0071] Furthermore, the diagnostic imaging catheter 1 in the first and second embodiments is not limited to a dual type that uses both IVUS and OCT, but may also be a type that uses only IVUS or only OCT. [Explanation of symbols]

[0072] 1. Diagnostic imaging catheter 2 External device 2a First drive unit 2b Second drive unit 2c control unit 2D display 3. Diagnostic imaging equipment 4 Sheath 4a Lumen of the sheath 5 Outer tube 6 Inner tube 6a Inner tube body 6b Flow path adjustment member 6c Insertion recess 7 Unit Connectors 7a Second sealing member 7b Stopper surface 8 Hubs 8a Hub body 8b port 8c connecting pipe 8d bearing 8e First sealing member 8f Connector section 9 Drive shaft 10 Housing 10a opening 11 Signal Transmitter / Receiver 11a Ultrasonic Transceiver Unit 11b Optical Transceiver Unit 12 Imaging Cores 13 Relay Connectors 13a Proximal inner circumferential surface 13b Stepped section 13c Inner circumferential surface on the tip side 14 Locking part 15 Electrical signal lines 15a electrical connector 16 Optical signal lines 16a Optical Connector 17. Tip component 18 Guide wire insertion member 19 Marker 20 Communication hole 21 Reinforcement member 22 Injection devices 22a connector 22b tube 23. Pullback mechanism 24 support tubes 25 Spacers 26 Notches 27 holes 28 recesses 29 Aperture section 30 Elastic membrane 30a opening 30b hole O center axis

Claims

1. It comprises an outer tube, a drive shaft provided radially inward from the outer tube, an inner tube provided radially inward from the outer tube and radially outward from the drive shaft, and movable axially relative to the outer tube and integrally with the drive shaft, and a unit connector connected to the base end of the outer tube and holding the inner tube so that it can move forward and backward, A diagnostic imaging catheter, wherein the inner tube has a notch that connects the flow path within the inner tube to the flow path between the inner tube and the outer tube when the inner tube is fully retracted from the outer tube, a locking portion provided behind the notch that catches on the inner wall of the unit connector when the inner tube is in the fully retracted position, and a constricting portion that narrows the tip of the flow path within the inner tube.

2. The imaging diagnostic catheter according to claim 1, wherein the notch includes a hole that, in the fully retracted state, connects the flow path within the inner tube to the flow path between the inner tube and the outer tube.

3. The imaging diagnostic catheter according to claim 2, wherein the hole penetrates a recess provided on the outer surface of the inner tube so as to extend from the tip to the proximal end of the inner tube.

Images