Diagnostic imaging catheters

Abstract

According to the present invention, an image diagnosis catheter has an outer tube, a support tube provided on the radially inner side of the outer tube, a spacer for integrally linking the outer tube and the support tube, and an inner tube that is provided on the radially inner side of the outer tube and the radially outer side of the support tube and that is movable in the axial direction relative to the outer tube and the support tube, a communication path communicating a channel between the outer tube and the support tube with the interior of the support tube being formed by the spacer.

Description

[Technical Field]

[0001] The present disclosure relates to diagnostic imaging catheters. [Background technology]

[0002] Diagnostic imaging catheters generally have a pull-back mechanism at their proximal end that changes the relative position between the sheath and the drive shaft in order to continuously observe cross sections inside a body cavity (see, for example, Patent Document 1). The pull-back mechanism has an outer tube, a support tube that is provided radially inward of the outer tube and radially outward of the drive shaft, a spacer that integrally connects the outer tube and the support tube, and an inner tube that is provided radially inward of the outer tube and radially outward of the support tube and is movable in the axial direction relative to the outer tube and the support tube.

[0003] When using a catheter for diagnostic imaging, the lumen is filled with a fluid to prime it. Priming is usually performed with the inner tube fully extended from the outer tube. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-360578 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional diagnostic imaging catheters, the flow path between the outer tube and the support tube is blocked by a spacer, and the flow path is connected to the inside of the support tube near the blocked part through a cutout such as a hole or slit provided in the support tube. This causes problems such as high flow resistance within the pull-back mechanism and difficulty in releasing air from the pull-back mechanism.

[0006] Therefore, an object of the present disclosure is to provide a catheter for diagnostic imaging that can achieve good priming within the pull-back mechanism. [Means for solving the problem]

[0007] A diagnostic imaging catheter according to a first aspect of the present disclosure comprises an outer tube, a support tube disposed radially inward of the outer tube, a spacer that integrally connects the outer tube and the support tube, and an inner tube disposed radially inward of the outer tube and radially outward of the support tube and that is movable axially relative to the outer tube and the support tube, wherein a communication passage that connects a flow path between the outer tube and the support tube to the interior of the support tube is formed by the spacer.

[0008] As one embodiment of the present disclosure, the diagnostic imaging catheter has a connector joined to the outer tube, the spacer is joined to the support tube, and the spacer has a retaining portion located axially between the outer tube and the connector.

[0009] In one embodiment of the present disclosure, the communication passage is defined by the spacer, the outer tube, and the connector.

[0010] In one embodiment of the present disclosure, the spacer has a spacer main body located between the outer peripheral surface of the support tube and the inner peripheral surface of the outer tube, and a protrusion that protrudes from the tip of the spacer main body toward the tip, further toward the tip than the tip surface of the outer tube.

[0011] In one embodiment of the present disclosure, the spacer body is cylindrical, and the outer surface of the spacer body has two flat surfaces extending along the axial direction and spaced apart from each other in a first direction along the radial direction. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide a catheter for diagnostic imaging that can achieve good priming within the pull-back mechanism. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a plan view showing a state in which an external device is connected to a diagnostic imaging catheter as a first embodiment. FIG. [Figure 2A] FIG. 2 is a side view showing the diagnostic imaging catheter shown in FIG. 1 in a state before a pull-back operation. [Figure 2B] FIG. 2 is a side view showing the diagnostic imaging catheter shown in FIG. 1 in a state after a pull-back operation. [Figure 3] FIG. 2 is a cross-sectional view showing the tip of the diagnostic imaging catheter shown in FIG. [Figure 4] FIG. 2 is a cross-sectional view showing the proximal end of the diagnostic imaging catheter shown in FIG. [Figure 5A] FIG. 2 is a cross-sectional view showing a part of the pull-back mechanism of the diagnostic imaging catheter shown in FIG. [Figure 5B] 5B is a cross-sectional view of the pull-back mechanism shown in FIG. 5A when viewed from a direction different by 90 degrees. [Figure 6A] FIG. 5B is a perspective view of the outer tube, the spacer, and the support tube shown in FIG. 5A. [Figure 6B] 6B is a plan view of the outer tube, the spacer, and the support tube shown in FIG. 6A as viewed from the distal end side. FIG. [Figure 7] FIG. 10 is a cross-sectional view showing a part of a pull-back mechanism in a second embodiment. [Figure 8A] FIG. 8 is a perspective view of the outer tube, the spacer, and the support tube shown in FIG. 7. [Figure 8B] 8B is a plan view of the outer tube, the spacer, and the support tube shown in FIG. 8A as viewed from the distal end side. [Figure 9A] FIG. 10 is a perspective view showing an outer tube, a spacer, and a support tube in a third embodiment. [Figure 9B] 9B is a plan view of the outer tube, the spacer, and the support tube shown in FIG. 9A as viewed from the distal end side. [Figure 10A] FIG. 10 is a perspective view showing an outer tube, a spacer, and a support tube in a fourth embodiment. [Figure 10B] 10B is a plan view of the outer tube, the spacer, and the support tube shown in FIG. 10A as viewed from the distal end side. [Figure 11] FIG. 11 is a perspective view showing an outer tube, a spacer, and a support tube in a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a diagnostic imaging catheter according to the present disclosure will be described in detail with reference to the drawings.

[0015] The diagnostic imaging catheter 1 according to this embodiment is a dual type that uses both intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The dual type diagnostic imaging catheter 1 has three modes: a mode for acquiring tomographic images using only IVUS, a mode for acquiring tomographic images using only OCT, and a mode for acquiring tomographic images using both IVUS and OCT, and these modes can be switched between for use. As shown in FIG. 1 , the diagnostic imaging catheter 1 is connected to and driven by an external device 2. The diagnostic imaging catheter 1 and the external device 2 constitute a diagnostic imaging device 3.

[0016] 1 to 4, the diagnostic imaging catheter 1 includes a sheath 4 to be 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 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 connected to the proximal end of the outer tube 5, which holds the inner tube 6 so that it can advance and retreat and which can release the hold of the inner tube 6, and a hub 8 connected to the proximal end of the inner tube 6. The diagnostic imaging catheter 1 also includes a drive shaft 9, a housing 10 fixed to the tip of the drive shaft 9, and an imaging core 12 housed in the housing 10 and including a signal transmitting and receiving unit 11 that transmits and receives signals such as ultrasound and / or light. The imaging core 12 is inserted into the sheath 4, the outer tube 5, and the inner tube 6, and is able to advance and retreat axially together with the inner tube 6 relative to the sheath 4 and the outer tube 5.

[0017] In this specification, the term "tip" refers to the end of the diagnostic imaging catheter 1 that is inserted into a body cavity, the term "base end" refers to the end of the diagnostic imaging catheter 1 that is held outside the body cavity, the term "axial direction" refers to the direction along the central axis O of the drive shaft 9 (i.e., the extension direction of the drive shaft 9), the term "radial direction" refers to the direction along a straight line perpendicular to the central axis O, and the term "circumferential direction" refers to the direction circumferentially around the central axis O.

[0018] As shown in FIG. 2A , the drive shaft 9 passes through the sheath 4, the outer tube 5, and the inner tube 6 and extends into the hub 8. The hub 8, the inner tube 6, the drive shaft 9, the housing 10, and the signal transmitter / receiver 11 are interconnected so as to be able to move axially back and forth together relative to the sheath 4 and the outer tube 5. For example, when the hub 8 is pushed toward the distal end, i.e., a pushing 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, the housing 10, and the signal transmitter / receiver 11, i.e., the imaging core 12, advance within the sheath 4, i.e., move toward the distal end. For example, when the hub 8 is pulled toward the proximal end, i.e., a pull-back 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 FIGS. 1 and 2B , and the imaging core 12 moves toward the proximal end within the sheath 4 as shown by arrow A2.

[0019] 2A, when the inner tube 6 is pushed all the way toward the distal end, the distal end of the inner tube 6 reaches the vicinity of the relay connector 13. At this time, the signal transmitting / receiving unit 11 is located at the distal end of the sheath 4 (near the distal end surface of the lumen of the sheath 4). The relay connector 13 connects the sheath 4 and the outer tube 5.

[0020] As shown in FIG. 2B , a locking portion 14 is provided at the tip of the inner tube 6 to prevent it from coming off. The locking portion 14 prevents the inner tube 6 from coming off the outer tube 5. The unit connector 7 also has a tip-side partial connector 7a and a base-side partial connector 7b that is detachably connected to the tip-side partial connector 7a. The locking portion 14 is configured to hook at a predetermined position on the inner wall of the base-side partial connector 7b of the unit connector 7 when the hub 8 is pulled all the way toward the base end, that is, when the inner tube 6 is pulled all the way out from the outer tube 5 and the unit connector 7. The inner tube 6, including the locking portion 14, can be removed from the outer tube 5 by detaching the base-side partial connector 7b from the tip-side partial connector 7a.

[0021] As shown in FIG. 3, the drive shaft 9 is a long hollow member, and an electric signal line (electric cable) 15 and an optical signal line (optical fiber) 16 connected to the signal transmitting / receiving unit 11 are arranged inside the drive shaft 9.

[0022] The drive shaft 9 is formed of a coil shaft. Although not shown, the coil shaft can be formed, for example, of a multi-layer coil with different winding directions. Each coil is usually of a multi-strand wound type. The coil shaft can be formed, for example, of a three-layer, two-strand wound coil, but the number of layers and threads can be changed as appropriate. Each coil is made of a metal such as stainless steel or a Ni-Ti (nickel-titanium) alloy.

[0023] The signal transmitting / receiving unit 11 has an ultrasonic transmitting / receiving unit 11a that transmits and receives ultrasonic waves, and an optical transmitting / receiving unit 11b that transmits and receives light. The ultrasonic transmitting / receiving unit 11a transmits ultrasonic waves based on a pulse signal into the body cavity and has a transducer that receives ultrasonic waves reflected from the biological tissue inside the body cavity. The transducer is electrically connected to an electrical connector 15a (see FIG. 4) via an electrical signal line 15. The transducer can be made of a piezoelectric material such as ceramics or quartz crystal.

[0024] The optical transmitter / receiver 11b has an optical element that transmits light into the body cavity and receives light reflected from biological tissue inside the body cavity. The optical element is optically connected to an optical connector 16a (see FIG. 4) via an optical signal line 16. The optical element can be formed by a lens such as a ball lens.

[0025] The signal transmitting / receiving unit 11 is accommodated 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 of a cylindrical metal tube, and an opening 10a is provided on the circumferential surface thereof so as not to impede the progression of signals transmitted and received by the signal transmitting / receiving unit 11. The housing 10 can be formed, for example, by laser processing or the like. The housing 10 may also be formed by cutting out a metal block or by MIM (metal powder injection molding), or the like.

[0026] A tip member 17 is provided at the tip of the housing 10. The tip member 17 has a substantially hemispherical outer shape, which reduces friction and snagging with the inner surface of the sheath 4. Note that the tip member 17 may not be provided.

[0027] The sheath 4 has an inner cavity 4a into which the drive shaft 9 is inserted so as to be able to advance and retreat. 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 inner cavity of the sheath 4. The sheath 4 and the guidewire insertion member 18 are joined by welding or the like. A marker 19 having radiopaque properties is provided on the guidewire insertion member 18. The marker 19 is made of a metal pipe having high radiopaque properties, such as Pt or Au.

[0028] A communication hole 20 that connects the inside of the lumen 4a to the outside is formed at the tip of the sheath 4. A reinforcing member 21 that is joined to the guidewire insertion member 18 is provided at the tip of the lumen 4a of the sheath 4. A through-hole that connects the inside of the lumen 4a, which is located on the proximal side of the reinforcing member 21, to the communication hole 20 is formed in the reinforcing member 21. The reinforcing member 21 does not necessarily have to be provided at the tip of the sheath 4.

[0029] The communication hole 20 is a priming solution discharge hole for discharging the priming solution. When using the diagnostic imaging catheter 1, when a priming process is performed to fill the sheath 4 with the priming solution, the priming solution can be discharged to the outside through the communication hole 20, and gas such as air can be discharged from the inside of the sheath 4 together with the priming solution.

[0030] A window having higher signal permeability than other portions is formed in the distal end portion of the sheath 4, which is the range within which the signal transmitting / receiving unit 11 moves in the axial direction of the sheath 4. The sheath 4, guidewire insertion member 18, and reinforcing member 21 are made of a flexible material, and the material is not particularly limited, and examples thereof 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 elastomers, and combinations of one or more of these (polymer alloys, polymer blends, laminates, etc.) can also be used.

[0031] 4, the hub 8 has a tubular hub body 8a that is coaxial with the inner tube 6 and is detachably attached integrally to the external device 2, a port 8b that protrudes radially outward from the hub body 8a and communicates with the interior of the hub body 8a, a connecting pipe 8c that is attached integrally to the outer circumferential surface of the drive shaft 9, a bearing 8d that rotatably supports the connecting pipe 8c, a seal member 8e that prevents the priming solution from leaking from between the connecting pipe 8c and the bearing 8d toward the base end, and a connector section 8f that has an electric connector 15a and an optical connector 16a and is detachably attached integrally to the first drive section 2a of the external device 2. The connector section 8f is rotatable integrally with the connecting pipe 8c and the drive shaft 9.

[0032] The distal end of the hub body 8a is integrally connected to the proximal end of the inner tube 6. The drive shaft 9 is drawn out from the inner tube 6 inside the hub body 8a.

[0033] 1, an injection device 22 (see FIG. 1) that injects a priming liquid when performing a priming process is connected to port 8b. Injection device 22 has a connector 22a that is connected to port 8b, and a syringe (not shown) that is connected to connector 22a via tube 22b.

[0034] The external device 2 has a first drive unit 2a for driving the drive shaft 9 to rotate, and a second drive unit 2b for moving the drive shaft 9 in the axial direction (i.e., for pushing / pulling back operations). The first drive unit 2a can be configured, for example, by an electric motor. The second drive unit 2b can be configured, for example, by 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, for example, by a ball screw or a rack-and-pinion mechanism.

[0035] The operations of the first drive unit 2a and the second drive unit 2b are controlled by a control device 2c electrically connected thereto. The control device 2c includes a CPU (Central Processing Unit) and a memory. The control device 2c is electrically connected to a display 2d.

[0036] The signal received by the ultrasonic transmitter / receiver 11a is sent to the control device 2c via the electrical connector 15a, where it is subjected to predetermined processing and displayed as an image on the display 2d. The signal received by the optical transmitter / receiver 11b is sent to the control device 2c via the optical connector 16a, where it is subjected to predetermined processing and displayed as an image on the display 2d.

[0037] During diagnosis, the sheath 4 is inserted into the body cavity, and the imaging core 12 is rotated and driven at a constant rotation speed of about 1,000 to 10,000 rpm by the first drive unit 2a of the external device 2, while the imaging core 12 is pulled back by the second drive unit 2b of the external device 2 to move it backward at a constant speed within the lumen 4a of the sheath 4. At this time, the control unit 2c of the external device 2 transmits and receives signals at the signal transmitting and receiving unit 11. Based on signals received by scanning due to this rotation and retreat, the state of the tissues around the body cavity is displayed as an image on the display 2d.

[0038] As described above, the diagnostic imaging catheter 1 has a pull-back mechanism 23 at its proximal portion that changes the relative positions of the sheath 4 and the drive shaft 9 in order to continuously observe a cross section of the interior of a body cavity. As shown in FIGS. 2A, 2B, and 5A to 6B, the pull-back mechanism 23 has an outer tube 5, a support tube 24 provided radially inward of the outer tube 5 and radially outward of the drive shaft 9, a spacer 25 that integrally connects the outer tube 5 and the support tube 24, an inner tube 6 provided radially inward of the outer tube 5 and radially outward of the support tube 24 and movable in the axial direction relative to the outer tube 5 and the support tube 24, a relay connector 13, and a unit connector 7. As described above, the relay connector 13 is integrally connected to the sheath 4, and the inner tube 6 is integrally connected to the hub 8.

[0039] In the pullback mechanism 23, the outer tube 5, the support tube 24, the inner tube 6 and the drive shaft 9 are arranged coaxially and have a common central axis O.

[0040] The relay connector 13 is cylindrical 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 step 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.

[0041] The spacer 25 has a spacer main body 25a located between the outer peripheral surface of the support tube 24 and the inner peripheral surface of the outer tube 5, and a protrusion 25b that protrudes from the tip of the spacer main body 25a toward the tip side beyond the tip surface of the outer tube 5. The protrusion 25b forms a retaining portion 25c located axially between the outer tube 5 and the relay connector 13. The retaining portion 25c has a base end face that abuts against the tip surface of the outer tube 5 to restrict movement toward the base end, and a tip end face that abuts against the step portion 13b of the relay connector 13 to restrict movement toward the tip side. The spacer 25 is made of, for example, a synthetic resin or a metal.

[0042] The spacer body 25a is cylindrical, and the outer peripheral surface of the spacer body 25a has two flat surfaces extending along the axial direction at two locations spaced apart in a first direction along the radial direction. Therefore, two axial flow paths 26 extending along the axial direction are formed between the outer peripheral surface of the spacer body 25a and the inner peripheral surface of the outer pipe 5 at two locations spaced apart in the first direction.

[0043] The protrusion 25b has a base 25d integrally connected to the tip of the spacer body 25a and two protrusions 25e extending from the tip of the base 25d toward the tip of the support tube 24. The two protrusions 25e are radially spaced apart from each other in a second direction perpendicular to the first direction. The outer peripheral surface of the protrusion 25b has two flat surfaces parallel to the central axis O at two locations spaced apart from each other in the first direction. Therefore, two gaps 27 spaced apart from each other in the first direction are formed between the outer peripheral surface of the protrusion 25b and the base-end inner peripheral surface 13a of the relay connector 13. A gap 28 is also formed between the two protrusions 25e. The tip of each axial flow path 26 is connected to the tip of the lumen of the support tube 24 via one of the gaps 27 and the gap 28.

[0044] In this way, the two axial flow paths 26, the two gaps 27, and the gap 28 form a communication path 29 (see FIGS. 5A and 5B) that connects the flow path between the outer tube 5 and the support tube 24 to the inside of the support tube 24. The communication path 29 is defined by the spacer 25, the outer tube 5, and the relay connector 13.

[0045] The outer peripheral surface of the tip of the support tube 24 is joined to the inner peripheral surface of the spacer body 25a by welding or the like. The outer tube 5 and the spacer 25 are not joined. As described above, the outer tube 5 is joined to the relay connector 13, the spacer 25 is joined to the support tube 24, and the spacer 25 has the retaining portion 25c, so that the relay connector 13, the outer tube 5, the support tube 24, and the spacer 25 are efficiently integrated with few joints. However, the outer tube 5 and the spacer 25 may be joined by welding or the like to further increase the connection strength of the pull-back mechanism 23.

[0046] The support tube 24 can be formed of, for example, a single-layer or multi-layer coil or tube. The support tube 24 is made of, for example, a synthetic resin or a metal. When the inner tube 6 and the drive shaft 9 are advanced relative to the outer tube 5 by a pushing operation, the support tube 24 supports the drive shaft 9 from the radially outer side, thereby preventing the drive shaft 9 from buckling inside the outer tube 5 and interfering with the smooth advancement of the drive shaft 9.

[0047] Priming is typically performed with the inner tube 6 pulled out to its fullest extent from the outer tube 5 (see FIG. 1). During priming, the priming liquid 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, flowing toward the distal end. As indicated by the dashed arrows in FIG. 5B, the priming liquid flowing through the flow path between the outer tube 5 and the support tube 24 passes through a communicating path 29 formed by the spacer 25, merges with the priming liquid flowing through the flow path inside the support tube 24, and continues flowing toward the distal end. In this way, forming the communicating path 29 using the spacer 25 reduces flow path resistance within the pull-back mechanism 23 and makes it easier for air to escape from the pull-back mechanism 23.

[0048] As described above, according to this embodiment, the spacer 25 forms the communication passage 29 that connects the flow path between the outer tube 5 and the support tube 24 to the inside of the support tube 24, thereby achieving good priming within the pull-back mechanism 23.

[0049] Furthermore, according to this embodiment, the relay connector 13 is joined to the outer tube 5, the spacer 25 is joined to the support tube 24, and the spacer 25 has the anti-slip portion 25c, so that an easily assembled pull-back mechanism 23 can be realized.

[0050] Furthermore, according to this embodiment, since the communication passage 29 is defined by the spacer 25, the outer tube 5, and the relay connector 13, good priming within the pull-back mechanism 23 can be achieved more reliably.

[0051] The configuration of the pull-back mechanism 23 can be modified in various ways as long as a communication passage 29 that connects the flow path between the outer tube 5 and the support tube 24 to the inside of the support tube 24 is formed by the spacer 25. For example, the pull-back mechanism 23 may have a configuration like that of a second embodiment shown in Figures 7 to 8B.

[0052] In the second embodiment, the spacer 25 has a spacer body 25a and a protruding portion 25b, and the protruding portion 25b forms a retaining portion 25c, and in this respect the configuration is similar to that of the first embodiment. However, in the second embodiment, the configurations of the spacer body 25a and the protruding portion 25b are different from those of the first embodiment.

[0053] In the second embodiment, the spacer body 25a is cylindrical and has one axial groove 30 extending in the axial direction at one location on its outer circumferential surface. Therefore, one axial flow path 26 extending along the axial direction is formed between the outer circumferential surface of the spacer body 25a and the inner circumferential surface of the outer pipe 5.

[0054] Furthermore, protrusion 25b is cylindrical and has one notch 31 extending axially at one circumferential location and connected to axial groove 30. The tip surface of protrusion 25b is flush with the tip surface of support tube 24. Notch 31 extends along the entire axial length on the outer peripheral surface of protrusion 25b and extends radially on the tip surface of protrusion 25b from the outer peripheral surface of support tube 24 to the outer peripheral edge of protrusion 25b. Therefore, at this notch 31, one gap 27 is defined by spacer 25, support tube 24, and relay connector 13.

[0055] Furthermore, the tip surface of the protrusion 25b abuts against the step 13b of the relay connector 13, and the outer diameter of the base-end inner circumferential surface 13a of the relay connector 13 is larger than the outer diameter of the support tube 24. Therefore, the gap 27 connects the axial flow path 26 to the tip of the lumen of the support tube 24. In this way, in the second embodiment, the communication path 29 is composed of one axial flow path 26 and one gap 27. The other configurations are the same as in the first embodiment. Even with this configuration, good priming within the pull-back mechanism 23 can be achieved.

[0056] The pull-back mechanism 23 may have a configuration similar to that of a third embodiment shown in FIGS. 9A and 9B. In the second embodiment, the axial flow path 26 is defined by the axial groove 30 provided on the outer peripheral surface of the spacer main body 25a and the inner peripheral surface of the outer pipe 5. However, in the third embodiment, the axial flow path 26 is defined by the axial groove 30 provided on the inner peripheral surface of the spacer main body 25a and the outer peripheral surface of the support tube 24. In addition, in the third embodiment, the notch 31 of the protruding portion 25b extends along the entire axial length on the inner peripheral surface of the protruding portion 25b and extends radially on the tip surface of the protruding portion 25b from the outer peripheral surface of the support tube 24 to the outer peripheral edge of the protruding portion 25b. Therefore, in this notch 31, one gap 27 is defined by the spacer 25, the support tube 24, and the relay connector 13. In the third embodiment, the communicating path 29 is defined by the axial flow path 26 and the gap 27. The other configurations are the same as those in the second embodiment. Even with this configuration, good priming within the pull-back mechanism 23 can be achieved.

[0057] The pullback mechanism 23 may have a configuration similar to that of a fourth embodiment shown in FIGS. 10A and 10B. In the second embodiment, the axial flow passage 26 is defined by an axial groove 30 provided on the outer peripheral surface of the spacer body 25a and the inner peripheral surface of the outer tube 5. However, in the fourth embodiment, the axial flow passage 26 is defined by two through holes 32 axially penetrating the spacer body 25a at two circumferential locations. The distal end of each through hole 32 extends radially inward to the outer peripheral surface of the support tube 24. Furthermore, in the fourth embodiment, the spacer 25 does not have a protrusion 25b, and the spacer 25 is formed only by the spacer body 25a. Therefore, in the fourth embodiment, the communication passage 29 is formed only by two axial flow passages 26. The other configurations are the same as those in the second embodiment. Even with this configuration, favorable priming within the pullback mechanism 23 can be achieved. The number of axial flow passages 26 can be increased or decreased as needed.

[0058] The pull-back mechanism 23 may have a configuration similar to that of a fifth embodiment shown in Fig. 11. In the fourth embodiment, the axial flow path 26 is defined by two through holes 32 that axially penetrate the spacer 25 (spacer body 25a), but in the fifth embodiment, the spacer 25 (spacer body 25a) is made of a porous material, and the axial flow path 26 is defined by a gap within the spacer 25. Therefore, in the fifth embodiment, the communication path 29 is defined only by a gap within the spacer 25. The other configurations are the same as those of the fourth embodiment. Even with such a configuration, good priming within the pull-back mechanism 23 can be achieved.

[0059] The above-described embodiment is merely an example of the present disclosure, and various modifications are possible, for example, as described below.

[0060] The diagnostic imaging catheter 1 has an outer tube 5, a support tube 24 provided radially inward of the outer tube 5, a spacer 25 connecting the outer tube 5 and the support tube 24 together, and an inner tube 6 provided radially inward of the outer tube 5 and radially outward of the support tube 24 and movable in the axial direction relative to the outer tube 5 and the support tube 24, and can be modified in various ways as long as a communication passage 29 that connects the flow path between the outer tube 5 and the support tube 24 to the inside of the support tube 24 is formed by the spacer 25.

[0061] However, it is preferable that the diagnostic imaging catheter 1 has a relay connector 13 joined to the outer tube 5, a spacer 25 joined to the support tube 24, and the spacer 25 has a retaining portion 25c located between the outer tube 5 and the relay connector 13 in the axial direction.

[0062] Furthermore, the communication passage 29 is preferably defined by the spacer 25 , the outer pipe 5 and the relay connector 13 .

[0063] It is also preferable that the spacer 25 has a spacer main body 25a located between the outer peripheral surface of the support tube 24 and the inner peripheral surface of the outer tube 5, and a protrusion 25b that protrudes from the tip of the spacer main body 25a toward the tip, further toward the tip side than the tip surface of the outer tube 5.

[0064] The spacer body 25a is cylindrical, and the outer peripheral surface of the spacer body 25a preferably has two flat surfaces extending along the axial direction and spaced apart from each other in a first direction along the radial direction.

[0065] The diagnostic imaging catheter 1 is not limited to a dual type that uses both IVUS and OCT, but may be a type that uses only IVUS or only OCT.

[0066] The pull-back mechanism 23 is not limited to a configuration in which the relay connector 13 is integrally connected to the sheath 4 and the inner tube 6 is integrally connected to the hub 8, but may also be a configuration in which the relay connector 13 is integrally connected to the hub 8 and the inner tube 6 is integrally connected to the sheath 4. [Explanation of symbols]

[0067] 1 Diagnostic imaging catheter 2 External device 2a First drive unit 2b Second drive unit 2c Control device 2D display 3 Diagnostic imaging equipment 4 Sheath 4a Sheath lumen 5 Outer tube 6 Inner tube 7 Unit Connector 7a Tip side connector 7b Base end connector 8 Hub 8a hub body 8b port 8c Connecting pipe 8d bearing 8e Sealing material 8f Connector part 9 Drive shaft 10. Housing 10a opening 11 Signal transmitter / receiver 11a Ultrasonic transmitter / receiver 11b Optical transmitter / receiver 12 Imaging Core 13 Relay connector 13a Proximal inner circumferential surface 13b Stepped section 13c Tip side inner surface 14 Locking part 15 Electrical signal line 15a electrical connector 16 Optical signal line 16a optical connector 17 Tip member 18 Guidewire insertion member 19 Marker 20 Communication hole 21 Reinforcement member 22 Injection Device 22a connector 22b tube 23 Pullback mechanism 24 support tubes 25 spacer 25a Spacer body 25b Protrusion 25c retaining part 25d base 25e protrusion 26 Axial flow passage 27 Gap 28 Gap 29 Communication path 30 Axial groove 31 Cutout 32 through holes O center axis

Claims

1. an outer tube; a support tube provided radially inward of the outer tube; a spacer that integrally connects the outer tube and the support tube; and an inner tube that is provided radially inward of the outer tube and radially outward of the support tube and is movable in the axial direction relative to the outer tube and the support tube, a communication passage that connects a flow path between the outer tube and the support tube to the inside of the support tube is formed by the spacer.

2. a connector joined to the outer tube, the spacer is joined to the support tube; The diagnostic imaging catheter according to claim 1 , wherein the spacer has a retaining portion located between the outer tube and the connector in the axial direction.

3. The diagnostic imaging catheter according to claim 2 , wherein the communication passage is defined by the spacer, the outer tube, and the connector.

4. 4. The diagnostic imaging catheter according to claim 1, wherein the spacer comprises: a spacer body located between an outer peripheral surface of the support tube and an inner peripheral surface of the outer tube; and a protrusion that protrudes from a tip of the spacer body toward the tip, further distal than the tip surface of the outer tube.

5. The spacer body is cylindrical, The diagnostic imaging catheter according to claim 4 , wherein the outer peripheral surface of the spacer body has two flat surfaces extending along the axial direction and spaced apart from each other in a first direction along the radial direction.

Images