Drive shaft and imaging catheter

Abstract

A drive shaft according to this disclosure is for forming an imaging core of a diagnostic imaging catheter, the drive shaft comprising: a coil shaft provided with a tip that is fixed to the base end of a housing that accommodates a signal transmission / reception unit; and a shaft member that is fixed to the base end of the coil shaft and that has a greater rigidity against torsion than the coil shaft. A diagnostic imaging catheter according to this disclosure comprises: an imaging core that includes the drive shaft according to this disclosure, the housing which is fixed to the tip of the coil shaft, and the signal transmission / reception unit which is accommodated in the housing; and a sheath into which the imaging core is inserted.

Description

[Technical field]

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

[0002] There is known a diagnostic imaging catheter that transmits ultrasonic and / or optical signals within a body cavity of a living organism and receives the reflected waves to image the surface and interior of a diseased area, thereby enabling diagnosis (see, for example, Patent Document 1). The diagnostic imaging catheter is configured to generate an image by retracting an imaging core having a signal transmitting and receiving unit while rotating it at a predetermined number of rotations within a sheath.

[0003] The imaging core has a housing that houses a signal transmitting / receiving unit and a drive shaft fixed to the base end of the housing, and is rotated by an external device. The drive shaft is usually formed of a coil shaft consisting of a multi-layer multi-filament coil as described in Patent Document 1, which extends over the entire length of the drive shaft. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-198425 A Summary of the Invention [Problem to be solved by the invention]

[0005] The imaging core described above usually rotates at a constant speed of about 1000 to 10000 rpm while repeatedly transmitting and receiving signals, enabling the generation of images. However, if the sheath is bent due to bending of the biological lumen or a lesion, and contact occurs between the sheath and the imaging core, the contact may cause the drive shaft to resonate. When resonance occurs, the actual rotation speed of the signal transmitting and receiving part deviates from the theoretical value, causing image distortion called NURD (Non-Uniformed Rotational Distortion).

[0006] Therefore, an object of the present disclosure is to provide a drive shaft and a catheter for diagnostic imaging that can suppress the occurrence of NURD. [Means for solving the problem]

[0007] A drive shaft according to a first aspect of the present disclosure is a drive shaft for constituting an imaging core of a catheter for diagnostic imaging, and includes a coil shaft having a tip fixed to a base end of a housing that houses a signal transmitting / receiving unit, and a shaft member fixed to the base end of the coil shaft and having greater torsional rigidity than the coil shaft.

[0008] In one embodiment of the present disclosure, the coil shaft has an axial length of 250 mm or more and 1000 mm or less.

[0009] In one embodiment of the present disclosure, the axial length of the shaft member is not less than 200 mm and not more than 1750 mm.

[0010] In one embodiment of the present disclosure, the shaft member is a pipe having a notch.

[0011] In one embodiment of the present disclosure, the notch is non-spiral.

[0012] In one embodiment of the present disclosure, the cutout includes a plurality of slits extending along the circumferential direction.

[0013] As one embodiment of the present disclosure, the shaft member has a main portion in which a plurality of slits of a predetermined width arranged in a circumferential direction are arranged in a predetermined pattern at a predetermined pitch in the axial direction.

[0014] In one embodiment of the present disclosure, the shaft member has a weakened portion having a torsional strength lower than both the main portion and the coil shaft.

[0015] In one embodiment of the present disclosure, the weakened portion has a plurality of slits arranged in the same pattern as the main portion, except that the predetermined width and / or the predetermined pitch is smaller than those of the main portion.

[0016] In one embodiment of the present disclosure, the weakened portion is located proximally relative to the main portion.

[0017] As one embodiment of the present disclosure, the specified pattern is a pattern in which a pair of slits of the specified width, which are radially opposed to each other and each extend along the circumferential direction, are arranged side by side while rotating a specified angle in the axial direction at the specified pitch.

[0018] A catheter for diagnostic imaging as a second aspect of the present disclosure has a drive shaft as the first aspect of the present disclosure, an imaging core having a housing fixed to the tip of the coil shaft and a signal transmitting / receiving unit contained in the housing, and a sheath into which the imaging core is inserted. Effect of the Invention

[0019] According to the present disclosure, it is possible to provide a drive shaft and a catheter for diagnostic imaging that can suppress the occurrence of NURD. [Brief description of the drawings]

[0020] [Figure 1] 1 is a plan view showing a state in which an external device is connected to a catheter for diagnostic imaging as one 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. [Diagram 3] FIG. 2 is a cross-sectional view showing the tip of the diagnostic imaging catheter shown in FIG. 1. [Figure 4] FIG. 2 is a cross-sectional view showing the base end of the diagnostic imaging catheter shown in FIG. [Diagram 5] FIG. 2 is a side view of the drive shaft shown in FIG. [Figure 6] FIG. 6 is a side view of the shaft member shown in FIG. 5. [Figure 7] 7 is a cross-sectional view taken along line AA in FIG. 6. [Figure 8] 7 is a cross-sectional view of FIG. 6 taken along line B-B. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a drive shaft and a catheter for diagnostic imaging according to the present disclosure will be described in detail with reference to the drawings.

[0022] 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 a tomographic image only by IVUS, a mode for acquiring a tomographic image only by OCT, and a mode for acquiring a tomographic image by IVUS and OCT, and these modes can be switched for use. As shown in FIG. 1, the diagnostic imaging catheter 1 is connected to an external device 2 and driven. The diagnostic imaging catheter 1 and the external device 2 constitute a diagnostic imaging device 3.

[0023] As shown in Figs. 1 to 4, the diagnostic imaging catheter 1 includes a sheath 4 inserted into a body cavity such as a blood vessel (blood vessel such as a coronary artery) of a living body, an outer tube 5 connected to a base end of the sheath 4, an inner tube 6 inserted into the outer tube 5 so as to be movable forward and backward, a unit connector 7 connected to the base end of the outer tube 5, which holds the inner tube 6 so as to be movable forward and backward and which can release the holding of the inner tube 6, and a hub 8 connected to the base end of the inner tube 6. The diagnostic imaging catheter 1 also includes an imaging core 12 including a drive shaft 9, a housing 10 fixed to the tip of the drive shaft 9, and a signal transmitting / receiving unit 11 housed in the housing 10 and which transmits and receives signals that are ultrasound and / or light. The imaging core 12 is inserted into the sheath 4, the outer tube 5, and the inner tube 6, and can be moved forward and backward in the axial direction together with the inner tube 6 relative to the sheath 4 and the outer tube 5.

[0024] In this specification, the tip means the end of the diagnostic imaging catheter 1 that is inserted into a body cavity, the base end means the end of the diagnostic imaging catheter 1 that is held outside the body cavity, the axial direction means the direction along the central axis O of the drive shaft 9 (i.e., the extension direction of the drive shaft 9), the radial direction means the direction along a straight line perpendicular to the central axis O, and the circumferential direction means the direction going around the central axis O.

[0025] 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 to the inside of the hub 8. The hub 8, the inner tube 6, the drive shaft 9, the housing 10, and the signal transmitting / receiving unit 11 are connected to each other so as to be able to advance and retreat in the axial direction as a unit relative to the sheath 4 and the outer tube 5. For this reason, for example, when the hub 8 is pushed toward the distal end, that is, when 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 transmitting / receiving unit 11, that is, the imaging core 12, advance inside the sheath 4, that is, move toward the distal end. For example, when the hub 8 is pulled toward the proximal end, that is, when 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 the arrow A1 in FIG. 1 and FIG. 2B, and the imaging core 12 moves inside the sheath 4 toward the proximal end as shown by the arrow A2.

[0026] 2A, when the inner tube 6 is pushed all the way toward the tip side, the tip of the inner tube 6 reaches near the relay connector 13. At this time, the signal transmitting / receiving unit 11 is located at the tip of the sheath 4 (near the lumen tip surface of the sheath 4). The relay connector 13 connects the sheath 4 and the outer tube 5.

[0027] As shown in FIG. 2B, a locking portion 14 for preventing the inner tube 6 from coming off is provided at the tip of the inner tube 6. The locking portion 14 prevents the inner tube 6 from coming off from the outer tube 5. The unit connector 7 has a tip-side partial connector 7a and a base-side partial connector 7b detachably connected to the tip-side partial connector 7a. The locking portion 14 is configured to be hooked 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 to the base end, that is, when the inner tube 6 is pulled out all the way from the outer tube 5 and the unit connector 7. The inner tube 6 including the locking portion 14 can be pulled out from the outer tube 5 by disengaging the base-side partial connector 7b from the tip-side partial connector 7a.

[0028] 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.

[0029] The signal transmitting / receiving unit 11 has 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 for transmitting ultrasonic waves based on a pulse signal into the body cavity and receiving ultrasonic waves reflected from the biological tissue in the body cavity. The transducer is electrically connected to an electric connector 15a (see FIG. 4) via an electric signal line 15. The transducer can be made of a piezoelectric material such as ceramics or quartz crystal.

[0030] The optical transmitter / receiver 11b has an optical element that transmits light into the body cavity and receives light reflected from biological tissue in 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 of a lens such as a ball lens.

[0031] 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 progress of the signal 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, MIM (metal powder injection molding), or the like.

[0032] 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 catching with the inner surface of the sheath 4. Note that a configuration without the tip member 17 may be adopted.

[0033] The sheath 4 has an inner cavity 4a into which the drive shaft 9 is inserted so as to be capable of advancing and retreating. 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 integrated by thermal fusion or the like. The guidewire insertion member 18 is provided with a marker 19 having X-ray contrast. The marker 19 is made of a metal pipe having high X-ray opacity, such as Pt or Au.

[0034] A communication hole 20 that communicates between the inside and outside of the lumen 4a is formed at the tip of the sheath 4. A reinforcing member 21 joined to the guidewire insertion member 18 is provided at the tip of the lumen 4a of the sheath 4. A communication passage 21a that communicates between the inside of the lumen 4a located on the proximal side of the reinforcing member 21 and 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.

[0035] The communication hole 20 is a priming liquid discharge hole for discharging the priming liquid. When using the diagnostic imaging catheter 1, when a priming process is performed to fill the sheath 4 with the priming liquid, the priming liquid can be discharged to the outside from the communication hole 20, and gas such as air can be discharged from the inside of the sheath 4 together with the priming liquid.

[0036] The distal end 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 having higher signal permeability than other portions. The sheath 4, the guidewire insertion member 18, and the reinforcing member 21 are formed 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 materials, and a combination of one or more of these (polymer alloy, polymer blend, laminate, etc.) can also be used.

[0037] 4, the hub 8 has a hub body 8a that is tubular and coaxial with the inner tube 6 and is detachably and integrally attached 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 connection pipe 8c that is attached integrally to the outer circumferential surface of the drive shaft 9, a bearing 8d that rotatably supports the connection pipe 8c, a seal member 8e that prevents the priming solution from leaking from between the connection pipe 8c and the bearing 8d toward the base end side, and a connector section 8f that includes an electric connector 15a and an optical connector 16a and is detachably and integrally attached to the first drive section 2a of the external device 2. The connector section 8f is rotatable integrally with the connection pipe 8c and the drive shaft 9.

[0038] The tip of the hub body 8a is integrally connected to the base end of the inner tube 6. The drive shaft 9 is pulled out from the inner tube 6 inside the hub body 8a.

[0039] 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 a tube 22b.

[0040] 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 operation). 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, a rack and pinion mechanism, or the like.

[0041] The operations of the first driving unit 2a and the second driving 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.

[0042] The signal received by the ultrasonic transmission / reception unit 11a is transmitted to the control device 2c via the electrical connector 15a, where it is subjected to a predetermined processing and displayed as an image on the display 2d. The signal received by the optical transmission / reception unit 11b is transmitted to the control device 2c via the optical connector 16a, where it is subjected to a predetermined processing and displayed as an image on the display 2d.

[0043] As shown in Fig. 5, the drive shaft 9 has a coil shaft 23 with a tip 23a (see Fig. 3) fixed to the base end of the housing 10, and a shaft member 24 with a tip 24a fixed to the base end 23b of the coil shaft 23 and having a greater torsional rigidity than the coil shaft 23. The axial length of the drive shaft 9 is preferably 1200 mm or more and 2000 mm or less. The outer diameter of the drive shaft 9 is not particularly limited, but is, for example, 0.56 mm. The inner diameter of the drive shaft 9 is not particularly limited, but is, for example, 0.3 mm.

[0044] The coil shaft 23 can be formed, for example, of a multi-layer coil 23c with different winding directions. Each coil 23c is usually of a multi-strand type. In the example shown in FIG. 5, the coil shaft 23 is formed of a three-layer two-strand type coil 23c, but the number of layers and threads can be changed as appropriate. Each coil 23c is made of a metal such as stainless steel or Ni-Ti (nickel-titanium) alloy. The base end 23b of the coil shaft 23 has a circumferential surface that is reduced in diameter by machining.

[0045] 6 to 8, the shaft member 24 is a pipe made of a metal such as stainless steel or a Ni-Ti (nickel-titanium) alloy, having a notch 25. The notch 25 includes a plurality of slits 25a.

[0046] The shaft member 24 has a main portion 26 in which a plurality of slits 25a of a predetermined width W arranged in the circumferential direction are arranged in a predetermined pattern at a predetermined pitch P in the axial direction, and a weakened portion 27 which has a lower torsional strength than both the main portion 26 and the coil shaft 23, i.e., which is more likely to be twisted off. The weakened portion 27 is located closer to the base end than the main portion 26. The main portion 26 occupies most of the axial length of the shaft member 24. The axial length of the weakened portion 27 is preferably 10 mm or more and 50 mm or less, more preferably 10 mm or more and 30 mm or less.

[0047] The shaft member 24 has a tip 24a located on the tip side of the main portion 26, and a base end 24b located on the base side of the weakened portion 27. The inner circumferential surface of the tip 24a of the shaft member 24 has a diameter enlarged at the tip side by machining. As shown in Fig. 5, the base end 23b of the coil shaft 23 is inserted into the tip 24a of the shaft member 24 and fixed by welding using solder or the like. As shown in Fig. 4, the connection pipe 8c is integrally attached to the base end 24b of the shaft member 24.

[0048] The predetermined pattern mentioned for the main portion 26 is a pattern in which a pair of slits 25a of a predetermined width W, which face each other in the radial direction and extend along the circumferential direction, are arranged side by side while rotating by a predetermined angle α in the axial direction at a predetermined pitch P. In the example shown in Figs. 5 to 8, the predetermined angle α is 90°. Note that the predetermined angle α is not limited to 90°.

[0049] The predetermined pattern may be a pattern in which a pair of slits 25a of a predetermined width W, which face each other in the radial direction and extend at an angle with respect to the circumferential direction, are arranged side by side while rotating in the axial direction by a predetermined angle α at a predetermined pitch P. The predetermined pattern may be a pattern in which three or more slits 25a of a predetermined width W arranged side by side in the circumferential direction are arranged side by side at a predetermined pitch P in the axial direction.

[0050] In the weakened portion 27, the plurality of slits 25a are arranged in the same pattern as in the main portion 26, except that the predetermined width W and the predetermined pitch P are smaller than those of the main portion 26. Note that the weakened portion 27 may be configured such that only one of the predetermined width W and the predetermined pitch P of the plurality of slits 25a is smaller than those of the main portion 26.

[0051] The slits 25a in the main portion 26 and the weakened portion 27 can be formed, for example, by cutting using a laser that is scanned in the circumferential direction while passing through the central axis O of the shaft member 24.

[0052] The predetermined width W, predetermined pitch P and circumferential length of the slits 25a in the main portion 26 can be set as appropriate. The predetermined width W of the slits 25a in the main portion 26 is, for example, 0.15 mm. The predetermined pitch P of the slits 25a in the main portion 26 is, for example, 0.25 mm. The circumferential length of the slits 25a in the main portion 26 is, for example, 0.63 mm (the length on the outer circumferential surface of the main portion 26).

[0053] The predetermined width W, predetermined pitch P and circumferential length of the slits 25a in the weakened portion 27 can be set appropriately. The predetermined width W of the slits 25a in the weakened portion 27 is, for example, 0.02 mm. The predetermined pitch P of the slits 25a in the weakened portion 27 is, for example, 0.07 mm. The circumferential length of the slits 25a in the weakened portion 27 is, for example, 0.63 mm (the length on the outer circumferential surface of the weakened portion 27).

[0054] 4, the weakened portion 27 is provided at the base end of the drive shaft 9, and is located inside the hub 8. Therefore, when the inner tube 6 is advanced to the maximum, the weakened portion 27 is located on the base side relative to the sheath 4, and when the inner tube 6 is advanced to the maximum, the weakened portion 27 is located on the base side relative to the unit connector 7.

[0055] During diagnosis, the sheath 4 is inserted into the body cavity, and while the imaging core 12 is rotated and driven at a constant rotation speed of about 1000 to 10000 rpm by the first drive unit 2a of the external device 2, the imaging core 12 is pulled back at a constant speed within the inner cavity 4a of the sheath 4 by a pull-back operation by the second drive unit 2b of the external device 2. At this time, the signal transmitting and receiving unit 11 is transmitted and received by the control device 2c of the external device 2. Based on the signal received by scanning by the rotation and retreat of this signal, the state of the tissue around the body cavity is displayed as an image on the display 2d.

[0056] During scanning of this signal, if the imaging core 12 comes into contact with the sheath 4 that is bent due to bending of the body lumen or a lesion, and the contact causes the drive shaft 9 to resonate, an image distortion called NURD occurs.

[0057] However, in this embodiment, the drive shaft 9 is composed not only of the coil shaft 23 but also of the coil shaft 23 and the shaft member 24 having a higher torsional rigidity than the coil shaft 23, so that the natural frequency of the drive shaft 9 can be increased. Therefore, the rotational speed range in which the drive shaft 9 resonates is set to be higher than the upper limit (e.g., 10,000 rpm) of the usable rotational speed of the imaging core 12 that can be set by the external device 2, thereby suppressing the occurrence of NURD. If the usable rotational speed of the imaging core 12 can be selected from a plurality of stages by the external device 2, the rotational speed range in which the drive shaft 9 resonates may be adjusted to a value that falls outside any of the selectable usable rotational speeds (for example, if three selectable rotational speeds of 1800 rpm, 3600 rpm, and 5600 rpm are available, the rotational speed range may be adjusted to a value that falls exactly halfway between 3600 rpm and 5600 rpm), thereby suppressing the occurrence of NURD.

[0058] In this embodiment, the distal end portion of the drive shaft 9 is made of the coil shaft 23, so that the distal end portion can be easily secured to have flexibility and kink resistance, thereby enabling stable scanning of signals. In this embodiment, the proximal end portion of the drive shaft 9 is made of the shaft member 24, so that the proximal end portion can be easily secured to have buckling resistance, thereby enabling easy pushing operation.

[0059] Here, the axial length of the coil shaft 23 is preferably 250 mm or more and 1000 mm or less. If it is 250 mm or more, the drive shaft 9 can flexibly follow and scan the curved biological lumen, and more reliably enable stable scanning of signals. If it is 1000 mm or less, the occurrence of NURD can be more reliably suppressed.

[0060] In addition, the axial length of the shaft member 24 is preferably 200 mm or more and 1750 mm or less. If it is 200 mm or more, the occurrence of NURD can be more reliably suppressed, and the pushing operation can be more reliably and easily performed. If it is 1750 mm or less, the axial length of the coil shaft 23 can be sufficiently secured, thereby more reliably enabling stable scanning of signals.

[0061] Generally, when the sheath 4 is inserted into a narrow lesion or a sharply curved blood vessel, if the imaging core 12 continues to rotate with the housing 10 or the like in contact with the sheath 4, there is a risk that the sheath 4 will be damaged due to friction between the sheath 4 and the housing 10 or the like.

[0062] However, in this embodiment, the shaft member 24 has a weakened portion 27 whose torsional strength is smaller than both the main portion 26 and the coil shaft 23. In other words, the drive shaft 9 has a weakened portion 27 whose torsional strength is locally reduced so that it is smaller than any other portion of the drive shaft 9. Therefore, if the imaging core 12 continues to rotate with the housing 10 or the drive shaft 9 at a portion distal to the weakened portion 27 in contact with the sheath 4, the weakened portion 27 will be twisted off first, thereby stopping the rotation of the imaging core 12 at the distal side of the weakened portion 27, and thereby suppressing damage to the sheath 4.

[0063] Furthermore, in this embodiment, the weakened portion 27 is located closer to the base end than the sheath 4 when the inner tube 6 is advanced to its farthest extent, thereby preventing the sheath 4 from being damaged by contact with the sharp cut surface of the weakened portion 27 when the weakened portion 27 is twisted off.

[0064] In this embodiment, the weakened portion 27 is located closer to the base end than the unit connector 7 when the inner tube 6 is advanced to its farthest point. Therefore, after the weakened portion 27 is twisted off, the retention of the inner tube 6 by the unit connector 7 can be released to expose the tip portion of the severed weakened portion 27 to the outside, and the imaging core 12 can be easily removed from within the sheath 4 by grasping the exposed weakened portion 27.

[0065] In this embodiment, since the weakened portion 27 is provided at the proximal end of the drive shaft 9, damage to the sheath 4 can be more reliably prevented.

[0066] In this embodiment, the weakened portion 27 is located closer to the proximal end than the main portion 26, and therefore damage to the sheath 4 can be more reliably prevented from occurring in this respect as well.

[0067] In this embodiment, the shaft member 24 is made of a pipe having a notch 25, so that it is possible to realize a shaft member 24 that has both appropriate flexibility for easy bending and appropriate torsional rigidity.

[0068] In this embodiment, since the notch 25 is non-spiral, it is possible to easily achieve an appropriate torsional rigidity.

[0069] In this embodiment, the cutout 25 includes a plurality of slits 25a extending along the circumferential direction, so that it is possible to easily realize a shaft member 24 that has both appropriate flexibility and appropriate torsional rigidity.

[0070] In this embodiment, the shaft member 24 has a main portion 26 in which a plurality of slits 25a of a predetermined width W arranged in the circumferential direction are arranged in a predetermined pattern at a predetermined pitch P in the axial direction, thereby making it possible to realize a shaft member 24 that has both high flexibility and high torsional rigidity.

[0071] In this embodiment, the specified pattern is a pattern in which a pair of slits 25a of a specified width W that face each other radially and extend along the circumferential direction are arranged side by side while rotating in the axial direction by a specified angle α at a specified pitch P, thereby more reliably realizing a shaft member 24 that has both high flexibility and high torsional rigidity.

[0072] In this embodiment, the weakened portion 27 has multiple slits 25a arranged in the same pattern as the main portion 26, except that the specified width W and specified pitch P are smaller than those of the main portion 26. Therefore, the weakened portion 27 can be formed simply by changing the specified width W and the specified pitch P, thereby making it possible to easily form the shaft member 24.

[0073] The above-described embodiment is merely an example of the present disclosure, and various modifications are possible, for example, as described below.

[0074] The drive shaft 9 is a drive shaft 9 for constituting the imaging core 12 of the diagnostic imaging catheter 1, and can be modified in various ways as long as it has a coil shaft 23 with a tip 23a fixed to the base end of the housing 10 that accommodates the signal transmitting / receiving unit 11, and a shaft member 24 fixed to the base end 23b of the coil shaft 23 and having greater torsional rigidity than the coil shaft 23.

[0075] However, it is preferable that the axial length of the coil shaft 23 be not less than 250 mm and not more than 1000 mm.

[0076] The axial length of the shaft member 24 is preferably not less than 200 mm and not more than 1750 mm.

[0077] The shaft member 24 is preferably a pipe having a notch 25 .

[0078] The notch 25 is preferably non-spiral.

[0079] The cutout 25 preferably includes a plurality of slits 25a extending along the circumferential direction.

[0080] The shaft member 24 preferably has a main portion 26 in which a plurality of slits 25a of a predetermined width W aligned in the circumferential direction are arranged in a predetermined pattern at a predetermined pitch P in the axial direction.

[0081] The shaft member 24 preferably has a weakened portion 27 that has less torsional strength than both the main portion 26 and the coil shaft 23 .

[0082] In the weakened portion 27, a plurality of slits 25a are preferably arranged in the same pattern as in the main portion 26, except that the predetermined width W and / or the predetermined pitch P is smaller than those in the main portion 26.

[0083] The weakened portion 27 is preferably located closer to the proximal end than the main portion 26 .

[0084] It is preferable that the specified pattern is a pattern in which a pair of slits 25a of a specified width W, which are radially opposed to each other and extend along the circumferential direction, are arranged side by side at a specified pitch P while rotating by a specified angle α in the axial direction.

[0085] The diagnostic imaging catheter 1 can be modified in various ways as long as it has a drive shaft 9, a housing 10 fixed to the tip 23a of the coil shaft 23, an imaging core 12 having a signal transmitting / receiving unit 11 contained in the housing 10, and a sheath 4 into which the imaging core 12 is inserted.

[0086] However, it is preferable that the diagnostic imaging catheter 1 has an outer tube 5 connected to the base end of the sheath 4, and an inner tube 6 inserted into the outer tube 5 together with the imaging core 12 so as to be capable of advancing and retreating.

[0087] It is preferable that the weakened portion 27 be located on the proximal side of the sheath 4 when the inner tube 6 is advanced to the maximum.

[0088] The diagnostic imaging catheter 1 has a unit connector 7 that is connected to the base end of the outer tube 5, holds the inner tube 6 so that it can be advanced and retreated, and can release the hold on the inner tube 6, and it is preferable that the weakened portion 27 is located closer to the base end than the unit connector 7 when the inner tube 6 is advanced to its furthest extent.

[0089] The weakened portion 27 is preferably located at the proximal end of the drive shaft 9 . [Explanation of symbols]

[0090] 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 part 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 14 Locking part 15 Electrical signal line 15a Electrical Connector 16 Optical signal line 16a Optical Connector 17 Tip member 18 Guide wire insertion member 19 Marker 20 Communication hole 21 Reinforcement members 22 Injection Device 22a Connector 22b tube 23 Coil shaft 23a Coil shaft tip 23b Base end of coil shaft 23c coil 24 Shaft member 24a Tip of shaft member 24b Base end of shaft member 25 Cutout 25a Slit 26 Main part 27 Weakened part O center axis P specified pitch W specified width α Predetermined angle

Claims

1. A drive shaft for constituting an imaging core of a catheter for diagnostic imaging, a coil shaft having a tip fixed to a base end of a housing that accommodates a signal transmitting / receiving unit; a shaft member fixed to a base end of the coil shaft and having a torsional rigidity greater than that of the coil shaft, The shaft member is a pipe having a notch.

2. The drive shaft of claim 1 , wherein the notches are non-spiral.

3. The drive shaft according to claim 1 or 2, wherein the cutout includes a plurality of slits extending along a circumferential direction.

4. The drive shaft according to any one of claims 1 to 3, wherein the shaft member has a main portion in which a plurality of circumferentially arranged slits of a predetermined width are arranged in a predetermined pattern at a predetermined pitch in the axial direction.

5. A drive shaft for constituting an imaging core of a catheter for diagnostic imaging, comprising: a coil shaft having a tip fixed to a base end of a housing that accommodates a signal transmitting / receiving unit; a shaft member fixed to a base end of the coil shaft and having a torsional rigidity greater than that of the coil shaft, The shaft member is a drive shaft having a main portion in which a plurality of circumferentially aligned slits of a predetermined width are arranged in a predetermined pattern at a predetermined pitch in the axial direction.

6. 6. The drive shaft according to claim 4, wherein the shaft member has a weakened portion having a torsional strength lower than both the main portion and the coil shaft.

7. 7. The drive shaft of claim 6, wherein the weakened portion has a plurality of slits arranged in the same pattern as the main portion except that the predetermined width and / or the predetermined pitch is smaller than those of the main portion.

8. The drive shaft of claim 6 or 7, wherein the weakened portion is located proximally of the main portion.

9. The drive shaft according to any one of claims 4 to 8, wherein the predetermined pattern is a pattern in which a pair of slits of the predetermined width, which are radially opposed to each other and each extend along the circumferential direction, are arranged side by side while rotating in the axial direction by a predetermined angle at the predetermined pitch.

10. A drive shaft described in any one of claims 1 to 9, wherein the axial length of the coil shaft is not less than 250 mm and not more than 1000 mm.

11. A drive shaft described in any one of claims 1 to 10, wherein the axial length of the shaft member is not less than 200 mm and not more than 1,750 mm.

12. An imaging core including the drive shaft according to any one of claims 1 to 11, a housing fixed to a tip of the coil shaft, and a signal transmitting / receiving unit accommodated in the housing; and a sheath into which the imaging core is inserted.

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