阅读说明：本技术 图像诊断用导管 (Catheter for image diagnosis ) 是由 清水克彦 石原弘之 坂本泰一 桑野阳一郎 于 2020-03-19 设计创作，主要内容包括：本发明的图像诊断用导管具有：插入生物体内的护套；能够在所述护套内收发超声波的超声波振子；在所述护套内保持所述超声波振子的壳体；和安装于所述壳体的近位侧且能够在所述护套内旋转的驱动轴,所述超声波振子中的朝向所述护套的径向的超声波收发面以使远位端与近位端相比接近所述护套的内周面的方式相对于所述护套的延伸方向倾斜,所述壳体在所述超声波收发面的面内方向上没有遮挡所述超声波振子的远位侧。(The catheter for image diagnosis of the present invention comprises: a sheath for insertion into a living body; an ultrasonic transducer capable of receiving and transmitting ultrasonic waves in the sheath; a housing that holds the ultrasonic transducer in the sheath; and a drive shaft that is attached to a proximal side of the case and is rotatable in the sheath, wherein an ultrasonic transmission/reception surface of the ultrasonic transducer facing a radial direction of the sheath is inclined with respect to an extending direction of the sheath such that a distal end is closer to an inner peripheral surface of the sheath than the proximal end, and the case does not block the distal side of the ultrasonic transducer in an in-plane direction of the ultrasonic transmission/reception surface.)

1. A catheter for image diagnosis, comprising:

a sheath for insertion into a living body;

an ultrasonic transducer capable of receiving and transmitting ultrasonic waves in the sheath;

a housing that holds the ultrasonic transducer in the sheath; and

a drive shaft mounted on a proximal side of the housing and rotatable within the sheath,

an ultrasonic wave transmitting and receiving surface of the ultrasonic transducer facing a radial direction of the sheath is inclined with respect to an extending direction of the sheath such that a distal end is closer to an inner peripheral surface of the sheath than a proximal end,

the housing does not block the far side of the ultrasonic transducer in the in-plane direction of the ultrasonic transmitting/receiving surface.

2. The catheter for image diagnosis according to claim 1,

the distal end of the case is not located on the distal side than the distal end of the ultrasonic vibrator, or

The case is located only on the back side of the ultrasound transmission/reception surface of the ultrasound transducer at a position closer to the distal end of the ultrasound transducer than the distal end.

3. The catheter for image diagnosis according to claim 1 or 2,

the far end face of the ultrasonic vibrator comprises a curved surface.

4. The catheter for image diagnosis according to any one of claims 1 to 3,

the housing has: a proximal cylinder portion disposed coaxially with the drive shaft; and a protruding portion protruding from the proximal tube portion toward the distal end and located on the back side of the ultrasound transmission/reception surface of the ultrasound transducer.

5. The catheter for image diagnosis according to claim 4,

the distal end of the protruding portion is not located on the distal side of the distal end of the ultrasonic transducer, or

The protrusion is located only on the back side of the ultrasound transmission/reception surface of the ultrasound transducer at a position on the distal side of the distal end of the ultrasound transducer.

6. The catheter for image diagnosis according to claim 4 or 5,

when the side facing the ultrasonic transmission/reception surface is an upper side and the opposite side is a lower side, the protruding portion is located lower than the center axis of the proximal tubular portion.

7. The catheter for image diagnosis according to any one of claims 4 to 6,

the ultrasonic transducer has a back surface material which is positioned between the protruding portion and the ultrasonic transducer and supports the ultrasonic transducer from the back surface side of the ultrasonic transmission/reception surface.

8. The catheter for image diagnosis according to claim 7,

the protruding portion is a concave plate portion having a cross section in a direction orthogonal to the central axis direction of the proximal cylinder portion and curved in an arc shape,

at least a portion of the back surface material is located in the concave portion of the concave plate portion.

9. The catheter for image diagnosis according to claim 7 or 8,

the back surface material has a distal covering section that covers a distal end surface of the ultrasonic transducer.

10. The catheter for image diagnosis according to claim 9,

the case does not cover the side end face of the ultrasonic transducer,

the side end surface of the ultrasonic vibrator includes a curved surface.

11. The catheter for image diagnosis according to any one of claims 7 to 10,

the back surface material contains a scattering agent that scatters ultrasonic waves.

12. The catheter for image diagnosis according to any one of claims 4 to 11,

the ultrasonic transducer is located radially inward of the outer peripheral surface of the proximal cylinder portion.

Technical Field

The present invention relates to a catheter for image diagnosis.

Background

As a catheter for image diagnosis for obtaining a tomographic image of a blood vessel or the like, a catheter for image diagnosis for obtaining an image by an intravascular ultrasound diagnostic method (IVUS: Intra Vascular Ultra Sound) has been known in the related art. Patent document 1 describes such a catheter for image diagnosis.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-56142

Disclosure of Invention

The catheter for image diagnosis described in patent document 1 is used to obtain a tomographic image of a thin tube such as a blood vessel. The catheter for image diagnosis described in patent document 1 is used in a heart cavity, for example, in consideration of the situation. However, since the space of the heart is larger than that of the blood vessel, it is necessary to increase the output of the ultrasonic wave in order to obtain a clear tomographic image. The present inventors have intensively studied and found that the following new problems arise due to the increase in the output of ultrasonic waves: objects outside the object are easily reflected in the tomographic image as interference.

Therefore, an object of the present invention is to provide a catheter for image diagnosis configured to be capable of suppressing a reflection of an object other than a target on a tomographic image as a disturbance.

A catheter for image diagnosis according to claim 1 of the present invention comprises: a sheath for insertion into a living body; an ultrasonic transducer capable of receiving and transmitting ultrasonic waves in the sheath; a housing that holds the ultrasonic transducer in the sheath; and a drive shaft that is attached to a proximal side of the case and is rotatable in the sheath, wherein an ultrasonic transmission/reception surface of the ultrasonic transducer facing a radial direction of the sheath is inclined with respect to an extending direction of the sheath such that a distal end is closer to an inner peripheral surface of the sheath than the proximal end, and the case does not block the distal side of the ultrasonic transducer in an in-plane direction of the ultrasonic transmission/reception surface.

In one embodiment of the present invention, the distal end of the case is not located on the distal side of the distal end of the ultrasonic transducer, or the case is located only on the back side of the ultrasonic transmission/reception surface of the ultrasonic transducer at a position located on the distal side of the distal end of the ultrasonic transducer.

In one embodiment of the present invention, the distal end surface of the ultrasonic transducer includes a curved surface.

As an embodiment of the present invention, the housing has: a proximal cylinder portion disposed coaxially with the drive shaft; and a protruding portion protruding from the proximal tube portion toward the distal end and located on the back side of the ultrasound transmission/reception surface of the ultrasound transducer.

In one embodiment of the present invention, the distal end of the protruding portion is not located on the distal side of the distal end of the ultrasonic transducer, or the protruding portion is located on the distal side of the distal end of the ultrasonic transducer, and is located only on the back side of the ultrasonic transmission/reception surface of the ultrasonic transducer.

In one embodiment of the present invention, when a side facing the ultrasonic transmission/reception surface is an upper side and an opposite side is a lower side, the protruding portion is located lower than a central axis of the proximal cylinder portion.

In one embodiment of the present invention, the catheter for image diagnosis includes a back surface material which is positioned between the protruding portion and the ultrasonic transducer and supports the ultrasonic transducer from the back surface side of the ultrasonic transmission/reception surface.

In one embodiment of the present invention, the protruding portion is a concave plate portion having a cross section in a direction orthogonal to the central axis direction of the proximal cylinder portion and curved in an arc shape, and at least a part of the back surface material is located in a concave portion of the concave plate portion.

In one embodiment of the present invention, the back surface material has a distal covering portion that covers a distal end surface of the ultrasonic transducer.

In one embodiment of the present invention, the case does not cover a side end surface of the ultrasonic transducer, and the side end surface of the ultrasonic transducer includes a curved surface.

As one embodiment of the present invention, the back surface material contains a scattering agent that scatters ultrasonic waves.

In one embodiment of the present invention, the ultrasonic transducer is located radially inward of the outer peripheral surface of the proximal tubular portion.

Effects of the invention

According to the present invention, it is possible to provide a catheter for image diagnosis configured to be able to suppress reflection of an object other than a target as a disturbance on a tomographic image

Drawings

Fig. 1 is a block diagram showing a schematic configuration of a catheter for image diagnosis according to an embodiment of the present invention and an image processing apparatus to which the catheter for image diagnosis is connected.

Fig. 2 is a schematic view showing a state in which the catheter for image diagnosis and the image processing apparatus shown in fig. 1 are connected.

Fig. 3 is a cross-sectional view showing a distal end portion of the catheter for image diagnosis shown in fig. 2.

Figure 4 is a side view of the imaging core shown in figure 3.

Figure 5 is a top view of the imaging core shown in figure 3.

Fig. 6 is a sectional view taken along line I-I of fig. 5.

Fig. 7 is a view showing a modification of the imaging core section shown in fig. 3, in which fig. 7 (a) is a side view of the imaging core section, and fig. 7 (b) is a plan view of the imaging core section.

Fig. 8 is a diagram showing another modification of the imaging core unit shown in fig. 3.

Fig. 9 is a view showing a state in which the catheter for image diagnosis shown in fig. 2 is inserted into the right atrium of the heart.

Detailed Description

Hereinafter, an embodiment of a catheter for image diagnosis according to the present invention will be described by way of example with reference to the accompanying drawings. The same reference numerals are given to the same components and portions in the drawings. In the present specification, the side of the catheter for diagnostic imaging of the present invention inserted into an organ or the like is referred to as the "distal side" or the "distal side", and the side of the hand to be operated is referred to as the "proximal side" or the "proximal side". The extending direction of the sheath of the catheter for image diagnosis of the present invention is simply referred to as "extending direction a", the circumferential direction of the sheath of the catheter for image diagnosis of the present invention is simply referred to as "circumferential direction B", and the radial direction of the sheath of the catheter for image diagnosis of the present invention is simply referred to as "radial direction C".

Fig. 1 is a block diagram showing a schematic configuration of a catheter for image diagnosis 20 as an embodiment of the catheter for image diagnosis of the present invention, and an image processing apparatus 1 to which the catheter for image diagnosis 20 is connected. Fig. 2 is a schematic diagram showing a state in which the catheter for image diagnosis 20 and the image processing apparatus 1 are connected. Fig. 3 shows a cross-sectional view of the distal end of the catheter for image diagnosis 20.

As shown in fig. 1 and 2, the image processing apparatus 1 includes a driving unit 50, a base 59, and an image processing unit 60. The image processing unit 60 includes a display unit 51, an input unit 52, a storage unit 53, a control unit 54, and an information input unit 55. The image processing unit 60 generates a tomographic image based on information of organs, blood vessels, or medical instruments obtained by an imaging core unit 21, which will be described later, of the image diagnostic catheter 20 inserted into the living body.

As shown in fig. 1 and 3, the catheter 20 for image diagnosis includes an imaging core 21, a drive shaft 22, and a sheath 23. The information input unit 55 of the image processing apparatus 1 is electrically connected to the imaging core unit 21 of the catheter for image diagnosis 20.

The imaging core unit 21 obtains information of organs such as a heart, blood vessels (hereinafter, appropriately referred to as "organs or the like"), or medical instruments located inside the organs or the like. Specifically, the imaging core section 21 has an ultrasonic transducer 31. The ultrasound transducer 31 of the imaging core unit 21 transmits ultrasound toward an organ or the like or a medical instrument located inside the organ or the like, and receives ultrasound reflected from the organ or the like or the medical instrument. The image processing apparatus 1 generates a tomographic image of an organ or the like or a medical instrument based on the ultrasonic information received by the ultrasonic transducer 31 of the imaging core unit 21 via the information input unit 55. The image processing apparatus 1 may generate and display a three-dimensional image of an organ or the like or a medical instrument based on a plurality of tomographic images sequentially generated.

The driving unit 50 incorporates a motor and is coupled to the driving shaft 22 of the catheter for image diagnosis 20. As shown in fig. 3, the imaging core 21 is mounted on the distal side of the driving shaft 22. Because, the rotational driving force of the driving section 50 is transmitted to the imaging core section 21 via the driving shaft 22. Thereby, the imaging core 21 is rotatable in the circumferential direction B in a sheath 23 described later.

As shown in fig. 2, the driving unit 50 is slidably mounted on the base 59. The image diagnosis catheter 20 is connected to a driving unit 50 attached to a base 59. The driving portion 50 is movable in the extending direction a with respect to the base 59. Thereby, the drive shaft 22 coupled to the drive unit 50 moves along the extending direction a together with the drive unit 50. Thereby, the imaging core unit 21 attached to the distal side of the drive shaft 22 also moves in the sheath 23 along the extending direction a following the drive shaft 22.

The display unit 51 displays and outputs the display information generated by the control unit 54. The display section 51 includes a display device such as a liquid crystal display or an organic EL display.

The input unit 52 receives input based on information or instructions by the operator, and outputs the received input information or input instructions to the control unit 54. The input unit 52 includes, for example, an input device such as a keyboard, a mouse, or a touch panel. When the input unit 52 includes a touch panel, the touch panel may be provided integrally with the display unit 51.

The storage unit 53 stores various information and programs for executing a specific function in the control unit 54. The storage 53 also stores therein a tomographic image of an organ or the like of the subject generated by the control 54. The storage unit 53 includes a storage device such as a RAM or a ROM.

The control unit 54 controls the operations of the respective components constituting the image processing apparatus 1. The control section 54 executes a specific function by reading a specific program. The control section 54 includes, for example, a processor.

The information input unit 55 receives input of ultrasonic information of organs and the like obtained by the imaging core unit 21, medical instruments and the like located inside the organs and the like. Specifically, the information input section 55 is electrically connected to the imaging core section 21 via the signal line 24 extending into the drive shaft 22, obtains a signal relating to the ultrasonic information obtained by the imaging core section 21, and sends the signal to the control section 54. The control unit 54 generates a tomographic image including an organ and a medical instrument located inside the organ based on the input information.

As shown in fig. 3, the imaging core unit 21 includes an ultrasonic transducer 31 capable of transmitting and receiving ultrasonic waves in the sheath 23, and a case 32 for holding the ultrasonic transducer 31 in the sheath 23.

As shown in fig. 3, the ultrasonic transducer 31 has an ultrasonic transmission/reception surface 31a capable of transmitting/receiving ultrasonic waves. The ultrasonic wave transmitting and receiving surface 31a faces the radial direction C. That is, the ultrasonic transducer 31 transmits the ultrasonic waves mainly in the radial direction C from the ultrasonic wave transmitting and receiving surface 31 a. The ultrasound transmission/reception surface 31a is inclined with respect to the extending direction a such that the distal end is closer to the inner circumferential surface of the sheath 23 than the proximal end. The details of which will be described later.

The ultrasonic transducer 31 transmits ultrasonic waves to a target portion and receives ultrasonic waves reflected from the target portion. Information such as the distance to the target site is obtained based on the time from transmission to reception of the ultrasonic wave.

As shown in fig. 3, the case 32 holds the ultrasonic transducer 31. The case 32 does not block the distal side of the ultrasonic transducer 31 in the in-plane direction D of the ultrasonic transmission/reception surface 31 a. The "in-plane direction of the ultrasonic wave transmission/reception surface" means an arbitrary direction parallel to the ultrasonic wave transmission/reception surface. More specifically, the distal end 32a of the case 32 of the present embodiment is not located on the distal side of the distal end 31e of the ultrasound transducer 31. The details of which will be described later.

The drive shaft 22 is mounted on the proximal side of the housing 32 of the imaging core 21. The proximal end of the drive shaft 22 is coupled to the drive unit 50. The drive shaft 22 can be formed of, for example, a plurality of layers of coils having different winding directions around the shaft. Examples of the material of the coil include stainless steel and a Ni — Ti (nickel-titanium) alloy.

The sheath 23 is a flexible tubular member that covers the imaging core portion 21 and the outside of the drive shaft 22 in the radial direction C. In the present embodiment, the sheath 23 defines a 1 st chamber 23a in which the imaging core 21 and the drive shaft 22 are housed. The sheath 23 defines a 2 nd lumen 23b into which the guide wire 10 can be inserted, in addition to the 1 st lumen 23 a. Fig. 3 shows a state in which the imaging core section 21 and the drive shaft 22 are housed in the 1 st lumen 23a and the guide wire 10 is inserted into the 2 nd lumen 23 b. The catheter 20 for image diagnosis is inserted into an organ or the like along the guide wire 10. The sheath 23 of the present embodiment is of a quick-change type (RX type) in which the 2 nd chamber 23b is defined only at the distal end, but is not limited to the RX type, and may be of an overall replacement type (OTW type), for example.

The distal end of chamber 1, 23a of sheath 23 is completely closed by wall 23 c. However, the distal end of the 1 st chamber 23a of the sheath 23 is not limited to a completely closed configuration, and may communicate with the outside, or may be provided with a wall portion in which a through hole having a smaller cross-sectional area than the 1 st chamber 23a is formed.

The sheath 23 can be formed of a material having flexibility. Specific materials for the sheath 23 are not particularly limited, and examples thereof include various thermoplastic elastomers such as styrenes, polyolefins, polyurethanes, polyesters, polyamides, polyimides, polybutadienes, trans-polyisoprenes, fluororubbers, chlorinated polyethylenes, and combinations of 1 or 2 or more thereof (mixture alloys, polymer blends, laminates, and the like).

The imaging core unit 21 of the catheter for image diagnosis 20 will be described in more detail. Fig. 4 is a side view of the imaging core portion 21. Fig. 5 is a plan view of the imaging core portion 21. Fig. 6 is a sectional view taken along line I-I of fig. 5. Here, the side view of the imaging core unit 21 of the present embodiment means a plan view viewed from the perspective in which the ultrasound transmitting and receiving surface 31a appears linear. The plan view of the imaging core 21 according to the present embodiment means a plan view of the imaging core 21 viewed from the ultrasound transmission/reception surface 31a side.

As described above, the imaging core unit 21 includes the ultrasonic transducer 31 and the case 32. As shown in fig. 3 and 4, the ultrasound transmitting/receiving surface 31a of the ultrasound transducer 31 is inclined with respect to the extending direction a so that the distal end is closer to the inner peripheral surface of the sheath 23 than the proximal end.

For example, when the output of the ultrasonic wave is increased, the ultrasonic transducer 31 may transmit the ultrasonic wave from a surface other than the ultrasonic wave transmitting/receiving surface 31 a. In such a case, the ultrasonic waves transmitted from the distal end surface 31b of the ultrasonic transducer 31 may be reflected by the wall 23c on the distal side of the 1 st cavity 23a of the sheath 23 and received by the ultrasonic transmitting/receiving surface 31 a. This may cause a problem that the wall 23c of the sheath 23, which is an object outside the object, is reflected in the tomographic image as a disturbance.

However, the ultrasonic transmission/reception surface 31a of the ultrasonic transducer 31 is inclined with respect to the extending direction a in a direction in which the distal end is closer to the inner peripheral surface of the sheath 23 than the proximal end. Therefore, even if the ultrasonic wave is transmitted from the distal end surface 31b of the ultrasonic transducer 31, the ultrasonic wave hardly reaches the wall portion 23c on the distal side of the 1 st cavity 23a of the sheath 23, as compared with the configuration in which the ultrasonic wave transmitting and receiving surface is parallel to the sheath extending direction a. Even if the ultrasonic waves reach and are reflected by the wall portion 23c on the distal side of the 1 st chamber 23a of the sheath 23, the ultrasonic wave transmitting and receiving surface 31a is inclined toward the proximal side, so that it is difficult for the ultrasonic wave transmitting and receiving surface 31a to receive the ultrasonic waves reflected by the wall portion 23c on the distal side of the 1 st chamber 23a of the sheath 23. Therefore, it is possible to suppress the reflection of the object outside the object, that is, the wall portion 23c of the sheath 23, as interference into the tomographic image.

The angle of the ultrasonic transmitting/receiving surface 31a with respect to the extending direction a is not particularly limited, and is, for example, preferably 5 ° to 15 °, and more preferably 7 ° to 12 °.

As shown in fig. 3 and 4, the case 32 does not shield the distal end side of the ultrasonic transducer 31 in the in-plane direction D of the ultrasonic transmission/reception surface 31 a. More specifically, the distal end 32a of the case 32 of the present embodiment is not located on the distal side of the distal end 31e of the ultrasound transducer 31. In the present embodiment, the position of the distal end 32a of the case 32 substantially coincides with the position of the distal end 31e of the ultrasound transducer 31 in the extending direction a, but the present invention is not limited to this configuration. The distal end 32a of the case 32 may be located closer to the distal end 31e of the ultrasound transducer 31.

By configuring the case 32 in this manner, it is possible to suppress the ultrasonic waves transmitted from the ultrasonic wave transmitting/receiving surface 31a and the distal end surface 31b of the ultrasonic transducer 31 from being reflected by the case 32 as an object outside the subject and being received by the ultrasonic wave transmitting/receiving surface 31a as ultrasonic interference. That is, the shell 32 as the object other than the object can be suppressed from being reflected as a disturbance to the tomographic image.

However, the case may be located only on the back side of the ultrasound transmission/reception surface of the ultrasound transducer at a position further toward the distal end of the ultrasound transducer (see fig. 7 a and 7 b). The same effects as described above can be obtained even with such a case.

As described above, according to the imaging core unit 21 shown in fig. 3 and 4, it is possible to suppress the ultrasonic transducer 31 from receiving the ultrasonic waves which are interfering from the far side in the in-plane direction D of the ultrasonic wave transmission/reception surface 31 a. That is, it is possible to suppress an object other than the object from being reflected in the tomographic image as a disturbance.

As shown in fig. 5, the distal end face 31b of the ultrasonic transducer 31 of the present embodiment includes a curved surface. By doing so, the traveling direction of the ultrasonic waves transmitted from the ultrasonic transducer 31 can be dispersed. That is, the ultrasonic waves transmitted from the distal end surface 31b of the ultrasonic transducer 31 hardly reach the wall portion 23c of the sheath 23. This can suppress reflection of the wall portion 23c of the sheath 23, which is an object other than the target object, as a disturbance in the tomographic image.

The distal end surface 31b of the present embodiment is a surface substantially perpendicular to the ultrasonic wave transmission and reception surface 31 a. The distal end surface 31b of the present embodiment is a convex surface curved in an arc shape in a plan view shown in fig. 5. However, the shape of the curved surface of the distal end surface 31b is not limited to the shape of the present embodiment. The distal end surface 31b may be, for example, a surface inclined with respect to the ultrasonic wave transmission and reception surface 31a in the side view shown in fig. 4, or may be a curved surface in the side view shown in fig. 4. Further, the distal end surface 31b may have irregularities. However, the distal end surface 31b is preferably a surface substantially perpendicular to the ultrasonic wave transmission/reception surface 31a as in the present embodiment, and is preferably a convex curved surface curved in a plan view shown in fig. 5. By doing so, the ultrasonic wave transmitting/receiving surface 31a can be easily secured wide, and the ultrasonic wave output can be easily increased. The shape of the ultrasonic transducer having the distal end surface including such a curved surface in a plan view may be, for example, a circular shape, an elliptical shape, a front-rear round bulge shape, or the like.

The ultrasonic transducer 31 may transmit ultrasonic waves from the side end surface 31c, not only from the distal end surface 31 b. The side end surface 31c is an end surface in a direction orthogonal to the extending direction a. Therefore, the side end surface 31c of the ultrasonic transducer 31 of the present embodiment is formed of a plane extending linearly in a plan view as shown in fig. 5, but is preferably a side end surface including a curved surface. By doing so, it is difficult to reflect ultrasonic interference caused by ultrasonic waves transmitted from the side end surface to a tomographic image, similarly to the distal end surface 31b described above. Fig. 7 is a diagram showing an imaging core unit 321 as a modification of the imaging core unit 21 according to the present embodiment. Fig. 7 (a) is a side view of the imaging core 321. Fig. 7 (b) is a plan view of the imaging core 321. The case 32 shown in fig. 7 (a) and 7 (b) does not cover the side end surface 331c of the ultrasonic transducer 331. The side end surface 331c of the ultrasonic transducer 331 includes a curved surface. More specifically, in the ultrasonic transducer 331 shown in fig. 7 a and 7 b, the distal end surface 331b and the side end surface 331c form a continuous circular arc shape in a plan view (see fig. 7 b). The shape of the side end surface 331c is not limited to the shape shown in fig. 7. However, for the same reason as the distal end surface 31b (see fig. 5) of the ultrasonic transducer 31, it is preferable that the curved surface is a convex curved surface which is substantially perpendicular to the ultrasonic wave transmitting and receiving surface 331a and which is curved in a plan view, as in the side end surface 331c shown in fig. 7 (a) and 7 (b).

However, from the viewpoint of the rectilinear propagation of the ultrasonic wave of the ultrasonic transducer, it is preferable to provide the side end surface 31c shown in fig. 5 as a flat surface extending linearly when viewed from above. In addition, from the viewpoint of the rectilinear propagation of the ultrasonic wave of the ultrasonic transducer, it is preferable that the distal end surface is also formed of a plane extending linearly when viewed from above.

The case 32 of the imaging core 321 shown in fig. 7 (a) and 7 (b) is located on the far side of the far end 331e of the ultrasonic transducer 331 only on the back surface 331d side of the ultrasonic transmitting/receiving surface 331a of the ultrasonic transducer 331. Therefore, the shell 32 can be suppressed from being reflected as a disturbance to the tomographic image.

Referring back to the present embodiment again, the imaging core unit 21 will be described in further detail with reference to fig. 3 to 6.

The imaging core unit 21 of the present embodiment further includes a back surface material 33 in addition to the ultrasonic transducer 31 and the case 32.

The ultrasonic transducer 31 of the present embodiment includes a piezoelectric element and an acoustic matching member. The piezoelectric element is composed of a flat piezoelectric body, a 1 st electrode laminated on at least one side of the piezoelectric body in the thickness direction, and a 2 nd electrode laminated on at least the other side of the piezoelectric body in the thickness direction.

The piezoelectric body of the piezoelectric element is formed of, for example, a piezoelectric ceramic sheet. Examples of the material of the piezoelectric ceramic sheet include piezoelectric ceramic materials such as lead zirconate titanate (PZT) and lithium niobate. The piezoelectric body may be made of crystal instead of a piezoelectric ceramic material.

For example, the 1 st electrode and the 2 nd electrode of the piezoelectric element can be formed by laminating mask materials as electrode layers on both surfaces in the thickness direction of the piezoelectric body by an ion plating method, a vapor deposition method, or a sputtering method. Examples of the material of the 1 st electrode and the 2 nd electrode include metals such as silver, chromium, copper, nickel, and gold, and a laminate of these metals.

One of the 1 st electrode and the 2 nd electrode in the present embodiment is formed of a folded electrode. Therefore, as shown in fig. 5, the signal line 24 is electrically connected to the 1 st electrode and the 2 nd electrode only on one side in the thickness direction of the piezoelectric element. However, the 1 st electrode and the 2 nd electrode may be common electrodes respectively located only on both sides in the thickness direction of the piezoelectric element.

The acoustic matching member is laminated on one side in the thickness direction of the piezoelectric element. By providing the acoustic matching means, the transmission efficiency of ultrasonic waves to the subject to be inspected can be improved. That is, the acoustic matching section constitutes an acoustic matching layer that improves the propagation efficiency of the ultrasonic wave. The ultrasonic transmission/reception surface 31a of the present embodiment is constituted by the acoustic matching means.

The acoustic matching layer as the acoustic matching member can be formed by a method of bonding a sheet forming the acoustic matching layer to the piezoelectric element, a method of applying a liquid acoustic matching material forming the acoustic matching layer and curing the material, or the like. Examples of the material of the acoustic matching member include resin materials such as epoxy resin. The acoustic matching member may be formed by a laminate of resin layers made of a resin material.

The ultrasonic transducer 31 of the present embodiment is formed by applying a convex curved surface to a distal side surface of a rectangular plate shape having a thickness of 1.5mm to 2.5mm in a plan view. The ultrasonic transducer 331 shown in fig. 7 has an outer diameter of 1.5mm to 2.5mm in a plan view. The output frequency of the ultrasonic waves transmitted from the ultrasonic transducers 31 (see fig. 5 and the like) and 331 (see fig. 7) is 7MHz to 20 MHz. The transmission voltage of the ultrasonic waves transmitted from the ultrasonic transducers 31 (see fig. 5 and the like) and 331 (see fig. 7) is, for example, 10Vp-p to 100 Vp-p.

The housing 32 of the present embodiment includes a proximal cylinder 41 disposed coaxially with the drive shaft 22, and a protruding portion 42 protruding from the proximal cylinder 41 toward the distal side and located on the back surface 31d side of the ultrasound transmitting/receiving surface 31a of the ultrasound transducer 31. With such a configuration, the case 32 can be configured to have a simple shape so that the case 32 does not shield the distal side of the ultrasonic transducer 31 in the in-plane direction D of the ultrasonic transmission/reception surface 31 a.

More specifically, the distal end 32a of the housing 32 of the present embodiment is the distal end of the projection 42. Therefore, as shown in fig. 3 and 4, in the present embodiment, the distal end of the protrusion 42 is not located on the distal side of the distal end 31e of the ultrasound transducer 31. As described above, according to the case 32 of the present embodiment, it is possible to realize a configuration in which the distal side of the ultrasonic transducer 31 is not shielded in the in-plane direction D of the ultrasonic transmission/reception surface 31a with a simple configuration. In particular, the protruding portion 42 is preferably not located on the distal side of the ultrasonic transducer 31 in the in-plane direction D and in the entire region in the direction orthogonal to the extending direction a (hereinafter referred to as "width direction E"). That is, the protruding portion 42 of the present embodiment has a portion located farther than the ultrasonic transducer 31 at both ends in the width direction E in the plan view of fig. 5, but preferably does not have such a portion. By doing so, reception of the ultrasonic transducer 31 from the remote side into interfering ultrasonic waves can be further suppressed. As shown in fig. 7 (b), the protrusion 42 may be located only on the back side of the ultrasound transmission/reception surface 331a of the ultrasound transducer 331 at a position on the distal side of the distal end 331e of the ultrasound transducer 331.

In other words, the housing 32 of the present embodiment has a cutout portion cut out to the distal end 32a in a side view (see fig. 4). The ultrasonic transducer 31 is disposed in the notch.

More specifically, the protruding portion 42 is a concave plate portion that is curved in an arc shape in a cross section (see fig. 6) in a direction orthogonal to a central axis direction (a direction substantially equal to the extending direction a within the sheath 23) parallel to the central axis of the proximal cylinder portion 41. In other words, the protruding portion 42 of the present embodiment is formed by a semi-cylindrical bent plate portion. The center axis of the proximal cylinder portion 41 coincides with the center axis of the drive shaft 22, and substantially coincides with the center axis of the sheath 23 in the sheath 23. In the present embodiment, the central axis of the proximal cylinder portion 41, the central axis of the drive shaft 22, and the central axis of the sheath 23 are all referred to as "central axes O". In fig. 3, for convenience of explanation, a gap is provided between the inner peripheral surface of the sheath 23 and the outer peripheral surface of the proximal cylinder portion 41 of the housing 32, but in reality, the gap is almost absent. That is, the inner diameter of the 1 st chamber 23a of the sheath 23 is substantially equal to the outer diameter of the proximal tubular portion 41, and the outer peripheral surface of the proximal tubular portion 41 abuts against the inner peripheral surface of the sheath 23 at a plurality of locations in the circumferential direction B or over the entire region in the circumferential direction B.

As shown in fig. 4, the ultrasonic transducer 31 of the present embodiment is positioned radially inward (in a direction substantially equal to the radial direction C in the sheath 23) of the outer peripheral surface of the proximal tubular portion 41. That is, the ultrasonic transducer 31 of the present embodiment does not protrude radially outward beyond the outer peripheral surface of the proximal cylinder portion 41. By doing so, even when the outer peripheral surface of the proximal cylinder portion 41 slides and rotates with the inner peripheral surface of the sheath 23, the ultrasonic transducer 31 is less likely to come into contact with the inner peripheral surface of the sheath 23. That is, the ultrasonic transducer 31 can be prevented from being damaged by contact with the inner peripheral surface of the sheath 23.

As shown in fig. 4, end surfaces 42a on both sides in the circumferential direction (the direction substantially equal to the circumferential direction B in the sheath 23) of the concave plate portion as the protruding portion 42 in the present embodiment extend obliquely with respect to the central axis direction in side view. The details of which will be described later.

As shown in fig. 5, the proximal end surface of the ultrasonic transducer 31 is disposed at a position separated from the proximal tube 41 toward the distal side in a plan view. By doing so, it is possible to suppress the reflection of the ultrasonic wave transmitted from the ultrasonic wave transmitting and receiving surface 31a of the ultrasonic transducer 31 by the proximal cylinder 41. As a result, it is possible to suppress the reception of the ultrasonic wave reflected by the proximal cylinder 41 and becoming interference by the ultrasonic wave transmitting and receiving surface 31 a. Further, an inclined distal end portion inclined with respect to the extending direction a may be formed at the distal end of the proximal tubular portion 41 in the circumferential region where the protruding portion 42 is not extended. The inclined distal end portion is inclined so as to approach the projection 42 toward the distal side. By doing so, the ultrasonic waves transmitted from the ultrasonic wave transmitting and receiving surface 31a of the ultrasonic transducer 31 are less likely to reach the proximal cylinder portion 41.

Examples of the material of the case 32 include metals such as stainless steel (SUS), nickel-titanium alloy (Ni-Ti), and tungsten.

The back surface material 33 is positioned between the protruding portion 42 and the ultrasonic transducer 31, and supports the ultrasonic transducer 31 from the back surface 31d side of the ultrasonic transmission/reception surface 31 a. The back material 33 is a sound absorber made of rubber, epoxy resin, or the like, into which metal powder such as tungsten powder is diffused, for example. By providing the back surface material 33, a part of the ultrasonic waves which are transmitted from the ultrasonic transducer 31 and cause interference can be absorbed.

The back surface material 33 of the present embodiment covers the entire area of the back surface 31d of the ultrasonic transducer 31. This allows the ultrasonic wave transmitted from the back surface 31d of the ultrasonic transducer 31 to be absorbed. The backing material 33 of the present embodiment is positioned on the proximal side of the ultrasonic transducer 31, and covers the proximal end face of the ultrasonic transducer 31. That is, the back surface material 33 of the present embodiment extends not only on the back surface 31d side of the ultrasonic transducer 31 but also continuously into the proximal tubular portion 41 over the entire region in the proximal tubular portion 41. This allows the ultrasonic wave transmitted from the proximal end surface of the ultrasonic transducer 31 to be absorbed.

The back surface material 33 is not limited to the back surface 31d of the ultrasonic transducer 31, and may cover the distal end surface 31b and the side end surface 31c of the ultrasonic transducer 31. By doing so, the ultrasonic waves transmitted from the distal end surface 31b and the side end surface 31c of the ultrasonic transducer 31 can be absorbed by the back material 33. Therefore, a part of the ultrasonic waves which are transmitted from the ultrasonic transducer 31 and cause the interference can be further absorbed. Fig. 8 is a diagram showing an imaging core section 421 as a modification of the imaging core section 21. The imaging core 421 shown in fig. 8 has the ultrasonic transducer 31, the case 32, and the back surface material 433. The back surface member 433 has a distal covering portion 433a covering the distal end surface 31b of the ultrasonic transducer 31, different from the back surface member 33. The back material 433 shown in fig. 8 has the distal covering portion 433a covering the distal end surface 31b of the ultrasonic transducer 31, but is not limited to this configuration, and may have a side end covering portion covering the side end surface of the ultrasonic transducer in addition to or instead of the distal covering portion 433 a.

In addition, the back surface material 433 shown in fig. 8 includes a scattering agent that scatters ultrasonic waves. Examples of the scattering agent include glass particles and polystyrene particles. By including such a scattering agent in the distal covering portion 433a of the back surface material 433, it is possible to scatter the ultrasonic waves transmitted from the distal end surface 31b in addition to the absorption effect of the ultrasonic waves by the back surface material 433, and it is possible to further suppress the reception of the ultrasonic waves, which become interference, by the ultrasonic wave transmitting and receiving surface 31 a.

The back surface material 433 preferably does not protrude radially outward beyond the outer peripheral surface of the proximal tubular portion 41 of the housing 32 regardless of the presence or absence of the scattering agent. By doing so, the back surface material 433 can be suppressed from abutting against the inner circumferential surface of the sheath 23 (see fig. 3).

The imaging core unit 21 of the present embodiment will be described with reference to fig. 4 and 6 again. As described above, the end surfaces 42a on both sides in the circumferential direction of the concave plate portion as the protruding portion 42 of the present embodiment extend obliquely with respect to the central axis line direction in side view. As shown in fig. 6, the back sheet 33 of the present embodiment includes: a main body portion 33c positioned in a recess 42b which is a concave plate portion of the protruding portion 42 of the housing 32; and a flange portion 33d projecting from the body portion 33c and supported by end surfaces 42a on both sides in the circumferential direction of the concave plate portion. Therefore, when the main body portion 33c of the back surface material 33 is filled into the concave portion 42b, the flange portion 33d of the back surface material 33 is supported and positioned on the end surface 42 a. That is, by using the end face 42a, the back material 33 can be easily positioned with respect to the concave plate portion as the protruding portion 42. As described above, the end face 42a is inclined with respect to the central axis direction in side view. Therefore, the support surface 33b of the backing material 33 supporting the ultrasonic transducer 31 can be inclined with respect to the extending direction a only by supporting and positioning the flange portion 33d of the backing material 33 on the end surface 42 a. Therefore, simply by placing the back surface 31d substantially parallel to the ultrasound transmitting and receiving surface 31a on the support surface 33b of the back surface material 33, it is possible to easily achieve a state in which the ultrasound transmitting and receiving surface 31a is inclined at a desired angle with respect to the extending direction a. That is, the ultrasonic wave transmitting/receiving surface 31a of the ultrasonic transducer 31 inclined at a desired angle can be easily realized.

The side of the imaging core 21 facing the ultrasound transmission/reception surface 31a is referred to as the upper side, and the opposite side is referred to as the lower side. In this case, the projecting portion 42 is preferably positioned below the center axis O of the proximal cylinder portion 41 in a side view shown in fig. 4. By doing so, the position of the ultrasonic transducer 31 is easily brought close to the position of the center axis O of the drive shaft 22. By bringing the position of the ultrasonic transducer 31 close to the position of the center axis O of the drive shaft 22, the rotation of the ultrasonic transducer 31 can be stabilized. With such a configuration, the signal line 24 can be easily drawn into the drive shaft 22. In particular, the rotation of the ultrasonic transducer 31 can be stabilized by matching the center position of the rotation of the ultrasonic transducer 31 with the position of the center axis O of the drive shaft 22. In the present embodiment, as shown in fig. 4, the proximal end of the end surface 42a on both sides in the circumferential direction of the concave plate portion of the protruding portion 42 is positioned below the central axis O of the proximal cylinder portion 41 in a side view. Therefore, as described above, the position of the ultrasonic transducer 31 can be easily aligned with the position of the central axis O of the drive shaft 22. Further, by bringing the position of the ultrasonic transducer 31 close to the position of the central axis O of the drive shaft 22, it is possible to suppress the variation in position accompanying the rotation, and to generate a tomographic image of the living tissue with higher accuracy.

The body portion 33c may not fill the entire space in the recess 42 b. However, considering the ultrasonic wave absorption performance, it is preferable to fill the entire space in the concave portion 42 b.

Further, the back material 33 has the flange portion 33d, and thus the end face 42a of the protruding portion 42 of the case 32 can be covered with the flange portion 33 d. This can prevent the ultrasonic wave transmitted from the ultrasonic transducer 31 from being reflected by the end face 42a of the protruding portion 42 of the case 32 and received as ultrasonic interference.

Finally, an example of an operation performed using the catheter for image diagnosis 20 according to the present embodiment will be described with reference to fig. 9. Fig. 9 shows a diagnostic imaging catheter 20 inserted into the right atrium RA of the heart. As shown in fig. 9, an operator such as a medical practitioner inserts the image diagnosis catheter 20 into the right atrium RA via the lower large vein IVC, which is the 1 st blood vessel having a smaller diameter than the right atrium RA of the subject. At this time, the operator inserts the puncture needle 80 as a medical instrument positioned in the right atrium RA into the right atrium RA by passing through the lower great vein IVC from the guide catheter 84. The puncture needle 80 is used to open the left atrium LA from the right atrium RA through the fossa ovalis H which isolates the right atrium RA from the left atrium LA.

As shown in fig. 9, the operator inserts the distal end of the catheter for image diagnosis 20 from the right atrium RA to the upper great vein SVC, which is a 2 nd blood vessel having a smaller diameter than the connected right atrium RA. Specifically, first, the guide wire 10 is inserted into the upper great vein SVC, and then the distal end of the catheter for image diagnosis 20 can be inserted into the upper great vein SVC along the guide wire 10. This suppresses vibration of the distal end of the catheter for image diagnosis 20. Then, the proximal side of the image diagnostic catheter 20 enters the lower large vein IVC having a smaller diameter than the right atrium RA, so that the image diagnostic catheter 20 extends in the range of the upper large vein SVC and the lower large vein IVC having a smaller diameter than the right atrium RA, and vibration and movement of the portion of the image diagnostic catheter 20 located in the right atrium RA are suppressed.

Further, by bending the portion of the catheter for image diagnosis 20 positioned in the right atrium RA, the 1 st cavity 23a of the sheath 23 in which the ultrasound transducer 31 is housed can be bent. By bending the 1 st chamber 23a in this manner, the extending direction a of the sheath 23 can be changed, and the position in the right atrium RA where the ultrasonic transducer 31 moves can be changed. Therefore, a site to be observed (for example, fossa ovalis H of the heart) on the inner wall surface of an organ or the like can be approached.

The ultrasonic transducer 31 moves in the extending direction a while rotating in the circumferential direction B in the 1 st chamber 23a of the sheath 23. During this time, the ultrasonic transducer 31 transmits ultrasonic waves in the radial direction C and receives ultrasonic waves reflected by the inner wall surface of the right atrium RA and the like. Thereby, the ultrasonic transducer 31 obtains position information of the inner wall surface of the right atrium RA as the surrounding information. The ultrasound transducer 31 obtains, as the peripheral information, the positional information of the puncture needle 80 as the medical instrument positioned in the right atrium RA. The control unit 54 generates a tomographic image in which the position information of the inner wall surface of the right atrium RA and the position information of the puncture needle 80 are reflected based on the peripheral information obtained by the ultrasound transducer 31.

As described above, by moving the ultrasonic transducer 31 within the sheath 23 in a state in which vibration and movement of the portion of the catheter for image diagnosis 20 located within the right atrium RA are suppressed, rotation of the ultrasonic transducer 31 in the circumferential direction B and movement of the ultrasonic transducer 31 in the extending direction a are stabilized. Therefore, the peripheral information such as the position information of the inner wall surface of the right atrium RA can be stably obtained. At this time, the storage unit 53 stores the tomographic image generated by the control unit 54 when the ultrasonic transducer 31 moves in the extension direction a as needed in association with the position of the ultrasonic transducer 31 in the extension direction a at that time.

The control unit 54 may generate a three-dimensional image of the right atrium RA by stacking the tomographic images using the information stored in the storage unit 53.

As described above, the ultrasound transducer 31 of the catheter for image diagnosis 20 is inclined so that the ultrasound transmission/reception surface 31a (see fig. 4 and the like) is directed toward the proximal side. Therefore, as shown in fig. 9, by disposing the ultrasound transducer 31 further to the back side than the fossa ovalis H punctured by the puncture needle 80 and generating a tomographic image closer to the position side than the position of the ultrasound transducer 31, it is easy to obtain a tomographic image in which the distal end position of the puncture needle 80 does not overlap with other portions of the puncture needle 80. That is, by configuring the ultrasound transmitting/receiving surface 31a (see fig. 4 and the like) to be inclined toward the proximal side, it is easy to obtain a tomographic image with a clear distal end position of the medical instrument used by being inserted into the living body together with the catheter for image diagnosis 20. This is not limited to the operation shown in fig. 9, and can be applied similarly to an operation performed in a relatively wide space in a living body such as an atrium.

In fig. 9, the right atrium RA of the heart is shown as an example of the lumen of an organ or the like, but the lumen of an organ or the like into which the catheter 20 for image diagnosis of the present invention is inserted is not particularly limited, and may be, for example, the left atrium of the heart or the lumen of an organ other than the heart.

The catheter for image diagnosis according to the present invention is not limited to the specific structure shown in the above-described embodiment and modification examples, and various modifications and changes can be made without departing from the scope of the invention.

Industrial applicability

The present invention relates to a catheter for image diagnosis.

Description of the reference numerals

1: image processing apparatus

10: guide wire

20: catheter for image diagnosis

21. 321, 421: imaging core

22: drive shaft

23: protective sleeve

23 a: 1 st Chamber

23 b: 2 nd chamber

23 c: wall part

24: signal line

31. 331: ultrasonic vibrator

31a, 331 a: ultrasonic transceiver

31b, 331 b: distal end face

31c, 331 c: side end face

31d, 331 d: back side of the panel

31e, 331 e: distal end of ultrasonic vibrator

32: shell body

32 a: distal end of the housing

33. 433: back material

33 b: bearing surface

33 c: main body part

33 d: flange part

41: proximal cylinder part

42: projection part

42 a: end face

42 b: concave part

50: driving part

51: display unit

52: input unit

53: memory part

54: control unit

55: information input unit

59: base seat

60: image processing unit

80: puncture needle

84: guide catheter

433 a: far position covering part

A: direction of extension of the sheath

B: the circumference of the sheath

C: radial direction of the sheath

D: in-plane direction of ultrasonic transmitting/receiving surface

E: width direction of the sheet

O: center axis of proximal cylinder, drive shaft, and sheath

LA: left atrium

RA: right atrium

IVC: inferior great vein

SVC: the superior vena cava.