Interventional variable-focus ultrasonic catheter

Abstract

An interventional variable-focus ultrasonic catheter, comprising: an inner tube; an outer tube, sleeved outside the inner tube and comprising: a first fixed section fixed relative to the inner tube and a slidable section capable of sliding in an axial direction relative to the inner tube, wherein the slidable section comprises a bendable section, and the bendable section is bent into a bent shape which is integrally concave inward from both ends to the middle when the slidable section slides towards the first fixed section; and a plurality of ultrasonic transducer arrays, arranged on the bendable section and spaced apart in a circumferential direction, wherein each of the ultrasonic transducer arrays comprises a plurality of ultrasonic transducers spaced apart in an axial direction. The interventional variable-focus ultrasonic catheter of the present application can not only enhance the local intensity of ultrasound and improve the local therapeutic effect of ultrasound, but also expand the action range of ultrasound in the circumferential direction and the radial direction, thereby significantly improving the therapeutic range and therapeutic efficiency of ultrasound.

Description

Interventional variable focus ultrasound catheter

[0001] Related applications

[0002] This application claims priority to Chinese Patent Application No. 202410502022.1, filed on April 24, 2024, and incorporates the entire contents of the aforementioned patent application as part of this application. Technical Field

[0003] This application relates to the field of medical catheter technology, and in particular to an interventional variable focus ultrasound catheter. Background Technology

[0004] Endovascular nerve ablation is an interventional treatment method used to alleviate symptoms of certain neurological disorders, such as hypertension and pulmonary hypertension caused by sympathetic overactivation. During the treatment, a catheter is inserted into the blood vessel corresponding to the nerve, and then the nerve tissue in the target area is destroyed using methods such as radiofrequency ablation, ultrasound ablation, cryoablation, or chemical ablation to achieve the therapeutic goal. Taking renal sympathectomy for hypertension as an example, renal afferent and efferent sympathetic nerves are distributed around the renal artery, with the nerves located 2mm to 7mm from the vessel wall.

[0005] Clinically, complete ablation of the nerves surrounding the blood vessels in a 360° direction is required to achieve a therapeutic effect. Compared to radiofrequency ablation, ultrasound has the advantage of a wider radiation range, making it easier to achieve deeper ablation depths. However, due to the small diameter of interventional catheters, it is difficult to achieve higher radiation power by increasing the size of the ultrasound transducer. Although focusing can enhance local ultrasound intensity, it also limits the treatment area.

[0006] It should be noted that the above description of the background technology is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background technology section of this application. Summary of the Invention

[0007] The purpose of this application is to provide an interventional variable focus ultrasound catheter to solve the problems mentioned in the background art or other similar problems.

[0008] This application provides an interventional variable-focus ultrasound catheter, comprising: an inner tube; an outer tube sleeved outside the inner tube, including a first fixed section fixed relative to the inner tube and a slidable section slidable relative to the inner tube in an axial direction, the slidable section including a bendable section, the bendable section bending into a curved shape that is concave from both ends to the middle as it slides toward the first fixed section; and a plurality of ultrasound transducer arrays disposed on the bendable section and spaced apart in the circumferential direction, each ultrasound transducer array including a plurality of ultrasound transducers spaced apart in the axial direction, the ultrasound waves generated by the plurality of ultrasound transducers in each ultrasound transducer array being focused when the bendable section is in the curved shape, the change in the bending amplitude of the bendable section causing a change in the focal length of the ultrasound waves, and the focusing positions of the ultrasound waves emitted by the ultrasound transducers of the plurality of ultrasound transducer arrays being distributed over the entire circumferential range outside the outer tube.

[0009] In some embodiments, the bendable segment includes a plurality of bendable strips, the plurality of bendable strips being at least partially spaced apart in the circumferential direction, each of the bendable strips extending along the axial direction, each of the ultrasonic transducer arrays being disposed on one of the bendable strips, and a plurality of ultrasonic transducers of each ultrasonic transducer array being spaced apart along the axial direction on the bendable strip.

[0010] In some embodiments, the middle portions of a plurality of the flexible strips are sequentially connected in the circumferential direction to form a first connecting ring, the first connecting ring restricting the bending of the middle portion of each of the flexible strips when the flexible segment bends.

[0011] In some embodiments, each of the flexible strips has a plurality of folds on its outer surface opposite to the inner tube, which cause the flexible segment to bend into the bent shape. The plurality of folds are spaced apart along the length direction of the flexible strip, and each fold extends along the width direction of the flexible strip.

[0012] In some embodiments, each of the flexible strips is provided with a metal foil that causes the flexible segment to bend into the bent shape, the metal foil having the same pre-deformed shape as the bent shape.

[0013] In some embodiments, the metal foil serves as an electrode of the ultrasonic transducer and is electrically connected to the ultrasonic transducer.

[0014] In some embodiments, the metal foil is disposed on the outer surface of the flexible section opposite to the inner tube; or, the metal foil is embedded in the sidewall of the flexible section; or, the metal foil is disposed on the inner surface of the flexible section facing the inner tube.

[0015] In some embodiments, the ultrasonic transducer is disposed on the outer surface of the flexible section opposite to the inner tube; or, the ultrasonic transducer is embedded in the side wall of the flexible section; or, the ultrasonic transducer is disposed on the inner surface of the flexible section facing the inner tube.

[0016] In some embodiments, the flexible segment is positioned close to the first fixed segment.

[0017] In some embodiments, the flexible segment is directly connected to the first fixed segment.

[0018] In some embodiments, the outer tube further includes a second fixed section and a flexible positioning section connected between the second fixed section and the first fixed section; the conduit further includes a slidable member axially slidable inside the inner tube, the slidable member being connected to the second fixed section, the slidable member driving the second fixed section to move toward the first fixed section, and the positioning section bending to form a curved shape that protrudes outward from both ends to the middle when the second fixed section moves toward the first fixed section.

[0019] In some embodiments, the slidable component includes a sliding tube and a sliding shaft. The sliding tube is located inside the positioning section. One end of the sliding tube is inserted into the inner tube and fixedly connected to one end of the sliding shaft. The other end of the sliding tube extends out of the inner tube and is fixedly connected to the second fixing section.

[0020] In some embodiments, the ultrasonic transducer is a focused ultrasonic transducer or a non-focused ultrasonic transducer.

[0021] In some embodiments, the ultrasonic waves emitted by the plurality of ultrasonic transducers in each ultrasonic transducer array are focused on a point or a region.

[0022] The interventional variable-focus ultrasound catheter of this application embodiment can not only enhance the local intensity of ultrasound and improve the local therapeutic effect of ultrasound, but also expand the range of action of ultrasound in the circumferential and radial directions, significantly improving the treatment range and efficiency of ultrasound. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0024] Figure 1 is a cross-sectional view of an interventional variable focus ultrasound catheter according to an embodiment of this application in its original state;

[0025] Figure 2 is a cross-sectional view of an interventional variable focus ultrasound catheter according to an embodiment of this application in its working state;

[0026] Figure 3 is a cross-sectional view of an interventional variable focus ultrasound catheter according to an embodiment of this application in its working state within a blood vessel.

[0027] Figure 4 is a three-dimensional structural diagram of the flexible section in a straightened state in another embodiment of this application;

[0028] Figure 5 is a three-dimensional structural diagram of the bendable segment in a bent state in another embodiment of this application;

[0029] Figure 6 is a three-dimensional structural diagram of the bendable segment in a bent state in another embodiment of this application. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0031] In the embodiments of this application, the terms "first," "second," etc., are used to distinguish different elements by name, but do not indicate the spatial arrangement or chronological order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one or more of the terms listed in association and all combinations thereof. The terms "comprising," "including," "having," etc., refer to the presence of the stated features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies.

[0032] In the embodiments of this application, the singular forms "a," "the," etc., may include the plural forms and should be broadly understood as "a kind" or "a class" rather than limited to the meaning of "one." In addition, the term "the" should be understood to include both the singular and plural forms unless the context clearly indicates otherwise. Furthermore, the term "according to" should be understood as "at least partially based on..." and the term "based on" should be understood as "at least partially based on..." unless the context clearly indicates otherwise. In addition, the term "multiple" means two or more, unless otherwise stated.

[0033] This application provides an interventional variable-focus ultrasound catheter for intravascular ultrasound therapy. The interventional variable-focus ultrasound catheter of this application includes an inner tube, an outer tube, and an array of multiple ultrasound transducers. The outer tube is fitted over the outer side of the inner tube. The outer tube includes a first fixed section fixed relative to the inner tube and a slidable section that can slide relative to the inner tube in an axial direction. The slidable section includes a bendable section that bends to form an overall concave shape from both ends to the middle when the slidable section slides toward the first fixed section.

[0034] Multiple ultrasonic transducer arrays are arranged at intervals along the circumferential direction in the flexible section. Each ultrasonic transducer array includes multiple ultrasonic transducers arranged at intervals along the axial direction. The ultrasonic waves generated by the multiple ultrasonic transducers in each ultrasonic transducer array are focused when the flexible section is in a curved shape. The change in the bending amplitude of the flexible section changes the focal length of the ultrasonic waves. The focusing position of the ultrasonic waves emitted by the ultrasonic transducers of the multiple ultrasonic transducer arrays is distributed over the entire circumferential range outside the outer tube.

[0035] The interventional variable-focus ultrasound catheter of this application can not only enhance the local intensity of ultrasound and improve the local therapeutic effect of ultrasound, but also expand the range of action of ultrasound in the circumferential and radial directions, significantly improving the treatment range and efficiency of ultrasound.

[0036] Specifically, this application sets up a flexible section and sets up multiple ultrasonic transducers arranged at intervals along the axial direction on the flexible section to focus the ultrasonic waves, thereby enhancing the local intensity of the ultrasonic waves. Furthermore, the focused intensity of the ultrasonic waves can be changed by changing the number of ultrasonic transducers in each ultrasonic transducer array.

[0037] In addition, in the circumferential direction, this application sets up multiple ultrasonic transducer arrays arranged at intervals along the circumferential direction, so that the focusing position of the ultrasonic waves is distributed throughout the entire circumferential range outside the outer tube, thereby increasing the focusing range of the ultrasonic waves in the circumferential direction and achieving the effect of treating the tissues (such as nerves) around the blood vessels. This makes the treatment range of the ultrasonic waves in the circumferential direction larger and the treatment efficiency higher.

[0038] In the radial direction, this application sets up a sliding segment with a bendable section. By adjusting the sliding distance of the sliding segment, the bending amplitude of the bendable segment can be adjusted, thereby adjusting the focal length of the ultrasound, that is, adjusting the focusing position of the ultrasound in the radial direction. This increases the focusing range of the ultrasound in the radial direction, achieving the effect of treating different depths of the tissue to be treated (such as nerves), making the treatment range of the ultrasound in the radial direction larger and the treatment efficiency higher.

[0039] It is worth mentioning that the continuous sliding of the sliding segment allows the bending amplitude of the bendable segment to be continuously adjusted, thereby enabling continuous and stepless adjustment of the focal length of the ultrasound in the radial direction, achieving the effect of treating all different depth locations of the tissue to be treated (such as nerves).

[0040] This application provides a novel method for controlling the focusing of ultrasound waves from multiple ultrasound transducer arrays by sliding an outer tube. This method is highly convenient, eliminating the need to bend the entire interventional variable-focus ultrasound catheter and maintaining its central axis position within the blood vessel. The central axis of the interventional variable-focus ultrasound catheter remains approximately parallel to the blood vessel. Furthermore, this application allows for simultaneous control of the focusing of multiple ultrasound transducer arrays via the sliding outer tube. The effective range of the ultrasound waves is the entire circumferential area (the entire annular region) outside the interventional variable-focus ultrasound catheter, eliminating the need for precise control of individual focusing points.

[0041] The interventional variable-focus ultrasound catheter of this application can be inserted into the blood vessel corresponding to the nerve to be ablated, and ablate the nerve around the blood vessel to achieve the therapeutic purpose of ultrasound ablation.

[0042] The embodiments of this application will now be described with reference to the accompanying drawings.

[0043] As shown in Figure 1, the interventional variable-focus ultrasound catheter 100 of this application has an overall elongated structure to enable it to be inserted into human blood vessels. The interventional variable-focus ultrasound catheter 100 has a proximal end and a distal end. The distal end is the end away from the operator and can be inserted into the patient's blood vessel; the proximal end is the end closer to the operator and can be located outside the patient's body or inside the patient's body.

[0044] As shown in Figure 1, the interventional variable-focus ultrasound catheter 100 of this application includes an outer tube 1 and an inner tube 2. Both the inner tube 2 and the outer tube 1 are slender tubular structures extending along an axial direction. The axial direction mentioned herein can refer to the direction in which the inner tube 2 or the outer tube 1 extends. The circumferential direction mentioned herein can refer to the circumferential direction of the inner tube 2 or the outer tube 1. The radial direction mentioned herein can refer to the radial direction of the inner tube 2 or the outer tube 1. All of these are explained here.

[0045] The materials of the inner tube 2 and the outer tube 1 can be common interventional catheter materials such as PVC, PEBAX, PE, TPU, Teflon, and polyimide. The inner tube 2 can be a one-piece structure or a split structure formed by connecting multiple tubes; this application does not limit this. The outer tube 1 can be a one-piece structure or a split structure formed by connecting multiple tubes; this application also does not limit this.

[0046] As shown in Figure 1, the outer tube 1 is sleeved on the outside of the inner tube 2, and the outer tube 1 and the inner tube 2 can be in a clearance fit. The outer tube 1 includes a first fixed section 11 and a sliding section 12. The first fixed section 11 is fixedly connected to the inner tube 2, so the first fixed section 11 is fixed relative to the inner tube 2 and the two cannot move relative to each other. For example, the first fixed section 11 and the inner tube 2 are fixed by welding.

[0047] The sliding section 12 is fitted only on the outside of the inner tube 2 without being connected to it. The two can be in a clearance fit and can slide relative to each other along the axial direction. The force driving this relative sliding can be applied by the operator at the proximal end of the ultrasound catheter or by a driving device; this application does not limit this. This force can be applied to the outer tube 1 or the inner tube 2, as long as relative sliding between them is possible; this application also does not limit this. When the force is applied to the outer tube 1, it can be a pushing force that pushes the outer tube 1 towards the distal end of the interventional variable-focus ultrasound catheter 100; when the force is applied to the inner tube 2, it can be a pulling force that pulls the inner tube 2 towards the proximal end of the interventional variable-focus ultrasound catheter 100.

[0048] Unless otherwise stated, the sliding of the sliding section 12 mentioned in this article refers to the sliding of the sliding section 12 relative to the inner tube 2 in the axial direction, which will be explained here as well.

[0049] As shown in Figures 1 and 2, the slidable section 12 of the outer tube 1 includes a bendable section 121. When the slidable section 12 of the outer tube 1 slides toward the first fixed section 11, the bendable section 121 is squeezed and bends, deforming from a straight tubular shape into a curved shape that is concave from both ends to the middle as a whole (as shown in Figure 2). This curved shape is roughly an inwardly concave arc shape. This arc shape means that the overall outline is roughly a concave arc shape, and it is not limited to a smooth concave arc shape. It can be a smooth or an unsmooth concave arc shape.

[0050] As shown in Figures 1 and 2, multiple ultrasonic transducer arrays 3 are arranged at intervals along the circumferential direction in the flexible section 121 of the outer tube 1. Each ultrasonic transducer array 3 includes multiple ultrasonic transducers 31 arranged at intervals along the axial direction. As shown in Figure 2, when the flexible section 121 of the outer tube 1 is curved inward from both ends to the middle, the ultrasonic waves 200 generated by the multiple ultrasonic transducers 31 of each ultrasonic transducer array 3 are focused. By adjusting the bending amplitude of the flexible section 121, the focal length of the focused ultrasonic waves 200 can be adjusted, thereby changing the focusing position 300 of the ultrasonic waves 200 in the radial direction (as shown by the arrow in Figure 2), so as to expand the range of action of the focused ultrasonic waves 200 in the radial direction. The focusing position 300 of the ultrasonic waves 200 generated by the ultrasonic transducers 31 of the multiple ultrasonic transducer arrays 3 is distributed throughout the entire circumferential range outside the outer tube 1, so as to expand the range of action of the focused ultrasonic waves in the circumferential direction.

[0051] Specifically, the interventional variable-focus ultrasound catheter 100 has an initial state (as shown in Figure 1) and a working state (as shown in Figure 2). The initial state refers to the state of the interventional variable-focus ultrasound catheter 100 when the entire outer tube 1 is straight, and the working state refers to the state of the interventional variable-focus ultrasound catheter 100 when the flexible section 121 of the outer tube 1 is bent. The interventional variable-focus ultrasound catheter 100 is inserted into and withdrawn from the blood vessel in its initial state. The overall outer diameter of the interventional variable-focus ultrasound catheter 100 in its initial state is small, which allows it to be easily inserted into or withdrawn from the blood vessel without damaging the vessel wall.

[0052] In use, as shown in Figure 2, when the interventional variable focus ultrasound catheter 100 is inserted into the blood vessel 400 in its original state and the flexible segment 121 reaches the nerve to be ablated, the outer tube 1 can be pushed toward the distal end of the interventional variable focus ultrasound catheter 100, so that the sliding segment 12 of the outer tube 1 slides toward the first fixed segment 11. The sliding of the sliding segment 12 causes the flexible segment 121 to bend, and at this time the interventional variable focus ultrasound catheter 100 is in working state. As the sliding distance of the sliding segment 12 increases, the bending amplitude of the flexible segment 121 gradually increases, and the focal length of the ultrasound transducer 31 on the flexible segment 121 gradually decreases. Therefore, the focused ultrasound waves can act on different depth positions of the nerve to be ablated, expanding the ablation range in the radial direction. During treatment, if repeated ablation of different depths of the nerve to be ablated is required, the outer tube 1 can be repeatedly pushed forward and pulled backward, causing it to slide back and forth. This back-and-forth sliding of the outer tube 1 causes the bending amplitude of the flexible segment 121 to repeatedly increase and decrease, and the focal length of the ultrasound transducer 31 on the flexible segment 121 to repeatedly increase and decrease, thereby allowing the focused ultrasound waves to repeatedly act on different depths of the nerve to be ablated. After treatment, the outer tube 1 can be pulled towards the proximal end of the interventional variable focus ultrasound catheter 100 to flatten it. At this time, the interventional variable focus ultrasound catheter 100 returns to its original state and can be easily withdrawn from the blood vessel.

[0053] To facilitate bending of the bendable segment 121, the bendable segment 121 can be configured as a discontinuous structure in the circumferential direction. For example, an opening can be provided on the bendable segment 121 to divide the bendable segment 121 into a discontinuous structure in the circumferential direction.

[0054] In the examples of Figures 4 to 6, the flexible section 121 is provided with openings 122 spaced apart in the circumferential direction to divide the flexible section 121 into multiple flexible strips 123. The multiple flexible strips 123 are at least partially spaced apart in the circumferential direction. Each flexible strip 123 extends in the axial direction. Each ultrasonic transducer array 3 is respectively disposed on a flexible strip 123. Multiple ultrasonic transducers 31 of each ultrasonic transducer array 3 are arranged spaced apart in the axial direction on the flexible strip 123. Therefore, when the sliding section 12 of the outer tube 1 slides toward the first fixed section 11, the multiple flexible strips 123 are squeezed and bend separately and simultaneously, deforming from a flat straight strip shape (as shown in Figure 4) into a concave arc shape that is concave from both ends to the middle as a whole (as shown in Figure 5).

[0055] To induce the bendable segment 121 to bend into a curved shape that is concave from both ends to the middle as a whole, the following two embodiments can be adopted, either individually or in combination.

[0056] In a first optional embodiment, as shown in Figures 4 and 5, the middle portions of multiple flexible strips 123 are sequentially connected in the circumferential direction to form a first connecting ring 124. That is, the multiple flexible strips 123 are partially spaced apart in the circumferential direction. In other words, the middle portions of the multiple flexible strips 123 are not spaced apart, but are sequentially connected to form the first connecting ring 124, while the remaining portions of the multiple flexible strips 123 are spaced apart.

[0057] The first connecting ring 124 restricts the bending of the middle part of each flexible strip 123 when the flexible section 121 bends. The first connecting ring 124 can be a ring structure that extends continuously in the circumferential direction. Since the first connecting ring 124 restricts the bending deformation of the middle part of the flexible section 121, the bending of the two ends of the flexible section 121 located on both sides of the middle part will make the flexible section 121 present a bent shape that is concave from both ends to the middle.

[0058] Optionally, as shown in Figures 4 and 5, each flexible strip 123 has multiple linear grooves 125 on its outer surface opposite to the inner tube 2, which cause the flexible section 121 to bend into a curved shape that is concave from both ends to the middle. The multiple grooves 125 are spaced apart along the length direction of the flexible strip 123, and each groove 125 extends along the width direction of the flexible strip 123. Since the wall thickness of the groove 125 is thinner than that of other parts of the flexible section 121, the flexible strip 123 will preferentially bend from each groove 125. Therefore, the arrangement of the grooves 125 can cause the flexible section 121 to bend.

[0059] The location of the fold 125 can be determined according to the required bending shape. For example, a fold 125 is provided at both ends of the first connecting ring 124, a fold 125 is provided at both ends of each flexible strip 123, and at least one fold 125 can be provided in the part between the two ends of each flexible strip 123.

[0060] Preferably, as shown in Figures 4 and 5, the grooves 125 on the flexible belt 123 are symmetrically distributed with respect to the first connecting ring 124, and the ultrasonic transducers 31 on the flexible belt 123 are symmetrically distributed with respect to the first connecting ring 124. Therefore, when the flexible belt 123 bends along the grooves 125, the ultrasonic transducers 31 located on both sides of the first connecting ring 124 also remain symmetrical, thereby enabling the ultrasonic waves of the ultrasonic transducers 31 to be accurately focused.

[0061] Although the arrangement of the fold 125 makes the bendable band 123 bend into a zigzag arc shape rather than a smooth arc shape, as shown in Figure 5, the bendable band 123 as a whole has a bend shape that is concave from both ends to the middle, thus enabling the ultrasonic waves generated by the ultrasonic transducer 31 located on the same bendable band 123 to be focused.

[0062] In the examples of Figures 4 and 5, each ultrasonic transducer array 3 includes four ultrasonic transducers 31, which are symmetrically distributed on both sides of the first connecting ring 124. Two ultrasonic transducers 31 are located on the flexible strip 123 on the left side of the first connecting ring 124 (referred to as the left side portion of the flexible strip), and the other two ultrasonic transducers 31 are located on the flexible strip 123 on the right side of the first connecting ring 124 (referred to as the right side portion of the flexible strip). Correspondingly, each flexible strip 123 is provided with six folds 125, which are symmetrically distributed on the left and right sides of the first connecting ring 124. Three folds 125 are located on the left side portion of the flexible strip, and the other three folds 125 are located on the right side portion of the flexible strip.

[0063] Taking the three folds 125 on the left side of the bendable belt as an example, the first fold 125 is located between the left end of the left side of the bendable belt and the body of the sliding section 12; the second fold 125 is located between the right end of the left side of the bendable belt and the left end of the first connecting ring 124; and the third fold 125 is located in the middle left of the left side of the bendable belt, dividing the left side of the bendable belt into a smaller area 1231 on the left and a larger area 1232 on the right. The larger area 1232 is used to install two ultrasonic transducers. The smaller region 1231 may not have an ultrasonic transducer 31 installed. Instead, it serves as the part with the largest tilt angle of the flexible section 121, as shown in Figure 5. When the flexible section 121 bends, the smaller region 1231 tilts outward relative to the inner tube 2 at a larger tilt angle than the larger region 1232. With the support of the smaller region 1231, the larger region 1232 and the ultrasonic transducer 31 on it are in a tilted state, so that the entire flexible section 121 has a curved shape that is concave from both ends to the middle.

[0064] Figures 4 and 5 only illustrate, by way of example, that the flexible section 121 includes four flexible strips 123, each of which is provided with four ultrasonic transducers 31 and six folds 125, but this is not intended to limit the application. The number of flexible strips 123, the number of ultrasonic transducers 31 and the number of folds 125 can be determined according to actual needs.

[0065] In a second alternative embodiment, as shown in Figures 1 and 2, each flexible strip 123 is provided with a metal foil 126 that causes the flexible segment 121 to bend into a curved shape that is concave inward from both ends to the middle. The metal foil 126 has a pre-deformation shape that is the same as the curved shape, that is, the metal foil 126 has a pre-deformation shape that is concave inward from both ends to the middle. Therefore, the metal foil 126 can assist the flexible strip 123 in bending into the curved shape. In the example of Figures 1 and 2, the pre-deformation shape of the metal foil 126 is a concave arc shape.

[0066] Optionally, the metal foil 126 serves as an electrode of the ultrasonic transducer 31 and is electrically connected to the ultrasonic transducer 31. Therefore, the metal foil 126 can not only assist in the bending of the flexible band 123, but also serve as an electrode of the ultrasonic transducer 31 to transmit driving signals to it, thus eliminating the need for additional electrodes and simplifying the structure of the ultrasonic catheter. The metal foil 126 can be disposed on the outer surface of the flexible section 121 facing away from the inner tube 2, or in the side wall of the flexible section 121, or on the inner surface of the flexible section 121 facing the inner tube 2. The metal foil 126 can be made of conductive metals such as copper, iron, or gold.

[0067] Of course, instead of using the metal foil 126 as the electrode of the ultrasonic transducer 31, an additional electrode can be provided, and the metal or non-metal sheet with the pre-deformed shape can be fixed to the electrode of the ultrasonic transducer 31 by means of adhesive or other methods. In this case, the metal or non-metal sheet only serves to assist the bending of the flexible strip 123.

[0068] Alternatively, the outer tube 1 can be fabricated using a flexible printed circuit board process, which allows for the convenient fabrication of electrodes and wires for the ultrasonic transducer 31 within the outer tube 1.

[0069] The first and second embodiments described above can be implemented separately or in combination. That is, the first connecting ring 124 and the metal foil 126 are provided at the same time. The combined implementation can better assist the bending of the flexible strip 123.

[0070] Figure 6 shows another embodiment of the flexible strip 123 in this application, which differs from the embodiments shown in Figures 4 and 5 in that the multiple flexible strips 123 are completely spaced apart in the circumferential direction and are not connected to form the first connecting loop 124 shown in Figures 4 and 5.

[0071] To facilitate bending of the bendable segment 121, the bendable segment 121 can be positioned close to the first fixed segment 11. Preferably, as shown in Figures 1 to 5, the bendable segment 121 is directly connected to the first fixed segment 11. That is, the bendable segment 121 is located at the end of the sliding segment 12 and is directly connected to the first fixed segment 11, which serves as an anchor point. Therefore, the force driving the sliding segment 12 to slide is ultimately concentrated on the bendable segment 121, causing the bendable segment 121 to bend quickly.

[0072] In the examples shown in Figures 1 to 6, the ultrasound transducer 31 is mounted on the outer surface of the flexible section 121 facing away from the inner tube 2. This not only facilitates installation but also allows for bending of the flexible section 121. To prevent the ultrasound transducer 31 from scratching the inner wall of the blood vessel, a covering layer 6 can be provided on the outside of each ultrasound transducer array 3 (as shown in Figures 1 to 3). The covering layer 6 completely covers the ultrasound transducer array 3, and its smooth outer surface facilitates the smooth and safe insertion or withdrawal of the interventional variable focus ultrasound catheter 100 into or from the blood vessel. However, this application is not limited to this; the ultrasound transducer 31 can also be embedded in the side wall of the flexible section 121 or mounted on the inner surface of the flexible section 121 facing the inner tube 2.

[0073] The ultrasonic transducer 31 can be made of piezoelectric materials such as PZT5 and PZT8. Each ultrasonic transducer 31 can have one or more resonant frequencies, and the frequency range of the ultrasonic waves generated by each ultrasonic transducer 31 can be 20kHz to 20MHz.

[0074] Each ultrasonic transducer 31 can be a regular square or a curved sheet. The curved ultrasonic transducer 31 can better fit the curved outer surface of the outer conduit.

[0075] Optionally, each ultrasonic transducer 31 in the embodiments of this application may be a focused ultrasonic transducer. Correspondingly, the ultrasonic waves generated by the multiple ultrasonic transducers 31 in each ultrasonic transducer array 3 are focused on a single point, thus achieving very high sound intensity at the focal point.

[0076] Optionally, each ultrasonic transducer 31 in the embodiments of this application may be a non-focused ultrasonic transducer. Correspondingly, the ultrasonic waves generated by the multiple ultrasonic transducers 31 in each ultrasonic transducer array 3 are focused on a region. This region means a focusing range larger than the focal area, so the ultrasonic range of the focusing region is larger.

[0077] Optionally, the ultrasonic array in this application embodiment includes both focused ultrasonic transducers and non-focused ultrasonic transducers. For example, some ultrasonic transducers 31 in the ultrasonic transducer array 3 are focused ultrasonic transducers, while the ultrasonic transducers 31 in the remaining ultrasonic transducer array 3 are focused ultrasonic transducers, thereby enabling the simultaneous acquisition of a focal point and a focal region.

[0078] In the examples of Figures 1 to 3, the outer tube 1 further includes a second fixed section 13 and a flexible positioning section 14 connected between the second fixed section 13 and the first fixed section 11; the interventional variable focus ultrasound catheter 100 also includes a slidable member 4 axially slidably disposed inside the inner tube 2, the slidable member 4 being connected to the second fixed section 13, the slidable member 4 driving the second fixed section 13 to move toward the first fixed section 11, the positioning section 14 bending into a curved shape that protrudes outward from both ends to the middle as a whole when the second fixed section 13 moves toward the first fixed section 11, the curved shape of the positioning section 14 can be a convex arc shape.

[0079] The outward protrusion of the positioning segment 14 serves to contact the inner wall of the blood vessel 400 (as shown in Figure 3), thereby positioning the interventional variable focus ultrasound catheter 100 in the center of the blood vessel 400, improving the circumferential uniformity and accuracy of ultrasound treatment.

[0080] By adjusting the distance by which the second fixed segment 13 slides toward the first fixed segment 11, the curvature of the positioning segment 14 can be adjusted, thereby changing the distance by which the positioning segment 14 protrudes outward to suit blood vessels of different diameters, enabling the interventional variable focus ultrasound catheter 100 to be centrally positioned in blood vessels of different diameters.

[0081] When the interventional variable focus ultrasound catheter 100 is in its original state, both the positioning section 14 and the flexible section 121 of the outer tube 1 are in a straight state. When the interventional variable focus ultrasound catheter 100 is in the working state, both the positioning section 14 and the flexible section 121 of the outer tube 1 are in a bent state.

[0082] In this embodiment, the sliding member 4 is used to transmit power. The power that drives the second fixed section 13 to move toward the first fixed section 11 can be applied to the sliding member 4 at the proximal end of the interventional variable focus ultrasound catheter 100. For example, the operator can pull the sliding member 4 toward the proximal end so that the sliding member 4 drives the second fixed section 13 to move toward the first fixed section 11. Of course, the sliding member 4 can also be pulled by a driving device (such as a linear driving device) to achieve automated control.

[0083] To facilitate bending of the positioning segment 14, the positioning segment 14 can be configured as a discontinuous structure in the circumferential direction. For example, an opening can be provided on the positioning segment 14 to divide the positioning segment 14 into a discontinuous structure in the circumferential direction.

[0084] For example, the positioning segment 14 is provided with a plurality of openings spaced apart in the circumferential direction to divide the positioning segment 14 into a plurality of bendable strips spaced apart in the circumferential direction. Therefore, when the second fixing segment 13 moves toward the first fixing segment 11, the plurality of bendable strips are squeezed and bend separately and simultaneously, bending from a flat straight strip shape to form a convex arc shape that bulges outward from both ends to the middle as a whole.

[0085] In order to make the positioning segment 14 bend into a curved shape that bulges outward from both ends to the middle, grooves 125 can also be provided at both ends of the positioning segment 14. Since the wall thickness of the grooves 125 is thinner than that of other parts of the positioning segment 14, the positioning segment 14 will bend preferentially from these two grooves 125, thus easily bending into an outward bulging arc shape.

[0086] For example, as shown in Figures 1 to 3, the sliding member 4 includes a sliding tube 41 and a sliding shaft 42. The sliding tube 41 is located inside the positioning section 14. One end of the sliding tube 41 is inserted into the inner tube 2 and fixedly connected to one end of the sliding shaft 42. The other end of the sliding tube 41 extends out of the inner tube 2 and is fixedly connected to the second fixing section 13.

[0087] Specifically, as shown in Figures 1 to 3, the sliding tube 41 is inserted into the inner tube 2, and the sliding tube 41 and the inner tube 2 can slide relative to each other, for example, with a clearance fit. The inner tube 2 can guide the sliding tube 41 to slide smoothly in the axial direction. The other end of the sliding tube 41 has a convex ring structure 411 that protrudes radially outward. The outer side wall of the convex ring structure 411 is fixedly connected to the inner side wall of the second fixed section 13, for example, by welding. An annular gap 5 is formed between the sliding tube 41 and the positioning tube. In the axial direction, the annular gap 5 is located between the convex ring structure 411 and the left end face 21 of the inner tube 2. The annular gap 5 provides sliding space for the sliding tube 41, and the end face of the convex ring structure 411 and the inner tube 2 serves as a limiting structure to limit the sliding limit position of the sliding tube 41.

[0088] As shown in Figure 1, the two grooves 125 on the outer side of the positioning section 14 are directly opposite to the right end face 412 of the convex ring structure 411 and the left end face 21 of the inner tube 2, respectively. Therefore, the entire part of the positioning section 14 corresponding to the annular gap 5 can protrude outward into a convex arc shape.

[0089] One end of the sliding shaft 42 is fixedly connected to one end of the sliding tube 41 that extends into the inner tube 2. The other end of the sliding shaft 42 can extend to the proximal end of the interventional variable focus ultrasound catheter 100. Therefore, the operator or the driving device can pull the other end of the sliding shaft 42 at the proximal end to move the second fixed section 13 of the outer tube 1 toward the first fixed section 11 via the sliding shaft 42 and the sliding tube 41, making the operation very convenient. When the pulling of the sliding shaft 42 is released, the positioning section 14 can automatically return to its straightened state by its own restoring force.

[0090] The above description is merely an embodiment of this specification and is not intended to limit this specification. Various modifications and variations can be made to this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of the claims of this specification.

Claims

1. An interventional variable-focus ultrasound catheter, characterized in that, include: Inner tube; The outer tube is fitted over the inner tube and includes a first fixed section fixed relative to the inner tube and a slidable section that can slide relative to the inner tube in the axial direction. The slidable section includes a bendable section, which bends into a curved shape that is concave from both ends to the middle as the slidable section slides toward the first fixed section. Multiple ultrasonic transducer arrays are disposed on the flexible section and spaced apart in the circumferential direction. Each ultrasonic transducer array includes multiple ultrasonic transducers spaced apart in the axial direction. The ultrasonic waves generated by the multiple ultrasonic transducers of each ultrasonic transducer array are focused when the flexible section is in the bent shape. The change in the bending amplitude of the flexible section causes the focal length of the ultrasonic waves to change. The focusing positions of the ultrasonic waves emitted by the multiple ultrasonic transducers of the ultrasonic transducer arrays are distributed over the entire circumferential range outside the outer tube.

2. The interventional variable-focus ultrasound catheter according to claim 1, characterized in that, The flexible section includes multiple flexible strips, which are at least partially spaced apart in the circumferential direction. Each flexible strip extends along the axial direction. Each ultrasonic transducer array is disposed on one of the flexible strips, and multiple ultrasonic transducers of each ultrasonic transducer array are spaced apart along the axial direction on the flexible strip.

3. The interventional variable-focus ultrasound catheter according to claim 2, characterized in that, The middle portions of the multiple flexible strips are sequentially connected in the circumferential direction to form a first connecting ring, which restricts the bending of the middle portion of each flexible strip when the flexible section bends.

4. The interventional variable-focus ultrasound catheter according to claim 2, characterized in that, Each of the bendable strips has a plurality of grooves on its outer surface opposite to the inner tube, which cause the bendable section to bend into the bend shape. The plurality of grooves are arranged at intervals along the length direction of the bendable strip, and each groove extends along the width direction of the bendable strip.

5. The interventional variable-focus ultrasound catheter according to any one of claims 2 to 4, characterized in that, Each of the flexible strips is provided with a metal foil that causes the flexible segment to bend into the bent shape, the metal foil having the same pre-deformed shape as the bent shape.

6. The interventional variable-focus ultrasound catheter according to claim 5, characterized in that, The metal foil serves as the electrode of the ultrasonic transducer and is electrically connected to the ultrasonic transducer.

7. The interventional variable-focus ultrasound catheter according to claim 5, characterized in that, The metal foil is disposed on the outer surface of the flexible section opposite to the inner tube; or, The metal foil is embedded in the sidewall of the flexible section; or, The metal foil is disposed on the inner surface of the flexible section facing the inner tube.

8. The interventional variable-focus ultrasound catheter according to claim 1, characterized in that, The ultrasonic transducer is disposed on the outer surface of the flexible section opposite to the inner tube; or, The ultrasonic transducer is embedded in the sidewall of the flexible section; or, The ultrasonic transducer is disposed on the inner surface of the flexible section facing the inner tube.

9. The interventional variable-focus ultrasound catheter according to claim 1, characterized in that, The flexible section is positioned close to the first fixed section.

10. The interventional variable-focus ultrasound catheter according to claim 9, characterized in that, The flexible section is directly connected to the first fixed section.

11. The interventional variable-focus ultrasound catheter according to claim 1, characterized in that, The outer tube also includes a second fixed section and a flexible positioning section connected between the second fixed section and the first fixed section; The conduit also includes a slidable member that is axially slidable inside the inner tube. The slidable member is connected to the second fixed section. The slidable member drives the second fixed section to move toward the first fixed section. When the second fixed section moves toward the first fixed section, the positioning section bends to form a curved shape that bulges outward from both ends to the middle as a whole.

12. The interventional variable-focus ultrasound catheter according to claim 11, characterized in that, The sliding component includes a sliding tube and a sliding shaft. The sliding tube is located inside the positioning section. One end of the sliding tube is inserted into the inner tube and fixedly connected to one end of the sliding shaft. The other end of the sliding tube extends out of the inner tube and is fixedly connected to the second fixing section.

13. The interventional variable-focus ultrasound catheter according to claim 1, characterized in that, The ultrasonic transducer is either a focused ultrasonic transducer or a non-focused ultrasonic transducer.

14. The interventional variable-focus ultrasound catheter according to claim 13, characterized in that, The ultrasonic waves emitted by the multiple ultrasonic transducers in each of the ultrasonic transducer arrays are focused on a point or a region.

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