Imaging catheter, preparation method thereof and OCT (optical coherence tomography) imaging catheter

Abstract

The invention relates to the technical field of medical instruments, and discloses an imaging catheter and a preparation method thereof and an OCT imaging catheter.The preparation method of the imaging catheter comprises the steps that an annular channel area is machined at the far end of the inner wall of an outer catheter of the imaging catheter, and thermosetting resin is injected into the annular channel area; cleaning and activating the far end of the inner wall of the outer tube and the welding area of the guide wire through low-temperature plasma; the welding area of the guide wire is inserted into the far end of the inner wall of the outer tube, and the welding area of the guide wire is made to communicate with the annular channel area; and preheating the far end of the inner wall of the outer pipe and the welding area of the guide wire through the first pulse laser to form a local micro-molten pool, scanning the local micro-molten pool through the second pulse laser, and rapidly welding the far end of the inner wall of the outer pipe and the welding area of the guide wire. By means of the method, the size of the guide pipe can be further reduced, rapid welding is achieved through staged pulse laser, the thermosetting resin can improve the connecting strength of the outer pipe and the guide wire, and reliability is improved.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to an imaging catheter, its preparation method, and an OCT imaging catheter. Background Technology

[0002] Optical coherence tomography (OCT) is a novel biomedical imaging method based on weak coherence optical tomography technology. It can perform in vivo tomographic imaging of biological tissues. With its high-resolution imaging characteristics, OCT imaging technology can clearly and completely present the details of the internal structure of blood vessels. It has now become the mainstream vascular imaging method. Currently, OCT imaging catheters are widely used in coronary arteries and intracranial blood vessels.

[0003] In clinical applications, the distal end of the OCT imaging catheter is pushed into the blood vessel, while the proximal end is connected to the COT host. The imaging probe inside the OCT imaging catheter is driven to rotate and move axially within the catheter. During imaging, the imaging probe is first moved through the lesion location within the blood vessel and reaches the distal end of the lesion location. Then, the imaging probe is rotated back to complete a 360° scan of a segment of the blood vessel, forming a spatial image of this segment of the blood vessel.

[0004] Traditional OCT imaging catheters cannot be made smaller due to their structural limitations, making them unsuitable for complex, slender, and multi-curved intracranial blood vessels. Furthermore, the distal sealing is not reliable, posing a risk of leakage of the filling fluid. Summary of the Invention

[0005] In view of this, the present invention provides an imaging catheter and its preparation method, as well as an OCT imaging catheter, to solve the problems that conventional OCT imaging catheters cannot be made smaller due to their own structural limitations, cannot adapt to intracranial blood vessels with multiple bends, thinness and high complexity, and have poor distal sealing reliability, posing a risk of leakage of filling fluid.

[0006] In a first aspect, the present invention provides a method for preparing an imaging catheter, comprising:

[0007] An annular channel region is machined at the distal end of the inner wall of the outer tube of the imaging catheter, and thermosetting resin is injected into the annular channel region.

[0008] The distal end of the inner wall of the outer tube and the welding area of ​​the guide wire are cleaned and activated by low-temperature plasma.

[0009] Insert the welding area of ​​the guide wire into the distal end of the inner wall of the outer tube, and make the welding area of ​​the guide wire communicate with the annular channel area;

[0010] The welding area of ​​the outer tube and the guide wire is preheated by the first pulse laser to form a local micro-melt pool. The welding area of ​​the outer tube and the guide wire is then rapidly welded by scanning the local micro-melt pool with the second pulse laser.

[0011] Optionally, the step of processing an annular channel region at the distal end of the inner wall of the outer tube and injecting thermosetting resin into the annular channel region specifically includes: continuously processing multiple annular microchannels at the distal end of the inner wall of the outer tube using photolithography or laser processing technology, wherein the multiple annular microchannels form the annular channel region, and the distance between the annular channel region and the tip of the distal end of the outer tube is 3 mm; the thermosetting resin is medical-grade epoxy resin.

[0012] Optionally, the step of cleaning and activating the distal end of the inner wall of the outer tube and the welding area of ​​the guide wire by low-temperature plasma specifically includes: treating the distal end of the inner wall of the outer tube and the welding area of ​​the guide wire with low-temperature plasma at a set power range of 50W to 100W and a set processing time of 30s to 60s.

[0013] Optionally, the step of preheating the distal end of the inner wall of the outer tube and the welding area of ​​the guide wire with a first pulse laser to form a local micro-molten pool, and then scanning the local micro-molten pool with a second pulse laser to perform rapid welding of the distal end of the inner wall of the outer tube and the welding area of ​​the guide wire, specifically includes: using a first pulse laser with a laser power range of 5W to 10W and a pulse width of 100μs to scan the distal end of the inner wall of the outer tube and the welding area of ​​the guide wire to preheat the distal end of the inner wall of the outer tube and the welding area of ​​the guide wire to form the local micro-molten pool; and using a second pulse laser with a laser power range of 20W to 30W and a pulse width of 50μs to scan the local micro-molten pool for rapid welding.

[0014] Optionally, a hydrophilic coating may be applied to the outer wall of the outer tube.

[0015] Secondly, the present invention provides an imaging catheter, which is prepared by the above-described imaging catheter preparation method, the imaging catheter comprising:

[0016] The outer tube has a ring-shaped channel area formed at the far end of the inner wall;

[0017] The guide wire has a welding area formed at its proximal end on the inner wall of the outer tube for insertion and mating with the distal end. The annular channel area contains a thermosetting resin that is fixedly mated with the welding area.

[0018] Optionally, the outer tube includes an inner cavity filled with a solution.

[0019] Optionally, the annular channel region is formed by a plurality of continuously arranged annular microchannels, and the distance between the annular channel region and the tip of the distal end of the outer tube is 3 mm; the thermosetting resin is medical grade epoxy resin.

[0020] Optionally, the outer tube includes a proximal tube and a distal tube welded together, wherein the hardness of the proximal tube is greater than that of the distal tube.

[0021] Thirdly, the present invention provides an OCT imaging catheter, including the imaging catheter described above.

[0022] Beneficial effects:

[0023] 1. The method for preparing the imaging catheter provided by the present invention includes:

[0024] An annular channel region is machined at the distal end of the inner wall of the outer tube of the imaging catheter, and thermosetting resin is injected into the annular channel region.

[0025] The distal end of the inner wall of the outer tube and the welding area of ​​the guide wire are cleaned and activated by low-temperature plasma.

[0026] Insert the welding area of ​​the guide wire into the distal end of the inner wall of the outer tube, and make the welding area of ​​the guide wire communicate with the annular channel area;

[0027] The welding area of ​​the outer tube and the guide wire is preheated by the first pulse laser to form a local micro-melt pool. The welding area of ​​the outer tube and the guide wire is then rapidly welded by scanning the local micro-melt pool with the second pulse laser.

[0028] Using the above preparation method, the thermosetting resin in the annular channel region can fill the microscopic gap between the welding area of ​​the guide wire and the inner wall of the outer tube through capillary action and pressure difference, forming a barrier to prevent the welding process from being affected by the solution filling the inner cavity of the outer tube. During the welding process, the activation effect of low-temperature plasma can increase the surface energy of the material at the distal end of the inner wall of the outer tube and the guide wire, promoting the wettability of the thermosetting resin. At the same time, it can generate active functional groups, such as hydroxyl and carboxyl groups, to enhance the surface activity of the material at the distal end of the inner wall of the outer tube and the guide wire, reduce the welding temperature, and promote the gradual curing of the thermosetting resin, so that the thermosetting resin can effectively block the solution. After the welding area of ​​the guide wire is inserted into the inner wall of the distal end of the outer tube, the formation of a local micro-melt pool by preheating with the first pulse laser can avoid severe heat diffusion. Combined with the second pulse laser, rapid welding can be achieved. Compared with traditional welding which requires temperatures above 1000℃, this process can control the temperature at 300℃ to 400℃, which greatly avoids the boiling or denaturation of the filling solution in the inner cavity of the outer tube due to excessive temperature. Furthermore, the thermosetting resin solidifies between the outer tube and the guide wire to form a continuous sealing barrier to ensure that the liquid does not leak out. This not only provides a sealing function but also enhances the connection strength between the outer tube and the guide wire, improving reliability.

[0029] Therefore, by directly welding the guidewire to the distal end of the outer tube using the above method to form the guidewire tip, a guidewire lumen can be eliminated, thereby further reducing the catheter size to accommodate intracranial blood vessels. Furthermore, the thermosetting resin's sealing effect prevents the catheter's internal filling fluid from affecting the welding process. Staged pulsed laser welding achieves rapid welding without affecting the strong filling solution within the outer tube. The thermosetting resin in the annular channel region enhances the connection strength between the outer tube and the guidewire, reduces the risk of leakage of the filling fluid from the outer tube, and improves the reliability of the distal end of the imaging catheter.

[0030] 2. The method for preparing the imaging catheter provided by the present invention, wherein the annular channel region is processed at the distal end of the inner wall of the outer tube, and thermosetting resin is injected into the annular channel region, specifically includes: continuously processing multiple annular microchannels at the distal end of the inner wall of the outer tube by photolithography or laser processing, the multiple annular microchannels forming the annular channel region, the distance between the annular channel region and the distal tip of the outer tube being 3mm. The annular channel region formed by multiple annular microchannels can ensure structural accuracy and connectivity. Medical-grade epoxy resin has the characteristics of high viscosity and rapid curing, and can accurately fill the micro-gap of the welding interface by utilizing capillary action and pressure difference, so as to form a sealing barrier for the filling liquid inside the outer tube and eliminate leakage paths. The 3mm distance between the annular channel region and the distal tip of the outer tube can increase the welding area between the outer tube and the guidewire, further improving the connection strength.

[0031] 3. The method for preparing the imaging catheter provided by the present invention, wherein the cleaning and activation of the distal inner wall of the outer tube and the welding area of ​​the guidewire by low-temperature plasma specifically includes: treating the distal inner wall of the outer tube and the welding area of ​​the guidewire with low-temperature plasma at a power range of 50W to 100W and a processing time of 30s to 60s. This setup, through low-temperature plasma bombardment, increases the microscopic roughness of the distal inner wall surface of the outer tube, including the annular channel region, enhances intermolecular forces, significantly increases surface energy, thereby promoting the spreading and penetration of medical-grade epoxy resin, facilitating the formation of a sealing barrier within the outer tube, and generating active functional groups, such as hydroxyl and carboxyl groups, to enhance the surface activity of the material at the distal inner wall of the outer tube and the guidewire, providing chemical bonding sites for subsequent welding and reducing the welding temperature.

[0032] 4. The method for fabricating an imaging catheter provided by the present invention includes: preheating the distal end of the inner wall of the outer tube and the welding area of ​​the guidewire with a first pulse laser to form a local micro-melt pool; and scanning the local micro-melt pool with a second pulse laser to form a first melt pool and a second melt pool respectively on the distal end of the inner wall of the outer tube and the welding area of ​​the guidewire. Specifically, the method includes: scanning the distal end of the inner wall of the outer tube and the welding area of ​​the guidewire with a first pulse laser with a laser power range of 5W to 10W and a pulse width of 100μs to preheat the distal end of the inner wall of the outer tube and the welding area of ​​the guidewire to form the local micro-melt pool; and scanning the local micro-melt pool with a second pulse laser with a laser power range of 20W to 30W and a pulse width of 50μs to form the first melt pool and the second melt pool.

[0033] This setup allows for the formation of a localized micro-molten pool through single-point preheating with the first pulse laser, preventing thermal stress concentration and severe heat diffusion. The second pulse laser then performs line scanning to facilitate the formation of both the first and second molten pools, enabling rapid welding. The phased coordination of the first and second pulse lasers allows for precise control of the welding temperature. Compared to traditional welding which requires temperatures above 1000°C, this process can control the temperature between 300°C and 400°C, greatly reducing the risk of the liquid filling the outer tube boiling or deteriorating due to excessively high temperatures.

[0034] 5. The method for preparing the imaging catheter provided by the present invention involves coating the outer wall of the outer tube with a hydrophilic coating. The hydrophilic coating can reduce the friction between the outer tube and the blood during the pushing process, greatly enhancing the pushability of the outer tube.

[0035] 6. The imaging catheter provided by the present invention is prepared by the above-described imaging catheter preparation method, and the imaging catheter comprises:

[0036] The outer tube has a ring-shaped channel area formed at the far end of the inner wall;

[0037] The guide wire has a welding area formed at its proximal end on the inner wall of the outer tube for insertion and mating with the distal end. The annular channel area contains a thermosetting resin that is fixedly mated with the welding area.

[0038] The annular channel area ensures sufficient coverage of the thermosetting resin, thereby more accurately filling the circumferential gap between the inner wall of the outer tube and the guidewire, improving sealing and connection strength. Moreover, directly welding the guidewire to the distal end of the outer tube eliminates the need for a guidewire channel, allowing for further reduction in the size of the imaging catheter to accommodate complex, delicate, and multi-curved intracranial vessels.

[0039] 7. The imaging catheter provided by the present invention includes an outer tube comprising an inner lumen filled with a solution. The imaging probe can be rotated and pulled back in the solution to perform vascular segment imaging. This can change the refraction of the imaging probe, eliminate the excess light halo around the imaging probe during scanning due to the lack of contrast agent filling the inner lumen of the outer tube, and reduce the resistance between the torque transmission tube and the inner wall of the outer tube during high-speed rotation, thereby improving image quality.

[0040] 8. The imaging catheter provided by this invention has an annular channel region formed by multiple continuously arranged annular microchannels, and the distance between the annular channel region and the distal tip of the outer tube is 3 mm. Maintaining a 3 mm distance between the annular channel region and the distal tip of the outer tube increases the welding area between the outer tube and the guidewire, further enhancing the connection strength. The thermosetting resin is medical-grade epoxy resin. Medical-grade epoxy resin has high viscosity and rapid curing characteristics, and can precisely fill the microscopic gaps at the welding interface using capillary action and pressure difference, thereby forming a sealing barrier against the filling fluid inside the outer tube and preventing leakage paths.

[0041] 9. The imaging catheter provided by the present invention includes an outer tube comprising a proximal tube and a distal tube welded together, wherein the hardness of the proximal tube is greater than that of the distal tube. The proximal tube can increase the delivery efficiency, and the distal tube can adapt to intracranial blood vessels with multiple bends, thinness, and high complexity, thereby undergoing corresponding bending deformation during delivery. Attached Figure Description

[0042] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is a flowchart of a method for preparing an imaging catheter according to an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of the structure of the OCT imaging catheter according to an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of the structure of the annular channel region according to an embodiment of the present invention;

[0046] Figure 4 for Figure 2 Enlarged view of point A in the middle;

[0047] Figure 5 This is a schematic diagram of the joint between the proximal and distal tubes in an embodiment of the present invention.

[0048] Figure 6 This is a schematic cross-sectional view of the proximal tube according to an embodiment of the present invention;

[0049] Figure 7 for Figure 2 Enlarged view of point B in the middle;

[0050] Figure 8 This is a schematic diagram of the torque transmission tube according to an embodiment of the present invention;

[0051] Figure 9 This is a cross-sectional structural diagram of the mounting and mating point between the first developing ring and the torque transmission tube in an embodiment of the present invention.

[0052] Explanation of reference numerals in the attached figures:

[0053] 1. Outer tube; 101. Inner layer; 102. Middle layer; 103. Outer layer; 104. Annular channel area; 105. Distal tip; 11. Proximal tube; 111. First step; 12. Distal tube; 121. Second step; 13. Axis marking strip; 14. Imaging window; 2. Guide wire; 211. Welding area; 3. Imaging structure; 31. Torque transmission tube; 32. Imaging probe; 33. First imaging ring; 34. Second imaging ring; 35. Optical fiber; 4. Connector; 5. Stress buffer tube; 6. Protective sleeve; 7. Protective cover. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] It should be noted that in this application, the end closer to the operator during use is referred to as the "proximal end," and the end farther from the operator is referred to as the "distal end." Based on this principle, the "proximal end" and "distal end" of any component of the OCT imaging catheter are defined. "Axial direction" generally refers to the length direction of the OCT imaging catheter during delivery, and "radial direction" generally refers to the direction of the OCT imaging catheter perpendicular to its "axial direction." Based on this principle, the "axial direction" and "radial direction" of any component of the OCT imaging catheter are defined.

[0056] like Figure 1 and Figure 3 As shown, Figure 1 A flowchart illustrating the fabrication method of the imaging catheter in this embodiment is shown. Figure 3 A schematic diagram of the annular channel region 104 is shown. In this embodiment, a method for fabricating an imaging catheter is provided, comprising:

[0057] Step S100: A ring channel region 104 is processed at the far end of the inner wall of the outer tube 1, and thermosetting resin is injected into the ring channel region 104.

[0058] Specifically, the outer tube 1 can be designed in segments, formed by splicing a proximal tube and a distal tube, with the annular channel region 104 formed on the distal end of the inner wall of the distal tube. To ensure the imaging effect of the imaging probe, a solution is filled in the inner cavity of the outer tube 1. The thermosetting resin can be medical-grade epoxy resin, which has high viscosity and rapid curing characteristics, and can precisely fill the microscopic gaps at the welding interface using capillary action and pressure difference, so as to form a sealing barrier for the solution filling the outer tube 1, eliminating leakage paths and preventing subsequent welding from affecting the solution.

[0059] In one specific embodiment, the process of machining an annular channel region 104 at the distal end of the inner wall of the outer tube 1 and injecting thermosetting resin into the annular channel region 104 specifically includes: continuously machining multiple annular microchannels at the distal end of the inner wall of the outer tube 1 using photolithography or laser processing technology, wherein the multiple annular microchannels form the annular channel region 104, and the distance between the annular channel region 104 and the distal tip of the outer tube 1 is 3mm. The formation of the annular channel region 104 by multiple annular microchannels can ensure structural accuracy and connectivity. The 3mm distance reserved between the annular channel region 104 and the distal tip of the outer tube 1 can increase the connection area between the outer tube 1 and the guide wire 2, further improving the connection strength.

[0060] In step S200, the welding area of ​​the guide wire 2 is inserted into the distal end of the inner wall of the outer tube 1, and the welding area of ​​the guide wire 2 is connected to the annular channel area 104.

[0061] Specifically, after the insertion is completed, medical-grade epoxy resin can seal the gap between the guide wire 2 and the annular channel area 104 to prevent the solution filled in the outer tube 1 from leaking out, which facilitates the subsequent welding steps.

[0062] Step S300: The distal end of the inner wall of the outer tube 1 and the welding area of ​​the guide wire 2 are cleaned and activated by low-temperature plasma.

[0063] Specifically, low-temperature plasma cleaning and activation refers to the treatment of the welding area of ​​the outer tube 1 inner wall distal end and the guide wire 2 by a low-temperature plasma treatment device in continuous wave or pulse mode.

[0064] In one specific embodiment, the cleaning and activation of the distal inner wall of the outer tube 1 and the welding area of ​​the guide wire 2 by low-temperature plasma specifically includes: treating the distal inner wall of the outer tube 1 and the welding area of ​​the guide wire 2 with low-temperature plasma at a power range of 50W to 100W and a processing time of 30s to 60s. The power and time settings can be adjusted according to the surface roughness of the distal inner wall of the outer tube 1 and the guide wire 2. With this setup, the low-temperature plasma bombardment increases the microscopic roughness of the distal inner wall surface of the outer tube 1, including the annular channel region 104, enhancing intermolecular forces and significantly increasing surface energy. This promotes the spreading and penetration of medical-grade epoxy resin, facilitating the formation of a sealing barrier within the outer tube 1. It also generates active functional groups, such as hydroxyl and carboxyl groups, to enhance the surface activity of the material on the distal inner wall of the outer tube 1 and the guide wire 2, providing chemical bonding sites for subsequent welding, reducing the welding temperature, and promoting the curing of the medical-grade epoxy resin, enabling it to effectively seal the solution.

[0065] In step S400, the welding area of ​​the outer tube 1 and the guide wire 2 is preheated by the first pulse laser to form a local micro-melt pool. The local micro-melt pool is then scanned by the second pulse laser to quickly weld the welding area of ​​the outer tube 1 and the guide wire 2.

[0066] Specifically, both the first pulse laser and the second pulse laser can be emitted by a fiber laser. The definitions of "first" and "second" are used to distinguish that they are emitted at different frequencies and with different pulse widths, thereby achieving different functions and realizing the purpose of phased scanning.

[0067] In one specific embodiment, the process of preheating the distal end of the inner wall of the outer tube 1 and the welding area of ​​the guide wire 2 using a first pulsed laser to form a local micro-molten pool, and then scanning the local micro-molten pool with a second pulsed laser to rapidly weld the distal end of the inner wall of the outer tube 1 and the welding area of ​​the guide wire 2, specifically includes: using a first pulsed laser with a laser power range of 5W to 10W and a pulse width of 100μs to scan the distal end of the inner wall of the outer tube 1 and the welding area of ​​the guide wire 2 to preheat the distal end of the inner wall of the outer tube 1 and the welding area of ​​the guide wire 2 to form the local micro-molten pool; and using a second pulsed laser with a laser power range of 20W to 30W and a pulse width of 50μs to scan the local micro-molten pool for rapid welding.

[0068] This setup allows for the formation of a localized micro-melt pool through single-point preheating with the first pulse laser, preventing thermal stress concentration and severe heat diffusion. Rapid welding is achieved through line scanning with the second pulse laser. The phased coordination of the first and second pulse lasers allows for precise temperature control. Compared to traditional welding requiring temperatures above 1000℃, this process maintains a temperature of 300℃ to 400℃, significantly reducing the risk of boiling or denaturation of the liquid filling the outer tube 1 due to excessive heat. The epoxy resin fully cures upon heating, firmly connecting the distal end of the inner wall of the outer tube 1, including the annular channel region 104, to the welding area of ​​the guide wire 2. Compared to ordinary welding methods, this approach improves sealing performance by 60%, increases connection strength by 35% to 300MPa to 400MPa, and simultaneously shortens welding time.

[0069] Using the above preparation method, the thermosetting resin in the annular channel region 104 can fill the microscopic gap between the welding area of ​​the guide wire 2 and the inner wall of the outer tube 1 through capillary action and pressure difference, and can form a barrier to prevent the welding process from being affected by the solution filling the outer tube 1. During the welding process, the activation effect of low-temperature plasma can increase the surface energy of the material at the distal end of the inner wall of the outer tube 1 and the guide wire 2, promote the wettability of the thermosetting resin, and generate active functional groups, such as hydroxyl and carboxyl groups, to enhance the surface activity of the material at the distal end of the inner wall of the outer tube 1 and the guide wire 2, reduce the welding temperature, and promote the gradual curing of the thermosetting resin, so that the thermosetting resin can effectively block the solution. After the welding area of ​​guide wire 2 is inserted into the distal inner wall of outer tube 1, the formation of a local micro-melt pool through preheating with the first pulse laser avoids severe heat diffusion. Combined with the second pulse laser, rapid welding is achieved. Compared to traditional welding which requires temperatures above 1000℃, this process can control the temperature between 300℃ and 400℃, greatly preventing the solution inside outer tube 1 from boiling or degenerating due to excessive temperature. Furthermore, the thermosetting resin solidifies between outer tube 1 and guide wire 2, forming a continuous sealing barrier to prevent liquid leakage. This not only provides a seal but also strengthens the connection between outer tube 1 and guide wire 2, improving reliability.

[0070] Therefore, by directly welding the guidewire 2 to the distal end of the outer tube 1 using the above method to form the guidewire tip, the guidewire 2 lumen can be eliminated, thereby further reducing the catheter size to accommodate intracranial blood vessels. Furthermore, the thermosetting resin's sealing effect prevents the catheter filling fluid from affecting the welding process. Rapid welding is achieved through staged pulsed laser treatment without affecting the strong filling solution inside the outer tube. The thermosetting resin in the annular channel region 104 enhances the connection strength between the outer tube 1 and the guidewire 2, reduces the risk of leakage of the filling fluid from the outer tube 1, and improves the reliability of the distal end of the imaging catheter.

[0071] In one specific embodiment, a hydrophilic coating is applied to the outer wall of the outer tube 1. The hydrophilic coating can be applied by dip-coating with a hyaluronic acid-based solution followed by heat curing. Since blood is composed of plasma and blood cells, with plasma comprising approximately 55% and water comprising 90%, the hydrophilic coating reduces the friction between the outer tube 1 and the blood during dispensing, significantly enhancing the dispensability of the outer tube 1.

[0072] like Figure 2 , Figure 3 and Figure 4 As shown, this embodiment provides an imaging catheter, which is prepared by the above-described imaging catheter preparation method. The imaging catheter includes:

[0073] The outer tube 1 has an annular channel region 104 formed at the far end of its inner wall;

[0074] The guide wire 2 has a welding area 211 formed on the inner wall of the outer tube at the proximal end and a welding area 211 for insertion and mating at the distal end. The annular channel area 104 contains a thermosetting resin that is fixedly mated with the welding area 211.

[0075] The annular channel region 104 ensures that the thermosetting resin has sufficient coverage area, thereby more accurately filling the external gap between the inner wall of the outer tube 1 and the guidewire 2, improving sealing and connection strength. Moreover, by directly welding the guidewire 2 to the distal end of the outer tube 1, there is no need to set up a guidewire channel, which allows for further reduction in the size of the imaging catheter to accommodate intracranial vessels with multiple bends, thinness, and high complexity.

[0076] In one embodiment of this invention, the outer tube 1 includes an inner cavity filled with a solution. The solution can be medical silicone oil. The imaging probe 32 can be rotated and pulled back in the solution to perform vascular segment imaging. This can change the refraction of the imaging probe 32, eliminating the excess light ring around the imaging probe 32 during scanning imaging due to the lack of contrast agent filling the inner cavity of the outer tube 1. It can also reduce the resistance between the torque transmission tube 31 and the inner wall of the outer tube 1 during high-speed rotation, thereby improving image quality.

[0077] In one embodiment of this invention, the outer surface of the outer tube 1 is coated with a hydrophilic coating. The hydrophilic coating can reduce the friction between the outer tube and the blood during the pushing process, greatly enhancing the pushability of the outer tube.

[0078] In one embodiment of this invention, the annular channel region 104 is formed by a plurality of continuously arranged annular microchannels, and the distance between the annular channel region 104 and the distal tip 105 of the outer tube 1 is 3 mm. Figure 3 The distance M shown is the distance between the annular channel region 104 and the distal tip 105 of the outer tube 1. M can be 3mm, and the length of the annular channel region 104 along the axial direction of the outer tube can be determined according to the actual situation. Maintaining a 3mm distance between the annular channel region 104 and the distal tip 105 of the outer tube 1 can increase the welding area between the outer tube 1 and the guide wire 2, further improving the connection strength. The thermosetting resin is medical-grade epoxy resin. Medical-grade epoxy resin has high viscosity and rapid curing characteristics, and can precisely fill the micro-gaps at the welding interface using capillary action and pressure difference, so as to form a sealing barrier for the filling liquid inside the outer tube and eliminate leakage paths.

[0079] like Figure 5As shown, in one embodiment of this invention, the outer tube 1 includes a proximal tube 11 and a distal tube 12 welded together, with the proximal tube 11 having a higher hardness than the distal tube 12. The proximal tube 11 can increase the pushing efficiency, while the distal tube 12 can adapt to intracranial blood vessels with multiple bends, thinness, and high complexity, thus undergoing corresponding bending deformation during the pushing process. The guidewire 2 is welded to the distal end of the inner wall of the distal tube 12, forming an annular channel region at the distal end of the inner wall of the distal tube 12.

[0080] In one embodiment of this invention, a first step 111 is formed at the distal end of the proximal tube 11. A second step 121 is formed at the proximal end of the distal tube 12, the second step 121 being adapted to the size of the first step 111, and the first step 111 and the second step 121 being suitable for insertion and mating. This arrangement avoids the formation of uneven surfaces or protrusions at the joint of the proximal tube 11 and the distal tube 12. Furthermore, the above method improves both the smoothness of the joint and the reliability of the connection, overcoming the contradiction between smoothness and reliability at the joint. This also prevents damage to intracranial blood vessels during the external tube's advancement and avoids breakage or detachment at the joint during advancement, further improving the reliability of the external tube.

[0081] like Figure 4 As shown, in one embodiment of this example, a first step 111 is formed on the distal end of the outer wall of the proximal tube 11, and a second step 121 is formed on the proximal end of the inner wall of the distal tube. The overlap area S1 of the first step 111 and the second step 121 is 6mm to 7mm. The outer diameter and inner diameter of the proximal tube 11 and the distal tube 12 are consistent. The outer diameter of the proximal tube 11 and the distal tube 12 can be 0.48mm, and the inner diameter can be 0.36mm. The wall thickness of the proximal tube 11 and the distal tube 12 can be 0.06mm. During processing, half of the wall thickness is peeled off at the distal end of the outer wall of the proximal tube 11, with a peeling length of 6mm to 7mm in the axial direction. Half of the wall thickness is peeled off at the proximal end of the inner wall of the distal tube 12, with a peeling length of 6mm to 7mm in the axial direction. The peeling lengths of the proximal tube 11 and the distal tube 12 are consistent. This arrangement helps to ensure that the overall outer diameter of the outer tube is consistent, allowing the outer tube to be made sufficiently thin.

[0082] like Figure 6As shown, in one embodiment of this invention, the proximal tube 11 includes an inner layer 101, a middle layer 102, and an outer layer 103 arranged sequentially from the inside to the outside. The inner layer 101 is made of polytetrafluoroethylene (PTFE), which has high lubricity and corrosion resistance, facilitating the movement of the imaging probe in the outer tube and preventing reaction with the contrast agent. The middle layer 102 is made of stainless steel braided wire, improving the mechanical strength of the proximal tube. The outer layer 103 is made of polyimide, giving the proximal tube good biocompatibility and reducing rejection reactions. The distal tube is made of polyether block polyamide, which has good elasticity, wear resistance, and fatigue resistance, adapting to intracranial vascular deformation and exhibiting good biocompatibility, reducing rejection reactions.

[0083] like Figure 5 As shown, in one embodiment of this example, the wall thickness of the inner layer 101 can be 0.015 mm, the wall thickness of the middle layer 102 can be 0.015 mm, and the wall thickness of the outer layer can be 0.03 mm. Peeling the distal end of the outer wall of the proximal tube 11 means peeling off the outer layer of the distal end of the outer wall of the proximal tube 11, exposing the middle layer 102.

[0084] In one embodiment of this invention, the outer wall of the distal end of the proximal tube 11 is provided with a hydrophilic coating, and the outer wall of the distal tube 12 is also provided with a hydrophilic coating. The hydrophilic coating can be applied by dipping in a hyaluronic acid-based solution followed by thermosetting. Since blood is composed of plasma and blood cells, with plasma comprising approximately 55% and water comprising 90%, the hydrophilic coating can reduce the friction between the outer tube and the blood during dispensing, greatly enhancing the dispensability of the outer tube. Alternatively, the outer wall of the proximal tube 11 is provided with a hydrophilic coating.

[0085] like Figure 2 and Figure 4 As shown, in this embodiment, an OCT imaging catheter is provided, including the outer tube 1 described above, and also including a guide wire 2, an imaging structure 3, a connector 4, a stress buffer tube 5, a protective sleeve 6, and a protective cap 7.

[0086] Guide wire 2 is connected to the distal end of outer tube 1. Guide wire 2 is used to guide outer tube 1 to move towards the lesion. Guide wire 2 can be welded to the distal end of outer tube 1 through welding area 211.

[0087] The connector 4 is connected to the proximal end of the outer tube 1 through the stress buffer tube 5. The connector 4 is used to connect to the OCT host. Since the outer tube 1 will bend and deform during the pushing process, the stress buffer tube 5 can make the stress be transmitted and dissipated more smoothly to the proximal end, avoiding the outer tube from breaking due to stress concentration.

[0088] Imaging structure 3 extends into outer tube 1 from the proximal end of connector 4 and is driven to move along the axial direction of outer tube 1 and / or rotate around the central axis of outer tube 1. Imaging structure 3 may include torque transmission tube 31, optical fiber, and imaging probe 32. Torque transmission tube 31 is sleeved on optical fiber, and imaging probe 32 is connected to the distal end of optical fiber. Torque transmission tube 31 can protect optical fiber and drive the movement of optical fiber and imaging probe 32. During use, the torque transmission tube 31 drives optical fiber and imaging probe 32 to move and / or rotate along the axial direction, thereby facilitating the imaging probe 32 to scan the inside of blood vessels. Meanwhile, the outer tube 1, guidewire 2, torque transmission tube 31, and imaging probe 32 form a sealed space. The part of the outer tube 1 near the guidewire 2 is the imaging window 14, which is filled with a solution, such as medical silicone oil. The imaging probe 32 rotates and retracts in the medical silicone oil to perform vascular segment imaging. This can change the refraction of the imaging probe 32, eliminate the excess light ring outside the imaging probe 32 during scanning imaging due to the lack of contrast agent filling the inner cavity of the outer tube 1, and reduce the resistance between the torque transmission tube 31 and the inner wall of the distal outer tube 1 when rotating at high speed, thereby improving image quality.

[0089] The protective sleeve 6 is fitted onto the outer wall of the connector 4, and the protective cover 7 is detachably fastened to the near end interface of the connector 4. The protective cover 7 can prevent dust from entering the connector 4 and protect the inside of the outer tube 1 from contamination.

[0090] In use, the outer tube 1 can be inserted into the corresponding lesion location under the guidance of the guidewire 2. Since the outer tube 1 is composed of a proximal tube 11 and a distal tube 12, it can ensure both efficient insertion and protection of intracranial blood vessels. After the outer tube 1 is inserted, the imaging structure 3 allows the imaging probe to move to the distal end of the lesion. Through the torque transmission tube 31, the imaging probe 32 is driven to rotate and retract simultaneously to perform a 360° scan of the lesion area, thereby imaging the lesion area. The imaging catheter prepared by the above method can be further refined in size and its sealing and connection strength can be improved.

[0091] In this embodiment, the effective length of the OCT imaging catheter can be L1, with L ranging from 1800mm to 1900mm. The effective length of the OCT imaging catheter refers to the length that can be inserted into the human body. The length of the hydrophilic coating is L2, which can range from 1450mm to 1550mm. The portion of the outer tube 1 near the guidewire 2 is the imaging window 14, which refers to the distal end of the outer tube 1 where the probe can be pulled back. The length of the imaging window 14 can be L3, ranging from 95mm to 105mm. The maximum outer diameter D1 of the outer tube 1 where the imaging window 14 is located is 0.43mm to 0.49mm, and the maximum outer diameter D2 of the entire outer tube 1 is 0.43mm to 0.49mm. The length of the guidewire 2 can range from 12mm to 18mm.

[0092] like Figure 7 As shown, in this embodiment, the outer cannula 1 is provided with an axis marker strip 13. The physician can determine the insertion position of the guidewire 2 by observing the axis marker strip 13. For example, when the axis marker strip 13 is pushed to the puncture position, it indicates that the guidewire 2 is about to enter a thinner artery, thus visually reminding the physician to slow down the pushing speed of the outer cannula 1. The axis marker strip 13 can be fixed to the proximal outer wall of the outer cannula 10 by laser printing, ink printing, or welding, and is set around the entire circumference, allowing the physician to observe it from any angle. The distance between the axis marker strip 13 and the distal end of the guidewire 2 can be 1450mm to 1550mm.

[0093] like Figure 4 As shown, in this embodiment, the torque transmission tube 31 can be a spring tube. A first developing ring 33 and a second developing ring 34 are spaced apart on the outer wall of the torque transmission tube 31. The first developing ring 33 is positioned close to the imaging probe 32 to mark its location. The second developing ring 34 is positioned near the proximal end of the first developing ring 33. The distance between the first developing ring 33 and the second developing ring 34 can be L5, ranging from 37mm to 43mm, or from 57mm to 63mm. The distance between the imaging probe 32 and the distal end of the guide wire 2 can be L6, ranging from 17mm to 20mm. The distance between the first developing ring 33 and the imaging probe 32 can be L7, which can be 1mm.

[0094] like Figure 8 and Figure 9 As shown, in this embodiment, the torque transmission tube 31 is a double-layer spring tube. The inner layer of the double-layer spring tube abuts against the light 35, and the outer layer is used to install the first developing ring 33 and the second developing ring 34. The first developing ring 33 and the second developing ring 34 are platinum-iridium developing rings. During preparation, the outer spring tube can be peeled to have an annular groove with a corresponding length and depth according to the size of the platinum-iridium developing ring. Then, the platinum-iridium developing ring is welded to the annular groove, and the outer diameter of the weld is ensured not to exceed the outer diameter of the double-layer spring tube. The first developing ring 33 and the second developing ring allow the size of the outer tube 1 to be further refined.

[0095] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for preparing an imaging catheter, characterized in that, include: An annular channel region is machined at the distal end of the inner wall of the outer tube of the imaging catheter, and thermosetting resin is injected into the annular channel region. The distal end of the inner wall of the outer tube and the welding area of ​​the guide wire are cleaned and activated by low-temperature plasma. Insert the welding area of ​​the guide wire into the distal end of the inner wall of the outer tube, and make the welding area of ​​the guide wire communicate with the annular channel area; The welding area of ​​the outer tube and the guide wire is preheated by the first pulse laser to form a local micro-melt pool. The welding area of ​​the outer tube and the guide wire is then rapidly welded by scanning the local micro-melt pool with the second pulse laser.

2. The method for preparing the imaging catheter according to claim 1, characterized in that, The process of machining an annular channel region at the distal end of the inner wall of the outer tube and injecting thermosetting resin into the annular channel region specifically includes: continuously machining multiple annular microchannels at the distal end of the inner wall of the outer tube using photolithography or laser processing technology, the multiple annular microchannels forming the annular channel region, and the distance between the annular channel region and the distal tip of the outer tube being 3mm; the thermosetting resin is medical-grade epoxy resin.

3. The method for preparing the imaging catheter according to claim 1, characterized in that, The step of cleaning and activating the distal end of the inner wall of the outer tube and the welding area of ​​the guide wire by low-temperature plasma specifically includes: treating the distal end of the inner wall of the outer tube and the welding area of ​​the guide wire with low-temperature plasma at a set power range of 50W to 100W and a set processing time of 30s to 60s.

4. The method for preparing the imaging catheter according to claim 1, characterized in that, The process involves preheating the distal inner wall of the outer tube and the welding area of ​​the guide wire using a first pulsed laser to form a localized micro-molten pool, and then scanning the localized micro-molten pool with a second pulsed laser to rapidly weld the distal inner wall of the outer tube and the welding area of ​​the guide wire. Specifically, this includes: using a first pulsed laser with a power range of 5W to 10W and a pulse width of 100μs to scan the distal inner wall of the outer tube and the welding area of ​​the guide wire to preheat and form the localized micro-molten pool; and using a second pulsed laser with a power range of 20W to 30W and a pulse width of 50μs to scan the localized micro-molten pool for rapid welding.

5. The method for preparing the imaging catheter according to any one of claims 1 to 4, characterized in that, A hydrophilic coating is applied to the outer wall of the outer tube.

6. An imaging catheter, characterized in that, The imaging catheter is prepared by the method of any one of claims 1 to 5, wherein the imaging catheter comprises: The outer tube (1) has an annular channel region (104) formed at the far end of the inner wall; The guide wire (2) has a welding area (211) formed at its proximal end that is inserted into the inner wall of the outer tube (1) and the annular channel area (104) contains a thermosetting resin that is fixedly fitted to the welding area (211).

7. The imaging catheter according to claim 6, characterized in that, The outer tube (1) includes an inner cavity filled with a solution.

8. The imaging catheter according to claim 6, characterized in that, The annular channel region (104) is formed by a plurality of continuously arranged annular microchannels, and the distance between the annular channel region (104) and the distal tip (105) of the outer tube (1) is 3 mm; the thermosetting resin is medical grade epoxy resin.

9. The imaging catheter according to claim 6, characterized in that, The outer tube (1) includes a proximal tube (11) and a distal tube (12) welded together, wherein the hardness of the proximal tube (11) is greater than that of the distal tube (12).

10. An OCT imaging catheter, characterized in that, Includes the imaging catheter as described in claim 6.

Images