Medical system and method for operating medical system

Abstract

This medical system comprises: a balloon catheter having an elongate first shaft and a balloon attached to the first shaft, the balloon catheter being for delivering, to the blood vessel wall of a blood vessel, a drug that can be activated by light emitted from a light irradiation body inserted into a lumen extending through the first shaft; an ultrasonic probe having an elongate second shaft and ultrasonic elements attached to the second shaft, the ultrasonic probe being insertable into the lumen and for transmitting ultrasonic waves toward the blood vessel wall from a plurality of positions on the first shaft along the longitudinal direction thereof and receiving reflected waves of the ultrasonic waves using the ultrasonic elements; and a controller that acquires ultrasonic information relating to the reflected waves received by the ultrasonic elements, calculates the vascular stiffness of the blood vessel corresponding to each of the plurality of positions on the basis of the acquired ultrasonic information, and outputs the calculated vascular stiffness in association with each of the plurality of positions.

Description

Medical System and Method of Operating a Medical System

[0001] The present disclosure relates to a medical system and a method of operating a medical system.

[0002] Patent Document 1 discloses a method for treating AAA, which is a type of aortic aneurysm, by disposing a reinforcing device or a reinforcing composition at at least one arterial site adjacent to the arterial site adjacent to AAA and increasing the mechanical rigidity of the site. "AAA" is an abbreviation for abdominal aortic aneurysm. Patent Document 2 discloses a device that displays a longitudinal sectional image of a blood vessel and an object representing the magnitude of the plaque burden at each position of the longitudinal sectional image along the axial direction of the blood vessel.

[0003] U.S. Patent Application Publication No. 2016 / 0262914 International Publication No. 2022 / 071121

[0004] As one of the causes of the occurrence and growth of aortic aneurysms, it is considered that there is a difference in hardness, so-called SAS, between adjacent aortic regions. "SAS" is an abbreviation for segmental aortic stiffness. In a normal blood vessel with uniform hardness, no axial wall stress occurs even when the blood vessel expands during the systolic phase of the heart. On the other hand, when a region with non-uniform blood vessel hardness occurs due to arteriosclerosis or the like, the flexible blood vessel site expands more than the adjacent hard site. As a result, at the boundary region of hardness, a stress occurs in which the blood vessel wall extends in the axial direction. This is considered to induce aneurysm expansion. For example, Patent Document 1 discloses that, in a mouse with an AAA model, applying a surgical adhesive externally to the region adjacent to the aortic aneurysm to make it hard reduces the wall stress difference between the aneurysm and the site adjacent to the aneurysm, and significantly reduces the growth of the aneurysm.

[0005] Similar to the method described above, for small aneurysms, it is conceivable to place a bare stent in the neck to increase vascular stiffness in order to suppress SAS, which causes aneurysm enlargement. The term "neck" is synonymous with the aortic aneurysm adjacency region adjacent to the end of an aortic aneurysm such as AAA, and specifically refers to the proximal neck, which is the part adjacent to the proximal end of the aortic aneurysm, or the distal neck, which is the part adjacent to the distal end of the aortic aneurysm. For example, Patent Document 1 discloses that aneurysm enlargement can be suppressed by stiffening the aortic aneurysm adjacency region by placing a bare stent.

[0006] However, one challenge is the risk of thrombus formation or dispersal, infection, or deterioration of implants such as bare stents. Additionally, if the aneurysm enlarges after the procedure, the implant can become an obstacle when additional treatment such as conventional EVAR or artificial blood vessel replacement is performed. "EVAR" is an abbreviation for endovascular aneurysm repair. Another challenge is that if the neck is hardened with an implant, a difference in vascular stiffness may be newly created between that site and healthy blood vessels, potentially leading to further aneurysm formation. There is also the challenge that it is difficult to identify the site where the difference in vascular stiffness occurs from CT or contrast images. "CT" is an abbreviation for computed tomography.

[0007] The purpose of this disclosure is to suppress the enlargement of tumors such as AAA without the need for implants.

[0008] Some aspects of this disclosure are shown below.

[0009] [1] A medical system comprising: a balloon catheter having a long first shaft and a balloon attached to the first shaft, for delivering a drug activated by light emitted from a light irradiator inserted into a lumen extending within the first shaft to the wall of a blood vessel; an ultrasonic probe having a long second shaft and an ultrasonic element attached to the second shaft, which is insertable into the lumen, for transmitting ultrasonic waves from multiple positions along the longitudinal direction of the first shaft toward the blood vessel wall using the ultrasonic element and receiving the reflected waves of the ultrasonic waves; and a controller that acquires ultrasonic information relating to the reflected waves received by the ultrasonic element, calculates the vascular stiffness of the blood vessel corresponding to each of the multiple positions based on the acquired ultrasonic information, and outputs the calculated vascular stiffness linked to each of the multiple positions.

[0010] [2] The medical system according to [1], wherein the controller determines the amount of light irradiation for each of the multiple positions according to the calculated vascular stiffness.

[0011] [3] The medical system according to [2], wherein the controller controls the amount of light emitted from the light irradiator in accordance with the determined amount of light emitted.

[0012] [4] The medical system according to any one of [1] to [3], wherein the controller determines the irradiation range of the light in the longitudinal direction according to the calculated difference in vascular stiffness between the multiple positions.

[0013] [5] The medical system according to [4], wherein the controller controls the movement of the light irradiating body in the longitudinal direction within the lumen in accordance with the determined irradiation range.

[0014] [6] The medical system according to any one of [1] to [5], wherein the controller controls the longitudinal movement of the ultrasound probe in the lumen to acquire the ultrasound information for at least one heartbeat or at least one pulse for each of the plurality of positions.

[0015] [7] The medical system according to [6], wherein the controller acquires the measurement result of heart rate or pulse rate and controls the movement based on the acquired measurement result.

[0016] [8] The medical system according to any one of [1] to [5], wherein the controller continuously calculates the diameter of the blood vessel from the acquired ultrasonic information for each of the multiple positions, identifies both the vasoconstriction initiation point at which the diameter of the blood vessel changes from increasing to decreasing and the vasodilation initiation point at which the diameter of the blood vessel changes from decreasing to increasing, and after identifying both the vasoconstriction initiation point and the vasodilation initiation point at each of the multiple positions at least once, controls the longitudinal movement of the ultrasonic probe in the lumen to move the ultrasonic element to the next position in the longitudinal direction.

[0017] [9] The medical system according to any one of [1] to [8], wherein the plurality of positions include at least three positions on the first shaft where the balloon is located.

[0018]

[10] The medical system according to any one of [1] to [9], wherein the controller generates an image of the blood vessel viewed from a direction perpendicular to the longitudinal direction based on the acquired ultrasound information, displays the generated image on a screen, and displays the calculated blood vessel stiffness in accordance with the position corresponding to each of the multiple positions in the generated image, thereby outputting the calculated blood vessel stiffness in association with each of the multiple positions.

[0019]

[11] The medical system according to

[10] , wherein the controller, if the vascular stiffness is already displayed for each of the multiple locations, acquires new ultrasound information, calculates the vascular stiffness of the blood vessels corresponding to each of the multiple locations based on the acquired new ultrasound information, and updates the vascular stiffness that has already been displayed to the newly calculated vascular stiffness.

[0020]

[12] The medical system according to

[10] or

[11] , wherein the controller identifies the longitudinal position of the light irradiator in the lumen and further displays the identified position on the generated image.

[0021]

[13] The medical system according to any one of

[10] to

[12] , wherein the controller determines the amount of light irradiation for each of the multiple positions according to the calculated vascular stiffness, and further displays the determined amount of light in the generated image in accordance with the position corresponding to each of the multiple positions.

[0022]

[14] The medical system according to any one of

[10] to

[13] , wherein the controller determines the irradiation range of the light in the longitudinal direction according to the calculated difference in vascular stiffness between the multiple positions, and further displays the determined irradiation range on the generated image.

[0023]

[15] The medical system according to any one of

[10] to

[14] , wherein the controller identifies the actual amount of light irradiated from the light irradiator and further displays the identified actual amount of light irradiated in accordance with the position corresponding to each of the multiple positions in the generated image.

[0024]

[16] The lumen extends toward the tip in the longitudinal direction of the first shaft beyond the location where the balloon is positioned, and the ultrasonic element can be inserted beyond the location toward the tip when the ultrasonic probe is inserted, according to any one of [1] to

[15] .

[0025]

[17] The medical system according to any one of [1] to

[16] , further comprising an optical probe having a long third shaft and the light irradiator, which is insertable into the lumen and the light irradiator is attached to the third shaft.

[0026]

[18] The medical system according to any one of [1] to

[16] , wherein the ultrasonic probe further comprises the light irradiator, and the light irradiator is attached to the second shaft together with the ultrasonic element.

[0027]

[19] A method for operating a medical system, comprising: a balloon catheter having a long first shaft and a balloon attached to the first shaft, which, when inserted into a blood vessel, delivers a drug activated by light emitted from a light-emitting body inserted into a lumen extending within the first shaft to the blood vessel wall of the blood vessel; an ultrasonic probe having a long second shaft and an ultrasonic element attached to the second shaft, which, when inserted into the lumen, transmits ultrasonic waves from multiple positions along the longitudinal direction of the first shaft toward the blood vessel wall using the ultrasonic element and receives the reflected waves of the ultrasonic waves; a controller acquiring ultrasonic information relating to the reflected waves received by the ultrasonic element; the controller calculating the vascular stiffness of the blood vessel corresponding to each of the multiple positions based on the acquired ultrasonic information; and the controller outputting the calculated vascular stiffness associated with each of the multiple positions.

[0028] According to this disclosure, it is possible to suppress the enlargement of tumors such as AAA without implants.

[0029] This is a block diagram showing the configuration of a medical system according to an embodiment of this disclosure. This is a diagram showing some configurations of a balloon catheter, an ultrasound probe, and an optical probe according to an embodiment of this disclosure. This is a cross-sectional view of the balloon catheter according to an embodiment of this disclosure, taken along line A-A. This is a flowchart showing how to operate the medical system according to an embodiment of this disclosure. This is a diagram showing an example of step S1. This is a diagram showing an example of step S2. This is a diagram showing an example of step S3. This is a diagram showing an example of step S4. This is a diagram showing an example of step S5. This is a diagram showing an example of the screen display of the medical system according to an embodiment of this disclosure. This is a diagram showing another example of the screen display of the medical system according to an embodiment of this disclosure. This is a diagram showing a modified example of the configuration shown in Figure 2.

[0030] Hereinafter, one embodiment of this disclosure will be described with reference to the figures.

[0031] In each figure, identical or corresponding parts are denoted by the same reference numerals. In the description of this embodiment, the description of identical or corresponding parts will be omitted or simplified as appropriate.

[0032] Referring to Figure 1, the configuration of the medical system 10 according to this embodiment will be described.

[0033] The medical system 10 comprises a balloon catheter 20, an ultrasound probe 30, an optical probe 40, a controller 50, and a console 60. The controller 50 is connected to the balloon catheter 20, ultrasound probe 30, optical probe 40, and console 60 via cable, network, or wirelessly.

[0034] As shown in Figures 2 and 3, the balloon catheter 20 has a long first shaft 21 and a balloon 22 attached to the first shaft 21. When the balloon catheter 20 is inserted into a blood vessel 70 as shown in Figures 5 to 9, it is used to deliver a drug activated by light emitted from a light-emitting body 42 inserted into a first lumen 23 extending within the first shaft 21 to the blood vessel wall 71 (specifically the inner wall) of the blood vessel 70. In each figure, the Z direction corresponds to the longitudinal direction of the first shaft 21, and the XY plane corresponds to a plane perpendicular to the longitudinal direction of the first shaft 21. The first lumen 23 is a lumen into which a guidewire, an ultrasound probe 30, and an optical probe 40 (not shown) are inserted. There is also a second lumen 24 within the first shaft 21, separate from the first lumen 23. The second lumen 24 is a lumen into which a fluid such as saline solution or a drug is injected to expand the balloon 22. The material of the first shaft 21 should preferably have excellent ultrasonic and light transmission properties. The balloon 22 may be a drug-coated balloon in which the balloon surface is coated with a drug, or a drug-releasing balloon in which the drug is released from micropores on the balloon surface. Generally, the neck diameter of a small aneurysm, i.e., the vessel diameter in the region adjacent to the aortic aneurysm, is 25.1 ± 4.0 mm, so it is desirable that the outer diameter of the balloon 22 when expanded be between 20 mm and 30 mm. It is desirable that the balloon 22 be a semi-compliance balloon or a compliance balloon, as this will broaden the range of applicable vessel diameters.

[0035] As shown in Figure 2, the ultrasonic probe 30 has a long second shaft 31 and an ultrasonic element 32 attached to the second shaft 31. The ultrasonic probe 30 is insertable into the first lumen 23. When inserted into the first lumen 23, the ultrasonic probe 30 is used to transmit ultrasound waves from multiple positions along the longitudinal direction of the first shaft 21 toward the blood vessel wall 71 using the ultrasonic element 32 and to receive the reflected ultrasound waves. In this embodiment, a known IVUS catheter is used as the ultrasonic probe 30. "IVUS" is an abbreviation for intravascular ultrasound. According to this embodiment, by measuring the change in blood vessel diameter before and after treatment using the ultrasonic probe 30, the stiffness of the blood vessel can be identified, and the extent of treatment and the completion of treatment can be determined.

[0036] As shown in Figure 2, the optical probe 40 has a long third shaft 41 and a light irradiator 42 attached to the third shaft 41. The optical probe 40 is insertable into the first lumen 23, similar to the ultrasound probe 30. When inserted into the first lumen 23, the optical probe 40 is used to irradiate light toward the blood vessel wall 71 to activate drugs that have been delivered to the blood vessel wall 71. In this embodiment, an optical irradiation catheter containing a known cylindrical or radial type optical fiber can be used as the optical probe 40. Both the cylindrical and radial types irradiate light in a direction intersecting the axis of the optical fiber, but the cylindrical type emits light over a relatively long axial range, while the radial type emits light over a relatively short axial range.

[0037] The drug can be any drug that is photoreactive and capable of crosslinking collagen or elastin, but in this embodiment, dimeric naphthalimide or a pharmaceutically acceptable salt thereof, for example, chemical name 2,2'-((ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl))bis(6-((2-(2-(2-aminoethoxy)ethoxy)ethyl)amino)-1H-benzo[de]isoquinoline-1,3(2H)-dione),6-[2-[2-(2-aminoethoxy)ethoxy]ethylamino]-2-[2-[2-[2-[6-[2-[2-(2-aminoethoxy)ethoxy]ethylamino]-1,3-dioxobenzo[de]isoquinoline-2-yl It is a drug that is described as ]ethoxy]ethoxy]ethyl]benzo[de]isoquinoline-1,3-dione, 2,2'-[1,2-ethanediylbis(oxy-2,1-ethanediyl)]bis[6-({2-[2-(2-aminoethoxy)ethoxy]ethyl}amino)-1H-benzo[de]isoquinoline-1,3(2H)-dione] or 1H-benzo[de]isoquinoline-1,3(2H)-dione, 2,2'-[1,2-ethanediylbis(oxy-2,1-ethanediyl)]bis[6-[[2-[2-(2-aminoethoxy)ethoxy]ethyl]amino]-(9Cl) or identified by CAS registration number 438200-66-9. "CAS" is an abbreviation for Chemical Abstracts Service. For example, suppose a balloon 22 is coated with dimerized naphthalimide, which is the drug of this embodiment, and the balloon 22 is expanded at the affected area to deliver the dimerized naphthalimide to the blood vessel wall 71 of the blood vessel 70. When light with a length of 450 nm is irradiated to the affected area from the light irradiator 42, the amino acids that make up collagen or elastin in the blood vessel wall 71 of the blood vessel 70 are oxidized, and reactive intermediates are formed. Crosslinking occurs when the reactive intermediates form covalent bonds with each other. Normally, the desired effect can be obtained by irradiating with light for one minute, but it is thought that the effect can be obtained in a shorter time if stronger light is irradiated. The greater the amount of light irradiated, the greater the degree of crosslinking of collagen or elastin, so the blood vessel wall 71 of the blood vessel 70 is reinforced in areas with a high amount of irradiation than in areas with a low amount of irradiation, and the stiffness of the blood vessel increases.Instead of dimeric naphthalimide, a drug may be used that is activated by light of a wavelength other than 450 nm, or by light other than visible light, and in which the degree of cross-linking of collagen or elastin increases with increasing light exposure. Specifically, examples include drugs such as riboflavin-5'-sodium phosphate, rose bengal, palladium bacteriochlorin 13'-(2-sulfoethyl)amide dipotassium salt, palladium bacteriopheoferbide, bifunctional diazopyruvoyl, or pterin, or combinations thereof. When using riboflavin-5'-sodium phosphate, it is preferable to irradiate with light at a length of approximately 375 nm or 450 nm; when using rose bengal, it is preferable to irradiate with light at a length of approximately 555 nm; when using palladium bacteriochlorin 13'-(2-sulfoethyl)amide dipotassium salt, it is preferable to irradiate with light at a length of approximately 750 nm; when using bifunctional diazopyruvoyl, it is preferable to irradiate with light at a length of approximately 320 to 390 nm; and when using pterin, it is preferable to irradiate with light at a length of approximately 320 to 400 nm. Methylene blue, methylene green, riboflavin, proflavin, fluorescein, eosin, or 4-amino-1,8-naphthalimide may also be used. The drug may appropriately contain additives such as pH adjusters or osmotic pressure adjusters. In this application, photoreactivity means the property of absorbing light and becoming activated (excited), causing chemical reactions such as the generation of reactive oxygen species or radicals, oxidation-reduction reactions, polymerization reactions, bond cleavage and generation, or changes in molecular structure.

[0038] At least the balloon 22 and the portion of the first shaft 21 where the balloon 22 is located are formed of a material that allows light with a length of 450 nm to pass through, and are transparent or translucent. However, if a drug other than dimerized naphthalimide is used, the material will be adjusted as appropriate. The light irradiator 42 also irradiates with light with a length of 450 nm in this embodiment, but if a drug other than dimerized naphthalimide is used, the wavelength will be adjusted as appropriate.

[0039] The controller 50 is a microcomputer built into an electronic device for a specific purpose, or a general-purpose computer such as a PC, a server computer such as a cloud server, or a dedicated computer. "PC" is an abbreviation for personal computer. The controller 50 may be installed in the same facility as the balloon catheter 20, ultrasound probe 30, optical probe 40, and console 60, such as a hospital, or it may be installed in a separate facility such as a data center.

[0040] The functions of the controller 50 are realized by executing the program according to this embodiment on a processor built into the controller 50. In other words, the functions of the controller 50 are realized by software. The processor is a general-purpose processor such as a CPU or GPU, or a dedicated processor specialized for a specific process. "CPU" is an abbreviation for central processing unit. "GPU" is an abbreviation for graphics processing unit. The program causes the computer to execute the operations of the controller 50, thereby causing the computer to function as the controller 50. In other words, the computer functions as the controller 50 by executing the operations of the controller 50 according to the program.

[0041] The program can be stored on a non-temporary computer-readable medium. Examples of non-temporary computer-readable mediums include flash memory, magnetic recording devices, optical discs, magneto-optical recording media, or ROM. The program can be distributed, for example, by selling, transferring, or lending portable media such as SD cards, DVDs, or CD-ROMs containing the program. "SD" is an abbreviation for Secure Digital. "DVD" is an abbreviation for digital versatile disc. "CD-ROM" is an abbreviation for compact disc read-only memory. The program may also be distributed by storing it in server storage and transferring it from the server to other computers. The program may also be provided as a program product.

[0042] A computer, for example, stores a program stored on a portable medium or a program transferred from a server in its main memory. Then, the computer reads the program stored in the main memory with its processor and executes the processing according to the read program. The computer may also read a program directly from the portable medium and execute the processing according to the program. The computer may also execute the processing according to the received program sequentially each time a program is transferred to it from a server. Processing may also be performed by a so-called ASP type service, which does not transfer programs from the server to the computer, but realizes its function only through execution instructions and result acquisition. "ASP" is an abbreviation for application service provider. A program includes information used for processing by an electronic computer that is equivalent to a program. For example, data that is not a direct instruction to the computer but has the nature of defining the computer's processing falls under "equivalent to a program".

[0043] Some or all of the functions of the controller 50 may be realized by a programmable circuit or a dedicated circuit built into the controller 50. That is, some or all of the functions of the controller 50 may be realized by hardware. The programmable circuit is, for example, an FPGA. "FPGA" is an abbreviation for field-programmable gate array. The dedicated circuit is, for example, an ASIC. "ASIC" is an abbreviation for application specific integrated circuit.

[0044] The console 60 includes a display such as an LCD or an organic EL display. "LCD" is an abbreviation for liquid crystal display. "EL" is an abbreviation for electro luminescent. The console 60 may further include a pointing device such as a mouse, a keyboard, or a touch screen provided integrally with the display.

[0045] As a modification, as shown in FIG. 12, the ultrasonic probe 30 may further include a light irradiator 42, and the light irradiator 42 may be attached to the second shaft 31 together with the ultrasonic element 32. That is, the ultrasonic probe 30 and the optical probe 40 may be integrated. In this modification, it is preferable that the light irradiator 42 is attached adjacent to the proximal end of the ultrasonic element 32.

[0046] According to the present embodiment, by reinforcing the neck, that is, the region adjacent to the aortic aneurysm, using a drug, it is possible to suppress the expansion of aneurysms such as AAA without an implant. Therefore, risks such as thrombus formation, scattering, infection, or deterioration of the implant due to the implant can be avoided. Since there is no implant, even if the aneurysm expands after the treatment, it is easy to perform additional treatments such as normal EVAR or artificial blood vessel replacement. After confirming the vessel hardness of the blood vessel 70 with the ultrasonic probe 30, by applying a gradation to the degree of reinforcement, the difference in vessel hardness can be reduced, and the possibility of further aneurysm progression can also be reduced. The gradation can be controlled by the application amount of the drug, the irradiation time of the light for activating the drug, or a combination thereof.

[0047] Referring to FIG. 4, the operation method of the medical system 10 according to this embodiment will be described.

[0048] In S1, as shown in FIG. 5, the balloon catheter 20 is inserted into the blood vessel 70, and the balloon 22 is arranged near the neck, that is, near the region adjacent to the aortic aneurysm, with a guide wire. At the time of S1, the hardness of the blood vessel 70 is unknown.

[0049] In S2, as shown in FIG. 6, the ultrasonic probe 30 is inserted into the first lumen 23, and the blood vessel 70 is observed through the balloon 22. For example, when calculating the hardness of the blood vessel 70 from the change in the diameter of the blood vessel 70 accompanying the heartbeat, the change in the diameter of the blood vessel 70 is observed. The observation does not necessarily have to be performed through the balloon 22.

[0050] The ultrasonic probe 30 transmits ultrasonic waves toward the blood vessel wall 71 from a plurality of positions in the longitudinal direction of the first shaft 21 using the ultrasonic element 32, and receives the reflected waves of the ultrasonic waves. The "plurality of positions" preferably includes at least three positions of the first shaft 21 where the balloon 22 is arranged. The controller 50 acquires ultrasonic information regarding the reflected waves received by the ultrasonic element 32. The controller 50 calculates the hardness of the blood vessel 70 corresponding to each of the plurality of positions based on the acquired ultrasonic information. The controller 50 outputs the calculated hardness of the blood vessel in association with each of the plurality of positions.

[0051] The vascular stiffness of blood vessel 70 is calculated from the change in the diameter of blood vessel 70 in association with the heartbeat. When the diameter of blood vessel 70 during cardiac systole is Ds, the diameter of blood vessel 70 during cardiac diastole is Dd, and the vascular stiffness of blood vessel 70 is ε, then ε = (Ds - Dd) / Dd × 100%. Alternatively, the vascular stiffness of blood vessel 70 may be calculated from the tissue state of blood vessel 70, such as wall thickness or the amount of fibrous tissue, as observed by IVUS. Ds, the diameter of blood vessel 70 during cardiac systole, refers to the diameter of blood vessel 70 during cardiac systole, especially at the end of systole, and is synonymous with the maximum blood vessel diameter when blood vessel 70 is most dilated at the treatment site, the neck, i.e., the region adjacent to the aortic aneurysm. Similarly, Dd, the diameter of blood vessel 70 during cardiac diastole, refers to the diameter of blood vessel 70 during cardiac diastole, especially at the end of diastole, and is synonymous with the minimum blood vessel diameter when blood vessel 70 is most constricted at the treatment site, the neck, i.e., the region adjacent to the aortic aneurysm. In other words, the vascular stiffness of the blood vessel 70 may be calculated from the change in the diameter of the blood vessel 70 in conjunction with the pulse.

[0052] A pullback operation is performed so that the IVUS scan position changes in accordance with the heartbeat or pulse. Since it is necessary to determine the systolic and diastolic diameters, the ultrasound element 32 must remain in place for at least one heartbeat or pulse duration at each location. For example, after observing for one heartbeat or pulse duration, the ultrasound element 32 is moved 5 mm and the observation for one heartbeat or pulse duration is repeated. The pullback operation may be performed manually by a user such as a physician or clinical engineer, or automatically by the controller 50. In the latter case, the controller 50 controls the longitudinal movement of the ultrasound probe 30 in the first lumen 23 to acquire ultrasound information for at least one heartbeat or pulse duration at each of the multiple locations. The controller 50 may acquire the heartbeat or pulse measurement result and control the longitudinal movement of the ultrasound probe 30 in the first lumen 23 based on the acquired measurement result. The heartbeat measurement result is acquired, for example, from a heart rate monitor or electrocardiogram. The pulse rate measurement results are obtained, for example, from a pulse meter.

[0053] As one variation, instead of matching the heart rate or pulse rate, a pullback operation may be performed so that the IVUS scan position changes when both the maximum and minimum diameters of the blood vessel 70 have been calculated. For example, after observing the change in the diameter of the blood vessel 70 with IVUS and identifying both the point where vasoconstriction begins to occur when the increasing diameter of the blood vessel 70 starts to decrease, and the point where vasodilation begins to occur when the decreasing diameter of the blood vessel 70 starts to increase, the ultrasonic element 32 is moved 5 mm and the observation is repeated. When the controller 50 performs the pullback operation automatically, the controller 50 controls the longitudinal movement of the ultrasonic probe 30 in the first lumen 23 and acquires ultrasonic information for each of the multiple positions until both the point where vasoconstriction begins and the point where vasodilation begins are identified. The controller 50 continuously calculates the diameter of the blood vessel 70 from the acquired ultrasound information, identifies both the vasoconstriction initiation point and the vasodilation initiation point at least once, and then controls the longitudinal movement of the ultrasound probe 30 in the first lumen 23 to move the ultrasound element 32 to the next position in the longitudinal direction. The diameter of the blood vessel 70 at the vasoconstriction initiation point is the maximum blood vessel diameter when the blood vessel 70 is most dilated in the treatment site, the neck, i.e., the region adjacent to the aortic aneurysm, and corresponds to Ds, the diameter of the blood vessel 70 during cardiac systole. The diameter of the blood vessel 70 at the vasodilation initiation point is the minimum blood vessel diameter when the blood vessel 70 is most constricted in the treatment site, the neck, i.e., the region adjacent to the aortic aneurysm, and corresponds to Dd, the diameter of the blood vessel 70 during cardiac diastole. In other words, the controller 50 continuously calculates the diameter of the blood vessel 70 from the acquired ultrasonic information for each of the multiple locations, and identifies both the vasoconstriction initiation point at that location where the diameter of the blood vessel 70 changes from increasing to decreasing, and the vasodilation initiation point where the diameter of the blood vessel 70 changes from decreasing to increasing. After identifying both the vasoconstriction initiation point and the vasodilation initiation point at each of the multiple locations at least once, the controller 50 may control the longitudinal movement of the ultrasonic probe 30 in the first lumen 23 to move the ultrasonic element 32 to the next position in the longitudinal direction.

[0054] In this embodiment, the controller 50 generates a longitudinal section image 80 as shown in Figure 10 based on the acquired ultrasound information. The longitudinal section image 80 is an image of the blood vessel 70 viewed from a direction perpendicular to the longitudinal direction. The controller 50 displays the generated longitudinal section image 80 on the console 60 and displays the calculated blood vessel stiffness at positions corresponding to each of the multiple positions in the generated longitudinal section image 80, thereby outputting the calculated blood vessel stiffness linked to each of the multiple positions. In the example shown in Figure 10, a gradient bar 81 representing the distribution of blood vessel stiffness of the blood vessel 70 in the longitudinal direction is displayed on the right side of the longitudinal section image 80. The gradient bar 81 indicates that the blood vessel 70 is softer as the color is lighter or brighter, and that the blood vessel 70 is stiffer as the color is darker or darker. By checking the blood vessel stiffness output linked to each of the multiple positions, such as the gradient bar 81, the user can appropriately determine the amount of light irradiation for each position according to the corresponding blood vessel stiffness. The user can appropriately determine the irradiation range in the longitudinal direction of the light according to the difference in vascular stiffness between multiple positions by checking the difference in vascular stiffness output linked to each position, such as the gradient bar 81. The vascular stiffness or the difference in vascular stiffness may be shown numerically. The amount of light irradiation is the integrated light amount determined by the intensity of the irradiated light per unit area and the irradiation time.

[0055] The controller 50 may, on behalf of the user, determine the amount of light irradiation for each of the multiple locations according to the calculated vascular stiffness. The controller 50 may further display the determined irradiation amount in the generated longitudinal section image 80, aligned with the position corresponding to each of the multiple locations. By confirming the displayed irradiation amount, the user can appropriately control the amount of light irradiation from the light irradiation body 42 in S4 in accordance with the irradiation amount determined by the controller 50. The irradiation amount may be shown numerically, or by a shape, color, or a combination thereof. The controller 50 may, on behalf of the user, determine the longitudinal irradiation range of the light according to the calculated difference in vascular stiffness between the multiple locations. The controller 50 may further display the determined irradiation range on the generated longitudinal section image 80. By confirming the displayed irradiation range, the user can appropriately control the longitudinal movement of the light irradiation body 42 in the first lumen 23 in S4 in accordance with the irradiation range determined by the controller 50. The irradiation range may be shown by a shape, color, or a combination thereof.

[0056] The controller 50 may, on behalf of the user, control the amount of light emitted from the light-emitting element 42 in accordance with the irradiation dose determined in S4. The controller 50 may, on behalf of the user, control the longitudinal movement of the light-emitting element 42 in the first lumen 23 in accordance with the irradiation range determined in S4.

[0057] In S3, as shown in Figure 7, the balloon 22 is moved to the treatment site, the neck, i.e., the region adjacent to the aortic aneurysm, and is expanded to the diameter of the blood vessel 70 while being observed with the ultrasound probe 30, and the drug is delivered to the neck. In other words, the balloon catheter 20 delivers the drug to the blood vessel wall 71. By expanding the balloon 22 while observing with IVUS, over-expansion of the neck can be suppressed. If the balloon 22 is a drug-releasing balloon, after the required amount of drug has been released, the expansion can be maintained by flowing in physiological saline, and cooling of the affected area during light irradiation in S4 is also possible.

[0058] In S4, as shown in Figure 8, the optical probe 40 is inserted into the first lumen 23, and light is irradiated in a gradient manner according to the observation results in S2, so that the degree of change in vascular stiffness decreases from the end of the aortic aneurysm to the adjacent region, thereby reinforcing the neck, which is the adjacent region of the aortic aneurysm. For example, if the vascular stiffness decreases sharply near the boundary with the aortic aneurysm in the adjacent region of the aortic aneurysm, the light irradiation is controlled so that the amount of light irradiated in the adjacent region of the aortic aneurysm gradually increases from the part away from the end of the aneurysm towards the boundary with the aortic aneurysm. As a result, the vessel 70 is reinforced so that the vascular stiffness in the adjacent region of the aortic aneurysm after treatment gradually increases towards the boundary with the aortic aneurysm.

[0059] The optical probe 40 irradiates light toward the blood vessel wall 71 to activate the drug already delivered to the blood vessel wall 71. Alignment of the light irradiation site with the site where vascular stiffness was measured by IVUS on the blood vessel 70 is performed by matching the insertion length of the optical probe 40 with the insertion length of the ultrasound probe 30 using a pullback mechanism. The measured vascular stiffness or ratio of vascular stiffness of the blood vessel 70 is recorded in relation to the insertion length of the ultrasound probe 30, and the light irradiation time for each site is adjusted while viewing this record. Alternatively, the measured vascular stiffness or ratio of vascular stiffness of each site on the blood vessel 70 where vascular stiffness was measured by IVUS may be reflected in the X-ray fluoroscopic image, and the light irradiation time for each site may be adjusted while viewing the X-ray fluoroscopic image. The cumulative light irradiation time for each site may be displayed on the screen. It is desirable that the irradiation position and irradiation dose be automatically controlled using a pullback mechanism.

[0060] In this embodiment, since the IVUS catheter and the light irradiation catheter travel through the same lumen, precise alignment is possible between evaluating the stiffness of the blood vessel 70 and reinforcing the blood vessel 70. As one modification, the IVUS catheter and the light irradiation catheter may be combined into a single integrated catheter.

[0061] As shown in Figure 10, the controller 50 may identify the longitudinal position of the light-emitting element 42 in the first lumen 23 and further display the identified position on the generated longitudinal section image 80. When the user manually controls the longitudinal movement of the light-emitting element 42 in the first lumen 23, they can easily control the movement by confirming the displayed position. The position may be indicated by a shape, color, or a combination thereof. In the example shown in Figure 10, a position bar 82, which is a straight line extending in a direction perpendicular to the longitudinal direction, is displayed on the longitudinal section image 80 to indicate the longitudinal position of the light-emitting element 42.

[0062] The controller 50 may identify the actual amount of light emitted from the light irradiator 42 and further display the identified actual amount of light emitted in accordance with the position corresponding to each of the multiple positions in the generated longitudinal section image 80. When the user manually controls the amount of light emitted from the light irradiator 42, they can easily control the amount of light emitted by checking the displayed actual amount of light emitted. The actual amount of light emitted may be shown numerically, or by a shape, color, or a combination thereof.

[0063] In S5, as shown in Figure 9, the vascular stiffness of the treated blood vessel 70 is confirmed with the ultrasound probe 30. If the difference in vascular stiffness between the neck (the region adjacent to the aortic aneurysm) and the aneurysm is still large, additional reinforcement may be performed by repeating steps S3 and S4 as needed.

[0064] If the controller 50 has already displayed the vascular stiffness for each of the multiple locations, it acquires new ultrasound information. Based on the newly acquired ultrasound information, the controller 50 newly calculates the vascular stiffness of the blood vessel 70 corresponding to each of the multiple locations. As shown in Figure 11, the controller 50 updates the already displayed vascular stiffness to the newly calculated vascular stiffness. In the example shown in Figure 10, the gradient bar 81 shows that the vascular stiffness decreases sharply near the boundary with the aortic aneurysm in the aortic aneurysm-adjacent region, whereas in the example shown in Figure 11, the gradient bar 81 shows that the vascular stiffness after treatment in the aortic aneurysm-adjacent region gradually increases towards the boundary with the aortic aneurysm.

[0065] As shown in Figure 12, the ultrasonic element 32 may be mounted on the second shaft 31 of the ultrasonic probe 30 adjacent to the ultrasonic element 32 so that the ultrasonic element 32 leads the optical irradiator 42 when moving in the longitudinal direction during light irradiation. In addition, ultrasonic information may be acquired by the ultrasonic element 32 simultaneously with light irradiation from the optical irradiator 42. Specifically, when the ultrasonic probe 30 is moved towards the proximal end, i.e., towards the user's hand, during light irradiation, the optical irradiator 42 is positioned adjacent to the proximal end of the ultrasonic element 32. As a result, as shown in Figure 11, the already displayed vascular stiffness is sequentially updated with the newly calculated vascular stiffness in accordance with the longitudinal movement of the optical irradiator 42. Therefore, when the user controls the amount of light irradiation, it becomes easier to achieve a more appropriate distribution of vascular stiffness with a single light irradiation.

[0066] Step S3 may be performed between S1 and S2. Step S2 may be performed with balloon 22 inflated. Keeping balloon 22 inflated makes it easier for the IVUS catheter and the photoirradiation catheter to pass through the same route.

[0067] Although not essential, in this embodiment, the first lumen 23 extends toward the tip of the first shaft 21 in the longitudinal direction beyond the location where the balloon 22 is positioned, allowing the ultrasonic element 32 to be inserted further toward the tip when the ultrasonic probe 30 is inserted. Therefore, when measuring the distribution of vascular stiffness in the blood vessel 70, the vascular stiffness can be checked further toward the tip than the balloon 22. Furthermore, the expansion position of the balloon 22 can be adjusted further toward the tip as needed. For example, knowing the vascular stiffness beyond the tip of the balloon 22 makes it easier to determine how far forward the balloon 22 should be advanced if it is in an inappropriate position.

[0068] In this embodiment, the procedure is performed on the proximal neck, which is the aortic aneurysm adjacent region located upstream of the aortic aneurysm, i.e., proximal to the aortic aneurysm. However, a similar procedure may be performed on the distal neck, which is located downstream of the aortic aneurysm, i.e., distal to the aortic aneurysm. The procedure is not limited to aortic aneurysms; it may also be performed on aneurysms in other parts of the body or adjacent regions of other lesions.

[0069] This disclosure is not limited to the embodiments described above. For example, two or more blocks shown in the block diagram may be combined, or one block may be divided. Instead of executing two or more steps shown in the flowchart in chronological order as described, they may be executed in parallel or in a different order, depending on the processing capacity of the device performing each step, or as necessary. Other modifications are possible without departing from the spirit of this disclosure.

[0070] 10 Medical system 20 Balloon catheter 21 First shaft 22 Balloon 23 First lumen 24 Second lumen 30 Ultrasound probe 31 Second shaft 32 Ultrasound element 40 Optical probe 41 Third shaft 42 Light irradiator 50 Controller 60 Console 70 Blood vessel 71 Blood vessel wall 80 Longitudinal section image 81 Gradation bar 82 Position bar

Claims

1. A medical system comprising: a balloon catheter having a long first shaft and a balloon attached to the first shaft, for delivering a drug activated by light emitted from a light-emitting body inserted into a lumen extending within the first shaft to the wall of a blood vessel; an ultrasonic probe having a long second shaft and an ultrasonic element attached to the second shaft, which is insertable into the lumen, for transmitting ultrasonic waves from multiple positions along the longitudinal direction of the first shaft toward the blood vessel wall using the ultrasonic element and receiving the reflected waves of the ultrasonic waves; and a controller that acquires ultrasonic information relating to the reflected waves received by the ultrasonic element, calculates the vascular stiffness of the blood vessel corresponding to each of the multiple positions based on the acquired ultrasonic information, and outputs the calculated vascular stiffness linked to each of the multiple positions.

2. The medical system according to claim 1, wherein the controller determines the amount of light irradiation for each of the multiple positions according to the calculated vascular stiffness.

3. The medical system according to claim 2, wherein the controller controls the amount of light emitted from the light irradiator in accordance with the determined irradiation amount.

4. The medical system according to claim 1, wherein the controller determines the irradiation range of the light in the longitudinal direction according to the calculated difference in vascular stiffness between the multiple positions.

5. The medical system according to claim 4, wherein the controller controls the movement of the light-emitting body in the longitudinal direction within the lumen in accordance with the determined irradiation range.

6. The medical system according to claim 1, wherein the controller controls the longitudinal movement of the ultrasound probe in the lumen to acquire ultrasound information for each of the plurality of positions for at least one heartbeat or at least one pulse.

7. The medical system according to claim 6, wherein the controller acquires the measurement result of heart rate or pulse rate and controls the movement based on the acquired measurement result.

8. The medical system according to claim 1, wherein the controller continuously calculates the diameter of the blood vessel from the acquired ultrasonic information for each of the multiple positions, identifies both the vasoconstriction initiation point at which the diameter of the blood vessel changes from increasing to decreasing and the vasodilation initiation point at which the diameter of the blood vessel changes from decreasing to increasing, and after identifying both the vasoconstriction initiation point and the vasodilation initiation point at each of the multiple positions at least once, controls the longitudinal movement of the ultrasonic probe in the lumen to move the ultrasonic element to the next position in the longitudinal direction.

9. The medical system according to claim 1, wherein the plurality of positions include at least three positions on the first shaft where the balloon is located.

10. The medical system according to claim 1, wherein the controller generates an image of the blood vessel viewed from a direction perpendicular to the longitudinal direction based on the acquired ultrasound information, displays the generated image on a screen, and displays the calculated blood vessel stiffness in accordance with the position corresponding to each of the multiple positions in the generated image, thereby outputting the calculated blood vessel stiffness linked to each of the multiple positions.

11. The medical system according to claim 10, wherein the controller, if it has already displayed the vascular stiffness for each of the multiple locations, acquires new ultrasonic information, calculates the vascular stiffness of the blood vessels corresponding to each of the multiple locations based on the acquired new ultrasonic information, and updates the already displayed vascular stiffness to the newly calculated vascular stiffness.

12. The medical system according to claim 10, wherein the controller identifies the longitudinal position of the light-emitting body in the lumen and further displays the identified position on the generated image.

13. The medical system according to claim 10, wherein the controller determines the amount of light irradiation for each of the multiple positions according to the calculated vascular stiffness, and further displays the determined irradiation amount in the generated image in accordance with the position corresponding to each of the multiple positions.

14. The medical system according to claim 10, wherein the controller determines the irradiation range of the light in the longitudinal direction according to the calculated difference in vascular stiffness between the multiple positions, and further displays the determined irradiation range on the generated image.

15. The medical system according to claim 10, wherein the controller identifies the actual amount of light irradiated from the light irradiator and further displays the identified actual amount of light irradiated in accordance with the position corresponding to each of the multiple positions in the generated image.

16. The medical system according to claim 1, wherein the lumen extends toward the tip in the longitudinal direction of the first shaft beyond the location where the balloon is positioned, and the ultrasonic element can be inserted beyond the location toward the tip when the ultrasonic probe is inserted.

17. The medical system according to any one of claims 1 to 16, further comprising an optical probe having a long third shaft and the light irradiator, which is insertable into the lumen and the light irradiator is attached to the third shaft.

18. The medical system according to any one of claims 1 to 16, wherein the ultrasonic probe further comprises the light irradiator, and the light irradiator is attached to the second shaft together with the ultrasonic element.

19. A method for operating a medical system, comprising: a balloon catheter having a long first shaft and a balloon attached to the first shaft, which, when inserted into a blood vessel, delivers a drug activated by light emitted from a light-emitting body inserted into the lumen extending within the first shaft to the blood vessel wall of the blood vessel; an ultrasonic probe having a long second shaft and an ultrasonic element attached to the second shaft, which, when inserted into the lumen, transmits ultrasonic waves from multiple positions along the longitudinal direction of the first shaft toward the blood vessel wall using the ultrasonic element and receives the reflected waves of the ultrasonic waves; a controller acquiring ultrasonic information relating to the reflected waves received by the ultrasonic element; the controller calculating the vascular stiffness of the blood vessel corresponding to each of the multiple positions based on the acquired ultrasonic information; and the controller outputting the calculated vascular stiffness associated with each of the multiple positions.

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