Blood vessel model observation device, and method for the same

Abstract

To provide an observation device that can simultaneously observe a fluoroscopic image and blood vessel model in itself of a catheter inserted into the blood vessel model without using an X-ray.SOLUTION: Inside a blood vessel model 5, a substance is arranged that has a near-infrared ray absorption characteristic different from a component material of the blood vessel model 5, and a catheter 1 comprises: a sheath 2; and wires 3 that are inserted into the sheath 2, the wires 3 have a body part, and a marker part, in which the body part of the wires 3 has a first fluorescence characteristic, and the marker part thereof has a second fluorescence characteristic. An observation device comprises: a first light source 20 that discharges a first near-infrared ray; a fluorescence-activation light source 30 that activates any one of the first fluorescence characteristic, or the second fluorescence characteristic; a first light reception unit 111 that can receive fluorescence from the first near-infrared ray, the main body part, or the marker part; a first image generation unit 121 that generates a first image based on the first near-infrared ray and fluorescence the first light reception unit 111 images; and a display 17 that displays the first image.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an apparatus and method for observing a blood vessel model and a catheter inserted into the blood vessel model. [Background technology]

[0002] When evaluating a catheter to be inserted into a blood vessel, or when performing technical training or evaluation of intravascular surgery, it is necessary to observe the shape of a blood vessel model (hereinafter referred to as "blood vessel shape") and the state of the catheter inserted into the blood vessel model. In order to observe the blood vessel shape and the state of the catheter inserted into the blood vessel model, in addition to direct visual observation, a visible light camera and an X-ray projection device are often used. It is easy to form a blood vessel model from a transparent material and fill the lumen of the blood vessel model (hereinafter referred to as the "lumen region") with a liquid colored with a dye or the like, and then observe the blood vessel shape and the catheter inserted into the blood vessel model visually or with a visible light camera. However, in this case, the catheter cannot be seen through, and the position and condition of the guide wire and other components that make up the catheter cannot be confirmed, so the reproducibility of intravascular surgery is low. This problem can be solved by using X-rays, but their use is not easy due to radiation exposure and management considerations.

[0003] Catheters generally have a multi-layer structure with wires (including balloons, coils, stents and other devices with therapeutic functions, drugs (liquids such as contrast agents and thrombolytic agents) and other sheaths) inserted into a thin, tubular sheath, and observation using visible light does not allow for detection of the position or condition of the tips of the wires inserted into the sheath in multiple layers. In actual treatment using catheters, information on the tip position and condition of wires inside the sheath is necessary. In addition, in practical catheters, in order to clearly indicate the specific positions of the sheath and wires, materials that do not transmit X-rays (X-ray opaque markers) are attached to the tips and middle parts of the catheters, making it possible to confirm their relative positions using the X-ray projection device used during treatment.

[0004] In order to observe the tip position and condition of wires within a sheath while avoiding exposure to X-rays, an observation method has been proposed that combines fluorescent observation technology and image processing technology (Non-Patent Document 1). Furthermore, Patent Document 1 proposes a lubricating liquid that ensures lubricity between the blood vessel model and the catheter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5992031 [Non-patent literature]

[0006] [Non-Patent Document 1] Kazuaki Fukasaku et al. “Intravascular treatment training is now possible anytime, anywhere – Development of an endovascular treatment simulation that does not expose doctors to X-rays”, [online], February 19, 2022, 51st Japanese Society of Neuroradiology https: / / www.u-ryukyu.ac.jp / news / 32074 / Summary of the Invention [Problem to be solved by the invention]

[0007] According to the observation method introduced in Non-Patent Document 1, a fluorescent material is applied to the area to be visualized. As a result, it becomes possible to distinguish two areas during transillumination observation. For example, it becomes possible to distinguish the main body and marker parts of wires, or to distinguish the sheath and wire. However, this method makes the coated surface opaque in the area where the fluorescent material is applied, so structures behind the coated surface cannot be observed through the light, and therefore it is not possible to simultaneously visualize the main body, marker, and sheath of the wires in a identifiable manner through the light. Furthermore, in order to visualize the blood vessel model, it is necessary to introduce a contrast agent (a liquid containing a fluorescent dye) into the liquid filling the lumen region of the blood vessel model.

[0008] For example, if the vascular model is made of a gel material such as polyvinyl alcohol, there is a risk that the contrast agent will seep into the material from which the vascular model is made or adhere to the inner surface of the vascular model, making it difficult for the model to withstand long-term use. On the other hand, when the blood vessel model is made of a cross-linked polymer material such as silicone rubber, the lumen of the blood vessel model needs to be filled with a lubricating liquid to ensure lubrication between the catheter and the blood vessel model (see Patent Document 1). When a contrast agent is mixed into the lubricating liquid, the lubricating function of the lubricating liquid may be reduced. [Means for solving the problem]

[0009] The inventors conducted extensive research to solve the above problems and discovered that by using near-infrared light, which has a higher material permeability than visible light and a more diverse light absorption rate depending on the material and wavelength than visible light, it is possible to simultaneously visualize the shape of blood vessels and the sheath and wires of a catheter without using contrast agents, etc. On the other hand, it was difficult to visualize the difference between the main body and the marker part of the wires (the area where another metal structure is laminated on the metal structure) using only near-infrared light. Therefore, we decided to visualize the main body and the marker part using fluorescent means.

[0010] Near-infrared absorptivity varies in various ways depending on the type of substance and the wavelength of the near-infrared used. Due to this characteristic, in near-infrared spectroscopy, the change in absorptivity in the near-infrared region is measured, and the components of the substance are identified by comparing the measurement results with a spectrum table showing the absorption characteristics. In addition, in many substances, the absorptivity changes greatly between the visible light region and the near-infrared region. Due to this characteristic of near-infrared light, liquids containing pigments that appear opaque in the visible light region can be observed transparently in the near-infrared region, and various soft polymers such as silicone rubber, various hard polymers such as acrylic resin, and various liquids such as water and oil that appear transparent in the visible light region can be observed as different colors (shades) in the near-infrared region without using contrast agents (hereinafter referred to as "near-infrared spectroscopic observation"). Furthermore, the near-infrared absorptivity (i.e., near-infrared transmittance) of each substance varies in various ways by changing the wavelength in the near-infrared region, so by utilizing this characteristic, differences in the shapes and materials of each part of a composite structure composed of different substances can be identified.

[0011] The inventors have found that, due to the characteristics of near-infrared light, by performing near-infrared spectroscopic observation, each part of a blood vessel model, which appears completely transparent in the visible light region, including the inside and outside, can be observed as an image in which the difference in shape and material can be distinguished, without using a contrast agent or the like. In addition, by changing the wavelength and light quantity of the near-infrared light used (the intensity of the light source and the exposure setting of the observation device), the balance of the light and shade of each part of the blood vessel model can be changed without performing any physical manipulation on the observation target. In addition, by changing the wavelength and light quantity of the near-infrared light, it has been found that the blood vessel shape can be selectively visualized or disappeared while the fluoroscopic image of the catheter is visualized on the observation screen.

[0012] On the other hand, near-infrared light, like X-rays, has the property of easily penetrating various materials, making it possible to perform fluoroscopic observation of objects (hereinafter referred to as "near-infrared fluoroscopic observation"). As a method that is simpler and safer than X-ray observation, it is used for non-destructive testing of semiconductors and foreign body inspection in liquids.

[0013] When observed with visible light, the blood vessel model is observed three-dimensionally (3D), but when observed with near-infrared fluoroscopy, a planar (2D) image like a shadow puppet is obtained due to its transparency. Such planar (2D) images are close to X-ray fluoroscopy images obtained in catheter intravascular surgery, and are suitable for reproducing a simulation of the same surgery. Furthermore, even when each part of the blood vessel model is three-dimensional, i.e., crosses in front of or behind the direction of near-infrared irradiation, a planar (2D) fluoroscopy image similar to an X-ray observation image can be obtained.

[0014] Actual catheters all have a common feature of a thin-film multi-layer structure, but the sheath material and film thickness are not uniform depending on the type (sheath materials include various soft resins such as polyester, polyethylene, polyamide (nylon), polyurethane, and silicone rubber). Catheters and wires also incorporate complex metal structures such as meshes and X-ray opaque markers, and mechanical structures such as balloons and coil detachment mechanisms. The inventors have found that by observing catheters with such features using both near-infrared fluoroscopy and near-infrared spectroscopy, the catheter can be reproduced as an image similar to an X-ray image observed during an actual operation, and further as an expanded observation image including information that cannot be obtained by X-ray observation.

[0015] By using near-infrared light, it is possible to observe the catheter through the fluoroscopic view, and to obtain an observation image that can distinguish differences in its structure and material. Furthermore, by changing the wavelength and light intensity of the near-infrared light used, it is possible to change the shading balance of the observation image without physically manipulating the blood vessel model. For example, it is possible to select a specific area of ​​the blood vessel model to be observed, change or reverse the shading balance of the selected specific area, or make the specific area visible or disappear.

[0016] When performing near-infrared fluoroscopic observation, it is preferable to simultaneously use two or more wavelengths with different absorption characteristics with respect to water. For the first wavelength of near-infrared light, one with absorption characteristics close to those of the material forming the blood vessel model and water (for example, wavelength: 1200 nm) is used. This allows only the outline of the blood vessel model to be observed. For the second wavelength of near-infrared light, one with particularly high absorption characteristics with respect to water (wavelength: 1450 nm) is used. This makes the walls of the blood vessel model appear white, and the water (pseudo blood) inside the blood vessel model appear black. By adjusting the intensities of these two types of near-infrared light, the proportion of the second wavelength is increased, causing the artificial blood to turn black, resulting in an image that is the same as that obtained when a contrast agent is injected into the human body during actual catheter surgery. It should be noted that by using two types of first wavelengths (for example, 1300 nm and 1200 nm) and stopping the irradiation of one of them, the proportion of the second wavelength can be relatively increased.

[0017] A first aspect of the present invention is defined as follows. An observation device for observing a blood vessel model into which a catheter is inserted, the observation device comprising: a substance having near-infrared absorption characteristics different from a constituent material of the blood vessel model disposed inside the blood vessel model; the catheter includes a sheath and wires inserted into the sheath, the wires having a main body portion and a marker portion; The body portion of the wire has a first fluorescent characteristic and the marker portion has a second fluorescent characteristic; a first light source emitting a first near infrared ray; a fluorescent light source that emits light that activates either the first fluorescent property or the second fluorescent property; A light receiving unit capable of receiving the first near-infrared light and the fluorescence from the main body unit or the marker unit; an observation device comprising: a first image generating unit that generates a first image based on the first near-infrared light and fluorescent light received by the light receiving unit; and a display that displays the first image. According to the blood vessel model observation device of the first aspect thus defined, since the substance placed in the blood vessel model has a near-infrared absorption specificity different from that of the constituent material of the blood vessel model, it is possible to visually confirm the boundary between the blood vessel wall cross-sectional area of ​​the blood vessel model (hereinafter referred to as "wall cross-sectional area") and the substance in near-infrared spectroscopic observation. At this time, since the catheter inserted in the blood vessel model has a permeability to near-infrared rays different from that of the constituent material of the blood vessel model and the substance, the catheter can be observed separately from the blood vessel model and the substance. Also, it is possible to distinguish between the sheath and wires in the catheter and to observe the transmission.

[0018] The wavelength of the light emitted by the fluorescent light source is not particularly limited as long as it can activate the first fluorescent property of the main body of the wire or the fluorescent property of the marker. In addition to wavelengths in the visible range such as blue, green, and red, wavelengths in the near infrared range can be used. Even when the wire is inside the sheath, it is necessary to distinguish the main body from the marker, so strong fluorescence that can penetrate the sheath is required. Therefore, it is preferable to use ultraviolet light with high energy. In addition, there is a risk that part of the light from the fluorescent light source will be reflected and enter the light receiving section, so it is preferable that the light receiving section is configured not to receive the light from the fluorescent light source. In other words, the light receiving section is capable of receiving the first near-infrared light and the fluorescent light from the first light source.

[0019] The first fluorescence characteristic and the second fluorescence characteristic indicate different fluorescence intensities (including zero fluorescence) with respect to light from a fluorescent light source. For example, there is a pattern in which the fluorescent material is applied (coated) only to the main body of the wire and not to the marker portion, and a pattern in which the fluorescent material is not applied to the main body but only to the marker portion. In the former case, since no fluorescence is emitted from the marker, that part is observed as black (dark), which is closer to actual observation using X-rays.

[0020] There are no particular limitations on the fluorescent material as long as it is activated by light from a fluorescent light source, but from the standpoint of the transmission efficiency of the sheath, it is preferable that the wavelength is relatively long and in a range that is not absorbed by water. There is no particular limitation on the method of attaching the fluorescent material to the wires, but it can be used in combination with an adhesive. Since the marker part is made of platinum and is not magnetized, a magnetic fluorescent material can be used, and a magnetic field can be applied to the wires to magnetize only the main body, and the magnetic fluorescent material can be attached only to the magnetized part. In this case, it is preferable that the magnetic field can be applied to the catheter during observation. It is preferable to apply the magnetic field intermittently, in order to prevent the wires from heating. Fine powder of the magnetic fluorescent material is dispersed in the simulated blood vessel, and this is attached to the main body of the wires as the magnetic field is applied. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a spectrum showing the near-infrared absorption characteristics of water and silicone rubber. [Diagram 2] FIG. 2 is a schematic diagram showing an observation device according to the present invention. [Diagram 3] FIG. 3 is a graph showing the relationship between particle radius, wavelength, and Rayleigh observation. [Figure 4] FIG. 4 shows an observed image of an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Near infrared generally refers to light with wavelengths between 780nm and 2500nm. The absorption rate of near-infrared rays varies depending on the wavelength and the material (see Figure 1). It can be seen that the infrared absorption rate of water varies greatly depending on the wavelength in the near-infrared region. The lumen of the blood vessel model is often filled with liquid to mimic blood, and as such a liquid, an aqueous solution is generally used, in which a lubricant component is mixed as necessary with a liquid mainly composed of water, like blood. In order to simultaneously and effectively perform both near-infrared fluoroscopic observation and near-infrared spectroscopic observation, the wavelength at which the absorption rate of water is significantly high in the near-infrared region is 1450 nm, which is easy to differentiate from the absorption rates of air and silicone rubber, and it can be seen that at wavelengths around 1200, there is no significant difference in the absorption rate between silicone rubber and water.

[0023] FIG. 2 shows the structure of the observation device 100. In the figure, reference numeral 1 denotes a catheter. This catheter 1 comprises a sheath 2 and wires 3 inserted into the sheath 2. Reference numeral 5 denotes a blood vessel model, the inner cavity of which is filled with a lubricating liquid 6. This lubricating liquid may be circulated to give it fluidity. The area around the blood vessel model 5 is filled with an immersion liquid 7 that does not contain a lubricating component. A fluorescent material is attached to the main body of the wire 3 (the part other than the X-ray opaque marker). The observation device 10 includes a first light receiving section 120, a fluorescent light source 30, a first light receiving section 111, a first image generating section 121, an image synthesizing section 130, and a display 17.

[0024] The blood vessel model is made of silicone rubber provided by Fine Biomedical LLC, with a membrane thickness of 0.3mm to 3.0mm and a lumen of 1mm to 15mm. The lumen area of ​​the blood vessel model is filled with a lubricating liquid made by mixing water with a lubricating component. This lubricating liquid is a substance with near-infrared absorption characteristics different from the constituent material of the blood vessel model. The catheter used was an Excelsior microcatheter manufactured by Stryker Japan Co., Ltd. The wires used were GDC coils manufactured by Stryker Japan Co., Ltd. The first light source 120 can emit two types of near infrared light, 1200 nm and 1450 nm, and the intensity of each can be independently adjusted. The near-infrared light emitted from the first light source 120 passes through the object to be observed and reaches the first light receiving section 111 .

[0025] The fluorescent light source 30 emits ultraviolet light of 365 nm, which activates the fluorescent material in the main body of the wire 3, causing it to emit fluorescent light of 600 nm. This fluorescent light can pass through the sheath 2, the blood vessel model 5, and the housing, and is received by the first light receiving unit 111. The fluorescent light source 30 is placed above the object to be observed and emits ultraviolet light toward the object below, thereby preventing the ultraviolet light from directly entering the observer's eyes. This first light receiving section 111 is capable of receiving near infrared light and fluorescent light from the first light source 20. It is not capable of receiving ultraviolet light from the fluorescent light source 30.

[0026] In the above, a water-soluble polymer is dissolved in the lubricating liquid 6 that fills the inside of the blood vessel model 5 and in the immersion liquid 7 that fills the periphery of the blood vessel model 5. Such a water-soluble polymer is considered to be a particle having a diameter of several nm in an aqueous solution, and generates Rayleigh scattering as shown in FIG. 3. As a result, the near-infrared light from the first light source is scattered in the liquid and efficiently irradiated onto the observation target. In addition, if such a liquid is used, scattering occurs when the near-infrared light passes through the surface of the blood vessel model or is reflected by the outer surface, and image information such as the surrounding environment image contained in the irradiated near-infrared light is lost. In addition to this method, a similar effect can be obtained by mixing particles that generate Rayleigh scattering into the material that forms the blood vessel model, thereby scattering the near-infrared light inside the structure of the blood vessel model.

[0027] FIG. 4 shows the results of observation using the observation device of FIG. A catheter is inserted into the blood vessel model, and the marker part and the main body of the wires in the sheath of the catheter can be clearly observed. Note that the coil (made of platinum) attached to the tip of the wires is not coated with fluorescent material, so it appears black (dark). When no fluorescent material is attached to the wires, the entire catheter, like the markers and coils, appears black (dark). This is due to the transmission of near-infrared light.

[0028] In the above, near-infrared light and fluorescent light are received by the same light receiving section to form an image, but it is also possible to receive near-infrared light and fluorescent light by separate light receiving sections to form images and then combine the individual images.

[0029] The present invention is not limited to the above-mentioned embodiment and examples. Various modifications within the scope of the claims and within the scope that can be easily conceived by a person skilled in the art are also included in the present invention. [Explanation of symbols]

[0030] 1 Catheter 2 Sheath 3 Wires 5. Vascular model 100 Observation equipment 20 Wire 30 Marker

Claims

[Claim 1] An observation device for observing a blood vessel model into which a catheter is inserted, the observation device comprising: a substance having near-infrared absorption characteristics different from a constituent material of the blood vessel model disposed inside the blood vessel model; the catheter includes a sheath and wires inserted into the sheath, the wires having a main body portion and a marker portion; The body portion of the wire has a first fluorescent characteristic and the marker portion has a second fluorescent characteristic; a first light source emitting a first near infrared ray; a fluorescent light source for activating either the first fluorescent property or the second fluorescent property; A light receiving unit capable of receiving the first near-infrared light and / or the fluorescent light from the main body unit or the marker unit; An observation device including a first image generating unit that generates a first image based on the first near-infrared light and fluorescent light captured by the light receiving unit, and a display that displays the first image.

Images