WO2017047820A1 - Lesion blood flow feature value visualization device, method, and computer software program - Google Patents

Abstract

[Solution] This device is provided with: an input unit in which a computer reads in medical images that include a target blood vessel site, and, from said medical images, reads in the pressure field and velocity field at each position of the target blood vessel site calculated in a prescribed coordinate system with numerical fluid analysis; a lesion area determining unit in which a computer determines a blood vessel lesion site from the medical images; a lesion coordinate system calculation unit in which a computer calculates a lesion coordinate system on the basis of geometric information about the acquired blood vessel lesion site; a coordinate system conversion unit in which a computer converts the calculated pressure field and velocity field from the aforementioned prescribed coordinate system to the aforementioned calculated lesion coordinate system; a lesion blood flow feature value calculation unit in which a computer calculates a lesion blood flow feature value on the basis of the velocity field and pressure field converted to the lesion coordinate system; and an output unit in which a computer outputs the lesion blood flow feature value.

Description

Lesion blood flow feature amount visualization device, method thereof, and computer software program thereof

The present invention relates to a device for automatically analyzing vascular lesions by a computer, a method thereof, and a computer software program thereof, and more particularly, a blood flow feature amount visualization device for visualizing a flow state in a blood inflow portion of an aneurysm, a method thereof, and the like. It relates to the computer software program.

An example of a vascular lesion is a cerebral aneurysm. A cerebral aneurysm refers to a part of a vascular wall of a cerebral artery that is locally raised and changed into a lumbar shape. When this cerebral aneurysm ruptures, it often results in subarachnoid hemorrhage and death. Therefore, for a cerebral aneurysm that is highly likely to rupture, it is necessary to perform appropriate preventive treatment such as stent or coil treatment. However, the risk of rupture is said to be about 1% from conventional clinical studies. Rather, taking into account that the preventive treatment itself as described above is also associated with a life risk, it should always be treated aggressively. However, in medical practice, it is required to appropriately determine only cerebral aneurysms that are likely to rupture and to treat them.

解 明 It is important to elucidate the mechanism of cerebral aneurysm rupture in order to identify cerebral aneurysms that are likely to rupture. From recent studies, it is known that blood flow in the cerebral aneurysm is a factor related to this rupture. For example, it has been reported that in a ruptured cerebral aneurysm, collisions of blood flow were frequently observed in the aneurysm before the rupture. Japanese Patent No. 5596865 discloses a technique for automatically analyzing the characteristics of blood flow in a target blood vessel site such as a cerebral aneurysm by computer simulation. There are still many unclear points about the causal relationship between the state of blood flow in the cerebral aneurysm and the rupture of the aneurysm. However, regarding the causal relationship, the big data database related to the cerebral aneurysm and automatic processing such as patent 5596865 It is expected to be clarified by utilizing and developing analysis technology.

However, the blood flow in the aneurysm is extremely complicated, and therefore it may be difficult for general medical practitioners who are not familiar with fluid dynamics to understand the blood flow analysis results as described above. there were.

Japanese Patent No. 5596865

The present invention has been made in view of the above-described circumstances, and an object thereof is to enable a computer to intuitively and easily understand a state quantity of blood flow in a vascular lesion, particularly a cerebral aneurysm. An apparatus, a method thereof, and a computer software program thereof are provided. *

In order to solve the above-described problem, according to a first main aspect of the present invention, a computer calculates a medical image including a target blood vessel site and a predetermined coordinate system calculated from the medical image by numerical fluid analysis. An input unit that reads a pressure field and a velocity field at each position of the target vascular site, a computer that determines a vascular lesion site from the medical image, and a computer that acquires the geometry of the acquired vascular lesion site A lesion coordinate system calculation unit that calculates a lesion coordinate system based on the scientific information, and the computer that converts the calculated pressure field and velocity field from the predetermined coordinate system to the calculated lesion coordinate system A system flow conversion unit, a lesion blood flow feature amount calculation unit for calculating a lesion blood flow feature amount based on a velocity field and a pressure field coordinate-converted into the lesion coordinate system, a computer Yuta is, blood flow visualization device is provided having an output section for outputting the lesion blood flow characteristic quantity.

Here, according to one embodiment of the present invention, when the vascular lesion site is an aneurysm, the lesion coordinate system has a point on the neck surface of the aneurysm as an origin. In this case, it is desirable that the lesion coordinate system has the center of gravity of the aneurysm neck surface of the aneurysm as the origin. Furthermore, in this case, it is desirable that the lesion coordinate system is a local coordinate system in which the center of mass of the aneurysm neck surface is the origin and the direction of aneurysm generation is the normal direction.

Further, according to another embodiment, the apparatus further includes a blood flow calculation unit for calculating the pressure field and the velocity field by the computer.

According to still another embodiment, the lesion blood flow characteristic amount includes an intra-aneurysmic inflow velocity, an intra-aneurysmic inflow flow rate, an intra-aneurysmal velocity isosurface, an intra-aneurysmal inflow and outflow velocity distribution, an intraaneurysmal streamline. , Including one or more pieces of information on the inner wall shear stress, the pressure in the aneurysm, and the energy loss in the aneurysm.

According to still another embodiment, the lesion portion determination unit determines the vascular lesion site from a three-dimensional blood vessel shape constructed from the medical image.

According to a second main aspect of the present invention, a computer uses a medical image including a target blood vessel part, and a pressure at each position of the target blood vessel part calculated from the medical image by a numerical fluid analysis in a predetermined coordinate system. An input step for reading a field and a velocity field; a lesion determination step in which a computer determines a vascular lesion site from the medical image; and a lesion coordinate based on the acquired geometric information of the vascular lesion site. A lesion coordinate system calculating step for calculating a system, a computer for converting the calculated pressure field and velocity field from the predetermined coordinate system to the calculated lesion coordinate system, and a computer, A lesion blood flow feature amount calculating step for calculating a lesion blood flow feature amount based on a velocity field and a pressure field coordinate system transformed into the lesion coordinate system; Blood flow visualization method and an output step of outputting the lesion blood flow characteristic amount is provided.

Moreover, according to a third main aspect of the present invention, there is provided a computer software program for visualizing blood flow, the following steps: a computer calculates a medical image including a target blood vessel site and a numerical value from the medical image An input step of reading a pressure field and a velocity field at each position of the target blood vessel site calculated in a predetermined coordinate system by fluid analysis; and a lesion site determination step in which a computer determines a blood vessel lesion site from the medical image; A lesion coordinate system calculating step in which a computer calculates a lesion coordinate system based on the acquired geometric information of the vascular lesion site; and the computer calculates the calculated pressure field and velocity field from the predetermined coordinate system. The coordinate system converting step for converting to the calculated lesion coordinate system, and a computer that converts the velocity field converted into the lesion coordinate system into the coordinate system; A computer software comprising: a lesion blood flow feature amount calculating step for calculating a lesion blood flow feature amount based on a force field; and a computer for executing an output step for outputting the lesion blood flow feature amount. A program is provided.

It should be noted that other features of the present invention other than those described above can be easily understood by those skilled in the art by referring to the “Description of Embodiments” and the drawings described below.

FIG. 1 is a schematic configuration diagram of a lesion blood flow feature amount visualization device 10 according to an embodiment of the present invention. FIG. 2 is a diagram showing a lesion blood flow feature amount visualization flow according to an embodiment of the present invention. 3A to 3H are diagrams for explaining processing in the blood flow calculation unit. FIG. 4 is a diagram for explaining determination of a lesioned part. FIG. 5 is a diagram for explaining the determination of the neck surface. 6A and 6B are diagrams for explaining a lesion coordinate system. FIG. 7 is a diagram illustrating coordinate system conversion. FIG. 8 is a diagram illustrating an example of a user graphical interface. FIGS. 9A and 9B are diagrams showing the velocity distribution on the ankle neck surface before and after coordinate conversion. FIG. 10 is a diagram showing a lesion blood flow feature amount visualization flow according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following, a case of a cerebral aneurysm will be described as a preferred example.

First, the concept underlying the present invention will be described. As described above, the first aspect of the present invention is a blood flow feature amount visualizing device, which is used for the state of blood flow in a vascular lesion, for example, blood flow in a cerebral aneurysm in a patient's brain. It provides an interface for the user to easily understand the status. The present invention separates and displays the flow of blood flowing in a normal blood vessel and the flow of blood flowing in a cerebral aneurysm. Velocity and pressure are used as physical values that serve as the basis for expressing this “flow”. The component of the velocity, which is a vector quantity, varies depending on the coordinate axis to be installed. The present invention uses this characteristic to separate and display the flow in the cerebral aneurysm. More specifically, the apparatus of the present invention automatically converts velocity field / pressure field information, which is a blood flow analysis result by computer simulation, into a lesion coordinate system, and automatically calculates a lesion blood flow feature amount in the lesion coordinate system. To do. In the case of a cerebral aneurysm, the lesion coordinate system is preferably a local coordinate system in which the center of gravity of the aneurysm neck surface is the origin and the aneurysm generation direction is the normal direction. For example, a cerebral aneurysm neck surface can be defined, and a cerebral aneurysm coordinate system can be set in which the top of the cerebral aneurysm is normal from the center of gravity of the neck surface.

Hereinafter, an embodiment of the present invention will be specifically described.

FIG. 1 is a schematic configuration diagram of a lesion blood flow feature amount visualization device 10 according to an embodiment of the present invention.

The lesion blood flow feature amount visualization device 10 has a program storage unit 60 and data storage units 70 and 71 connected to a bus 50 to which a CPU 11, a RAM 12 and an input / output IF 13 are connected. In the device 10, the bus 50 may be further connected to other devices and / or communication ports that store various external reference data. Further, an input device (not shown) such as a mouse, a keyboard, or a touch screen, a display (not shown), or another output device can be connected to the input / output IF 13 of the apparatus 10.

The program storage unit 60 includes an input unit 14, a blood flow calculation unit 15, a lesion part determination unit 16, a lesion coordinate system calculation unit 17, a coordinate system conversion unit 18, a lesion blood flow feature amount calculation unit 19, and a display unit 20. ing.

The data storage unit 70 stores medical images input from an input device or a communication port. The data storage unit 71 stores a velocity field / pressure field 25, a vascular lesion part 26, and a lesion feature 27.

The above configuration (input unit 14, blood flow calculation unit 15, lesion part determination unit 16, lesion coordinate system calculation unit 17, coordinate system conversion unit 18, lesion blood flow feature amount calculation unit 19, and display unit 20) Is configured by computer software stored in the storage area of the hard disk, and is configured to function as each component of the present embodiment by being called by the CPU 11 and expanded and executed on the RAM 12. It has become.

FIG. 2 is a diagram showing a lesion blood flow feature amount visualization flow of the apparatus 10 in the present embodiment. The input is a medical image. When a medical image is input, the apparatus 10 performs blood flow calculation, determines a lesion coordinate system, performs coordinate conversion, and then automatically calculates and outputs a lesion blood flow feature amount. In the following, the function of each part of the above configuration will be described together with the respective processes.

(Input section)
The input unit 14 reads a medical image or the like (step S1). In this embodiment, the input medical image is a device capable of acquiring a tomographic image of a target blood vessel site such as MRA (magnetic resonance image), CTA (X-ray computed tomography image), DSA (angiographic image), or the like. In addition, it may be obtained by various apparatuses capable of acquiring image data in a target blood vessel site, such as US (ultrasonic image), IVUS (intravascular ultrasonic image), OCT (near infrared image). The target blood vessel site may be, for example, a cerebral artery, a coronary artery, a carotid artery, an aorta, or another target blood vessel site of a subject.

The medical image is once recorded in the data storage unit 70 via the input / output IF 13 or by a communication port (not shown) or other transfer means, and then input to the blood flow calculation unit 15.

(Blood flow calculator)
The blood flow calculation unit 15 performs blood flow simulation using computational fluid dynamics (CFD) (step S2). In this embodiment, the flow of blood flow simulation adopts the generalized method shown in FIG. A specific flow will be described below.

When the blood flow calculation unit 15 acquires the medical image including the target blood vessel site, the blood flow calculation unit 15 first constructs a blood vessel shape (surface mesh) from the medical image (FIG. 3B). Next, a calculation grid (volume mesh) is generated inside (FIG. 3C). Next, blood physical properties and boundary conditions (wall surface, inlet, outlet) are set (FIG. 3D). Next, based on pre-defined calculation conditions, (1) the continuous equation and (2) the Navier-Stokes equation, which are the governing equations, are sequentially calculated to obtain the pressure field and the velocity field ( An approximate solution of the velocity field is acquired and output (FIGS. 3E to 3G). In the following steps, the flow is visualized by extracting feature values from the numerical information of the pressure field and velocity field acquired here.

The blood flow calculation unit 15 may correct the blood vessel shape constructed from the medical image and obtain approximate solutions of the blood flow pressure field and the velocity field for the corrected blood vessel shape. it can. As an example of the correction process, there is a correction for reproducing the blood vessel shape after treatment. When the correction process is performed, the post-process (steps S2 to S6) is performed on the corrected blood vessel shape.

(Lesion determination part)
The lesion site determination unit 16 determines a blood vessel lesion site using the blood vessel shape constructed from the medical image (step S2).

In the present embodiment, when the vascular lesion is a cerebral aneurysm, the blood vessel shape of the target blood vessel and its center line are analyzed, and the change rate of the blood vessel shape along the center line is within the normal range as the normal part. By determining and determining the blood vessel region that does not enter the normal part as an abnormal part, the normal part and the abnormal part are divided. The cerebral aneurysm shown here is an enlargement of a local blood vessel shape and becomes an abnormal part. That is, a cerebral aneurysm is accompanied by reversal of curvature from a parent blood vessel, and an abnormal portion (lesioned portion) is specified by tracking this curvature reversal portion. Referring to FIG. 4, when the change rate of the blood vessel shape is analyzed along the center line 1 for the blood vessel including the cerebral aneurysm A, the parent blood vessel B which is a normal blood vessel has a convex curvature, while The converted portion A has a concave curvature, and the portion of the cerebral aneurysm is determined by tracking this boundary surface.

In another embodiment, after the dividing process, the shape of the divided abnormal part may be further analyzed so that the aneurysm is determined only when the shape of the abnormal part satisfies a predetermined criterion. . This shape analysis measures geometrical features by measuring some or all of the volume, surface area, spherical shape, representative length, and vascular site where the anomaly is located, or other geometric parameters. This can be done by calculating.

On the other hand, if a vascular lesion is not identified by the above processing of the lesion determination unit 16, this apparatus displays that fact and ends the processing, and the coordinate system conversion unit 18 and lesion blood flow feature amount calculation described below are performed. Each process of the unit 19 is not performed. Alternatively, the lesion site determination unit 16 may receive an input of further information for specifying the vascular lesion site and determine the lesion site based on the further information.

The determination of the vascular lesion is performed in parallel with the subsequent calculation processing (FIGS. 3C to 3H) in the blood flow calculation unit 15 after the vascular shape shown in FIG. 3B is constructed. This is possible, but is not limited to this.

(Lesion coordinate system calculation unit)
The lesion coordinate system calculation unit 17 calculates a lesion coordinate system based on the acquired vascular lesion part information (step S3). Hereinafter, the processing of the lesion coordinate system calculation unit 17 will be described in detail.

In the present embodiment, the blood vessel lesion data acquired by the lesion determination unit 16 is based on a three-dimensional absolute coordinate system (X, Y, Z). The absolute coordinate system corresponds to an image coordinate system. That is, it is a machine coordinate system of a device capable of acquiring the image data, for example, a medical image capturing device such as a CT. In many machine coordinate systems, the Z axis is arranged in the body axis direction, and the Y axis and the X axis are set in the orthogonal direction to the front, rear, left and right. The origin of the machine coordinate system is the origin of the imaging device and is unique to the device. Therefore, the lesion coordinate system calculation unit 17 calculates a three-dimensional lesion coordinate system (X ′, Y ′, Z ′) based on the information on the vascular lesion part expressed in the absolute coordinate system.

For example, in the case of a cerebral aneurysm, as shown in FIG. 5, the lesion coordinate system calculation unit 17 first determines the neck surface N for the vascular lesion part determined by the lesion part determination unit 16, that is, the cerebral aneurysm A. This determination is automatically performed by detecting the boundary surface between the normal part and the abnormal part described above as the neck surface N.

The lesion coordinate system calculation unit 17 may further include means for allowing the user to manually set the neck surface in addition to the above automatic setting. As an example, the manual setting is performed by allowing the user to select three points including the neck surface.

Thereafter, as shown in FIGS. 6A and 6B, the center of gravity (G) of the determined neck surface N of the cerebral aneurysm A is the origin, and the direction perpendicular to the aneurysm neck surface N is Z ′. By arranging normal vectors so that the axis and the short axis direction of the neck surface are the X ′ axis, and the axis at the 90 ° position starting from the X ′ axis is the Y ′ axis, the lesion coordinate system (cerebral aneurysm) (Coordinate system) is calculated. In the present embodiment, the direction of the normal vector is the normal direction in the direction in which the aneurysm is generated. Thereby, in the cerebral aneurysm coordinate system, an inflow normal velocity, which will be described later, has a plus component, and an outflow normal velocity has a minus component. In this embodiment, the case where the center of gravity of the neck surface is used as the origin as a suitable lesion coordinate system calculation has been described. However, the present invention is not limited to this, and other positions on the neck surface are used as the origin, for example. Also good.

(Coordinate system conversion unit)
As shown in FIG. 7, the coordinate system conversion unit 18 converts the velocity field and pressure field based on the absolute coordinate system acquired by the blood flow calculation unit 15 into the lesion coordinate system calculated by the lesion coordinate system calculation unit 17. (Step S4). That is, in the case of a cerebral aneurysm, a cerebral aneurysm coordinate system corresponding to the target aneurysm is set. This cerebral aneurysm coordinate system is set in order to calculate the flow property of the target cerebral aneurysm from the viewpoint of the aneurysm in a later step.

Specifically, the coordinate system conversion unit 18 calculates a coordinate system conversion matrix and performs multiplication with the velocity field and the pressure field acquired by the blood flow calculation unit 15 to obtain a velocity field after the coordinate system conversion. , Output pressure field. The coordinate system conversion line example includes parallel movement and rotational movement. In this embodiment, the conversion from the velocity (U, V, W) in the absolute coordinate system to the velocity (U ′, V ′, W ′) in the lesion coordinate system is performed using the coordinate system conversion example M. It is expressed by a formula. U, V and W are velocity components in the respective directions of the absolute coordinate systems X, Y and Z, and U ′, V ′ and W ′ are the respective velocity components in the lesion coordinate systems X ′, Y ′ and Z ′. It is the velocity component in the direction.

(Lesion blood flow feature calculation unit)
The lesion blood flow feature amount calculation unit 19 calculates the lesion blood flow feature amount from the velocity field and pressure field based on the lesion coordinate system acquired by the coordinate system conversion unit 18 (step S5). The calculation target is determined according to the type of vascular lesion and is stored in advance in the computer. In the present embodiment, the following feature amounts are calculated in the case of a cerebral aneurysm.
(1) Inlet flow rate (2) Inlet flow rate (3) Intracranial velocity isosurface (4) Inlet flow / outflow velocity distribution (5) Inlet flow line (6) Inner wall shear stress (7 ) Pressure inside the aneurysm (8) Energy loss within the aneurysm When the inflow velocity is calculated by the velocity field and the pressure field based on the cerebral aneurysm coordinate system, that is, the lesion coordinate system, for example, The inflow component is expressed as plus and the outflow component is expressed as minus.

(Display section)
The display unit 20 generates a display screen for displaying necessary information such as the feature amount acquired by the lesion blood flow feature amount calculation unit 19 and displays it on the user interface displayed on the display (S6).

FIG. 8 shows an example of the user graphical interface 40. In the upper left 41 of FIG. 8, the velocity distribution after coordinate conversion is displayed superimposed on the three-dimensional shape of the blood vessel including the aneurysm. In addition, in the upper left 42 of FIG. 8, the velocity distribution after the coordinate system conversion on the neck surface of the aneurysm is displayed. Further, the pressure distribution, the direction of the wall shear stress, the magnitude of the wall shear stress, and the fluctuation value of the direction of the wall shear stress are respectively displayed in the lower portions 43, 44, 45, and 46 in FIG.

As described above, on the user graphical interface 40, one or more of the above-described feature quantities (1) to (8) and other information related to the target aneurysm can be collectively displayed. For example, a display format selection button may be displayed on the user interface 40 so that the user can select a desired display format, and various information is displayed on the user interface 40 according to the selected display format. To be able to.

Here, with reference to FIG. 9, the difference in velocity distribution on the ankle neck surface before and after coordinate transformation will be described. Only the magnitude of the speed before coordinate transformation (machine absolute coordinate system) can be evaluated. That is, the velocity is a vector quantity, but the component analysis of the velocity vector in the machine absolute coordinate system is not effective in analyzing the blood flow state in the aneurysm. FIG. 9 (a) shows an example of the velocity distribution (UMMagnitude [m / s]) in the machine absolute coordinate system. In FIG. 9A, both the P1 and P2 regions show larger values than the P3 region.

On the other hand, FIG. 9B shows a velocity distribution after coordinate transformation (cerebral aneurysm coordinate system), specifically, a velocity component (UZ ′ [m] in a direction Z ′ orthogonal to the neck surface and having a positive inflow direction. / S]). In FIG. 9B, the speed UZ ′ shows almost 0 in the P3 ′ region, whereas the P1 ′ region has a lower negative value (a value less than −0.1) compared to the P3 ′ region. That is, the outflow shows a higher positive value (value exceeding +0.05), that is, inflow in the P2 ′ region than in the P3 ′ region. In this way, in the cerebral aneurysm coordinate system, by analyzing the velocity vector at each position, it is possible to easily and easily identify the inflow and outflow locations in the cerebral aneurysm that could not be observed before coordinate conversion. It can be visually recognized.

According to the above, by placing the viewpoint on the vascular lesion and calculating and visualizing the lesion blood flow feature in the lesion coordinate system, the location of the inflow and outflow in the cerebral aneurysm can be specified, and the blood flow in the aneurysm can be identified. The state can be easily and intuitively understood. This will be effective in elucidating the causal relationship between aneurysm rupture and the state of blood flow. In addition, it may be a useful means in examining a treatment policy such as coil embolization, for example, what kind of coil is used or in what posture the coil is placed.

In the above embodiment, the case where the lesion blood flow characteristic amount visualization device 10 includes the blood flow calculation process 15 and the lesion part determination unit 16 and performs the calculation of the velocity field / pressure field and the determination of the lesion part has been described. However, the present invention is not limited to this. For example, in another embodiment, at least one of a velocity field / pressure field and a vascular lesion part calculated and specified by another apparatus may be input to the visualization apparatus of the present invention. For example, as shown in FIG. 10, a velocity field / pressure field obtained by blood flow analysis based on a medical image by another apparatus, a specified lesioned part or a blood vessel shape including the lesioned part, etc. Can be input. In this case, for example, when the input data is read into the input unit 14 (step S11), the lesion coordinate system calculation unit 17, the coordinate system conversion unit 18, the lesion blood flow feature amount calculation unit 19, and the display unit 20 perform each process ( Steps S12 to S15) are performed in the same manner as in the lesion blood flow feature amount visualization apparatus 10 described above. In another embodiment, a velocity field / pressure field obtained by blood flow analysis based on a medical image by another apparatus and a medical image or blood vessel shape that is the basis of the blood flow analysis can be input. . In this case, for example, when the input data is read into the input unit 14 (step S11), the lesion determination unit 16, the lesion coordinate system calculation unit 17, the coordinate system conversion unit 18, the lesion blood flow feature amount calculation unit 19, and the display unit. 20 performs each process in the same manner as the above-mentioned lesion blood flow characteristic amount visualization apparatus 10.

In the above-described embodiment, the case of an aneurysm has been described. However, the present invention is not limited to this, and the present invention can be applied to other lesions as long as the same effect is obtained.

In the above embodiment, the case has been described in which both the velocity field and the pressure field are calculated, coordinate conversion is performed, and the feature quantities (1) to (8) are calculated. However, the present invention is limited to this. The desired feature amount can be calculated as long as substantially the same operation is achieved. For example, at least one of the velocity field and the pressure field is calculated, coordinate-converted, and some desired lesion blood flow feature quantities among the lesion blood flow feature quantities (1) to (8) as described above Can be calculated.

In addition, the configuration of each part of the apparatus according to the present invention is not limited to the illustrated configuration example, and various modifications are possible as long as substantially the same operation is achieved.

Claims (21)

An input unit for reading a medical image including a target blood vessel part, and a pressure field and a velocity field at each position of the target blood vessel part calculated from the medical image by a numerical fluid analysis in a predetermined coordinate system;
A computer, a lesion site determination unit that determines a vascular lesion site from the medical image;
A lesion coordinate system calculation unit that calculates a lesion coordinate system based on the acquired geometric information of the vascular lesion site;
The computer converts the calculated pressure field and velocity field from the predetermined coordinate system to the calculated lesion coordinate system;
A lesion blood flow feature amount calculation unit that calculates a lesion blood flow feature amount based on a velocity field and a pressure field that are coordinate system transformed into the lesion coordinate system;
A blood flow visualization apparatus, comprising: an output unit that outputs the lesion blood flow characteristic amount. The blood flow visualization device according to claim 1, wherein when the vascular lesion site is an aneurysm, the lesion coordinate system has a point on the aneurysm neck surface of the aneurysm as an origin. . 3. The blood flow visualization device according to claim 2, wherein the lesion coordinate system uses the center of gravity of the aneurysm neck surface of the aneurysm as an origin. 2. The blood flow visualization device according to claim 1, wherein when the vascular lesion site is an aneurysm, the lesion coordinate system has an aneurysm neck surface center of gravity of the aneurysm as an origin and an aneurysm generation direction as a normal direction. A device characterized by a local coordinate system. 2. The blood flow visualization device according to claim 1, wherein the device further includes a blood flow calculation unit that calculates the pressure field and the velocity field. 2. The blood flow visualization device according to claim 1, wherein the lesion blood flow characteristic amount includes an intra-aneurysmic inflow velocity, an intra-aneurysmal flow rate, an intra-aneurysmal velocity isosurface, an intraluminal inflow and outflow velocity distribution, an intraluminal streamline, An apparatus comprising one or more pieces of information on an inner wall shear stress, an inner pressure, and an inner energy loss. The blood flow visualization device according to claim 1,
The lesion part determining unit determines the vascular lesion part from a three-dimensional blood vessel shape constructed from the medical image. An input process in which a computer reads a medical image including a target blood vessel part, and a pressure field and a velocity field at each position of the target blood vessel part calculated from the medical image by a numerical fluid analysis in a predetermined coordinate system;
A lesion determination step in which a computer determines a vascular lesion site from the medical image;
A lesion coordinate system calculating step in which a computer calculates a lesion coordinate system based on the acquired geometric information of the vascular lesion site;
The coordinate system converting step in which the computer converts the calculated pressure field and velocity field from the predetermined coordinate system to the calculated lesion coordinate system;
A lesion blood flow feature amount calculating step in which a computer calculates a lesion blood flow feature amount based on a velocity field and a pressure field coordinate system transformed into the lesion coordinate system;
A blood flow visualization method, comprising: an output step in which a computer outputs the lesion blood flow characteristic amount. 9. The blood flow visualization method according to claim 8, wherein when the vascular lesion site is an aneurysm, the lesion coordinate system has a point on the aneurysm neck surface of the aneurysm as an origin. . 10. The method of visualizing blood flow according to claim 9, wherein the lesion coordinate system has an origin at the center of aneurysm neck surface of the aneurysm. 9. The blood flow visualization method according to claim 8, wherein when the vascular lesion site is an aneurysm, the lesion coordinate system has an aneurysm neck surface center of gravity of the aneurysm as an origin and an aneurysm generation direction as a normal direction. A method, characterized in that it is a local coordinate system. 9. The blood flow visualization method according to claim 8, wherein the method further comprises a computer having a blood flow calculation step of calculating the pressure field and the velocity field. The blood flow visualization method according to claim 8, wherein the lesion blood flow characteristic amount includes an intra-aneurysmic inflow velocity, an intra-aneurysmic flow rate, an intra-aneurysmal velocity isosurface, an intraluminal inflow and outflow velocity distribution, an intraluminal streamline, A method comprising one or more pieces of information on an inner wall shear stress, an intra-aneurysm pressure, and an intra-aneurysm energy loss. The blood flow visualization method according to claim 8,
The method according to claim 1, wherein the lesion site determination step determines the vascular lesion site from a three-dimensional blood vessel shape constructed from the medical image. A computer software program for visualizing blood flow comprising the following steps:
An input process in which a computer reads a medical image including a target blood vessel part, and a pressure field and a velocity field at each position of the target blood vessel part calculated from the medical image by a numerical fluid analysis in a predetermined coordinate system;
A lesion determination step in which a computer determines a vascular lesion site from the medical image;
A lesion coordinate system calculating step in which a computer calculates a lesion coordinate system based on the acquired geometric information of the vascular lesion site;
The coordinate system converting step in which the computer converts the calculated pressure field and velocity field from the predetermined coordinate system to the calculated lesion coordinate system;
A lesion blood flow feature amount calculating step in which a computer calculates a lesion blood flow feature amount based on a velocity field and a pressure field coordinate system transformed into the lesion coordinate system;
A computer software program comprising: an instruction for causing a computer to execute the output step of outputting the lesion blood flow characteristic amount. 16. The computer software program according to claim 15, wherein when the vascular lesion site is an aneurysm, the lesion coordinate system has a point on the aneurysm neck surface of the aneurysm as an origin. program. 17. The computer software program according to claim 16, wherein the lesion coordinate system has an origin at the center of gravity of the aneurysm neck surface of the aneurysm. 16. The computer software program according to claim 15, wherein when the vascular lesion site is an aneurysm, the lesion coordinate system is a local region having the aneurysm neck surface center of gravity of the aneurysm as an origin and the aneurysm generation direction as a normal direction. A computer software program, characterized in that it is a coordinate system. 16. The computer software program according to claim 15, further comprising a blood flow calculation step of calculating the pressure field and the velocity field. 16. The computer software program according to claim 15, wherein the lesion blood flow characteristic amount includes an intra-aneurysmic inflow velocity, an intra-aneurysmic flow rate, an intra-aneurysmic velocity isosurface, an intra-aneurysal inflow and outflow velocity distribution, an intra-aneurysmal streamline, an aneurysm. A computer software program characterized by including one or more pieces of information on inner wall shear stress, pressure in the aneurysm, and energy loss in the aneurysm. The computer software program according to claim 15, wherein
A computer software program characterized in that the lesion site determination step determines the vascular lesion site from a three-dimensional blood vessel shape constructed from the medical image.

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