Medical image processing device and x-ray diagnostic device

Abstract

To quantitatively measure a blood flow during INOCA examination without using a sensor wire.SOLUTION: A medical image processing device according to an embodiment includes an acquisition unit, a first calculation unit, a second calculation unit, and a display control unit. The acquisition unit acquires a 0-th contrast image in a case where a heart with non-obstructive coronary artery disease is in a reference state, a first contrast image in a case where the heart is in an acetylcholine loading state, and a second contrast image in a case where the heart is in an adenosine loading state. The first calculation unit calculates a first blood flow ratio representing a ratio between a 0-th blood flow amount of a myocardium in the reference state and a first blood flow amount of the myocardium in the acetylcholine loading state on the basis of the 0-th contrast image and the first contrast image. The second calculation unit calculates a second blood flow ratio representing a ratio between the 0-th blood flow amount and a second blood flow amount of the myocardium in the adenosine loading state on the basis of the 0-th contrast image and the second contrast image. The display control unit causes the first blood flow ratio and the second blood flow ratio to be displayed side by side on a display.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments disclosed in this specification and the drawings relate to a medical image processing apparatus and an X-ray diagnostic apparatus. [Background technology]

[0002] In the field of cardiovascular ischemia, there has been a growing trend to address ischemia with no obstructive coronary artery disease (INOCA), a condition characterized by functional abnormalities such as poor myocardial blood flow despite the absence of structural abnormalities such as blockage or stenosis in the cardiac blood vessels. INOCA is primarily caused by two factors: microvascular spasm and microvascular failure. Correctly distinguishing between these two causes is expected to lead to appropriate treatment. Because noninvasive tests such as magnetic resonance imaging (MRI), positron emission tomography (PET), and transthoracic echocardiography have low sensitivity, invasive tests using sensor wires to assess microcirculatory resistance (IMR) and coronary flow reserve (CFR), or lactate levels, have become the gold standard for identifying the cause.

[0003] In addition, invasive testing involves a first test for one of the two main causes, vasospastic angina, and a second test for the other, microvascular angina. These two types of invasive testing correctly distinguish the cause of INOCA. The order of the first and second tests may be reversed depending on the country, and is not limited to this order.

[0004] First, in the first test, an acetylcholine challenge test is performed as a coronary spasm provocation test for vasospastic angina, and whether or not it is positive is determined based on symptoms, electrocardiogram changes, and lactate levels. If the first test is positive, treatment for vasospastic angina, which is one of the causes, is initiated.

[0005] If the first test is negative, a second test for the other cause is performed. In the second test, an adenosine stress test for microvascular angina is performed, and the result is determined based on the CFR and IMR. If the second test is positive, treatment for the other cause, microvascular angina, is performed.

[0006] However, according to the inventor's research, there is room for improvement in such invasive tests. For example, the first test monitors symptoms, electrocardiogram changes, and lactate levels, but does not quantitatively measure blood flow, which indicates the actual degree of ischemia. Furthermore, the second test requires the use of a sensor wire, which is time-consuming and costly, cannot evaluate all branches of the coronary arteries, and involves the risk of inserting the sensor wire.

[0007] Therefore, it is desirable to quantitatively measure blood flow without using a sensor wire during an INOCA examination. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-106990 Summary of the Invention [Problem to be solved by the invention]

[0009] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to quantitatively measure blood flow during an INOCA examination without using a sensor wire. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of each configuration shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0010] A medical image processing apparatus according to an embodiment includes an acquisition unit, a first calculation unit, a second calculation unit, and a display control unit. The acquisition unit acquires a zeroth contrast-enhanced image of a subject's heart with non-obstructive coronary artery disease when the heart is in a reference state, a first contrast-enhanced image of the heart when the heart is in an acetylcholine-stressed state, and a second contrast-enhanced image of the heart when the heart is in an adenosine-stressed state. The first calculation unit calculates a first blood flow ratio representing the ratio of a zeroth myocardial blood flow volume in the reference state to a first myocardial blood flow volume in the acetylcholine-stressed state based on the zeroth contrast-enhanced image and the first contrast-enhanced image. The second calculation unit calculates a second blood flow ratio representing the ratio of the zeroth blood flow volume to a second myocardial blood flow volume in the adenosine-stressed state based on the zeroth contrast-enhanced image and the second contrast-enhanced image. The display control unit displays the first blood flow ratio and the second blood flow ratio side by side on a display. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing an example of a medical image processing apparatus according to the first embodiment and its peripheral configuration. [Figure 2] FIG. 2 is a flowchart illustrating the operation in the first embodiment. [Figure 3] FIG. 3 is a diagram showing an example of a contrast image in the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a display example in the first embodiment. [Figure 5] FIG. 5 is a schematic diagram for explaining a display example of a ratio image in the second embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining a display example of a ratio image in a modified example of the second embodiment. [Figure 7] FIG. 7 is a schematic diagram showing an example of a graph display in the third embodiment. [Figure 8] FIG. 8 is a schematic diagram showing an example of a graph display in the fourth embodiment. [Figure 9] FIG. 9 is a schematic diagram showing an example of a graph display in a modified example of the fourth embodiment. [Figure 10] FIG. 10 is a schematic diagram showing an example of a graph display in a modified example of the fourth embodiment. [Figure 11] FIG. 11 is a schematic diagram showing an example of a graph display in a modified example of the fourth embodiment. [Figure 12] FIG. 12 is a schematic diagram showing an example of a graph display in a modified example of the fourth embodiment. [Figure 13] FIG. 13 is a block diagram showing an example of a medical image processing apparatus and its peripheral configuration according to the fifth embodiment. [Figure 14] FIG. 14 is a flowchart for explaining the operation in the fifth embodiment. [Figure 15] FIG. 15 is a schematic diagram showing a display example in the sixth embodiment. [Figure 16] FIG. 16 is a block diagram showing an example of the configuration of an X-ray diagnostic apparatus according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a medical image processing apparatus and an X-ray diagnostic apparatus according to each embodiment will be described with reference to the drawings. In the following description, components having substantially the same functions and configurations are designated by the same reference numerals, and redundant description will be omitted. In the following description, content that is not necessarily required for understanding the measurement or display of the blood flow ratio will be omitted as appropriate.

[0013] First Embodiment FIG. 1 is a block diagram showing an example of a medical image processing apparatus and its peripheral configuration according to the first embodiment. An X-ray diagnostic apparatus 10, an image storage apparatus 20, and a medical image processing apparatus 30 are connected to each other via a network, whether wireless or wired, so that they can communicate with each other. The network is, for example, a LAN (Local Area Network). Note that the connection line is not limited to a LAN as long as security is ensured by a VPN (Virtual Private Network) or the like. In this case, the network may be, for example, a public communication line such as the Internet.

[0014] The X-ray diagnostic apparatus 10 collects projection image data of a subject by performing X-ray imaging on the subject. The X-ray diagnostic apparatus 10 also collects contrast image data of the subject's cardiac region by performing X-ray imaging on the subject after a contrast agent has been injected into the cardiac region. Each of the projection image and contrast image data is accompanied by X-ray imaging conditions. The X-ray imaging conditions include, for example, the region to be imaged, tube voltage, tube current, irradiation time, the product of the tube current (mA) and the irradiation time (s) (hereinafter referred to as the tube current-time product (mAs)), the subject's position (posture) during X-ray imaging, and the injection amount and injection rate of the contrast agent. The scan conditions and X-ray imaging conditions correspond to imaging conditions. The volume data, contrast image data, and projection image data correspond to medical image data. The position refers to the subject's position during imaging. For example, the body position in the scan conditions is supine position, both arms raised, supine position, lateral position, prone position, etc. Furthermore, the body position in the X-ray imaging conditions is supine position, lateral position, both arms hanging down, etc. Note that the body position of the subject does not have to be included in the imaging conditions.

[0015] The image storage device 20 is a device that stores medical image data collected by the X-ray diagnostic device 10. The image storage device 20 acquires medical image data from the X-ray diagnostic device 10 via a network, and stores the acquired contrast image data in a memory provided inside or outside the device. For example, the image storage device 20 is realized by a computer device such as a server device.

[0016] The medical image processing device 30 acquires medical image data from the X-ray diagnostic device 10 or the image storage device 20 via a network, and performs various processes using the acquired medical image data. The medical image processing device 30 is realized by, for example, a computer device such as a workstation. Note that the X-ray diagnostic device 10, the image storage device 20, and the medical image processing device 30 may be installed in any location as long as they can be connected via a network. For example, the medical image processing device 30 may be installed in a facility, hospital, or the like different from the X-ray diagnostic device 10. Furthermore, the medical image processing device 30 may be mounted on the X-ray diagnostic device 10.

[0017] The medical image processing device 30 includes an input interface 31, a display 32, a memory 33, and a processing circuit .

[0018] The input interface 31 accepts various input operations from an operator, converts the accepted input operations into electrical signals, and outputs the converted electrical signals to the processing circuitry 34. For example, the input interface 31 may be implemented by a mouse, keyboard, trackball, switch, button, joystick, a touchpad that performs input operations by touching the operation surface, a touchscreen that integrates a display screen and a touchpad, a non-contact input circuit using an optical sensor, a voice input circuit, or the like. The input interface 31 may also be configured by a tablet terminal or the like that is capable of wireless communication with the medical image processing device 30. The input interface 31 is not limited to those that have physical operation components such as a mouse and keyboard. For example, an electrical signal processing circuit that receives electrical signals corresponding to input operations from an external input device provided separately from the medical image processing device 30 and outputs the electrical signals to the processing circuitry 34 is also included as an example of the input interface 31. The input interface 31 is an example of an input unit.

[0019] The display 32 is composed of a display main body that displays various information such as medical images, an internal circuit that supplies display signals to the display main body, and peripheral circuits such as connectors and cables that connect the display main body to the internal circuit. The internal circuit generates display data by superimposing additional information such as subject information and projection data generation conditions on image data supplied from the processing circuitry 34, and performs D / A conversion and TV format conversion on the obtained display data to display it on the display main body. For example, the display 32 outputs medical images acquired or generated by the processing circuitry 34, a GUI (Graphical User Interface) for accepting various operations from an operator, and the like. For example, the display 32 is a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 32 is an example of a display unit. The display 32 may be a desktop type or may be configured as a tablet terminal or the like that is capable of wireless communication with the medical image processing device 30 main body. The display 32 is an example of a display unit.

[0020] The memory 33 is a storage device such as a ROM (Read Only Memory), RAM (Random Access Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or integrated circuit storage device that stores various information. The memory 33 may also be a drive device that reads and writes various information from and to a portable storage medium such as a CD-ROM drive, a DVD drive, or a flash memory. The memory 33 does not necessarily have to be realized by a single storage device. For example, the memory 33 may be realized by multiple storage devices. The memory 33 may also be located in another computer connected to the medical image processing apparatus 30 via a network.

[0021] The memory 33 stores medical image data acquired from the X-ray diagnostic apparatus 10 or the image storage device 20. Examples of medical image data include a zeroth contrast-enhanced image of a subject with non-occlusive coronary artery disease when the heart is in a baseline state, a first contrast-enhanced image of the heart when the heart is in an acetylcholine-stimulated state, and a second contrast-enhanced image of the heart when the heart is in an adenosine-stimulated state. The zeroth contrast-enhanced image, the first contrast-enhanced image, and the second contrast-enhanced image are medical images captured under substantially identical imaging conditions, except for the state of the heart. The memory 33 also stores various data before, during, and after processing by the various functions of the processing circuitry 34. Examples of the various data include index data such as blood flow rate and blood flow ratio, and image data such as ratio images based on the index data. The memory 33 also stores programs for implementing the various functions of the processing circuitry 34 in a computer. These programs may be stored in the memory 33 in advance. Also, for example, this program may be stored in a non-transitory computer-readable storage medium and distributed, and may be read from the non-transitory computer-readable storage medium and installed in memory 33. Memory 33 is an example of a storage unit.

[0022] The processing circuitry 34 controls the overall operation of the medical image processing apparatus 30 in response to electrical signals of input operations output from the input interface 31. For example, the processing circuitry 34 includes, as hardware resources, a processor such as a CPU, MPU, or GPU (Graphics Processing Unit), and memories such as ROM and RAM. The processing circuitry 34 is a processor that calls and executes programs stored in the memory 33, thereby realizing an acquisition function 34a, a setting function 34b, a calculation function 34c, a ratio image generation function 34d, and a display control function 34e corresponding to the programs. Note that, in FIG. 1, the acquisition function 34a, the setting function 34b, the calculation function 34c, the ratio image generation function 34d, and the display control function 34e are described as being realized by a single processing circuit 34. However, the processing circuit may be configured by combining multiple independent processors, and each processor may execute a program to realize each function. The acquisition function 34a, setting function 34b, calculation function 34c, ratio image generation function 34d, and display control function 34e may be called an acquisition circuit, setting circuit, calculation circuit, ratio image generation circuit, and display control circuit, respectively, and may be implemented as individual hardware circuits. The various functions in the processing circuit 34 may be incorporated into the processing circuit of the X-ray diagnostic apparatus 10, for example. In this case, the medical image processing apparatus 30 is configured to be built into the X-ray diagnostic apparatus 10.

[0023] The acquisition function 34a acquires a zeroth contrast image when the heart of a subject with non-occlusive coronary artery disease is in a reference state, a first contrast image when the heart is in an acetylcholine-stressed state, and a second contrast image when the heart is in an adenosine-stressed state. Here, the reference state is a reference state when calculating the blood flow ratio, specifically, a state in which no drug that constricts or dilates cardiac blood vessels is administered. Therefore, the reference state may be interpreted as other terms such as a normal state, a standard state, or an unstressed state. The acetylcholine-stressed state is a state in which a drug (acetylcholine) that constricts cardiac blood vessels is administered. The adenosine-stressed state is a state in which a drug (adenosine) that dilates cardiac blood vessels is administered. The acquisition destination of each contrast image by the acquisition function 34a is, for example, the image storage device 20. The acquisition function 34a also stores each acquired contrast image in the memory 33. The acquisition function 34a is an example of an acquisition unit.

[0024] The setting function 34b sets a region of interest common to the 0th contrast image, the first contrast image, and the second contrast image. For example, the setting function 34b may manually set a region of interest in one of the 0th to 2nd contrast images and automatically set a region of interest in the remaining two contrast images. Specifically, the setting function 34b may set a region of interest in the 0th contrast image in response to an operation by an operator, and may set the region of interest at the same position in the first contrast image and the second contrast image in conjunction with the position of the region of interest in the 0th contrast image. The setting function 34b is an example of a setting unit.

[0025] The calculation function 34c calculates a first blood flow ratio representing the ratio between the zeroth myocardial blood flow rate in the baseline state and the first myocardial blood flow rate in the acetylcholine-stressed state based on the zeroth contrast-enhanced image and the first contrast-enhanced image. For example, the calculation function 34c may calculate the first blood flow ratio in each region of interest in the zeroth contrast-enhanced image and the first contrast-enhanced image. The first blood flow ratio in the region of interest may be calculated as, for example, the maximum or average absolute value of the blood flow ratio for each pixel in the region of interest. Alternatively, for example, the calculation function 34c may calculate the first blood flow ratio for each corresponding pixel in the zeroth contrast-enhanced image and the first contrast-enhanced image. Alternatively, for example, the calculation function 34c may calculate the first blood flow ratio by dividing the pixel values ​​of corresponding pixels in the myocardial region of the zeroth contrast-enhanced image and the myocardial region of the first contrast-enhanced image.

[0026] Furthermore, the calculation function 34c calculates a second blood flow ratio representing the ratio between the zeroth blood flow rate and a second blood flow rate in the myocardium under adenosine stress based on the zeroth contrast-enhanced image and the second contrast-enhanced image. For example, the calculation function 34c may calculate the second blood flow ratio in each region of interest in the zeroth contrast-enhanced image and the second contrast-enhanced image. The second blood flow ratio in the region of interest may be calculated as, for example, the maximum or average absolute value of the blood flow ratio for each pixel in the region of interest. For example, the calculation function 34c may calculate the second blood flow ratio for each corresponding pixel in the zeroth contrast-enhanced image and the second contrast-enhanced image. For example, the calculation function 34c may calculate the second blood flow ratio by dividing the pixel values ​​of corresponding pixels in the myocardial region of the zeroth contrast-enhanced image and the myocardial region of the second contrast-enhanced image. The calculation function 34c is an example of a first calculator and a second calculator.

[0027] The ratio image generating function 34d generates a first ratio image having pixel values ​​corresponding to the first blood flow ratio calculated for each pixel, and a second ratio image having pixel values ​​corresponding to the second blood flow ratio calculated for each pixel. The ratio image generating function 34d is an example of a ratio image generating unit.

[0028] The display control function 34e controls the display to display a desired screen. For example, the display control function 34e displays the first blood flow ratio and the second blood flow ratio side by side on the display 32. Furthermore, for example, the display control function 34e may display the first blood flow ratio and the second blood flow ratio on the display 32 in at least one of a numerical format and an image format. For example, in the case of a numerical format, the display control function 34e may display the first blood flow ratio in a first display mode when the first blood flow ratio in the region of interest is equal to or less than a first threshold, and may display the second blood flow ratio in a second display mode when the second blood flow ratio in the region of interest is equal to or less than a second threshold. Here, the first display mode may be, for example, a mode in which a color display or an alert display is displayed indicating an abnormality in the first blood flow ratio. The second display mode may be, for example, a mode in which a color display or an alert display is displayed indicating an abnormality in the second blood flow ratio. Furthermore, in the case of an image format, the display control function 34e may display the first ratio image and the second ratio image in color on the display 32 by assigning colors to pixel values. The display control function 34e may further display at least the first blood flow rate and the second blood flow rate, among the zeroth blood flow rate, the first blood flow rate, and the second blood flow rate, side by side on the display 32. The display control function 34e is an example of a display control unit.

[0029] Next, the operation of the medical image processing apparatus configured as described above will be described with reference to the flowchart in Fig. 2 and the schematic diagrams in Fig. 3 and Fig. 4. It is assumed that the image storage device 20 stores a 0th contrast image, a 1st contrast image, and a 2nd contrast image acquired in advance by the X-ray diagnostic apparatus 10. The 0th contrast image is an X-ray image of the heart of a subject with non-obstructive coronary artery disease in a reference state. The 1st contrast image is an X-ray image of the heart in an acetylcholine-stimulated state. The 2nd contrast image is an X-ray image of the heart in an adenosine-stimulated state.

[0030] (Step ST10) As shown in Fig. 2, processing circuitry 34 of medical image processing device 30 acquires the zeroth contrast image, the first contrast image, and the second contrast image of the subject from image storage device 20 in response to an operation by an operator, and stores each contrast image in memory 33. As shown in Fig. 3, the zeroth contrast image g0 is a moving image having multiple frames in chronological order, and depicts the flow of contrast agent injected from a catheter into the myocardial region via the coronary arteries and capillaries in chronological order. The same is true for the first and second contrast images.

[0031] (Step ST20) In response to the operator's operation, processing circuitry 34 displays a 0th contrast image g0, a first contrast image g1, and a second contrast image g2 on display 32 as shown in the upper part of FIG. 4 . In response to the operator's operation, processing circuitry 34 also sets a region of interest (ROI) common to the 0th contrast image g0, the first contrast image g1, and the second contrast image g2. For example, in response to the operation of cursor cs, processing circuitry 34 sets an artery ROI 201 in a portion of the coronary artery in 0th contrast image g0, and sets a myocardial ROI 202 in a portion of the myocardial region of 0th contrast image g0. In response to the position of artery ROI 201 in 0th contrast image g0, processing circuitry 34 also sets artery ROI 201 at the same position in first contrast image g1 and second contrast image g2. Similarly, the processing circuitry 34 sets the myocardial ROI 202 at the same position in each of the first contrast image g1 and the second contrast image g2 in conjunction with the position of the myocardial ROI 202 in the 0th contrast image g0.

[0032] (Step ST30) Based on the 0th contrast image g0 and the first contrast image g1, the processing circuitry 34 calculates a first blood flow ratio representing the ratio between the 0th myocardial blood flow rate in the reference state and the 1st myocardial blood flow rate in the acetylcholine-stressed state. For example, the processing circuitry 34 calculates the first blood flow ratio in the myocardial ROI 202 of each of the 0th contrast image g0 and the first contrast image g1. The 1st myocardial blood flow ratio may be obtained by calculating the 0th blood flow rate and the 1st blood flow rate, respectively, and dividing the 1st blood flow rate by the 0th blood flow rate.

[0033] For example, let La be the thickness of the blood vessels of the subject along the X-ray path, Lm be the thickness of the myocardium of the subject along the X-ray path, Im(t) be the brightness of the myocardium in the 0th contrast image g0 at time t after the start of contrast agent injection, and Ia(τ) be the brightness of the blood vessels in the 0th contrast image g0 at time τ (0≦τ≦t). At this time, processing circuitry 34 calculates the 0th myocardial blood flow rate K1 in the reference state based on equation (1).

[0034]

number

[0035] Similarly, let Im(t)ACh be the luminance of the myocardium in the first contrast image g1 at time t, and let Ia(τ) be the luminance of the blood vessel in the first contrast image g1 at time τ. Then, the processing circuitry 34 calculates the first blood flow rate K1_ACh of the myocardium in the acetylcholine stress state based on equation (2).

[0036]

number

[0037] Thereafter, the processing circuitry 34 divides the calculated first blood flow rate K1_ACh by the calculated 0th blood flow rate K1 to calculate the first myocardial blood flow ratio (K1_ACh / K1).

[0038] Similarly, let Im(t)ATP be the brightness of the myocardium in the second contrast image g2 at time t, and let Ia(τ) be the brightness of the blood vessel in the second contrast image g2 at time τ. The processing circuitry 34 calculates the second myocardial blood flow rate K1_ATP in the adenosine stress state based on equation (3).

[0039]

number

[0040] Thereafter, the processing circuitry 34 divides the calculated second blood flow rate K1_ATP by the calculated 0th blood flow rate K1 to calculate a second myocardial blood flow ratio (K1_ATP / K1).

[0041] (Step ST40) The processing circuitry 34 generates a first ratio image r1 having pixel values ​​corresponding to the first blood flow ratio (K1_ACh / K1) calculated for each pixel, and a second ratio image r2 having pixel values ​​corresponding to the second blood flow ratio (K1_ATP / K1) calculated for each pixel. The processing circuitry 34 also generates a 0th blood flow image f0 having pixel values ​​corresponding to the 0th blood flow K1 calculated for each pixel. Similarly, the processing circuitry 34 generates a first blood flow image f1 having pixel values ​​corresponding to the first blood flow K1_ACh calculated for each pixel, and a second blood flow image f2 having pixel values ​​corresponding to the second blood flow K2_ATP calculated for each pixel.

[0042] (Step ST50) As shown in the second row of FIG. 4, the processing circuit 34 displays the zeroth blood flow image f0, the first blood flow image f1, and the second blood flow image f2 side by side on the display 32. Furthermore, as shown in the third row of FIG. 4, the processing circuit 34 displays the first ratio image r1 and the second ratio image r2 side by side on the display 32. The first ratio image r1 and the second ratio image r2 are examples of displaying the first blood flow ratio and the second blood flow ratio in the form of an image. The first ratio image r1 includes a vasospasm region A1 with a relatively low first blood flow ratio within the image. The second ratio image r2 includes a vasodilatation region A2 with a relatively high second blood flow ratio within the image. The zeroth blood flow image f0, the first blood flow image f1, the second blood flow image f2, the first ratio image r1, and the second ratio image r2 are displayed in color by assigning a color to each pixel according to its pixel value.

[0043] 4, the processing circuit 34 causes the display 32 to display the zeroth blood flow rate K1 (e.g., 3.0), the first blood flow rate K1_ACh (e.g., 2.4), and the second blood flow rate K1_ATP (e.g., 3.9) side by side as values ​​in the myocardial ROI 202. Similarly, the processing circuit 34 causes the display 32 to display the zeroth blood flow ratio (1.0), the first blood flow ratio (e.g., 0.8 times (=2.4 / 3.0)), and the second blood flow ratio (e.g., 1.3 times (=3.9 / 3.0)) side by side as values ​​in the myocardial ROI 202.

[0044] In addition, under acetylcholine loading, no change is normal and a change (decreased blood flow) is abnormal. Under adenosine loading, no change is abnormal and a change (increased blood flow) is normal.

[0045] To add, in an acetylcholine challenge test, a normal state is when the first blood flow rate K1_ACh remains unchanged from the zeroth blood flow rate K1, and a decrease in the first blood flow rate K1_ACh indicates a disease. Specifically, in an acetylcholine challenge test, a normal state is when the first blood flow ratio exceeds a first threshold (e.g., 0.5 times), and a decrease in the first blood flow ratio below the first threshold indicates a disease. The disease detected by an acetylcholine challenge test corresponds to microvascular spasm, one of the causes of INOCA.

[0046] Furthermore, in an adenosine stress test, if the second blood flow rate K1_ATP remains unchanged from the zero blood flow rate K1, it indicates a disease, and if the second blood flow rate K1_ATP increases, it indicates a normal state. Specifically, in an adenosine stress test, if the second blood flow ratio is below the second threshold (e.g., 1.8 times), it indicates a disease, and if the second blood flow ratio increases beyond the second threshold, it indicates a normal state. Diseases detected by an adenosine stress test correspond to the inability of microvasculature to dilate, one of the causes of INOCA.

[0047] In FIG. 4, the hatching around the second blood flow ratio "1.3 times" is an example of an alert display indicating an abnormality when the second blood flow ratio in the myocardial ROI 202 is equal to or less than the second threshold (1.8 times).

[0048] Therefore, as shown in an example in Figure 4, the operator can check the blood flow and blood flow ratio for each of the subject's baseline state, acetylcholine-stimulated state, and adenosine-stimulated state, along with each contrast image g0 to g2, each blood flow image f0 to f2, and each ratio image r1, r2.

[0049] As described above, according to the first embodiment, processing circuitry 34 acquires a zeroth contrast image g0 when the heart of a subject with non-occlusive coronary artery disease is in a baseline state, a first contrast image g1 when the heart is in an acetylcholine-stressed state, and a second contrast image g2 when the heart is in an adenosine-stressed state. Based on the zeroth contrast image g0 and the first contrast image g1, processing circuitry 34 calculates a first blood flow ratio representing the ratio of the zeroth myocardial blood flow volume K1 in the baseline state to the first myocardial blood flow volume K1_ACh in the acetylcholine-stressed state. Based on the zeroth contrast image g0 and the second contrast image g2, processing circuitry 34 calculates a second blood flow ratio representing the ratio of the zeroth blood flow volume K1 to the second myocardial blood flow volume K1_ATP in the adenosine-stressed state. Processing circuitry 34 displays the first blood flow ratio and the second blood flow ratio side by side on display 32. In this way, by using a configuration that calculates the blood flow ratio from a contrast image, blood flow can be quantitatively measured from a contrast image during an INOCA examination without using a sensor wire, and measurement results such as blood flow volume and blood flow ratio can be displayed.

[0050] Furthermore, according to the first embodiment, the processing circuitry 34 displays the first blood flow ratio and the second blood flow ratio in the form of at least one of a numerical value and an image on the display 32. Therefore, in addition to the above-mentioned effects, the blood flow ratios can be displayed in a desired format.

[0051] Furthermore, according to the first embodiment, processing circuitry 34 sets artery ROI 201 and myocardial ROI 202 as regions of interest common to 0th contrast image g0, 1st contrast image g1, and 2nd contrast image g2. Processing circuitry 34 calculates a first blood flow ratio in myocardial ROI 202 in each of 0th contrast image g0 and 1st contrast image g1. Processing circuitry 34 calculates a second blood flow ratio in myocardial ROI 202 in each of 0th contrast image g0 and 2nd contrast image g2. In the case of a numerical format, processing circuitry 34 displays the first blood flow ratio in a first display mode when the first blood flow ratio in myocardial ROI 202 is equal to or less than a first threshold. Similarly, processing circuitry 34 displays the second blood flow ratio in a second display mode when the second blood flow ratio in myocardial ROI 202 is equal to or less than a second threshold. Therefore, in addition to the above-mentioned effects, when the first blood flow ratio and the second blood flow ratio are each equal to or less than the threshold, the display in the first display mode and the second display mode can attract the operator's attention.

[0052] Furthermore, according to the first embodiment, the first display mode is a mode in which a color display or an alert display is performed to indicate an abnormality in the first blood flow ratio. The second display mode is a mode in which a color display or an alert display is performed to indicate an abnormality in the second blood flow ratio. Therefore, in addition to the effects described above, the color display or the alert display can further attract the operator's attention.

[0053] Furthermore, according to the first embodiment, the processing circuitry 34 calculates a first blood flow ratio for each corresponding pixel in the 0th contrast image g0 and the first contrast image g1. The processing circuitry 34 calculates a second blood flow ratio for each corresponding pixel in the 0th contrast image g0 and the second contrast image g2. The processing circuitry 34 generates a first ratio image r1 having pixel values ​​corresponding to the first blood flow ratio calculated for each pixel, and a second ratio image r2 having pixel values ​​corresponding to the second blood flow ratio calculated for each pixel. In the case of an image format, the processing circuitry 34 assigns colors to the pixel values ​​to display the first ratio image and the second ratio image in color on the display 32. Therefore, in addition to the effects described above, the configuration that displays the blood flow ratio for each pixel in color makes it possible to visually and easily present to the operator the distribution of blood flow ratios in non-occlusive coronary artery disease.

[0054] Furthermore, according to the first embodiment, the processing circuit 34 further displays at least the first blood flow rate K1_ACh and the second blood flow rate K1_ATP among the zeroth blood flow rate K1, the first blood flow rate K1_ACh, and the second blood flow rate K1_ATP side by side on the display 32. In this case, in addition to the above-mentioned effects, the operator can visually recognize the first blood flow rate K1_ACh and the second blood flow rate K1_ATP of the myocardium.

[0055] Furthermore, according to the first embodiment, the 0th contrast image g0, the first contrast image g1, and the second contrast image g2 are medical images captured under substantially the same imaging conditions except for the state of the heart. Therefore, in addition to the above-mentioned effects, when measuring the blood flow ratio from multiple contrast images, the influence of changes in imaging conditions between the contrast images can be suppressed.

[0056] (Modification of the first embodiment) In the first embodiment, the first blood flow ratio is calculated by calculating the zeroth blood flow rate K1 and the first blood flow rate K1_ACh, but this is not limiting. For example, the processing circuitry 34 may not calculate the zeroth blood flow rate K1 and the first blood flow rate K1_ACh, but may instead obtain the first myocardial blood flow ratio (K1_ACh / K1) as the brightness ratio (Im(t)ACh / Im(t)) between the first contrast-enhanced image and the zeroth contrast-enhanced image, as shown in Equation (4). Specifically, the processing circuitry 34 may calculate the first blood flow ratio by dividing the pixel values ​​of corresponding pixels in the myocardial region of the zeroth contrast-enhanced image g0 and the myocardial region of the first contrast-enhanced image g1.

[0057]

number

[0058] In this case, in addition to the effect of the first embodiment, the load and time required to calculate the zeroth blood flow rate K1 and the first blood flow rate K1_ACh can be reduced.

[0059] Similarly, in the first embodiment, the second blood flow ratio is calculated by calculating the zeroth blood flow rate K1 and the second blood flow rate K1_ATP, but this is not limiting. For example, the processing circuitry 34 may not calculate the zeroth blood flow rate K1 and the second blood flow rate K1_ATP, but may instead obtain the second myocardial blood flow ratio (K1_ATP / K1) as the brightness ratio (Im(t)ATP / Im(t)) between the second contrast image and the zeroth contrast image, as shown in equation (5). Specifically, the processing circuitry 34 may calculate the second blood flow ratio by dividing the pixel values ​​of corresponding pixels in the myocardial region of the zeroth contrast image g0 and the myocardial region of the second contrast image g2.

[0060]

number

[0061] In this case, in addition to the effect of the first embodiment, the load and time required to calculate the zeroth blood flow rate K1 and the second blood flow rate K1_ATP can be reduced.

[0062] In the first embodiment, the first blood flow ratio and the second blood flow ratio relative to the zeroth blood flow rate in the reference state are calculated, but this is not limiting. For example, the calculation function 34c of the processing circuitry 34 may calculate the third blood flow ratio (K1_ATP / K1_ACh) by dividing the pixel values ​​of corresponding pixels in the myocardial region of the first contrast image g1 and the myocardial region of the second contrast image g2. For example, the processing circuitry 34 may calculate the third blood flow ratio as the brightness ratio (Im(t)ATP / Im(t)ACh) between the second contrast image g2 and the first contrast image g1, as shown in Equation (6). Alternatively, the processing circuitry 34 may calculate the third blood flow ratio as the ratio between the second blood flow rate K1_ATP in Equation (3) and the first blood flow rate K1_ACh in Equation (2), as shown in Equation (6). When calculating the third blood flow ratio, the first blood flow ratio and the second blood flow ratio may be omitted, or may be calculated in the same manner as described above. The calculation function 34c is an example of a third calculation unit. The processing circuitry 34 also causes the display 32 to display the third blood flow ratio.

[0063]

number

[0064] According to this modification, in addition to the effects of the first embodiment, it is possible to measure the blood flow ratio without using data from the 0th contrast image g0 in the reference state. Note that reducing the amount of data used eliminates the need for alignment and various linearization processes, enabling faster and more stable processing.

[0065] In the first embodiment, both the first blood flow image f1 and the second blood flow image f2 and the first ratio image r1 and the second ratio image r2 are displayed. However, this is not limiting. For example, the processing circuitry 34 may omit displaying the first ratio image r1 and the second ratio image r2. Alternatively, the processing circuitry 34 may omit displaying the first blood flow image f1 and the second blood flow image f2. Furthermore, whether or not to display the contrast image, the blood flow image, and the ratio image may be appropriately selected depending on the operator's operation. In this modification, the same effect as in the first embodiment can be obtained while simplifying the display. Furthermore, this modification can also be applied to a configuration in which blood flow is displayed instead of the blood flow ratio while only the blood flow ratio is displayed. Therefore, it can be similarly applied to other embodiments related to the display range of the ratio image and the graphical display of the blood flow ratio.

[0066] <Second embodiment> The second embodiment differs from the first embodiment in that the display ranges of the first ratio image r1 and the second ratio image r2 are not aligned, in that the display ranges of the first ratio image r1 and the second ratio image r2 are aligned.

[0067] Accordingly, in addition to the above-described functions, the display control function 34e of the processing circuit 34 assigns colors to pixel values ​​so that the baseline (0) of the display range (0-1) of the first ratio image r1 and the baseline (1) of the display range (1-2) of the second ratio image r2 are aligned, as shown in FIG. 5 as an example. Here, the display range (0-1) of the first ratio image r1 corresponds to the range (0-1) of the first blood flow ratio in an acetylcholine-stressed state that causes microvascular spasm. This is because the first blood flow ratio becomes a value of 1 or less due to microvascular spasm. In the first ratio image r1, 256 colors are assigned to the 256 pixel values ​​corresponding to the first blood flow ratio from 0 to 1. The colors used are white, blue, light blue, yellow-green, yellow, and red, varying in 256 steps. Similarly, the display range (1-2) of the second ratio image r2 corresponds to the range (1-2) of the second blood flow ratio in an adenosine-stressed state that causes microvascular dilation. This is because the second blood flow ratio becomes a value of 1 or more as the microvessels expand. Note that the upper limit of the second blood flow ratio may exceed 2. However, in this example, the upper limit of the second blood flow ratio is set to 2, so that the second blood flow ratio is normalized to a range of 1 or more and 2 or less. In the second ratio image r2, 256 levels of color are assigned to 256 levels of pixel values ​​corresponding to the second blood flow ratio normalized to a range of 1 or more and 2 or less.

[0068] The other configurations are the same as those in the first embodiment.

[0069] According to the above configuration, the processing circuitry 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, the processing circuitry 34 causes the display 32 to display the first ratio image r1 and the second ratio image r2 with the baselines of the display ranges aligned. This allows the operator to visually recognize the distribution of the first blood flow ratio in the first ratio image r1 and the distribution of the second blood flow ratio in the second ratio image r2 by displaying them in color in the same display range.

[0070] As described above, according to the second embodiment, the processing circuitry 34 assigns colors to pixel values ​​so as to align the baseline of the display range of the first ratio image r1 with the baseline of the display range of the second ratio image r2. This not only achieves the effects described above, but also makes it possible to display the first ratio image r1 and the second ratio image r2 in color with the baselines of the display ranges aligned.

[0071] (Modification of the second embodiment) In the second embodiment, the baselines of the display ranges of the first ratio image r1 and the second ratio image r2 are aligned, but this is not limiting. For example, as shown in Fig. 6, the processing circuitry 34 may display the first ratio image r1 and the second ratio image r2 in color so as to assign the same color to a pixel value corresponding to a first threshold value th1 that distinguishes between normal and abnormal values ​​of the first blood flow ratio in the first ratio image r1 and a pixel value corresponding to a second threshold value th2 that distinguishes between normal and abnormal values ​​of the second blood flow ratio in the second ratio image r2.

[0072] Here, the display range (0-1) of the first ratio image r1 is as described above. In contrast, the display range (1-2.6) of the second ratio image r2 is obtained by normalizing the second blood flow ratio to a range of 1 to 2.6 by setting the upper limit of the second blood flow ratio to 2.6 in order to match the second threshold th2 with the first threshold th1. In the second ratio image r2 of the modified example, 256 levels of color are assigned to 256 levels of pixel values ​​corresponding to the second blood flow ratio normalized to a range of 1 to 2.6.

[0073] The other configurations are the same as those in the first embodiment.

[0074] According to the above-described modification of the second embodiment, the processing circuitry 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, the processing circuitry 34 adjusts the baseline of the display range, adjusts the first threshold value, and displays the first ratio image r1 and the second ratio image r2 on the display 32. This allows the operator to visually recognize the abnormal region of the first blood flow ratio in the first ratio image r1 and the abnormal region of the second blood flow ratio in the second ratio image r2, displayed in the same color. Therefore, in addition to the effects of the second embodiment, it is possible to more easily visually recognize whether the blood flow ratios in the first ratio image r1 and the second ratio image r2 are abnormal.

[0075] <Third embodiment> The third embodiment differs from the second embodiment in terms of the display range of each of the first ratio image r1 and the second ratio image r2, and is a form in which a first graph representing the first blood flow ratio and a second graph representing the second blood flow ratio are displayed.

[0076] 7, the display control function 34e of the processing circuitry 34 displays a first graph representing the first blood flow ratio and the first threshold value th1 in the myocardial ROI 202 and a second graph representing the second blood flow ratio and the second threshold value th2 in the myocardial ROI 202 side by side on the display 32. For example, the processing circuitry 34 may display the first graph and the second graph on the display 32 in any of the display areas 211 to 213.

[0077] The display area 211 displays the first graph and the second graph side by side so that the baseline of the description range (0-1) of the first graph and the baseline of the description range (1-2) of the second graph are aligned. This display area 211 corresponds to the form shown in FIG. 5.

[0078] The display area 212 displays the first graph and the second graph side by side so that the first threshold value th1 in the first graph and the second threshold value th2 in the second graph are aligned. That is, the description range (0-1) of the first graph is the same as that of the display area 211. The description range (1-2.6) of the second graph is obtained by normalizing the second blood flow ratio to a range of 1 to 2.6 by setting the upper limit of the second blood flow ratio to 2.6 in order to align the second threshold value th2 with the first threshold value th1. This display area 212 corresponds to the form shown in FIG. 6 described above.

[0079] The display area 213 displays a normal range and an abnormal range in the first graph with a first threshold value th1 as the boundary, and displays a normal range and an abnormal range in the second graph with a second threshold value th2 as the boundary.

[0080] The other configurations are the same as those of the second embodiment.

[0081] According to the above configuration, the processing circuitry 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, the processing circuitry 34 causes the display 32 to display a first graph representing the first blood flow ratio and the first threshold value th1 in the myocardial ROI 202 and a second graph representing the second blood flow ratio and the second threshold value th2 side by side. For example, the processing circuitry 34 causes the display 32 to display the first graph and the second graph as shown in any of the display areas 211 to 213. This allows the operator to visually recognize the first graph representing the first blood flow ratio and the first threshold value th1 and the second graph representing the second blood flow ratio and the second threshold value th2.

[0082] As described above, according to the third embodiment, the processing circuitry 34 displays a first graph representing the first blood flow ratio and the first threshold value in the myocardial ROI 202 and a second graph representing the second blood flow ratio and the second threshold value in the myocardial ROI 202 side by side on the display. Therefore, in addition to the above-described effects, the operator can visually recognize each blood flow ratio and each threshold value th1, th2 in the form of a bar graph. Note that, although the first and second graphs in FIG. 7 are each bar graphs, this is not limiting. However, it is preferable that the first and second graphs be the same type of graph to facilitate comparison.

[0083] Furthermore, according to the third embodiment, the processing circuitry 34 may display the first graph and the second graph side by side so that the baseline of the description range of the first graph and the baseline of the description range of the second graph are aligned. In this case, the first graph and the second graph can be displayed side by side with the baselines of the description ranges aligned.

[0084] Furthermore, according to the third embodiment, the processing circuitry 34 may display the first graph and the second graph side by side so that the first threshold value in the first graph and the second threshold value in the second graph are aligned. In this case, it is easier to visually determine whether the blood flow ratios in the first graph and the second graph are abnormal.

[0085] Furthermore, according to the third embodiment, the processing circuitry 34 may display a normal range and an abnormal range in the first graph with a first threshold value th1 as the boundary, and may display a normal range and an abnormal range in the second graph with a second threshold value th2 as the boundary. In this case, it is even easier to visually determine whether the blood flow ratios in the first graph and the second graph are abnormal.

[0086] <Fourth embodiment> The fourth embodiment differs from the third embodiment in that a plurality of graphs are displayed side by side, in that the first blood flow ratio and the second blood flow ratio are displayed in one graph.

[0087] Accordingly, in addition to the above-mentioned functions, the display control function 34e of the processing circuitry 34 causes the display 32 to display a comparison graph that compares each of the first blood flow ratio and the second blood flow ratio in the myocardial ROI 202 with the reference value, where the blood flow ratio (K1 / K1) at the zeroth blood flow amount K1 is set to 1. For example, the processing circuitry 34 may display on the display 32 the comparison graph in either form of a comparison graph 221 or 221a, as shown in FIG.

[0088] Here, the comparison graph 221 shows the blood flow ratio for each state, with the vertical axis representing the blood flow ratio and the horizontal axis representing the state. Specifically, the comparison graph 221 connects the first blood flow ratio (white circle in the figure) in the acetylcholine-loaded state ACh and the second blood flow ratio (white square in the figure) in the adenosine-loaded state ATP with a straight line, relative to the reference value (1) in the reference state Bs.

[0089] The comparative graph 221a is in a form in which the normal range and the abnormal range are displayed within the comparative graph 221 for each of the first blood flow ratio and the second blood flow ratio.

[0090] The other configurations are the same as those of the third embodiment.

[0091] According to the above configuration, the processing circuitry 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, when the blood flow ratio (K1 / K1) at the zeroth blood flow amount K1 is set to 1, which is the reference value, the processing circuitry 34 displays on the display 32 a comparison graph 221 or 221a that shows the first blood flow ratio and the second blood flow ratio in the myocardial ROI 202 compared with the reference value. Therefore, the operator can visually recognize the comparison graph 221 or 221a that shows the first blood flow ratio and the second blood flow ratio with respect to the reference value.

[0092] As described above, according to the fourth embodiment, when the blood flow ratio (K1 / K1) at the zeroth blood flow amount K1 is set to the reference value of 1, the processing circuitry 34 displays the comparison graphs 221 and 221a on the display 32, which show the first blood flow ratio and the second blood flow ratio in the myocardial ROI 202 compared with the reference value. This allows the two blood flow ratios to be compared and visually recognized in one comparison graph 221 or 221a.

[0093] Furthermore, according to the fourth embodiment, the processing circuitry 34 can display the comparison graph 221a in a form in which the normal range and the abnormal range for each of the first blood flow ratio and the second blood flow ratio are displayed within the comparison graph 221. This not only achieves the effects described above, but also makes it possible to visually determine whether the two blood flow ratios are in the normal range or the abnormal range on the comparison graph 221a.

[0094] (Modification of the fourth embodiment) Furthermore, in the fourth embodiment, the horizontal axis of the comparison graphs 221 and 221a represents the state, but this is not limiting. For example, as shown in FIG. 9, the processing circuit 34 may display on the display 32 a comparison graph 222 or 222a in a form in which the horizontal axis of the comparison graph 221 or 221a represents the load. Since the horizontal axis of the comparison graphs 222 and 222a represents the load, "ACh," which indicates the acetylcholine load state, is placed near the white circle indicating the first blood flow ratio, and "ATP," which indicates the adenosine load state, is placed near the white square indicating the second blood flow ratio. Even with this modification, the same effects as those of the fourth embodiment can be obtained.

[0095] In addition, in the modification of the fourth embodiment, the first blood flow ratio and the second blood flow ratio are each divided upward and downward from the reference value "1" in the comparison graphs 222 and 222a. However, this is not limiting. For example, as shown in FIGS. 10 and 11, the processing circuitry 34 may display the first blood flow ratio in the comparison graphs 223 and 223a with the descriptive range inverted around the reference value, and may also display the thresholds th1 and th2 for the first blood flow ratio and the second blood flow ratio in the comparison graphs 223 and 223a. The processing circuitry 34 may also display normal and abnormal ranges for the first blood flow ratio and the second blood flow ratio. According to this modification, the comparison graph 223 can be visually recognized in a form in which the first blood flow ratio and the second blood flow ratio each extend upward from the reference value "1."

[0096] In addition, in the modification of the fourth embodiment, the comparison graph 223a displays normal and abnormal ranges for each of the first and second blood flow ratios, but this is not limiting. For example, as shown in Fig. 12, the processing circuit 34 may display the first blood flow ratio in the comparison graph 224 with the reference value "1" at the bottom and the descriptive range reversed (0 at the bottom and 1 at the top), and may also display the thresholds th1 and th2 for the first and second blood flow ratios in the comparison graph 224. According to this modification, the comparison graph 224 can be visually recognized as having a normal and abnormal range common to both the first and second blood flow ratios, with each of the first and second blood flow ratios extending upward from the reference value "1."

[0097] <Fifth embodiment> The fifth embodiment differs from the first to fourth embodiments in that it determines whether the cause of INOCA is the blood vessels or the myocardium. Specifically, the fifth embodiment distinguishes between coronary spasm of the epicardial coronary arteries and microvascular spasm (MVS) of the coronary microvessels to determine the cause of INOCA.

[0098] Here, the processing circuitry 34 further includes a determination function 34f, as shown in Fig. 13. The determination function 34f determines whether the myocardial blood flow of the subject has decreased based on the myocardial blood flow image, and whether the subject's blood vessels have narrowed based on the first contrast image, and detects coronary spasm when the determination results in both a decrease and narrowing, and detects microvascular spasm when the determination results in a decrease and no narrowing. The determination function 34f is an example of a determination unit.

[0099] Accordingly, in addition to the above-mentioned functions, the acquisition function 34a of the processing circuitry 34 further acquires myocardial blood flow images when the subject's heart is in an acetylcholine stress state. The myocardial blood flow images are, for example, electrocardiogram-gated coronary angiography images obtained by X-ray angiography using the X-ray diagnostic apparatus 10. The image is acquired from, for example, the image storage device 20.

[0100] In addition to the above-mentioned functions, the display control function 34e of the processing circuit 34 also causes the display 32 to display the detected results.

[0101] The other configurations are the same as those in the first embodiment.

[0102] Next, the operation of the medical image processing device configured as above will be explained using the flowchart in Fig. 14. It is assumed that the image storage device 20 stores myocardial blood flow images acquired in advance by the X-ray diagnostic device 10. The myocardial blood flow images are electrocardiogram-gated coronary angiography images obtained by X-ray angiography when the subject's heart is in an acetylcholine-stressed state.

[0103] As shown in Figure 14, the processing circuit 34 of the medical image processing device 30 acquires a myocardial blood flow image when the subject's heart is in an acetylcholine stress state from the image storage device 20 in response to the operator's operation (step ST110), and stores the myocardial blood flow image in the memory 33.

[0104] The processing circuitry 34 determines whether the subject's myocardial blood flow has decreased based on the myocardial blood flow image (step ST120), and if not, detects that there is no vasospasm (step ST130), displays the detected result on the display 32, and terminates the processing.

[0105] Furthermore, if the result of the determination in step ST120 is that the myocardial blood flow has decreased, the processing circuitry 34 determines whether or not the subject's blood vessels have become constricted based on the above-described first contrast image g1 (step ST140).

[0106] If the result of the determination in step ST140 is that the stenosis has occurred, the processing circuitry 34 detects that the subject's heart has coronary spasm (step ST150), displays the detection result on the display 32, and ends the processing.

[0107] On the other hand, if the result of the determination in step ST140 is that there is no stenosis, the processing circuitry 34 detects that there is microvascular spasm (MVS) in the subject's heart (step ST160), displays the detection result on the display 32, and terminates the processing.

[0108] Therefore, the operator can visually check the display screen of the detected results and understand the condition of the subject's heart, such as the presence or absence of vasospasm, coronary spasm, and microvascular spasm.

[0109] As described above, according to the fifth embodiment, the processing circuitry 34 further acquires a myocardial blood flow image when the heart is in an acetylcholine-stressed state. The processing circuitry 34 determines whether the subject's myocardial blood flow has decreased based on the myocardial blood flow image, and determines whether the subject's blood vessels have narrowed based on the first contrast-enhanced image. If the determination results in both a decrease and narrowing, the processing circuitry detects coronary spasm, and if the determination results in a decrease and narrowing, the processing circuitry detects microvascular spasm. The processing circuitry 34 displays the detection results on the display 32. Therefore, in addition to the effects described above, coronary spasm and microvascular spasm in the subject's heart can be detected based on the myocardial blood flow image and the first contrast-enhanced image when the heart is in an acetylcholine-stressed state.

[0110] Sixth Embodiment The sixth embodiment is different from the first embodiment in that it displays the blood flow rate and the blood flow ratio, and instead displays the blood flow rate, the transit time, and the blood flow ratio.

[0111] Specifically, for example, in addition to the above-mentioned functions, the processing circuitry 34 causes the display 32 to display a measurement value display area 231, a time-density curve 232, and a schematic diagram 233, as shown in FIG.

[0112] The measurement value display area 231 is an area that displays the measurement values ​​of indices related to cardiac blood flow and the assumed causes of abnormal measurement values ​​in association with each other. The measurement values ​​include the blood flow rate (K1) in the reference state, the transit time between the artery and the vein, the first blood flow ratio (K1_ACh / K1) in the acetylcholine-loaded state, and the second blood flow ratio (K1_ATP / K1) in the adenosine-loaded state.

[0113] The factors include, for example, increased microvascular resistance related to blood flow (K1), slow flow related to transit time T, microvascular spasm related to the first blood flow ratio (K1_ACh / K1), and impaired microvascular dilation related to the second blood flow ratio (K1_ATP / K1). Note that slow flow is an index related to the speed at which the contrast medium flows, and can be expressed as the reciprocal of the transit time T (note that distance = speed × time).

[0114] In the time-density curve 232, the vertical axis represents the contrast agent concentration C, and the horizontal axis represents time. The time-density curve 232 represents the time dependence of the contrast agent concentration C in the arterial ROI 201, the time dependence of the contrast agent concentration C in the myocardial ROI 202, and the time dependence of the contrast agent concentration C in the venous ROI 203, all of which are shown in a schematic diagram 233. A longer time than usual is used for measurement of this time-density curve 232 in order to obtain the time dependence of the contrast agent concentration C in the venous ROI 203. As a result, the transit time T of the contrast agent between the artery and the vein can be obtained from the time-density curve 232 as the time difference between the peak time of the contrast agent concentration in the artery and the peak time of the contrast agent concentration in the vein. The transit time T is displayed in the measurement value display area 231.

[0115] A schematic diagram 233 shows, in contrast images g0 to g2, an artery ROI 201, a myocardium ROI 202, and a vein ROI 203. The right half of the schematic diagram 233 is a line drawing that schematically shows the relationship between the arteries, capillaries, myocardium, and veins.

[0116] Additionally, the time-density curve 232 is measured for each frame, pixel, or region of interest of the contrast-enhanced image. Equation (7) is derived from a two-compartment model.

[0117]

number

[0118] Here, in equation (7) and diagram 233, K1 is the transfer constant of the contrast agent from the artery to the myocardial region, and its unit is mL / min / g. k2 is the transfer constant of the contrast agent from the myocardial region to the vein. Ca(t) is the contrast agent concentration in the artery, and corresponds to the curve indicated by "artery" in time-concentration curve 232. Cm(t) is the contrast agent concentration in the myocardial region, and corresponds to the curve indicated by "myocardial" in time-concentration curve 232. K1 is also the blood flow rate mentioned above.

[0119] In the early stage after contrast injection, the inflow of contrast from the arteries into the myocardium is much greater than the outflow from the myocardium into the veins, so we can assume that K1Ca(t) >> k2Cm(t). Therefore, equation (7) can be transformed into equation (8).

[0120]

number

[0121] If the contrast agent concentrations Ca(t) and Cm(t) can be measured from the image, K1 can be calculated. However, in coronary X-ray angiography, since the X-ray image is a planar image, only the integral information along the X-ray path can be measured, and the contrast agent concentration C(t) cannot be measured directly.

[0122] However, assuming that the contrast agent concentration C(t) is the average concentration along the X-ray path L, I(t) = C(t)L can be measured from the X-ray image. Here, I(t) is the image brightness in the baseline-subtracted X-ray image. Here, the X-ray path L can be expressed, for example, as the arterial path length La in cm and the myocardial path length Lm in cm. Accordingly, the equation for image brightness I(t) = C(t)L can be expressed, for example, as the myocardial image brightness Im(t) = Cm(t)Lm and the arterial image brightness Ia(t) = Ca(t)La. Furthermore, by using the relationships of the contrast agent concentrations Cm(t) = Im(t) / Lm and Ca(t) = Ia(t) / La, which are modified equations for the myocardial and arterial image brightness, Equation (8) can be transformed into Equation (9).

[0123]

number

[0124] The above-mentioned formula (1) is obtained from formula (9).

[0125] The other configurations are the same as those in the first embodiment.

[0126] According to the above configuration, the processing circuitry 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, the processing circuitry 34 displays the measurement value display area 231, the time-density curve 232, and the schematic diagram 233 on the display 32. This allows the operator to visually recognize the relationships between the four indices in the measurement value display area 231, the time-density curve 232, and the ROIs in the schematic diagram 233.

[0127] As described above, according to the sixth embodiment, the processing circuit 34 displays the blood flow rate (K1) in the reference state, the transit time T between the artery and the vein, the first blood flow ratio (K1_ACh / K1) in the acetylcholine-loaded state, and the second blood flow ratio (K1_ATP / K1) in the adenosine-loaded state on the display 32. Therefore, in addition to the effects described above, the operator can visually confirm the transit time T between the artery and the vein.

[0128] Furthermore, according to the sixth embodiment, the measurement value of an index related to cardiac blood flow is displayed in association with the possible causes of an abnormality in the measurement value, thereby assisting in the prediction of the cause in the event that the measurement value is abnormal.

[0129] Seventh Embodiment The seventh embodiment differs from the first embodiment in that the medical image processing device 30 acquires images from an external image storage device 20, in that the medical image processing device 30 mounted on the X-ray diagnostic device 10 acquires contrast images and calculates and displays the blood flow ratio.

[0130] 16 is a diagram showing an example of the configuration of an X-ray diagnostic apparatus 10 according to the seventh embodiment. The X-ray diagnostic apparatus 10 includes a high-voltage generator 11, an X-ray tube 13, an X-ray diaphragm device 15, an X-ray detector 17, a support frame 19, a bed (not shown) having a tabletop 21, an input interface 31, a display 32, a memory 33, and a processing circuitry 34. The processing circuitry 34 includes a system control function 341, an acquisition function 34a, a setting function 34b, a calculation function 34c, a ratio image generation function 34d, and a display control function 34e. The input interface 31, the display 32, the memory 33, and the processing circuitry 34 form a console device 37. A configuration in which the system control function 341 is omitted from the console device 37 corresponds to a medical image processing apparatus 30.

[0131] Here, the high voltage generator 11 generates a tube current to be supplied to the X-ray tube 13 and a tube voltage (high voltage) to be applied to the X-ray tube 13. Under the control of the system control function 341 in the processing circuitry 34, the high voltage generator 11 supplies the X-ray tube 13 with a tube current suitable for X-ray imaging and X-ray fluoroscopy in accordance with the X-ray imaging conditions. Under the control of the system control function 341, the high voltage generator 11 applies to the X-ray tube 13 a tube voltage suitable for X-ray imaging and X-ray fluoroscopy in accordance with the X-ray imaging conditions. The application of the tube voltage by the high voltage generator 11 may be a method of applying a tube voltage to the X-ray tube 13 continuously in time, or a method of applying a pulsed high voltage to the X-ray tube 13 by switching the high voltage (hereinafter referred to as a high-voltage pulse application method). In the following description, the high voltage generator 11 will be described as performing X-ray fluoroscopy using the high-voltage pulse application method.

[0132] The X-ray tube 13 generates X-rays from an X-ray focus (hereinafter referred to as the tube focus) based on the tube current supplied from the high voltage generator 11 and the tube voltage applied by the high voltage generator 11. The X-rays generated from the tube focus are irradiated onto the subject P, with X-rays from unnecessary regions being blocked by the X-ray diaphragm device 15. The maximum irradiation range 131 of the X-rays is indicated by a dotted line. In this embodiment, the X-ray tube 13 is described as a rotating anode X-ray tube. However, the X-ray tube 13 in this embodiment may be another type of X-ray tube, such as a fixed anode X-ray tube. The X-ray tube 13 generates discrete pulsed X-rays at predetermined time intervals as a pulsed high voltage is applied by switching the high voltage. A lead cone is attached to the X-ray emission window of the X-ray tube 13 to block off-focal X-rays generated outside the tube focus.

[0133] The X-ray limiting device 15 is provided adjacent to the X-ray emission window of the X-ray tube 13 and in front of the X-ray tube 13. The X-ray limiting device 15 limits the irradiation range of the X-rays generated at the tube focus. Note that the X-ray limiting device 15 may have various filters (a radiation quality adjustment filter, an additional filter, a dose reduction filter, etc.) in addition to the X-ray filter.

[0134] The X-ray detector 17 faces the X-ray tube 13 and detects X-rays generated from the X-ray tube 13. The X-ray detector 17 is configured, for example, by a flat panel detector (hereinafter referred to as FPD). The FPD has a plurality of semiconductor detection elements. Note that an image intensifier may also be used as the X-ray detector 17. Electrical signals generated by the plurality of semiconductor detection elements in response to incidence of X-rays are output to an analog to digital converter (hereinafter referred to as A / D converter), not shown. The A / D converter converts the electrical signals into digital data. The A / D converter outputs the digital data to the processing circuitry 34.

[0135] The support frame 19 movably supports the X-ray tube 13 and the X-ray detector 17. Specifically, the support frame 19 is a C-arm. The C-arm mounts the X-ray tube 13 and the X-ray detector 17 so that they face each other. A support column (not shown) supports the C-arm slidably in a direction along the C-shape of the C-arm (hereinafter referred to as the first direction) via guide rails, linear bearings, etc. The support column is provided on the floor of the examination room. The support column supports the C-arm rotatably in a direction perpendicular to the first direction (hereinafter referred to as the second direction) via bearings, etc. Note that the support column can also support the C-arm movably in parallel in the minor axis direction (X axis) and major axis direction (Y axis) of the tabletop 21 via bearings, etc. The C-arm also supports the X-ray tube 13 and the X-ray detector 17 via, for example, guide rails and linear bearings, so that the distance between the tube focus of the X-ray tube 13 and the center of the X-ray detector 17 (source image distance (SID)) can be changed.

[0136] Note that an Ω arm may be used as support frame 19 instead of a C-arm, or two arms (such as robot arms) that independently support X-ray tube 13 and X-ray detector 17 may be used. Also, support frame 19 may have a biplane structure made up of a C-arm and an Ω arm.

[0137] A bed (not shown) movably supports a top board 21 (also called a supine table) on which the subject P is placed. The subject P is placed on the top board 21.

[0138] A driving device (not shown) drives, for example, the support frame 19 and the bed. The driving device has, for example, a motor and a transmission mechanism (for example, a chain drive, a belt drive, a ball screw, etc.) that transmits the force generated by the motor to various units to be driven. The driving device slides the support frame 19 in a first direction and rotates it in a second direction in accordance with a drive signal corresponding to a control signal output from the processing circuitry 34. Note that the driving device may also rotate the X-ray detector 17 around the SID as a rotation axis under the control of the system control function 341.

[0139] The driving device drives the top 21 under the control of the system control function 341 to move the top 21. As a result, during X-ray fluoroscopy and X-ray imaging, the subject P placed on the top 21 is positioned between the X-ray tube 13 and the X-ray detector 17. Specifically, the driving device slides the top 21 in the short axis direction (X-axis direction) of the top 21 and in the long axis direction (Y-axis direction) of the top 21 via bearings, guide rails, linear bearings, etc., based on a control signal output from the processing circuitry 34. The driving device also raises and lowers the top 21 in the vertical direction (Z-axis direction) via bearings, guide rails, linear bearings, etc. In addition, the driving device may rotate the top 21 via bearings, guide rails, linear bearings, etc., in order to tilt the top 21 about an axis of rotation in at least one of the long axis direction and the short axis direction.

[0140] The input interface 31 is used to input X-ray imaging conditions, fluoroscopy and imaging positions, X-ray irradiation range (imaging field of view), position and size of a region of interest in an X-ray image, and the like, according to instructions from an operator.

[0141] The processing circuitry 34 reads out from the memory 33 various programs for controlling the various circuits, drive devices, etc. in the X-ray diagnostic apparatus 10 and executes the read programs to realize various functions. The processing circuitry 34 temporarily stores in a memory (not shown) information such as operator instructions and X-ray imaging conditions such as imaging conditions and fluoroscopy conditions sent from the input interface 31. The processing circuitry 34 controls the high-voltage generator 11, the X-ray diaphragm device 15, the drive devices, etc., to perform X-ray imaging and X-ray fluoroscopy (pulse X-ray imaging) according to the operator instructions, fluoroscopy and imaging positions, X-ray imaging conditions, etc. stored in the memory using a system control function 341.

[0142] The acquisition function 34a, setting function 34b, calculation function 34c, ratio image generation function 34d, and display control function 34e of the processing circuitry 34 function in the same manner as described above, except that the acquisition function 34a acquires the 0th contrast image g0, the 1st contrast image g1, and the 2nd contrast image g2 from the memory 33, not from the image storage device 20.

[0143] According to the above configuration, the X-ray diagnostic apparatus 10 performs X-ray imaging based on imaging conditions. That is, the X-ray tube 13 irradiates X-rays onto the subject P into which a contrast agent has been injected. The X-ray detector 17 detects the X-rays irradiated from the X-ray tube 13 and transmitted through the subject P, and outputs the X-ray detection result. The processing circuitry 34 generates a contrast-enhanced image of the subject P based on the output of the X-ray detector 17, and stores the contrast-enhanced image in the memory 33.

[0144] In this way, the X-ray diagnostic apparatus 10 generates and stores a 0th contrast image g0 when the heart with INOCA is in a reference state, a 1st contrast image g1 when the heart is in an acetylcholine-stressed state, and a 2nd contrast image g2 when the heart is in an adenosine-stressed state.

[0145] Thereafter, the processes of steps ST10 to ST50 are executed in the same manner as described above, except that the processing circuitry acquires the contrast images g0 to g2 from the memory 33.

[0146] As described above, according to the seventh embodiment, processing circuitry 34 in X-ray diagnostic apparatus 10 acquires a zeroth contrast image g0 of a subject with non-occlusive coronary artery disease when the heart is in a baseline state, a first contrast image g1 of the heart when the heart is in an acetylcholine-stressed state, and a second contrast image g2 of the heart when the heart is in an adenosine-stressed state. Based on the zeroth contrast image g0 and the first contrast image g1, processing circuitry 34 calculates a first blood flow ratio representing the ratio of the zeroth myocardial blood flow volume K1 in the baseline state to the first myocardial blood flow volume K1_ACh in the acetylcholine-stressed state. Based on the zeroth contrast image g0 and the second contrast image g2, processing circuitry 34 calculates a second blood flow ratio representing the ratio of the zeroth blood flow volume K1 to the second myocardial blood flow volume K1_ATP in the adenosine-stressed state. Processing circuitry 34 displays the first blood flow ratio and the second blood flow ratio side by side on display 32. In this way, by configuring the processing circuitry 34 in the X-ray diagnostic apparatus 10 to calculate the blood flow ratio from the contrast image, the effects of the above-described embodiments can be obtained in real time after the end of contrast imaging.

[0147] According to at least one of the embodiments described above, blood flow can be quantitatively measured without using a sensor wire during an INOCA examination.

[0148] The term "processor" used in the above description refers to a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an Application Specific Integrated Circuit (ASIC), a programmable logic device (e.g., a Simple Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), or a Field Programmable Gate Array (FPGA)). If the processor is a CPU, for example, the processor realizes its function by reading and executing a program stored in a memory circuit. On the other hand, if the processor is an ASIC, instead of storing a program in a memory circuit, the function is directly incorporated into the processor circuit as a logic circuit. Note that each processor in this embodiment is not limited to being configured as a single circuit, but may be configured as a single processor by combining multiple independent circuits to realize its function. Furthermore, multiple components in FIGS. 1, 13, and 16 may be integrated into a single processor to realize its function.

[0149] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents as defined in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0150] 10 X-ray diagnostic equipment 11 High voltage generator 13 X-ray tube 15 X-ray aperture device 17 X-ray detector 19 Support frame 20 Image Archive 21 Top plate 30 Medical image processing device 31 Input Interface 32 Display 33 Memory 34 Processing circuit 34a Acquisition Function 34b Setting Function 34c Calculation Function 34d ratio image generation function 34e Display control function 34f Judgment function 201 Arterial ROI 202 Myocardial ROIs 203 venous ROIs 221,221a,222,222a,223,223a,224 Comparison Graph ACh Acetylcholine loading state ATP adenosine loading state Bs reference condition g0 0th contrast image g1 First contrast image g2 Second contrast image r1 First ratio image r2 2nd ratio image th1 First threshold th2 Second threshold

Claims

1. an acquisition unit that acquires a 0th contrast-enhanced image of a heart of a subject having non-obstructive coronary artery disease when the heart is in a reference state, a first contrast-enhanced image of the heart when the heart is in an acetylcholine-stressed state, and a second contrast-enhanced image of the heart when the heart is in an adenosine-stressed state; a first calculation unit that calculates a first blood flow ratio representing a ratio between a zeroth myocardial blood flow rate in the reference state and a first myocardial blood flow rate in the acetylcholine-stressed state based on the zeroth contrast image and the first contrast image; a second calculation unit that calculates a second blood flow ratio representing a ratio of the zeroth blood flow rate to a second blood flow rate in the myocardium in the adenosine stress state based on the zeroth contrast image and the second contrast image; a display control unit that displays the first blood flow ratio and the second blood flow ratio side by side on a display; A medical image processing device comprising:

2. the display control unit causes the display to display the first blood flow ratio and the second blood flow ratio in at least one of a numerical value and an image format. The medical image processing device according to claim 1 .

3. a setting unit that sets a region of interest common to the 0th contrast image, the first contrast image, and the second contrast image; the first calculator calculates the first blood flow ratio in the region of interest of each of the zeroth contrast image and the first contrast image; the second calculator calculates the second blood flow ratio in the region of interest of each of the zero contrast image and the second contrast image; the display control unit, in the case of the numerical format, causes the first blood flow ratio to be displayed in a first display mode when the first blood flow ratio in the region of interest is equal to or less than a first threshold, and causes the second blood flow ratio to be displayed in a second display mode when the second blood flow ratio in the region of interest is equal to or less than a second threshold. The medical image processing device according to claim 2 .

4. the first display mode is a mode of performing a color display or an alert display indicating an abnormality in the first blood flow ratio, The second display mode is a mode in which a color display or an alert display is performed to indicate an abnormality in the second blood flow ratio. The medical image processing device according to claim 3 .

5. Further comprising a ratio image generating unit, the first calculator calculates the first blood flow ratio for each corresponding pixel in the zeroth contrast image and the first contrast image; the second calculator calculates the second blood flow ratio for each corresponding pixel in the zeroth contrast image and the second contrast image; the ratio image generating unit generates a first ratio image having a pixel value corresponding to the first blood flow ratio calculated for each pixel, and a second ratio image having a pixel value corresponding to the second blood flow ratio calculated for each pixel, the display control unit, in the case of the image format, causes the first ratio image and the second ratio image to be displayed in color on the display by assigning colors to the pixel values; The medical image processing device according to claim 2 .

6. the display control unit assigns colors to the pixel values ​​so as to align a baseline of a display range of the first ratio image with a baseline of a display range of the second ratio image. The medical image processing device according to claim 5 .

7. the display control unit displays the first ratio image and the second ratio image in color so as to assign the same color to a pixel value in the first ratio image corresponding to a first threshold value for distinguishing between normal and abnormal states of the first blood flow ratio and a pixel value in the second ratio image corresponding to a second threshold value for distinguishing between normal and abnormal states of the second blood flow ratio. The medical image processing device according to claim 5 .

8. a setting unit that sets a region of interest common to the 0th contrast image, the first contrast image, and the second contrast image; the first calculator calculates the first blood flow ratio in the region of interest of each of the zeroth contrast image and the first contrast image; the second calculator calculates the second blood flow ratio in the region of interest of each of the zero contrast image and the second contrast image; the display control unit displays a first graph representing the first blood flow ratio and the first threshold value in the region of interest and a second graph representing the second blood flow ratio and the second threshold value in the region of interest side by side; The medical image processing device according to claim 1 .

9. the display control unit displays the first graph and the second graph side by side so that a baseline of a description range of the first graph and a baseline of a description range of the second graph are aligned; The medical image processing device according to claim 8 .

10. the display control unit displays the first graph and the second graph side by side so that the first threshold value in the first graph and the second threshold value in the second graph are aligned. The medical image processing device according to claim 9 .

11. the display control unit displays a normal range and an abnormal range in the first graph with the first threshold as a boundary, and displays a normal range and an abnormal range in the second graph with the second threshold as a boundary, The medical image processing device according to claim 10.

12. a setting unit that sets a region of interest common to the 0th contrast image, the first contrast image, and the second contrast image; the first calculator calculates the first blood flow ratio in the region of interest of each of the zeroth contrast image and the first contrast image; the second calculator calculates the second blood flow ratio in the region of interest of each of the zero contrast image and the second contrast image; the display control unit causes the display to display a comparison graph showing a comparison of each of the first blood flow ratio and the second blood flow ratio in the region of interest with respect to a reference value of 1 when the blood flow ratio at the zero blood flow rate is set to the reference value. The medical image processing device according to claim 1 .

13. the display control unit causes a normal range and an abnormal range for each of the first blood flow ratio and the second blood flow ratio to be displayed in the comparison graph. The medical image processing device according to claim 12 .

14. the display control unit displays the first blood flow ratio in the comparison graph with a description range inverted around the reference value, and displays threshold values ​​for each of the first blood flow ratio and the second blood flow ratio in the comparison graph. The medical image processing device according to claim 12 .

15. Further comprising a determination unit, the acquiring unit further acquires a myocardial blood flow image when the heart is in an acetylcholine stress state; the determining unit determines whether or not the myocardial blood flow of the subject has decreased based on the myocardial blood flow image, and determines whether or not the blood vessel of the subject has narrowed based on the first contrast image, and detects coronary spasm when the determination results in both the decrease and the narrowing, and detects microvascular spasm when the determination results in the decrease and the narrowing, The display control unit causes the detection result to be displayed on the display. The medical image processing device according to claim 1 .

16. the first calculator calculates the first blood flow ratio by dividing pixel values ​​of corresponding pixels in the myocardial region of the 0th contrast image and the myocardial region of the first contrast image; the second calculator calculates the second blood flow ratio by dividing pixel values ​​of corresponding pixels in the myocardial region of the 0th contrast image and the myocardial region of the second contrast image. The medical image processing device according to claim 1 .

17. a third calculator configured to calculate a third blood flow ratio by dividing pixel values ​​of corresponding pixels in the myocardial region of the first contrast image and the myocardial region of the second contrast image; the display control unit further causes the display to display the third blood flow ratio. The medical image processing device according to claim 1 .

18. the display control unit causes the display to further display at least the first blood flow rate and the second blood flow rate among the zero blood flow rate, the first blood flow rate, and the second blood flow rate side by side. The medical image processing device according to any one of claims 1 to 17.

19. the 0th contrast image, the first contrast image, and the second contrast image are medical images captured under substantially the same imaging conditions except for the state of the heart; The medical image processing device according to any one of claims 1 to 17.

20. an acquisition unit that acquires a 0th contrast-enhanced image of a heart of a subject having non-obstructive coronary artery disease when the heart is in a reference state, a first contrast-enhanced image of the heart when the heart is in an acetylcholine-stressed state, and a second contrast-enhanced image of the heart when the heart is in an adenosine-stressed state; a first calculation unit that calculates a first blood flow ratio representing a ratio between a zeroth myocardial blood flow rate in the reference state and a first myocardial blood flow rate in the acetylcholine-stressed state based on the zeroth contrast image and the first contrast image; a second calculation unit that calculates a second blood flow ratio representing a ratio of the zeroth blood flow rate to a second blood flow rate in the myocardium in the adenosine stress state based on the zeroth contrast image and the second contrast image; a display control unit that displays the first blood flow ratio and the second blood flow ratio side by side on a display; An X-ray diagnostic device comprising:

Images