Medical image processing apparatus and x-ray diagnostic apparatus

Abstract

The invention provides a medical image processing apparatus and an X-ray diagnostic apparatus, which can quantitatively measure blood flow without using a sensor line during INOCA examination. The medical image processing apparatus includes a processing circuit. The processing circuit acquires a zeroth contrast image when the heart of a subject is in a reference state, a first contrast image when the heart is in an acetylcholine-loaded state, and a second contrast image when the heart is in an adenosine-loaded state. The processing circuit calculates, on the basis of the zeroth contrast image and the first contrast image, a first blood flow ratio indicating the ratio of a zeroth blood flow rate of the cardiac muscle in a reference state to a first blood flow rate of the cardiac muscle in an acetylcholine-loaded state. On the basis of the zeroth contrast image and the second contrast image, the processing circuit calculates a second blood flow ratio indicating the ratio of the zeroth blood flow to a second blood flow of the cardiac muscle in an adenosine-loaded state. The processing circuit displays the first blood flow ratio and the second blood flow ratio on the display in parallel.

Description

[0001] Cross-references to related applications

[0002] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2024-043857, filed on Mar. 19, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The embodiments of the present invention generally relate to a medical image processing apparatus and an X-ray diagnostic apparatus. Background Art

[0004] In the field of circulatory ischemia, efforts are underway to address non-occlusive coronary artery disease (INOCA). This disease is characterized by functional impairments in the myocardium, despite the absence of structural abnormalities such as occlusion or stenosis of the heart's blood vessels. The main causes of INOCA are microvascular spasm and microvascular dysplasia, and accurate differentiation of these causes is crucial for effective treatment. Furthermore, due to the low sensitivity of non-invasive tests such as MRI (magnetic resonance imaging), PET (positron emission tomography), and transthoracic echocardiography, the gold standard for distinguishing the causes is the use of invasive methods such as IMR (microcirculatory resistance index) and CFR (coronary flow reserve) using sensor lines, or the use of lactate.

[0005] To further clarify, invasive examinations include a first test for one of the two main causes, coronary artery spasm angina, and a second test for the other cause, microvascular angina. Invasive examinations use these two tests to accurately distinguish the cause of INOCA. The order of the first and second tests may be reversed depending on the country, and the order is not limited to this.

[0006] First, in the first examination, an acetylcholine stress test is performed as a coronary artery spasm induction test related to coronary artery spasm angina. The positive result is determined based on symptoms, electrocardiogram changes, and lactate levels. If the first examination is positive, treatment for the coronary artery spasm angina as a cause is initiated.

[0007] If the first test is negative, a second test related to another cause is performed. In the second test, an adenosine stress test related to microvascular angina is performed, and a positive result is determined based on the CFR or IMR. If the second test is positive, treatment for the microvascular angina as the other cause is performed.

[0008] However, the present inventors' research has revealed that this invasive test has room for improvement. For example, while the first test observes symptoms, electrocardiogram changes, and lactate levels, it cannot quantitatively measure blood flow, which indicates the actual degree of ischemia. Furthermore, the second test, for example, uses sensor wires, which increases the effort and cost, cannot evaluate all coronary artery branches, and carries the risk of inserting sensor wires. This also leaves room for improvement.

[0009] Therefore, when examining INOCA, it is preferable to quantitatively measure blood flow without using a sensor wire.

[0010] Prior art literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-106990 Summary of the Invention

[0012] Technical problem to be solved by the invention

[0013] One of the technical problems addressed by the embodiments disclosed in this specification and accompanying drawings is to quantitatively measure blood flow during INOCA examinations without using sensor wires. However, the technical problems addressed by the embodiments disclosed in this specification and accompanying drawings are not limited to the aforementioned technical problems. Technical problems corresponding to the effects of the various configurations described in the embodiments described below can also be identified as other technical problems.

[0014] The medical image processing device of the embodiment includes a processing circuit. The processing circuit is configured to obtain a zeroth contrast image when the heart of the subject is in a baseline state, a first contrast image when the heart is in an acetylcholine load state, and a second contrast image when the heart is in an adenosine load state. The processing circuit is configured to calculate a first blood flow ratio representing the ratio of the zeroth blood flow of the myocardium in the baseline state to the first blood flow of the myocardium in the acetylcholine load state based on the zeroth contrast image and the first contrast image. The processing circuit is configured to calculate a second blood flow ratio representing the ratio of the zeroth blood flow to the second blood flow of the myocardium in the adenosine load state based on the zeroth contrast image and the second contrast image. The processing circuit is configured to display the first blood flow ratio and the second blood flow ratio in parallel on a display.

[0015] Effects of the Invention

[0016] According to the medical image processing apparatus having the above configuration, during INOCA examination, it is possible to quantitatively measure blood flow without using sensor lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a block diagram showing an example of the configuration of the medical image processing apparatus and its peripherals according to the first embodiment.

[0018] Figure 2 This is a flowchart for explaining the operation in the first embodiment.

[0019] Figure 3 This is a diagram showing an example of a contrast-enhanced image in the first embodiment.

[0020] Figure 4 It is a schematic diagram showing a display example in the first embodiment.

[0021] Figure 5 It is a schematic diagram for explaining a display example of a comparison image in the second embodiment.

[0022] Figure 6 It is a schematic diagram for explaining a display example of a comparison image in a modification of the second embodiment.

[0023] Figure 7 It is a schematic diagram showing an example of display of a graph in the third embodiment.

[0024] Figure 8 It is a schematic diagram showing an example of display of a graph in the fourth embodiment.

[0025] Figure 9 It is a schematic diagram showing a display example of a graph in a modification of the fourth embodiment.

[0026] Figure 10 It is a schematic diagram showing a display example of a graph in a modification of the fourth embodiment.

[0027] Figure 11 It is a schematic diagram showing a display example of a graph in a modification of the fourth embodiment.

[0028] Figure 12 It is a schematic diagram showing a display example of a graph in a modification of the fourth embodiment.

[0029] Figure 13 This is a block diagram showing an example of the configuration of a medical image processing apparatus and its peripherals according to the fifth embodiment.

[0030] Figure 14 This is a flowchart for explaining the operation in the fifth embodiment.

[0031] Figure 15It is a schematic diagram showing a display example in the sixth embodiment.

[0032] Figure 16 This is a block diagram showing a configuration example of an X-ray diagnostic apparatus according to a seventh embodiment.

[0033] Description of Reference Numerals

[0034] 10...X-ray diagnostic device, 11...high voltage generator, 13...X-ray tube, 15...X-ray beam limiter device, 17...X-ray detector, 19...support frame, 20...image storage device, 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...comparison image generation function, 34e...display control function, 34f... …determination function, 201…arterial ROI, 202…myocardial ROI, 203…venous ROI, 221, 221a, 222, 222a, 223, 223a, 224…comparison chart, ACh…acetylcholine load state, ATP…adenosine load state, Bs…baseline state, g0…zeroth contrast image, g1…first contrast image, g2…second contrast image, r1…first ratio image, r2…second ratio image, th1…first threshold value, th2…second threshold value. DETAILED DESCRIPTION

[0035] The following describes various embodiments of a medical image processing apparatus and an X-ray diagnostic apparatus with reference to the accompanying drawings. In the following description, components having substantially the same functions and configurations are denoted by the same reference numerals to omit duplicate descriptions. Furthermore, in the following description, details not necessarily required for understanding the measurement or display of blood flow ratios are omitted as appropriate.

[0036] <First embodiment>

[0037] Figure 1 This is a block diagram showing an example of the medical image processing apparatus and its peripheral configuration according to the first embodiment. The X-ray diagnostic apparatus 10, image storage device 20, and medical image processing apparatus 30 are interconnected via a network, whether wirelessly or wired, to enable communication with each other. An example of the network is a LAN (Local Area Network). Furthermore, the connection line is not limited to a LAN, as long as security can be ensured using a VPN (Virtual Private Network). In this case, the network may also be a public communication line such as the Internet.

[0038] The X-ray diagnostic apparatus 10 collects projection image data related to the subject by performing X-ray photography on the subject. Furthermore, the X-ray diagnostic apparatus 10 collects contrast image data related to the subject's cardiac region by performing X-ray photography on the subject after a contrast agent has been injected into the cardiac region. Furthermore, X-ray photography conditions are included in the data for each of the projection image and the contrast image. X-ray photography conditions include, for example, the imaging target site, tube voltage, tube current, irradiation time, the product of tube current (mA) and irradiation time (s) (hereinafter referred to as tube current-time product (mAs)), the subject's position (posture) during X-ray photography, and the injection volume / injection rate of the contrast agent. Scanning conditions and X-ray photography conditions are equivalent to imaging conditions. Volume data, contrast image data, and projection image data are equivalent to medical image data. Body position refers to the subject's posture when the subject is imaged. For example, body positions in scanning conditions include dorsal decubitus position, upper limbs raised, supine position, lateral decubitus position, and abdominal decubitus position. In addition, the body position in the X-ray imaging conditions includes, for example, the supine position, the lateral position, the upper limbs hanging down, etc. In addition, the body position of the subject may not be included in the imaging conditions.

[0039] The image storage device 20 stores medical image data collected by the X-ray diagnostic apparatus 10. The image storage device 20 obtains medical image data from the X-ray diagnostic apparatus 10 via a network and stores the obtained contrast image data in a memory device located within or outside the apparatus. For example, the image storage device 20 is implemented as a computer device such as a server.

[0040] The medical image processing device 30 obtains medical image data from the X-ray diagnostic apparatus 10 or the image storage device 20 via a network and performs various processing operations using the obtained medical image data. The medical image processing device 30 is implemented, for example, by a computer such as a workstation. Furthermore, the X-ray diagnostic apparatus 10, the image storage device 20, and the medical image processing device 30 can be installed in any location as long as they can be connected via a network. For example, the medical image processing device 30 can be installed in a facility or hospital separate from the X-ray diagnostic apparatus 10. Furthermore, the medical image processing device 30 can be installed on the X-ray diagnostic apparatus 10.

[0041] The medical image processing apparatus 30 includes an input interface 31 , a display 32 , a memory 33 , and a processing circuit 34 .

[0042] The input interface 31 accepts various input operations from the operator, converts the accepted input operations into electrical signals, and outputs the converted electrical signals to the processing circuit 34. For example, the input interface 31 is implemented by a mouse, a keyboard, a trackball, a switch, a button, a joystick, a touchpad for performing input operations by touching the operation surface, a touch screen integrating a display screen and a touchpad, a non-contact input circuit using an optical sensor, a sound input circuit, etc. In addition, the input interface 31 can also be composed of a tablet terminal that can wirelessly communicate with the medical image processing device 30. In addition, the input interface 31 is not limited to an interface with physical operating components such as a mouse and a keyboard. For example, a processing circuit that receives an electrical signal corresponding to an input operation from an external input device that is separate from the medical image processing device 30 and outputs the electrical signal to the processing circuit 34 is also included in the example of the input interface 31. The input interface 31 is an example of an input unit.

[0043] The display 32 is composed of a display body that displays various information such as medical images, an internal circuit that supplies a display signal to the display body, and peripheral circuits such as connectors and cables that connect the display body and the internal circuit. The internal circuit superimposes the accompanying information such as the subject information and the projection data generation conditions on the image data supplied from the processing circuit 34 to generate display data, performs D / A conversion and TV format conversion on the obtained display data, and displays it on the display body. For example, the display 32 outputs the medical image obtained or generated by the processing circuit 34, a graphical user interface GUI (Graphical User Interface) for accepting various operations from the operator, etc. For example, the display 32 is a liquid crystal display or a cathode ray tube CRT (Cathode Ray Tube) display. In addition, the display 32 is an example of a display unit. In addition, the display 32 can be a desktop type, or it can be composed of a tablet terminal that can communicate wirelessly with the medical image processing device 30 body. The display 32 is an example of a display unit.

[0044] 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 types of information. Alternatively, the memory 33 may be a drive device that reads and writes various types of information to and from a portable storage medium such as a CD-ROM drive, DVD drive, or flash memory. Furthermore, the memory 33 does not necessarily need to be implemented by a single storage device. For example, the memory 33 may be implemented by multiple storage devices. Alternatively, the memory 33 may be located in another computer connected to the medical image processing apparatus 30 via a network.

[0045] 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 image of the heart of a subject with non-occlusive coronary artery disease in a baseline state, a first contrast image of the heart in an acetylcholine stress state, and a second contrast image of the heart in an adenosine stress state. The zeroth contrast image, the first contrast image, and the second contrast 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 based on the various functions of the processing circuit 34. Examples of these various data include index data such as blood flow and blood flow ratio, and image data such as ratio images based on this index data. The memory 33 also stores programs for causing a computer to implement the various functions of the processing circuit 34 installed in the medical image processing apparatus 30. These programs, for example, may also be pre-stored in the memory 33. Furthermore, for example, the 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 the memory 33. The memory 33 is an example of a storage unit.

[0046] The processing circuit 34 controls the overall operation of the medical image processing device 30 based on the electrical signal of the input operation output from the input interface 31. For example, the processing circuit 34 has a processor such as a CPU, an MPU, a GPU (Graphics Processing Unit) and a memory such as a ROM and a RAM as hardware resources. The processing circuit 34 is a processor that realizes the acquisition function 34a, the setting function 34b, the calculation function 34c, the image generation function 34d and the display control function 34e corresponding to the program by calling and executing the program in the memory 33. In addition, Figure 1 In the description, a single processing circuit 34 is described as implementing the acquisition function 34a, setting function 34b, calculation function 34c, comparison image generation function 34d, and display control function 34e. However, a processing circuit may be formed by combining multiple independent processors, with each processor executing a program to implement each function. Furthermore, the acquisition function 34a, setting function 34b, calculation function 34c, comparison image generation function 34d, and display control function 34e may be referred to as an acquisition circuit, a setting circuit, a calculation circuit, a comparison image generation circuit, and a display control circuit, respectively, and may be implemented as separate hardware circuits. Furthermore, the various functions within the processing circuit 34 may also 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 integrated into the X-ray diagnostic apparatus 10.

[0047] The acquisition function 34a acquires the zeroth contrast image when the subject's heart is in a reference state, the first contrast image when the heart is in an acetylcholine load state, and the second contrast image when the heart is in an adenosine load state. Here, the reference state is a state that serves as a reference for calculating the blood flow ratio, specifically, a state in which no drug that causes spasm or dilation of the heart's blood vessels is administered. Therefore, the reference state can also be replaced by other names such as a normal state, a standard state, or a no-load state. The acetylcholine load state is a state in which a drug (acetylcholine) that causes spasm of the heart's blood vessels is administered. The adenosine load state is a state in which a drug (adenosine) that dilates the heart's blood vessels is administered. The acquisition destination of each contrast image of the acquisition function 34a is, for example, the image storage device 20. In addition, the acquisition function 34a saves each acquired contrast image in the memory 33. The acquisition function 34a is an example of an acquisition unit.

[0048] The setting function 34b sets a common region of interest for the zeroth contrast image, the first contrast image, and the second contrast image. For example, the setting function 34b can manually set a region of interest for one of the zeroth through second contrast images, and automatically set regions of interest for the remaining two contrast images. Specifically, for example, the setting function 34b can set a region of interest for the zeroth contrast image based on an operator's operation, and then set regions of interest at the same location in the first and second contrast images in conjunction with the location of the region of interest in the zeroth contrast image. The setting function 34b is an example of a setting unit.

[0049] The calculation function 34c calculates a first blood flow ratio representing the ratio of the zeroth blood flow of the myocardium in the baseline state to the first blood flow of the myocardium in the acetylcholine-loaded state based on the zeroth contrast image and the first contrast image. For example, the calculation function 34c may calculate the first blood flow ratio in the region of interest of each of the zeroth contrast image and the first contrast image. The first blood flow ratio in the region of interest may be calculated as, for example, the maximum or average value of the 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 image and the first contrast image. Alternatively, for example, the calculation function 34c may calculate the first blood flow ratio by dividing the pixel values ​​of the corresponding pixels in the myocardial region of the zeroth contrast image and the myocardial region of the first contrast image.

[0050] In addition, the calculation function 34c calculates a second blood flow ratio representing the ratio of the zeroth blood flow to the second blood flow of the myocardium under adenosine loading based on the zeroth contrast image and the second contrast image. For example, the calculation function 34c may also calculate the second blood flow ratio in the respective regions of interest of the zeroth contrast image and the second contrast image. The second blood flow ratio in the region of interest may be calculated as, for example, the maximum value or average value of the absolute value of the blood flow ratio of each pixel in the region of interest. In addition, for example, the calculation function 34c may also calculate the second blood flow ratio for each corresponding pixel in the zeroth contrast image and the second contrast image. In addition, for example, the calculation function 34c may also calculate the second blood flow ratio by dividing the pixel values ​​of the corresponding pixels in the myocardial region of the zeroth contrast image and the myocardial region of the second contrast image. The calculation function 34c is an example of the first calculation unit and the second calculation unit.

[0051] The ratio image generation 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 generation function 34d is an example of a ratio image generation unit.

[0052] The display control function 34e controls the display to display a desired image. For example, the display control function 34e causes the first blood flow ratio and the second blood flow ratio to be displayed side by side on the display 32. Alternatively, for example, the display control function 34e may cause the first and second blood flow ratios to be displayed on the display 32 in at least one of numerical and graphical formats. For example, in the case of numerical formats, the display control function 34e may cause the first blood flow ratio to be displayed in a first display format when the first blood flow ratio in the region of interest is below a first threshold, and may cause the second blood flow ratio to be displayed in a second display format when the second blood flow ratio in the region of interest is below a second threshold. Here, the first display format may, for example, be a color display or an alarm display indicating an abnormality in the first blood flow ratio. The second display format may, for example, be a color display or an alarm display indicating an abnormality in the second blood flow ratio. Furthermore, in the case of graphical formats, the display control function 34e may cause the display 32 to display the first and second ratio images in color 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 zero blood flow rate, the first blood flow rate, and the second blood flow rate in parallel on the display 32. The display control function 34e is an example of a display control unit.

[0053] Next, use Figure 2 Flowchart and Figure 3 and Figure 4The operation of the medical image processing apparatus configured as described above is explained with reference to a schematic diagram. Furthermore, it is assumed that the image storage device 20 has previously stored the zeroth contrast image, the first contrast image, and the second contrast image collected by the X-ray diagnostic apparatus 10. The zeroth contrast image is an X-ray image of the heart of a subject with non-occlusive coronary artery disease in a baseline state. The first contrast image is an X-ray image of the heart in an acetylcholine-loaded state. The second contrast image is an X-ray image of the heart in an adenosine-loaded state.

[0054] (Step ST10)

[0055] like Figure 2 As shown, the processing circuit 34 of the medical image processing apparatus 30 obtains the zeroth contrast image, the first contrast image, and the second contrast image of the subject from the image storage apparatus 20 according to the operator's operation, and stores each contrast image in the memory 33. Figure 3 As shown, the zeroth contrast-enhanced image g0 is a dynamic image having multiple frames along a time series, and shows how the contrast agent injected from the catheter flows into the myocardial area through the coronary arteries and capillaries along a time series. The same applies to the first contrast-enhanced image and the second contrast-enhanced image.

[0056] (Step ST20)

[0057] The processing circuit 34 processes the data according to the operator's operation. Figure 4 As shown in the upper section of FIG, the display 32 displays the zeroth contrast image g0, the first contrast image g1, and the second contrast image g2. Furthermore, the processing circuit 34 sets a common region of interest (ROI) for the zeroth contrast image g0, the first contrast image g1, and the second contrast image g2 in response to an operator's operation. For example, the processing circuit 34 sets an arterial ROI 201 for a portion of the coronary artery within the zeroth contrast image g0 and a myocardial ROI 202 for a portion of the myocardial region within the zeroth contrast image g0 in response to the operation of the cursor cs. Furthermore, the processing circuit 34 sets the arterial ROI 201 at the same position within the first contrast image g1 and the second contrast image g2, respectively, in conjunction with the position of the arterial ROI 201 within the zeroth contrast image g0. Similarly, the processing circuit 34 sets the myocardial ROI 202 at the same position within the first contrast image g1 and the second contrast image g2, respectively, in conjunction with the position of the myocardial ROI 202 within the zeroth contrast image g0.

[0058] (Step ST30)

[0059] Based on the zeroth contrast-enhanced image g0 and the first contrast-enhanced image g1, the processing circuit 34 calculates a first blood flow ratio representing the ratio of the zeroth blood flow of the myocardium in the baseline state to the first blood flow of the myocardium in the acetylcholine-loaded state. For example, the processing circuit 34 calculates the first blood flow ratio in the myocardial ROI 202 in each of the zeroth contrast-enhanced image g0 and the first contrast-enhanced image g1. Alternatively, the first myocardial blood flow ratio can be obtained by separately calculating the zeroth blood flow and the first blood flow and dividing the first blood flow by the zeroth blood flow.

[0060] 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 zeroth contrast-enhanced image g0 at time t from the start of contrast agent injection, and Ia(τ) be the brightness of the blood vessels in the zeroth contrast-enhanced image g0 at time τ (0 ≤ τ ≤ t). In this case, the processing circuit 34 calculates the zeroth myocardial blood flow K1 in the reference state based on equation (1).

[0061]

[0062] Similarly, the brightness of the myocardium in the first contrast-enhanced image g1 at time t is defined as Im(t)ACh, and the brightness of the blood vessels in the first contrast-enhanced image g1 at time τ is defined as Ia(τ). At this time, the processing circuit 34 calculates the first myocardial blood flow K1_ACh under acetylcholine loading based on equation (2).

[0063]

[0064] Then, the processing circuit 34 calculates a first myocardial blood flow ratio (K1_ACh / K1) by dividing the calculated first blood flow K1_ACh by the calculated zeroth blood flow K1.

[0065] Similarly, the brightness of the myocardium in the second contrast-enhanced image g2 at time t is defined as Im(t)ATP, and the brightness of the blood vessels in the second contrast-enhanced image g2 at time τ is defined as Ia(τ). The processing circuit 34 calculates the second myocardial blood flow K1_ATP under adenosine loading based on equation (3).

[0066]

[0067] Then, the processing circuit 34 calculates a second myocardial blood flow ratio (K1_ATP / K1) by dividing the calculated second blood flow K1_ATP by the calculated zeroth blood flow K1.

[0068] (Step ST40)

[0069] The processing circuit 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. Furthermore, the processing circuit 34 generates a zeroth blood flow image f0 having pixel values ​​corresponding to the zeroth blood flow K1 calculated for each pixel. Similarly, the processing circuit 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.

[0070] (Step ST50)

[0071] like Figure 4 As shown in the second section of FIG, the processing circuit 34 causes the display 32 to display the zeroth blood flow image f0, the first blood flow image f1, and the second blood flow image f2 in parallel. Figure 4 As shown in the third section of FIG, the processing circuit 34 causes the display 32 to display the first ratio image r1 and the second ratio image r2 in parallel. The first ratio image r1 and the second ratio image r2 are examples of images displaying the first and second blood flow ratios. The first ratio image r1 includes a vasospasm region A1 within the image, which has a relatively low first blood flow ratio. The second ratio image r2 includes a vasodilation region A2 within the image, which has a relatively high second blood flow ratio. The zero 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 each pixel a color corresponding to the pixel value.

[0072] In addition, the processing circuit 34 is as follows Figure 4 As shown in the lower portion of FIG, the zeroth blood flow K1 (e.g., 3.0), the first blood flow K1_ACh (e.g., 2.4), and the second blood flow K1_ATP (e.g., 3.9) are displayed in parallel on the display 32 as values ​​within the myocardial ROI 202. Similarly, the processing circuit 34 displays 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)) in parallel on the display 32 as values ​​within the myocardial ROI 202.

[0073] Furthermore, under acetylcholine loading, no change is normal, while changes (decreased blood flow) are abnormal. Under adenosine loading, no change is abnormal, while changes (increased blood flow) are normal.

[0074] If supplementation is performed, then during an acetylcholine stress test, if the first blood flow rate K1_ACh remains unchanged compared to the zero blood flow rate K1, it is normal; however, a decrease in the first blood flow rate K1_ACh indicates a disease. Specifically, during an acetylcholine stress test, if the first blood flow ratio exceeds a first threshold (e.g., 0.5 times), it is normal; while if the first blood flow ratio decreases below the first threshold, it indicates a disease. Diseases detected during an acetylcholine stress test correspond to microvascular spasms, a cause of INOCA.

[0075] Furthermore, during an adenosine stress test, if the second blood flow rate K1_ATP remains unchanged compared to the zero blood flow rate K1, it indicates a disease, while an increase in the second blood flow rate K1_ATP indicates normality. Specifically, during an adenosine stress test, if the second blood flow ratio is below a second threshold value (e.g., 1.8 times), it indicates a disease, while an increase in the second blood flow ratio exceeding the second threshold value indicates normality. Diseases detected during an adenosine stress test correspond to nondilation of microvasculature, a cause of INOCA.

[0076] In addition, Figure 4 In FIG. 2 , the hatching around the second blood flow ratio “1.3 times” is an example of an alarm display indicating an abnormality when the second blood flow ratio in the myocardial ROI 202 is equal to or less than the second threshold value (1.8 times).

[0077] Therefore, as in Figure 4 As shown in FIG. 1 , the operator can check contrast images g0 to g2 , blood flow images f0 to f2 , ratio images r1 and r2 , blood flow volume, and blood flow ratio for each of the subject's baseline state, acetylcholine load state, and adenosine load state.

[0078] As described above, according to the first embodiment, the processing circuit 34 obtains the zeroth contrast image g0 of the subject's heart in a baseline state, the first contrast image g1 of the heart in an acetylcholine stress state, and the second contrast image g2 of the heart in an adenosine stress state. Based on the zeroth contrast image g0 and the first contrast image g1, the processing circuit 34 calculates a first blood flow ratio, representing the ratio of the zeroth blood flow K1 of the myocardium in the baseline state to the first blood flow K1_ACh of the myocardium in the acetylcholine stress state. Based on the zeroth contrast image g0 and the second contrast image g2, the processing circuit 34 calculates a second blood flow ratio, representing the ratio of the zeroth blood flow K1 to the second blood flow K1_ATP of the myocardium in the adenosine stress state. The processing circuit 34 displays the first and second blood flow ratios side by side on the display 32. By calculating the blood flow ratio based on contrast images in this manner, during INOCA examinations, blood flow can be quantitatively measured from contrast images without using sensor wires, and measurement results such as blood flow and blood flow ratio can be displayed.

[0079] Furthermore, according to the first embodiment, the processing circuit 34 displays the first blood flow ratio and the second blood flow ratio in at least one of numerical values ​​and images on the display 32. Therefore, in addition to the above-described effects, the blood flow ratio can be displayed in a desired form.

[0080] Furthermore, according to the first embodiment, the processing circuit 34 sets the arterial ROI 201 and the myocardial ROI 202 as common regions of interest in the zeroth contrast-enhanced image g0, the first contrast-enhanced image g1, and the second contrast-enhanced image g2. The processing circuit 34 calculates the first blood flow ratio in the myocardial ROI 202 for each of the zeroth contrast-enhanced image g0 and the first contrast-enhanced image g1. The processing circuit 34 calculates the second blood flow ratio in the myocardial ROI 202 for each of the zeroth contrast-enhanced image g0 and the second contrast-enhanced image g2. When the first blood flow ratio in the myocardial ROI 202 is below a first threshold value, the processing circuit 34 displays the first blood flow ratio in a first display mode. Similarly, when the second blood flow ratio in the myocardial ROI 202 is below a second threshold value, the processing circuit 34 displays the second blood flow ratio in a second display mode. Therefore, in addition to the aforementioned effects, the display in the first and second display modes when the first and second blood flow ratios are below the threshold values ​​can encourage the operator's attention.

[0081] Furthermore, according to the first embodiment, the first display mode is a color display or an alarm display indicating an abnormality in the first blood flow ratio. The second display mode is a color display or an alarm display indicating an abnormality in the second blood flow ratio. Therefore, in addition to the aforementioned effects, the color display or the alarm display can further encourage the operator's attention.

[0082] Furthermore, according to the first embodiment, the processing circuit 34 calculates a first blood flow ratio for each corresponding pixel in the zeroth contrast image g0 and the first contrast image g1. The processing circuit 34 calculates a second blood flow ratio for each corresponding pixel in the zeroth contrast image g0 and the second contrast image g2. The processing circuit 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 image format, the processing circuit 34 assigns colors to the pixel values, causing the display 32 to display the first and second ratio images in color. Therefore, in addition to the aforementioned effects, the color display of the blood flow ratio for each pixel allows the operator to easily and visually present the distribution of blood flow ratios in non-obstructive coronary artery disease.

[0083] Furthermore, according to the first embodiment, the processing circuit 34 further arranges at least the first blood flow K1_ACh and the second blood flow K1_ATP among the zero blood flow K1, the first blood flow K1_ACh, and the second blood flow K1_ATP, and displays them on the display 32. In this case, in addition to the aforementioned effects, the operator can also visually recognize the first blood flow K1_ACh and the second blood flow K1_ATP of the myocardium.

[0084] Furthermore, according to the first embodiment, the zeroth contrast-enhanced image g0, the first contrast-enhanced image g1, and the second contrast-enhanced image g2 are medical images captured under substantially identical imaging conditions, excluding the cardiac condition. Therefore, in addition to the aforementioned effects, when measuring blood flow ratios based on multiple contrast-enhanced images, the effects of variations in imaging conditions between the contrast-enhanced images can be suppressed.

[0085] (Modification of the first embodiment)

[0086] In the first embodiment, the first blood flow ratio is calculated by calculating the zeroth blood flow K1 and the first blood flow K1_ACh, but this is not limiting. For example, instead of calculating the zeroth blood flow K1 and the first blood flow K1_ACh, the processing circuit 34 may determine the first myocardial blood flow ratio (K1_ACh / K1) as the ratio of the brightness of the first contrast image to the zeroth contrast image (Im(t)ACh / Im(t)), as shown in equation (4). Specifically, the processing circuit 34 may calculate the first 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 first contrast image g1.

[0087]

[0088] In this case, in addition to the effects of the first embodiment, the load and time for calculating the zero-th blood flow rate K1 and the first blood flow rate K1_ACh can be reduced.

[0089] Similarly, in the first embodiment, the second blood flow ratio is calculated by calculating the zeroth blood flow K1 and the second blood flow K1_ATP, but the present invention is not limited to this. For example, instead of calculating the zeroth blood flow K1 and the second blood flow K1_ATP, the processing circuit 34 may determine 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 circuit 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.

[0090]

[0091] In this case, in addition to the effects of the first embodiment, the load and time for calculating the zeroth blood flow rate K1 and the second blood flow rate K1_ATP can be reduced.

[0092] In addition, in the first embodiment, the first blood flow ratio and the second blood flow ratio are calculated relative to the zeroth blood flow in the baseline state, but the present invention is not limited to this. For example, the calculation function 34c of the processing circuit 34 can also calculate the third blood flow ratio (K1_ATP / K1_ACh) by dividing the pixel values ​​of the corresponding pixels in the myocardial region of the first contrast image g1 and the myocardial region of the second contrast image g2. For example, as shown in formula (6), the processing circuit 34 can also calculate the third blood flow ratio as the brightness ratio (Im(t)ATP / Im(t)ACh) of the second contrast image g2 and the first contrast image g1. Alternatively, the processing circuit 34 can also calculate the third blood flow ratio as the ratio of the second blood flow K1_ATP in formula (3) to the first blood flow K1_ACh in formula (2), as shown in formula (6). In addition, when calculating the third blood flow ratio, the first blood flow ratio and the second blood flow ratio can be omitted, or they can be calculated in the same manner as described above. The calculation function 34c is an example of a third calculation unit. In addition, the processing circuit 34 causes the display 32 to display the third blood flow ratio.

[0093]

[0094] According to this modification, in addition to the effects of the first embodiment, the blood flow ratio can be measured without using the data of the zeroth contrast image g0 in the reference state. Furthermore, since alignment and various linearization operations are not required when reducing the data used, faster and more stable processing can be achieved.

[0095] Furthermore, in the first embodiment, both the first blood flow image f1 and the second blood flow image f2, as well as the first ratio image r1 and the second ratio image r2, are displayed, but this is not limiting. For example, the processing circuit 34 may omit the display of the first ratio image r1 and the second ratio image r2. Alternatively, the processing circuit 34 may omit the display of the first blood flow image f1 and the second blood flow image f2. Furthermore, the presence or absence of the display of the contrast image, the blood flow image, and the ratio image may be appropriately selected based on the operator's operation. In such a modified embodiment, the display can be simplified while achieving the same effects as the first embodiment. Furthermore, this modified embodiment can also be applied to a method in which blood flow is displayed instead of blood flow ratio when only blood flow ratio is displayed. Therefore, it can also be similarly applied to other embodiments related to the display range of the ratio image and the graphical display of the blood flow ratio.

[0096] <Second embodiment>

[0097] The second embodiment is different from the first embodiment in that the display ranges of the first comparison image r1 and the second comparison image r2 are not aligned, and the display ranges of the first comparison image r1 and the second comparison image r2 are aligned.

[0098] In addition to the aforementioned functions, the display control function 34e of the processing circuit 34 also includes: Figure 5 As shown in the example, the pixel values ​​are assigned colors so that the baseline (0) of the display range (0-1) of the first comparison image r1 is aligned with the baseline (1) of the display range (1-2) of the second comparison image r2. Here, the display range (0-1) of the first comparison image r1 corresponds to the range (0-1) of the first blood flow ratio in the acetylcholine loading state, which causes microvascular spasm. This is because the first blood flow ratio decreases to a value below 1 as microvascular spasm occurs. The first comparison image r1 assigns 256 levels of color to the 256 levels of pixel values ​​corresponding to the first blood flow ratio from 0 to 1. The colors used vary in 256 levels, from white to blue, light blue, yellow-green, yellow, and red. Similarly, the display range (1-2) of the second comparison image r2 corresponds to the range (1-2) of the second blood flow ratio in the adenosine loading state, which causes microvascular dilation. This is because the second blood flow ratio increases to a value above 1 as microvascular dilation occurs. Furthermore, the upper limit of the second blood flow ratio may exceed 2. However, in this example, the second blood flow ratio is normalized within the range of 1 to 2 by setting the upper limit of the second blood flow ratio to 2. In the second ratio image r2, 256 levels of color are assigned to the 256 levels of pixel values ​​corresponding to the second blood flow ratio normalized to the range of 1 to 2.

[0099] The other configurations are the same as those of the first embodiment.

[0100] With the above configuration, the processing circuit 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, the processing circuit 34 causes the display 32 to display the first ratio image r1 and the second ratio image r2, aligned with the baseline of the display range. Therefore, the operator can 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 the same color in the display range.

[0101] As described above, according to the second embodiment, the processing circuit 34 assigns colors to pixel values ​​so that the baselines of the display range of the first comparison image r1 and the display range of the second comparison image r2 are aligned. This, in addition to the aforementioned effects, allows the first comparison image r1 and the second comparison image r2 to be displayed in color with their display range baselines aligned.

[0102] (Modification of the Second Embodiment)

[0103] In the second embodiment, the baselines of the display ranges of the first comparative image r1 and the second comparative image r2 are aligned, but the present invention is not limited thereto. Figure 6 As shown, the processing circuit 34 may also display the first ratio image r1 and the second ratio image r2 in color by assigning the same color to the pixel values ​​corresponding to the first threshold th1 for distinguishing between normal and abnormal first blood flow ratios in the first ratio image r1 and the pixel values ​​corresponding to the second threshold th2 for distinguishing between normal and abnormal second blood flow ratios in the second ratio image r2.

[0104] 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 normalized to a range of 1 to 2.6 by setting the upper limit of the second blood flow ratio to 2.6 to align the second threshold th2 with the first threshold th1. The second blood flow ratio in the modified example, r2, is normalized to a range of 1 to 2.6. The 256 levels of color are assigned to the 256 pixel values ​​corresponding to the second blood flow ratio normalized to a range of 1 to 2.6.

[0105] The other configurations are the same as those of the first embodiment.

[0106] According to the above-described variation of the second embodiment, the processing circuit 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, the processing circuit 34 aligns the baselines of the display range and the first and second thresholds, causing the display 32 to display the first and second comparison images r1 and r2. Consequently, the operator can visually identify abnormal areas of the first blood flow ratio within the first comparison image r1 and abnormal areas of the second blood flow ratio within the second comparison image r2 using the same color display. In addition to the advantages of the second embodiment, this also makes it easier to visually identify abnormalities in the blood flow ratios of the first and second comparison images r1 and r2.

[0107] <Third embodiment>

[0108] The third embodiment differs from the second embodiment in the display range of each of the first comparison image r1 and the second comparison image r2 in that a first graph indicating the first blood flow ratio and a second graph indicating the second blood flow ratio are displayed.

[0109] In addition to the aforementioned functions, the display control function 34e of the processing circuit 34 also includes: Figure 7As shown, a first graph showing a first blood flow ratio and a first threshold value th1 in the myocardial ROI 202 and a second graph showing a second blood flow ratio and a second threshold value th2 in the myocardial ROI 202 are displayed side by side on the display 32. For example, the processing circuit 34 may display the first graph and the second graph on the display 32 in any of the display areas 211 to 213.

[0110] The display area 211 displays the first graph and the second graph side by side in such a manner that the baseline of the description range (0-1) of the first graph is aligned with the baseline of the description range (1-2) of the second graph. Figure 5 The method shown corresponds to

[0111] The display area 212 displays the first and second graphs side by side in such a way that the first threshold value th1 in the first graph is aligned with the second threshold value th2 in the second graph. That is, the description range (0-1) of the first graph is the same as that of the display area 211. The description range (1-3.5) of the second graph is to set the upper limit of the second blood flow ratio to 3.5 so that the second threshold value th2 matches the first threshold value th1, thereby normalizing the second blood flow ratio within the range of 1 or more and 3.5 or less. This display area 212 is similar to the aforementioned Figure 6 The method shown corresponds to

[0112] The display area 213 displays the normal range and the abnormal range using the first threshold th1 as a dividing line in the first graph, and displays the normal range and the abnormal range using the second threshold th2 as a dividing line in the second graph.

[0113] The other configurations are the same as those of the second embodiment.

[0114] With the above configuration, the processing circuit 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, the processing circuit 34 displays a first graph showing the first blood flow ratio and the first threshold value th1 in the myocardial ROI 202, and a second graph showing 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 circuit 34 displays the first graph and the second graph on the display 32 as shown in any of the display areas 211 to 213. Therefore, the operator can visually recognize the first graph showing the first blood flow ratio and the first threshold value th1, and the second graph showing the second blood flow ratio and the second threshold value th2.

[0115] As described above, according to the third embodiment, the processing circuit 34 displays a first graph showing the first blood flow ratio and the first threshold value in the myocardial ROI 202 and a second graph showing 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 aforementioned effects, the operator can visually recognize each blood flow ratio and each threshold value th1, th2 in the form of a bar graph. Figure 7 In the embodiment, the first graph and the second graph are each a bar graph, but the present invention is not limited thereto. However, from the perspective of easy comparison, the first graph and the second graph are preferably graphs of the same type.

[0116] Furthermore, according to the third embodiment, the processing circuit 34 may display the first and second graphs side by side so that the baseline of the description range of the first graph is aligned with the baseline of the description range of the second graph. In this case, the first and second graphs can be displayed side by side with the baselines of the description ranges aligned.

[0117] Furthermore, according to the third embodiment, the processing circuit 34 may display the first and second graphs side by side so that the first threshold value in the first graph is aligned with the second threshold value in the second graph. In this case, it is easier to visually determine whether the blood flow ratio in each of the first and second graphs is abnormal.

[0118] Furthermore, according to the third embodiment, the processing circuit 34 may display the normal range and the abnormal range in the first graph using the first threshold value th1 as a dividing line, and display the normal range and the abnormal range in the second graph using the second threshold value th2 as a dividing line. In this case, it is easier to visually identify whether the blood flow ratio in each of the first and second graphs is abnormal.

[0119] <Fourth embodiment>

[0120] The fourth embodiment differs from the third embodiment in that a plurality of graphs are displayed in parallel, in that the first blood flow ratio and the second blood flow ratio are displayed in one graph.

[0121] In addition to the aforementioned functions, the display control function 34e of the processing circuit 34 causes the display 32 to display a comparison chart showing the first blood flow ratio and the second blood flow ratio in the myocardial ROI 202 compared with the reference value, when the blood flow ratio (K1 / K1) at the zeroth blood flow K1 is set to the reference value of 1. For example, Figure 8 As shown, the processing circuit 34 may also display the comparison charts 221 and 221 a on the display 32 .

[0122] Here, the comparison chart 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 chart 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 to the reference value (1) in the reference state Bs with straight lines.

[0123] The comparison chart 221 a displays the normal range and the abnormal range for the first blood flow ratio and the second blood flow ratio, respectively, within the comparison chart 221 .

[0124] The other configurations are the same as those of the third embodiment.

[0125] With the above configuration, the processing circuit 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, the processing circuit 34 sets the blood flow ratio (K1 / K1) at the zeroth blood flow rate K1 to the reference value of 1, and causes the display 32 to display a comparison chart 221 or 221a showing the first and second blood flow ratios in the myocardial ROI 202, respectively, compared with the reference value. Therefore, the operator can visually recognize the comparison chart 221 or 221a showing the first and second blood flow ratios relative to the reference value.

[0126] As described above, according to the fourth embodiment, the processing circuit 34 causes the display 32 to display comparison graphs 221 and 221a that compare the first and second blood flow ratios in the myocardial ROI 202 with the reference value, respectively, when the blood flow ratio (K1 / K1) at the zeroth blood flow rate K1 is set to 1. This allows the two blood flow ratios to be compared and visually recognized within a single comparison graph 221 or 221a.

[0127] Furthermore, according to the fourth embodiment, the processing circuit 34 can display a comparison chart 221a in which the normal range and the abnormal range are displayed for the first blood flow ratio and the second blood flow ratio, respectively, within the comparison chart 221. This provides, in addition to the aforementioned effects, a visual indication of whether the two blood flow ratios are within the normal range or the abnormal range can be obtained on the comparison chart 221a.

[0128] (Modification of the Fourth Embodiment)

[0129] In addition, in the fourth embodiment, the horizontal axis of the comparison charts 221 and 221a is set to state, but it is not limited to this. Figure 9As shown, the processing circuit 34 may also display a comparison chart 222 or 222a on the display 32, in which the horizontal axis of the comparison chart 221 or 221a represents load. In the comparison charts 222 and 222a, the horizontal axis represents load, so "ACh," indicating the acetylcholine load state, is placed near the white circle representing the first blood flow ratio, and "ATP," indicating the adenosine load state, is placed near the white square representing the second blood flow ratio. This modification also achieves the same effects as the fourth embodiment.

[0130] In the modified example of the fourth embodiment, the first blood flow ratio and the second blood flow ratio are separated in the vertical direction from the reference value "1" in the comparison charts 222 and 222a, but the present invention is not limited to this. Figure 10 and Figure 11 As shown, the processing circuit 34 may display the first blood flow ratio in comparison charts 223 and 223a in a state where the description range is inverted centered around the reference value, and may also display the threshold values ​​th1 and th2 for the first and second blood flow ratios, respectively, in comparison charts 223 and 223a. Furthermore, the processing circuit 34 may display the normal range and abnormal range for the first and second blood flow ratios, respectively. According to this variation, the comparison chart 223 can be visually recognized in a manner where the first and second blood flow ratios, respectively, extend upward from the reference value "1."

[0131] In addition, in the modified example of the fourth embodiment, the comparison chart 223a displays the normal range and the abnormal range for the first blood flow ratio and the second blood flow ratio, respectively, but the present invention is not limited thereto. For example, the processing circuit 34 may also display the normal range and the abnormal range as shown in FIG. Figure 12 As shown, with the reference value "1" positioned at the bottom, the first blood flow ratio is displayed in the comparison chart 224 in an inverted state (0 at the bottom and 1 at the top) with the description range restored, and the threshold values ​​th1 and th2 for the first and second blood flow ratios are displayed in the comparison chart 224. According to this modification, the comparison chart 224 can be visually recognized as follows: the first blood flow ratio and the second blood flow ratio both have a common normal range and abnormal range, and the first blood flow ratio and the second blood flow ratio each extend upward from the reference value "1."

[0132] <Fifth embodiment>

[0133] The fifth embodiment differs from the first to fourth embodiments in that it displays blood flow ratios in that it determines whether the cause of INOCA is vascular or myocardial. Specifically, the fifth embodiment distinguishes between coronary artery spasm of the epicardial coronary arteries and microvascular spasm (MVS) of the coronary microvessels.

[0134] Here, if Figure 13 As shown, the processing circuit 34 further includes a determination function 34f. Determination function 34f determines whether myocardial blood flow in the subject is reduced based on the myocardial blood flow image, and determines whether blood vessels in the subject are stenotic based on the first contrast image. The determination result is that if myocardial blood flow in the subject is reduced and blood vessels in the subject are stenotic, coronary artery spasm is detected; if myocardial blood flow in the subject is reduced and blood vessels in the subject are not stenotic, microvascular spasm is detected. Determination function 34f is an example of a determination unit.

[0135] In addition to the aforementioned functions, the acquisition function 34a of the processing circuit 34 also acquires a myocardial blood flow image when the subject's heart is under acetylcholine stress. The myocardial blood flow image is, for example, an electrocardiogram-synchronized coronary angiography image obtained by X-ray angiography using the X-ray diagnostic apparatus 10. The acquisition destination is, for example, the image storage device 20.

[0136] Furthermore, in addition to the aforementioned functions, the display control function 34 e of the processing circuit 34 causes the display 32 to display the detected results.

[0137] The other configurations are the same as those of the first embodiment.

[0138] Next, use Figure 14 The flowchart of FIG2 illustrates the operation of the medical image processing apparatus configured as described above. Furthermore, the image storage device 20 pre-stores myocardial blood flow images collected by the X-ray diagnostic apparatus 10. These myocardial blood flow images are electrocardiogram-synchronized coronary angiography images obtained by X-ray angiography while the subject's heart is under acetylcholine stress.

[0139] like Figure 14 As shown, the processing circuit 34 of the medical image processing apparatus 30 acquires a myocardial blood flow image of the subject's heart in an acetylcholine stress state from the image storage apparatus 20 according to an operator's operation (step ST110 ), and stores the myocardial blood flow image in the memory 33 .

[0140] The processing circuit 34 determines whether the myocardial blood flow of the subject is reduced based on the myocardial blood flow image (step ST120 ). If not, it detects the absence of vasospasm (step ST130 ), displays the detection result on the display 32 , and ends the processing.

[0141] If the result of determination in step ST120 is that myocardial blood flow is reduced, the processing circuit 34 determines whether or not a blood vessel of the subject is stenotic based on the first contrast-enhanced image g1 (step ST140 ).

[0142] If the result of determination in step ST140 is that the blood vessels of the subject are stenotic, the processing circuit 34 detects coronary artery spasm in the heart of the subject (step ST150 ), displays the detection result on the display 32 , and ends the processing.

[0143] On the other hand, if the result of step ST140 is that the blood vessels of the subject are not stenotic, the processing circuit 34 detects the presence of microvascular spasm (MVS) in the heart of the subject (step ST160), displays the detection result on the display 32, and ends the processing.

[0144] Therefore, the operator can visually check the display screen of the detection results and can understand the presence or absence of vasospasm, coronary artery spasm, and microvascular spasm in the heart of the subject.

[0145] As described above, according to the fifth embodiment, the processing circuit 34 also obtains a myocardial blood flow image when the heart is under acetylcholine stress. Based on the myocardial blood flow image, the processing circuit 34 determines whether the subject's myocardial blood flow is reduced, and based on the first contrast image, determines whether the subject's blood vessels are stenotic. The processing circuit 34 determines that coronary artery spasm has been detected if both the subject's myocardial blood flow and blood vessels are stenotic, and that microvascular spasm has been detected if both the subject's myocardial blood flow and blood vessels are not stenotic. The processing circuit 34 displays this detection result on the display 32. Therefore, in addition to the aforementioned effects, it is possible to detect coronary artery spasm and microvascular spasm in the subject's heart based on the myocardial blood flow image and the first contrast image when the heart is under acetylcholine stress.

[0146] <Sixth embodiment>

[0147] The sixth embodiment differs from the first embodiment in that the blood flow rate and blood flow ratio are displayed, and is a method of displaying the blood flow rate, transit time, and blood flow ratio.

[0148] Specifically, for example, in addition to the aforementioned functions, the processing circuit 34 may also: Figure 15 As shown, the display 32 is also caused to display a measurement value display area 231 , a time-density curve 232 , and a schematic diagram 233 .

[0149] The measured value display area 231 displays the measured values ​​of indicators related to cardiac blood flow, along with potential causes of abnormal measured values. These values ​​include baseline blood flow (K1), arterial-venous transit time, the first blood flow ratio (K1_ACh / K1) under acetylcholine loading, and the second blood flow ratio (K1_ATP / K1) under adenosine loading.

[0150] Examples of major causes include increased microvascular resistance associated with blood flow (K1), slow flow associated with transit time T, microvascular spasm associated with the first blood flow ratio (K1_ACh / K1), and impaired microvascular dilation associated with the second blood flow ratio (K1_ATP / K1). Slow flow is an indicator related to the velocity of contrast agent flow, and can be expressed as the inverse of transit time T (distance = velocity × time).

[0151] The vertical axis of time-density curve 232 represents contrast agent concentration C, and the horizontal axis represents time. Time-density curve 232 shows the time dependence of contrast agent concentration C in arterial ROI 201, myocardial ROI 202, and venous ROI 203, as shown in schematic diagram 233. This time-density curve 232 uses a longer-than-usual measurement time to determine the time dependence of contrast agent concentration C in venous ROI 203. Thus, based on time-density curve 232, the contrast agent transit time T between the artery and vein is determined as the time difference between the peak contrast agent concentration in the artery and the peak contrast agent concentration in the vein. Transit time T is displayed in measurement value display area 231.

[0152] Schematic diagram 233 shows, in contrast-enhanced images g0 to g2, an artery ROI 201, a myocardial ROI 202, and a vein ROI 203. Schematic diagram 233 schematically shows the relationship among arteries, capillaries, myocardium, and veins in the line graph on the right half.

[0153] If supplementation is performed, the time-density curve 232 is measured for each frame, each pixel, or each region of interest of the contrast image. Equation (7) is obtained based on a two-compartment model.

[0154]

[0155] Here, in equation (7) and schematic diagram 233, K1 is the migration constant of the contrast agent from the artery to the myocardial region, expressed in mL / min / g. k2 is the migration constant of the contrast agent from the myocardial region to the vein. Ca(t) is the contrast agent concentration in the artery, corresponding to the curve indicated by "artery" in time-concentration curve 232. Cm(t) is the contrast agent concentration in the myocardial region, corresponding to the curve indicated by "myocardial" in time-concentration curve 232. K1 is also the aforementioned blood flow rate.

[0156] In the early stage after contrast agent injection, the inflow of contrast agent from the artery to the myocardium is much greater than the outflow from the myocardium to the vein, so it can be assumed that K1Ca(t)>>k2Cm(t). Therefore, equation (7) can be transformed into equation (8).

[0157]

[0158] Here, 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 X-ray images are planar, only integrated information along the X-ray path can be measured, and the contrast agent concentration C(t) cannot be directly measured.

[0159] 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 determined from the X-ray image. Here, I(t) is the image brightness in the X-ray image after baseline subtraction. Here, the X-ray path L can be expressed, for example, as the path length La of the artery in centimeters and the path length Lm of the myocardium in centimeters. Accordingly, the image brightness I(t) = C(t)L can be expressed, for example, as the image brightness Im(t) = Cm(t)Lm of the myocardium and the image brightness Ia(t) = Ca(t)La of the artery. Furthermore, by using the contrast agent concentration Cm(t) = Im(t) / Lm and Ca(t) = Ia(t) / La, which are the relationships for the image brightness of the myocardium and arteries, respectively, Equation (8) can be transformed into Equation (9).

[0160]

[0161] Furthermore, the above-mentioned formula (1) can be obtained from formula (9).

[0162] In addition, the other configurations are the same as those of the first embodiment.

[0163] With the above configuration, processing circuit 34 executes steps ST10 to ST50 in the same manner as described above. However, in step ST50, processing circuit 34 causes display 32 to display measurement value display area 231, time-density curve 232, and graph 233. This allows the operator to visually recognize the relationship between the four indicators in measurement value display area 231, time-density curve 232, and each ROI in graph 233.

[0164] As described above, according to the sixth embodiment, the processing circuit 34 causes the display 32 to display the blood flow rate (K1) in the reference state, the transit time T between the artery and vein, the first blood flow ratio (K1_ACh / K1) in the acetylcholine loading state, and the second blood flow ratio (K1_ATP / K1) in the adenosine loading state. Therefore, in addition to the aforementioned effects, the operator can also visually recognize the transit time T between the artery and vein.

[0165] Furthermore, according to the sixth embodiment, by displaying the measured values ​​of the index related to cardiac blood flow and the main cause assumed when the measured values ​​are abnormal in association with each other, it is possible to assist in assuming the main cause when the measured values ​​are abnormal.

[0166] <Seventh embodiment>

[0167] Unlike the first embodiment in which the medical image processing apparatus 30 obtains images from an external image storage device 20 , the seventh embodiment is a method in which the medical image processing apparatus 30 mounted on the X-ray diagnostic apparatus 10 obtains contrast images and calculates and displays the blood flow ratio.

[0168] Figure 16 This diagram shows 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 beam limiter device 15, an X-ray detector 17, a support frame 19, a diagnostic table (not shown) with a top plate 21, an input interface 31, a display 32, a memory 33, and a processing circuit 34. The processing circuit 34 includes a system control function 341, an acquisition function 34a, a setting function 34b, a calculation function 34c, a comparison image generation function 34d, and a display control function 34e. The input interface 31, display 32, memory 33, and processing circuit 34 constitute a console device 37. A configuration omitting the system control function 341 from the console device 37 corresponds to the medical image processing apparatus 30.

[0169] The high voltage generator 11 generates a tube current supplied to the X-ray tube 13 and a tube voltage (high voltage) applied to the X-ray tube 13. Under the control of the system control function 341 in the processing circuit 34, the high voltage generator 11 supplies tube currents suitable for X-ray imaging and X-ray fluoroscopy to the X-ray tube 13, respectively, in accordance with X-ray imaging conditions. Under the control of the system control function 341, the high voltage generator 11 applies tube voltages suitable for X-ray imaging and X-ray fluoroscopy to the X-ray tube 13, respectively, in accordance with X-ray imaging conditions. The application of the tube voltage by the high voltage generator 11 can be a method of applying the tube voltage continuously to the X-ray tube 13 over 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). The following describes the case where the high voltage generator 11 performs X-ray fluoroscopy using the high voltage pulse application method.

[0170] The X-ray tube 13 generates X-rays from the focus of the X-rays (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 to the subject P in a state where the X-rays in the unnecessary area are shielded by the X-ray beam limiter device 15. The maximum irradiation range 131 of the X-rays is indicated by a dotted line. The X-ray tube 13 in this embodiment is described as a rotating anode type X-ray tube. In addition, the X-ray tube 13 in this embodiment can also be another type of X-ray tube such as a fixed anode type X-ray tube. The X-ray tube 13 generates pulsed X-rays discrete at predetermined time intervals as a pulsed high voltage is applied based on a high voltage switch. A lead cone is installed on the X-ray radiation window of the X-ray tube 13 to block out-of-focus X-rays generated outside the tube focus.

[0171] The X-ray beam limiter 15 is located in front of the X-ray tube 13, adjacent to the X-ray radiation window of the X-ray tube 13. The X-ray beam limiter 15 limits the irradiation range of the X-rays generated at the tube's focal point. Furthermore, the X-ray beam limiter 15 may include various filters (such as a radiation quality adjustment filter, an additional filter, and a radiation dose reduction filter) in addition to the X-ray filter.

[0172] The X-ray detector 17 is opposite to the X-ray tube 13 and detects X-rays generated from the X-ray tube 13. The X-ray detector 17 is composed of, for example, a flat panel detector (FPD). The FPD has a plurality of semiconductor detection elements. Alternatively, an image intensifier may be used as the X-ray detector 17. The electrical signals generated by the plurality of semiconductor detection elements in response to the incidence of X-rays are output to an analog-to-digital converter (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 circuit 34.

[0173] The support frame 19 supports the X-ray tube 13 and the X-ray detector 17 so as to be movable. Specifically, the support frame 19 is a C-arm. The C-arm carries the X-ray tube 13 and the X-ray detector 17 in such a manner that the X-ray tube 13 and the X-ray detector 17 are opposite to each other. The pillar (not shown) supports the C-arm via guide rails and linear motion bearings so as to be able to slide in the direction along the C-shape of the C-arm (hereinafter referred to as the first direction). The pillar is set on the floor of the examination room. The pillar supports the C-arm via bearings so as to be able to rotate in a direction orthogonal to the first direction (hereinafter referred to as the second direction). In addition, the pillar can also support the C-arm via bearings so as to be able to move parallel to the short axis direction (X axis) and the long axis direction (Y axis) of the top plate 21. In addition, the C-arm supports the X-ray tube 13 and the X-ray detector 17 in a manner that enables the distance between the focus of the tube ball in the X-ray tube 13 and the center of the X-ray detector 17 (the source image distance (Source Image Distance: hereinafter referred to as SID)) to be changed, for example, via guide rails and linear motion bearings.

[0174] Alternatively, an Ω arm may be used as the support frame 19 instead of a C arm. For example, two arms (e.g., robotic arms) may be used to independently support the X-ray tube 13 and the X-ray detector 17. Furthermore, the support frame 19 may have a dual-plane structure using a C arm and an Ω arm.

[0175] The examination table (not shown) movably supports a top plate 21 (also referred to as a supine position table) on which the subject P is placed. The subject P is placed on the top plate 21 .

[0176] The drive device (not shown) drives, for example, the support frame 19 and the diagnostic table. The drive device includes, for example, a motor and a transmission mechanism (e.g., a chain drive, belt drive, ball screw, etc.) that transmits the force generated by the motor to various components of the drive. The drive device slides the support frame 19 in a first direction and rotates it in a second direction in response to a drive signal corresponding to a control signal output from the processing circuit 34. Alternatively, the drive device can rotate the X-ray detector 17 about the SID as the rotation axis under the control of the system control function 341.

[0177] The drive device drives the top plate 21 under the control of the system control function 341, thereby moving the top plate 21. Thus, during X-ray fluoroscopy and X-ray photography, the subject P placed on the top plate 21 is arranged between the X-ray tube 13 and the X-ray detector 17. Specifically, based on the control signal output from the processing circuit 34, the drive device slides the top plate 21 along the short axis direction (X-axis direction) and the long axis direction (Y-axis direction) of the top plate 21 via bearings, guide rails, linear motion bearings, etc. In addition, the drive device raises and lowers the top plate 21 in the vertical direction (Z-axis direction) via bearings, guide rails, linear motion bearings, etc. In addition, in order to tilt the top plate 21 with at least one of the long axis direction and the short axis direction as the rotation axis, the drive device can also rotate the top plate 21 via bearings, guide rails, linear motion bearings, etc.

[0178] The input interface 31 inputs X-ray imaging conditions, fluoroscopy / 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 the operator.

[0179] The processing circuit 34 reads various programs for controlling the various circuits and drive devices in the X-ray diagnostic apparatus 10 from the memory 33 and executes the read programs to implement various functions. The processing circuit 34 temporarily stores information such as operator instructions, imaging conditions, and fluoroscopy conditions, sent from the input interface 31, in a memory (not shown). The processing circuit 34, through the system control function 341, controls the high voltage generator 11, the X-ray beam limiter device 15, the drive device, and other devices in accordance with the operator instructions, fluoroscopy / imaging positions, and X-ray imaging conditions stored in the memory, thereby performing X-ray imaging and X-ray fluoroscopy (pulsed X-ray imaging).

[0180] The acquisition function 34a, setting function 34b, calculation function 34c, ratio image generation function 34d, and display control function 34e of the processing circuit 34 function in the same manner as described above. However, the acquisition function 34a acquires the zeroth contrast image g0, the first contrast image g1, and the second contrast image g2 from the memory 33, not from the image storage device 20.

[0181] With the above configuration, the X-ray diagnostic apparatus 10 performs X-ray imaging based on imaging conditions. Specifically, the X-ray tube 13 irradiates the subject P, into which a contrast agent has been injected, with X-rays. The X-ray detector 17 detects the X-rays emitted from the X-ray tube 13 and transmitted through the subject P, and outputs the X-ray detection results. Based on the output of the X-ray detector 17, the processing circuit 34 generates a contrast image of the subject P and stores this contrast image in the memory 33.

[0182] In this manner, the X-ray diagnostic apparatus 10 generates and stores the zeroth contrast image g0 when the heart having INOCA is in the reference state, the first contrast image g1 when the heart is in the acetylcholine stress state, and the second contrast image g2 when the heart is in the adenosine stress state.

[0183] The following steps ST10 to ST50 are executed in the same manner as described above, but the processing circuit 34 acquires the contrast images g0 to g2 from the memory 33 .

[0184] As described above, according to the seventh embodiment, the processing circuit 34 within the X-ray diagnostic apparatus 10 obtains a zeroth contrast image g0 of the subject's heart in a baseline state, a first contrast image g1 of the heart in an acetylcholine stress state, and a second contrast image g2 of the heart in an adenosine stress state. Based on the zeroth contrast image g0 and the first contrast image g1, the processing circuit 34 calculates a first blood flow ratio representing the ratio of the zeroth blood flow K1 of the myocardium in the baseline state to the first blood flow K1_ACh of the myocardium in the acetylcholine stress state. Based on the zeroth contrast image g0 and the second contrast image g2, the processing circuit 34 calculates a second blood flow ratio representing the ratio of the zeroth blood flow K1 to the second blood flow K1_ATP of the myocardium in the adenosine stress state. The processing circuit 34 displays the first and second blood flow ratios side by side on the display 32. In this manner, the processing circuit 34 within the X-ray diagnostic apparatus 10 calculates blood flow ratios based on contrast images. This configuration enables the effects of each of the aforementioned embodiments to be achieved in real time after the contrast imaging is completed.

[0185] According to at least one embodiment described above, during INOCA examination, blood flow can be quantitatively measured without using a sensor line.

[0186] The term "processor" used in the description refers to, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an application-specific integrated circuit (ASIC), a programmable logic device (for example, a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). When the processor is, for example, a CPU, the processor implements its functions by reading and executing a program stored in a storage circuit. On the other hand, when the processor is an ASIC, instead of storing the program in the storage circuit, the function is directly loaded into the circuit of the processor as a logic circuit. In addition, the processors of the present embodiment are not limited to being configured as a single circuit for each processor, but a plurality of independent circuits may be combined to form one processor to implement its functions. In addition, Figure 1 、 Figure 13 and Figure 16 Multiple components in a processor are integrated into one to realize its functions.

[0187] In addition, several embodiments of the present invention have been described, but these embodiments are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. These embodiments and their variations are included in the scope and spirit of the invention, and are also included in the invention described in the claims and their equivalents.

Claims

1. A medical image processing device, wherein: have: an acquisition unit that acquires a zeroth contrast-enhanced image when the subject's heart is in a reference state, a first contrast-enhanced image when the heart is in an acetylcholine stress state, and a second contrast-enhanced image when the heart is in an adenosine stress state; a first calculation unit that calculates a first blood flow ratio indicating a ratio of a zeroth blood flow rate of the myocardium in the reference state to a first blood flow rate of the myocardium in the acetylcholine loading state based on the zeroth contrast-enhanced image and the first contrast-enhanced image; a second calculation unit that calculates a second blood flow ratio indicating a ratio of the zeroth blood flow to a second blood flow of the myocardium in the adenosine loading state based on the zeroth contrast-enhanced image and the second contrast-enhanced image; as well as The display control unit causes the display to display the first blood flow ratio and the second blood flow ratio in parallel.

2. The medical image processing apparatus according to claim 1, wherein: The display control unit causes the display to display the first blood flow ratio and the second blood flow ratio in the form of at least one of numerical values ​​and images.

3. The medical image processing apparatus according to claim 2, wherein: further comprising a setting unit that sets a common region of interest for the zeroth contrast-enhanced image, the first contrast-enhanced image, and the second contrast-enhanced image, The first calculation unit calculates the first blood flow ratio in the region of interest of each of the zeroth contrast-enhanced image and the first contrast-enhanced image. The second calculation unit calculates the second blood flow ratio in the region of interest of each of the zeroth contrast-enhanced image and the second contrast-enhanced image. When displayed in the form of the numerical value, when the first blood flow ratio in the area of ​​interest is below a first threshold value, the display control unit displays the first blood flow ratio in a first display mode, and when the second blood flow ratio in the area of ​​interest is below a second threshold value, the display control unit displays the second blood flow ratio in a second display mode.

4. The medical image processing apparatus according to claim 3, wherein: The first display mode is a mode of performing color display or alarm display for indicating an abnormality in the first blood flow ratio. The second display mode is a mode of performing color display or alarm display for indicating abnormality of the second blood flow ratio.

5. The medical image processing apparatus according to claim 2, wherein: It also includes an image generating unit, The first calculation unit calculates the first blood flow ratio according to each corresponding pixel in the zeroth contrast-enhanced image and the first contrast-enhanced image. The second calculation unit calculates the second blood flow ratio for each corresponding pixel in the zeroth contrast-enhanced image and the second contrast-enhanced image. The ratio image generating unit 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. When displaying in the image format, the display control unit assigns colors to the pixel values ​​to display the first ratio image and the second ratio image in color on the display.

6. The medical image processing apparatus according to claim 5, wherein: The display control unit assigns a color to the pixel value so that a baseline of a display range of the first ratio image and a baseline of a display range of the second ratio image are aligned.

7. The medical image processing apparatus according to claim 5, wherein: The display control unit displays the first ratio image and the second ratio image in color by assigning the same color to pixel values ​​corresponding to a first threshold in the first ratio image and pixel values ​​corresponding to a second threshold in the second ratio image, wherein the first threshold is used to distinguish between normal and abnormal values ​​of the first blood flow ratio, and the second threshold is used to distinguish between normal and abnormal values ​​of the second blood flow ratio.

8. The medical image processing apparatus according to claim 1, wherein: further comprising a setting unit that sets a common region of interest for the zeroth contrast-enhanced image, the first contrast-enhanced image, and the second contrast-enhanced image, The first calculation unit calculates the first blood flow ratio in the region of interest of each of the zeroth contrast-enhanced image and the first contrast-enhanced image. The second calculation unit calculates the second blood flow ratio in the region of interest of each of the zeroth contrast-enhanced image and the second contrast-enhanced image. The display control unit displays a first graph indicating the first blood flow ratio and a first threshold value in the region of interest and a second graph indicating the second blood flow ratio and a second threshold value in the region of interest in parallel.

9. The medical image processing apparatus according to claim 8, wherein: The display control unit displays the first graph and the second graph side by side so that the baseline of the description range of the first graph is aligned with the baseline of the description range of the second graph.

10. The medical image processing apparatus according to claim 9, wherein: 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.

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

12. The medical image processing apparatus according to claim 1, wherein: further comprising a setting unit that sets a common region of interest for the zeroth contrast-enhanced image, the first contrast-enhanced image, and the second contrast-enhanced image, The first calculation unit calculates the first blood flow ratio in the region of interest of each of the zeroth contrast-enhanced image and the first contrast-enhanced image. The second calculation unit calculates the second blood flow ratio in the region of interest of each of the zeroth contrast-enhanced image and the second contrast-enhanced image. When the blood flow ratio at the zeroth blood flow rate is set to 1 as a reference value, the display control unit causes the display to display a comparison graph showing the first blood flow ratio and the second blood flow ratio in the region of interest compared with the reference value.

13. The medical image processing apparatus according to claim 12, wherein: The display control unit displays a normal range and an abnormal range for the first blood flow ratio and the second blood flow ratio, respectively, on the comparison graph.

14. The medical image processing apparatus according to claim 12, wherein: The display control unit displays the first blood flow ratio in the comparison chart in a state where the description range is inverted around the reference value, and displays threshold values ​​corresponding to the first and second blood flow ratios in the comparison chart.

15. The medical image processing apparatus according to claim 1, wherein: It also has a judgment unit. The acquisition unit further acquires a myocardial blood flow image when the heart is in an acetylcholine load state. The determination unit determines whether the myocardial blood flow of the subject is reduced based on the myocardial blood flow image, and determines whether the blood vessels of the subject are stenotic based on the first angiography image. If the determination result is both reduced and stenotic, the determination unit determines that coronary artery spasm has been detected. If the determination result is both reduced and not stenotic, the determination unit determines that microvascular spasm has been detected. The display control unit displays the detected result on the display.

16. The medical image processing apparatus according to claim 1, wherein: The first calculation unit calculates the first blood flow ratio by dividing 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. The second calculation unit calculates the second blood flow ratio by dividing 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.

17. The medical image processing apparatus according to claim 1, wherein: The apparatus further includes a third calculation unit configured to calculate a third blood flow ratio by dividing pixel values ​​of corresponding pixels in the myocardial region of the first contrast-enhanced image and the myocardial region of the second contrast-enhanced image. The display control unit further causes the display to display the third blood flow ratio.

18. The medical image processing apparatus according to any one of claims 1 to 17, wherein: 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 in parallel.

19. The medical image processing apparatus according to any one of claims 1 to 17, wherein: The zeroth contrast-enhanced image, the first contrast-enhanced image, and the second contrast-enhanced image are medical images captured under substantially the same imaging conditions, except for the state of the heart.

20. An X-ray diagnostic apparatus, wherein: have: an acquisition unit that acquires a zeroth contrast-enhanced image when the subject's heart is in a reference state, a first contrast-enhanced image when the heart is in an acetylcholine stress state, and a second contrast-enhanced image when the heart is in an adenosine stress state; a first calculation unit that calculates a first blood flow ratio indicating a ratio of a zeroth blood flow rate of the myocardium in the reference state to a first blood flow rate of the myocardium in the acetylcholine loading state based on the zeroth contrast-enhanced image and the first contrast-enhanced image; a second calculation unit that calculates a second blood flow ratio indicating a ratio of the zeroth blood flow to a second blood flow of the myocardium in the adenosine loading state based on the zeroth contrast-enhanced image and the second contrast-enhanced image; as well as The display control unit causes the display to display the first blood flow ratio and the second blood flow ratio in parallel.

Images