Medical image processing device, X-ray diagnostic device, and medical image processing program

Abstract

To determine a good DSA image by reducing an operation burden on a user.SOLUTION: A medical image processing device includes a positioning unit, a coincidence calculation unit, and a determination unit. The positioning unit executes positioning between one contrast image and each of a plurality of mask images. The coincidence calculation unit calculates a plurality of coincidences between the plurality of positioned mask images and the one contrast image on the basis of the plurality of positioned mask images and the one contrast image which are positioned. The determination unit determines a difference between the mask image and the one contrast image having the greatest coincidence of the plurality of coincidences as one difference image corresponding to the one contrast image.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In a conventional digital subtraction angiography (DSA) imaging of a patient who has difficulty holding their breath during abdominal imaging using an X-ray cardiovascular diagnostic device, a plurality of mask images are collected over a plurality of frames, and a user selects an optimum mask image for a contrast image from the plurality of mask images to create a DSA image. However, when a user visually selects an optimum mask image for a contrast image, this task takes a long time, which places a burden on the user.

[0003] For this reason, the X-ray cardiovascular diagnostic system may evaluate the similarity between the contrast image and multiple mask images and select the mask image with the highest similarity as the mask image optimal for the DSA image. In this case, the image quality of the generated DSA image may be degraded due to misalignment between the contrast image and the selected mask image. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-146333 Summary of the Invention [Problem to be solved by the invention]

[0005] One of the problems to be solved by the embodiments disclosed in this specification and the drawings is to determine a good DSA image while reducing the operational burden on the user. However, the problems to be solved by the embodiments disclosed in this specification and the drawings are not limited to the above problem. Problems corresponding to the effects of the configurations shown in the embodiments described below can also be positioned as other problems. [Means for solving the problem]

[0006] The medical image processing apparatus according to this embodiment includes a registration unit, a coincidence calculation unit, and a determination unit. The registration unit performs registration between one contrast image and each of multiple mask images. The coincidence calculation unit calculates multiple degrees of coincidence between the aligned mask images and the one contrast image based on the aligned mask images and the one contrast image. The determination unit determines a difference between the mask image corresponding to the largest degree of coincidence among the multiple degrees of coincidence and the one contrast image as a difference image corresponding to the one contrast image. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram showing the configuration of an X-ray diagnostic apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an example of calculation of a degree of coincidence according to the embodiment. [Figure 3] FIG. 3 is a flowchart showing an example of a procedure of a DSA image determination process according to the embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a plurality of difference images displayed on a display according to the embodiment. [Figure 5] FIG. 5 is a diagram showing an example of a plurality of difference images displayed on a display according to a first modified example of the embodiment. [Figure 6] FIG. 6 is a diagram showing an example of a plurality of difference images displayed on a display according to a second modified example of the embodiment. [Figure 7]FIG. 7 is a diagram showing an example of a plurality of difference images displayed on a display according to a third modified example of the embodiment. [Figure 8] FIG. 8 is a diagram showing an example of a plurality of difference images displayed on a display according to a fourth modified example of the embodiment. [Figure 9] FIG. 9 is a diagram showing an example of a user interface related to setting of a region of interest and setting of a DSA image determination process according to a fifth modified example of the embodiment. [Figure 10] FIG. 10 is a diagram showing an example of a plurality of set ROIs and a plurality of difference images displayed on a display according to the plurality of ROIs, according to a fifth modified example of the embodiment. [Figure 11] FIG. 11 is a diagram showing an example of a plurality of regions divided in one contrast image and one difference image displayed on a display, according to a seventh modified example of the embodiment. [Figure 12] FIG. 12 is a diagram showing an example of an outline of imaging related to bolus DSA according to an eighth modification of the embodiment. [Figure 13] FIG. 13 is a diagram showing an example of an outline of generation of a long image related to bolus DSA according to an eighth modification of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of a medical image processing apparatus, an X-ray diagnostic apparatus, and a medical image processing program will be described with reference to the drawings. In the following embodiments, parts with the same reference numerals perform similar operations, and redundant explanations will be omitted as appropriate. In addition, the content described in one embodiment is, in principle, also applicable to modified examples, etc.

[0009] (Embodiment) 1 is a block diagram showing the configuration of an X-ray diagnostic apparatus 1 according to an embodiment. The X-ray diagnostic apparatus 1 has, as a data acquisition system, an X-ray generator 3, an X-ray detector 5, a bed 7, a C-arm 9, an X-ray controller 11, a high-voltage generator 13, and a C-arm / bed mechanism control unit 15. The X-ray diagnostic apparatus 1 has, as a data processing system, a position data memory 21, a system control unit 22, an input interface 23, a display 24, a memory 25, and a processing circuit 26.

[0010] The X-ray generating unit 3 has an X-ray tube 3a and an X-ray aperture 3b. The X-ray tube 3a is a vacuum tube that generates X-rays. The X-ray tube 3a accelerates thermions emitted from a cathode (filament) by a high voltage and causes the accelerated electrons to collide with a tungsten anode, thereby generating X-rays.

[0011] The X-ray aperture 3b is located between the X-ray tube 3a and the X-ray detector 5 and is made of a lead plate as a metal plate. The X-ray aperture 3b is controlled by the X-ray controller 11. The X-ray aperture 3b blocks X-rays outside the aperture area. In this way, the X-ray aperture 3b narrows the X-rays generated by the X-ray tube 3a so that they are irradiated onto a region of interest of the subject P. For example, the X-ray aperture 3b has multiple aperture blades. The X-ray aperture 3b adjusts the region of interest blocked by X-rays to any size by sliding these aperture blades. The aperture blades of the X-ray aperture 3b are driven by a driving device (not shown) under the control of the X-ray controller 11 according to the region of interest set by the region setting function 26c.

[0012] The X-ray detector 5 detects X-rays generated by the X-ray tube 3a. For example, the X-ray detector 5 detects X-rays that have passed through the subject P. The X-ray detector 5 can be of a direct conversion type that directly converts X-rays into electric charges, or an indirect conversion type that converts X-rays into light and then converts it into electric charges. Hereinafter, as an example, the X-ray detector 5 will be described as being of the direct conversion type, but it may also be of the indirect conversion type.

[0013] The X-ray detector 5 includes, for example, a flat panel detector (FPD) that converts X-rays transmitted through the subject P into electric charges and accumulates the electric charges, and a gate driver that generates drive pulses for reading out the electric charges accumulated in the FPD. The size of the FPD is generally 8 to 16 inches. The FPD is configured by arranging tiny detection elements two-dimensionally in the column and line directions. Each detection element includes a photoelectric film that senses X-rays and generates electric charges according to the amount of incident X-rays, a charge storage capacitor that stores the electric charges generated on the photoelectric film, and a TFT (thin film transistor) that outputs the electric charges accumulated in the charge storage capacitor at a predetermined timing. The accumulated electric charges are sequentially read out by drive pulses supplied by the gate driver.

[0014] A projection data generation circuit (not shown) is provided downstream of the X-ray detector 5. The projection data generation circuit has a charge-to-voltage converter, an A / D converter, and a parallel-to-serial converter. The charge-to-voltage converter converts the charges read out in parallel from the FPD row by row or column by column into voltage. The A / D converter converts the output from the charge-to-voltage converter into a digital signal. The parallel-to-serial converter converts the digitally converted parallel signal into a time-series serial signal. The projection data generation circuit outputs the serial signal to the processing circuit 26 as time-series projection data.

[0015] The bed 7 has a mechanism that allows it to be raised, lowered, and positioned while the subject P is still placed on it. The bed 7 is provided with a state detector (not shown) that detects information related to the geometric arrangement of the bed 7, such as the position of the bed 7 itself. The state detector outputs information related to the geometric arrangement of the bed 7 to the C-arm and bed mechanism control unit 15.

[0016] The C-arm 9 holds the X-ray generator 3 and the X-ray detector 5 so that they face each other across the subject P and the top of the bed 7. Specifically, the C-arm 9 is held by a holder (not shown) so as to be rotatable about an X-axis perpendicular to both the Z-axis perpendicular to the top of the bed 7 and the Y-axis perpendicular to the longitudinal direction of the top. The C-arm 9 has a substantially arc-shaped configuration centered on the Y-axis and is held by the holder so as to be slidable along the substantially arc-shaped configuration. Alternatively, the C-arm 9 can rotate about the X-axis around the holder. The C-arm 9 can acquire X-ray images from various angles by combining the sliding and rotating motions. The C-arm 9 is equipped with multiple power sources at appropriate locations to realize such sliding and rotating motions.

[0017] Furthermore, the C-arm 9 is equipped with a status detector (not shown) that detects information related to its geometric arrangement, such as its angle, posture, and position. The status detector may be, for example, a potentiometer that detects the rotation angle or movement amount, or an encoder that is a position detection sensor. As the encoder, for example, so-called absolute encoders such as magnetic, brush, or photoelectric encoders can be used. Furthermore, as the status detector, various types of position detection mechanisms can be used as appropriate, such as a rotary encoder that outputs rotational displacement as a digital signal or a linear encoder that outputs linear displacement as a digital signal. This type of status detector outputs information related to the geometric arrangement of the C-arm 9 to the C-arm / bed mechanism controller 15. Note that the information related to the geometric arrangement of the C-arm 9 corresponds to the information related to the geometric arrangement of the X-ray tube 3a and the X-ray detector 5.

[0018] The X-ray controller 11 is controlled by the system control unit 22. The X-ray controller 11 controls the X-ray aperture 3b, the X-ray control unit 13a, and the high voltage generator 13b.

[0019] The high voltage generator 13 includes an X-ray control unit 13a and a high voltage generator 13b.

[0020] Based on the X-ray irradiation conditions supplied from the X-ray controller 11, the X-ray control unit 13a controls the tube current, tube voltage, application time, application timing, repetition frequency, etc. in the high voltage generator 13b.

[0021] The high voltage generator 13b is controlled by the X-ray controller 11, generates a high voltage to be applied between the anode and the cathode in order to accelerate the thermoelectrons generated from the cathode of the X-ray tube 3a, and applies the generated high voltage to the X-ray tube 3a.

[0022] The C-arm / bed mechanism control unit 15 is controlled by the system control unit 22 and individually drives and controls the C-arm 9 and the bed 7. The C-arm / bed mechanism control unit 15 writes information relating to the geometric arrangement of the C-arm 9 and information relating to the geometric arrangement of the bed 7 received from a status detector (not shown) into a position data memory 21.

[0023] The position data memory 21 stores information relating to the geometric arrangement of the C-arm 9 and information relating to the geometric arrangement of the bed 7.

[0024] The system control unit 22 is a central processing unit that controls the collection of image data, and controls the image processing of the collected image data, image reproduction processing, etc. The system control unit 22 temporarily stores information such as command signals input from the input interface 23 and various initial setting conditions, and then transmits this information to the X-ray controller 11, the C-arm and bed mechanism control unit 15, and / or the processing circuitry 26.

[0025] The input interface 23 is used to input subject information, set X-ray imaging conditions including X-ray irradiation conditions, input various command signals, etc. The input interface 23 is realized by, for example, a trackball for instructing the movement of the C-arm 9 and setting a region of interest (ROI), a switch button, a mouse, a keyboard, a touchpad for inputting operations by touching the operation surface, a touch panel display in which a display screen and a touchpad are integrated, etc.

[0026] The input interface 23 is connected to the system control unit 22. The input interface 23 converts input operations received from the user into electrical signals and outputs them to the system control unit 22. In this specification, the input interface 23 is not limited to an interface having physical operating components such as a mouse or keyboard. For example, an example of the input interface 23 also includes an electrical signal processing circuit that receives electrical signals corresponding to input operations from an external input device provided separately from the device and outputs these electrical signals to the system control unit 22. The input interface 23 corresponds to an input unit.

[0027] The display 24 is composed of a display main body that displays medical images, etc., an internal circuit that supplies display signals to the display main body, and peripheral circuits such as connectors and cables that connect the display main body and the internal circuit. The internal circuit generates display data by superimposing additional information on image data supplied from the processing circuit 26. The additional information includes, for example, subject information and projection data generation conditions. The internal circuit performs D / A conversion and TV format conversion on the generated display data, and displays an image corresponding to the display data on the display main body. The display 24 corresponds to a display unit.

[0028] The memory 25 includes a memory body that records electrical information, such as a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hardware Disk Drive), and an image memory, as well as peripheral circuits associated with the memory body, such as a memory controller and a memory interface. The memory 25 stores, for example, a plurality of programs executed by the processing circuitry 26, X-ray images generated by the processing circuitry 26, data used in various processes executed by the processing circuitry 26, data during processing, and data after processing. The data used in the processing by the processing circuitry 26 may include, for example, anatomical information related to the region to be imaged in the X-ray image. The plurality of programs executed by the processing circuitry 26 correspond, for example, to an image calculation function 26a, a display data generation function 26b, a region setting function 26c, a positioning function 26d, a coincidence calculation function 26e, and a determination function 26f, respectively.

[0029] Processing circuitry 26 is a processor that implements an image calculation function 26a, a display data generation function 26b, a region setting function 26c, a positioning function 26d, a degree of coincidence calculation function 26e, and a determination function 26f corresponding to the programs by reading and executing the programs stored in memory 25. Similarly, X-ray controller 11, C-arm / bed mechanism control unit 15, and system control unit 22 shown in Fig. 1 are also implemented by processors that execute programs corresponding to the various functions performed in these units.

[0030] Here, the term "processor" refers to a circuit such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an Application Specific Integrated Circuit (ASIC), a programmable logic device (e.g., a Simple Programmable Logic Device (SPLD), a Complex Programmable Logic Device (CPLD), and a Field Programmable Gate Array (FPGA)).

[0031] Instead of storing the program in memory 25, the program may be directly embedded in the circuit of the processor. In this case, the processor realizes the functions by reading and executing the program embedded in the circuit. Also, in FIG. 1, the image calculation function 26a, the display data generation function 26b, the area setting function 26c, the positioning function 26d, the coincidence calculation function 26e, and the determination function 26f are described as being realized by a single processing circuit 26. However, this is not limited to this, and the processing circuit may be configured by combining multiple independent processors, and each processor may execute a program to realize each function.

[0032] The processing circuit 26 has an image calculation function 26a, a display data generation function 26b, and an area setting function 26c. The image calculation function 26a has a positioning function 26d, a coincidence calculation function 26e, and a determination function 26f. The processing circuit 26 that realizes the image calculation function 26a may be realized by an image calculation circuit. The processing circuit 26 or the image calculation circuit that realizes the image calculation function 26a corresponds to an image calculation unit. Furthermore, the processing circuit 26 that realizes the display data generation function 26b may be realized by a display data generation circuit. The processing circuit 26 or the display data generation circuit that realizes the display data generation function 26b corresponds to a display data generation unit. The processing circuit 26 that realizes the area setting function 26c corresponds to an area setting unit.

[0033] The processing circuit 26 uses the image calculation function 26a to sequentially store the time-series projection data output from the projection data generation circuit of the X-ray detector 5 in a projection data storage circuit (not shown). The image calculation function 26a generates an X-ray image made up of two-dimensional projection data based on the time-series projection data. The image calculation function 26a stores the generated X-ray image in the memory 25.

[0034] The X-ray images that the image calculation function 26a can generate include a mask image (non-contrast image) and a contrast image (contrast image). A mask image is an X-ray image generated by X-ray imaging of the subject P before the administration of a contrast agent, and is a projection image having a bone image. A contrast image is an X-ray image generated by X-ray imaging of the subject P after the administration of a contrast agent, and is a projection image having bone and blood vessel images. A mask image is generated for each X-ray irradiation condition. In other words, multiple mask images are generated at a predetermined frame rate corresponding to the number of X-ray irradiations per second. Similarly, multiple contrast images are also generated at the predetermined frame rate.

[0035] The processing circuitry 26 may generate 3D image data by using the image calculation function 26a to perform a predetermined reconstruction process on the projection data that is collected by continuously rotating the X-ray tube 3a and the X-ray detector 5 around the subject P and stored in the memory 25. The image calculation function 26a stores the generated 3D image data in the memory 25.

[0036] The processing circuitry 26 uses the display data generation function 26b to generate display data including the X-ray image generated by the image calculation function 26a. The display data generation function 26b sends the display data to the display 24.

[0037] The processing circuitry 26 sets a region of interest in the X-ray image using the region setting function 26c. The region setting function 26c may set the region of interest based on, for example, anatomical information about the region to be imaged in the X-ray image. The anatomical information may include information about the region to be imaged and information about the geometric arrangement of the X-ray tube 3a and the X-ray detector 5. The region setting function 26c may estimate the position of the field of view based on, for example, information about the region to be imaged in the examination protocol acquired from the system control unit 22 and the angle and position of the C-arm 9 acquired from the system control unit 22, and set the region of interest from the position of the field of view. Furthermore, the region setting function 26c may set the region of interest using the position of the bed 7, the source-image distance (SID), the field of view (FOV), subject information (height and weight), subject position information, etc., in addition to information about the geometric arrangement of the X-ray tube 3a and the X-ray detector 5.

[0038] The processing circuitry 26 performs alignment between one of the plurality of contrast images and each of the plurality of mask images using an alignment function 26d. The one contrast image is, for example, a contrast image selected from the plurality of contrast images displayed on the display 24 by a user instruction via the input interface 23. The processing circuitry 26 that realizes the alignment function 26d corresponds to an alignment unit.

[0039] For example, the alignment function 26d performs alignment by applying at least one of translation and rotation to the multiple mask images based on one contrast image and each of the multiple mask images. Note that the alignment function 26d may perform the above alignment for each of the multiple contrast images. That is, the alignment function 26d may perform alignment with the multiple mask images for all contrast images.

[0040] The processing circuitry 26 calculates, using the coincidence calculation function 26e, multiple degrees of coincidence between the aligned mask images and one contrast image based on the aligned mask images and one contrast image. The coincidence is an index indicating the degree of coincidence between the aligned mask images and one contrast image. In other words, the coincidence corresponds to an index (e.g., similarity) indicating the degree of similarity between the aligned mask images and one contrast image. The processing circuitry 26 realizing the coincidence calculation function 26e corresponds to a coincidence calculation unit.

[0041] Specifically, the processing circuit 26 calculates the difference between each of the aligned mask images and one contrast image using the coincidence calculation function 26e across the total number of aligned mask images, thereby calculating multiple images (hereinafter referred to as difference images). For the sake of concreteness, the total number of contrast images corresponding to the multiple frames is assumed to be n (n is a natural number equal to or greater than 2). In addition, one contrast image C selected by the user is calculated as follows: j is the j-th frame. In addition, the total number of aligned mask images M is m (m is a natural number equal to or greater than 2). Also, the aligned mask image corresponding to the i-th frame (1≦i≦m) is defined as M i This will be expressed as follows.

[0042] A difference image D corresponding to the i-th frame among the multiple difference images i(1≦i≦m) is M i -C j The processing circuit 26 calculates the degree of coincidence by using a plurality of pixel values ​​in each of the plurality of difference images using the degree of coincidence calculation function 26e. The degree of coincidence is calculated by, for example, i It should be noted that the degree of match is not limited to the variance or standard deviation value, but can be calculated by the variance or standard deviation value of each of the aligned mask images M i and contrast image C j The degree of match may be calculated by any known method as long as it indicates the similarity between the images. For the sake of concreteness, the degree of match is assumed to be a variance value. In this case, the maximum degree of match corresponds to the minimum variance value. The degree of match calculation function 26e stores the calculated degrees of match and the difference images in the memory 25 in association with each other.

[0043] The processing circuit 26 calculates the average image (M ave =1 / m×Σ i=1 m (M i )) and one contrast image C selected by the user. j The average difference image D ave Next, the matching calculation function 26e calculates the average difference image D ave The average degree of match may be calculated using the above formula. In this case, the average degree of match is included in the multiple degrees of match. Furthermore, when alignment with multiple mask images is performed for all contrast images, the degree of match calculation function 26e calculates multiple degrees of match according to the combinations of the aligned mask images and the aligned contrast images.

[0044] 2 is a diagram showing an example of calculation of the degree of coincidence. As shown in FIG. 2, the processing circuit 26 calculates the degree of coincidence by using the degree of coincidence calculation function 26e. j and the aligned mask images M i The difference between the images is calculated over a total of m images, and m difference images D i (=Mi -C j ) is calculated. The coincidence calculation function 26e calculates the coincidence between one contrast image C selected by the user. j and the average mask image M ave Difference image D ave (=M ave -C j ) may be calculated.

[0045] The processing circuit 26 determines, by a determination function 26f, the difference between a mask image corresponding to the highest degree of matching among the plurality of degrees of matching and one contrast image as one difference image corresponding to the one contrast image. The processing circuit 26 realizing the determination function 26f corresponds to a determination unit. The determination function 26f determines the differences between a predetermined number of mask images, each having the highest degree of matching among the plurality of degrees of matching, and one contrast image as multiple difference images, including one difference image corresponding to the one contrast image. Here, the predetermined number is a natural number equal to or greater than two and is set in advance. For the sake of concreteness, the predetermined number is assumed to be three.

[0046] Specifically, the processing circuit 26 uses the determination function 26f to identify the highest degree of match among multiple degrees of match. The determination function 26f reads the difference image corresponding to the highest degree of match from the memory 25 and determines the read difference image as one subtraction image corresponding to one contrast image. The one subtraction image corresponds to a DSA image related to one contrast image. The determination function 26f may also identify a predetermined number (e.g., three) of degrees of match in descending order from the highest degree of match. In this case, the determination function 26f reads a predetermined number of difference images corresponding to the identified predetermined number of degrees of match from the memory 25 and determines the read difference images as three subtraction images corresponding to one contrast image.

[0047] The processing circuit 26 generates a plurality of difference images for display based on the determined plurality of difference images using the display data generation function 26b, and the display 24 displays the generated plurality of difference images.

[0048] The overall configuration of the X-ray diagnostic apparatus 1 according to the embodiment has been described above. In this configuration, the X-ray diagnostic apparatus 100 according to the embodiment executes a process (hereinafter referred to as a DSA image determination process) of determining a difference image (DSA image) corresponding to one contrast image designated by a user and displaying it on the display 24. The procedure of the DSA image determination process will be described below with reference to Fig. 3. Fig. 3 is a flowchart showing an example of the procedure of the DSA image determination process.

[0049] (DSA image determination process) (Step S301) The system control unit 22 performs imaging of the subject P before administration of a contrast agent at a predetermined frame rate (hereinafter referred to as mask imaging). The processing circuitry 26 uses the image calculation function 26a to generate multiple mask images in time series based on multiple pieces of time-series projection data generated by the mask imaging. The image calculation function 26a stores the multiple mask images in the memory 25. At this time, the multiple mask images may be displayed on the display 24.

[0050] (Step S302) The system control unit 22 performs imaging of the subject P after the administration of a contrast agent at a predetermined frame rate (hereinafter referred to as contrast imaging). The processing circuitry 26 uses the image calculation function 26a to generate a plurality of contrast images in time series based on a plurality of time-series projection data generated by the contrast imaging. The image calculation function 26a stores the plurality of contrast images in the memory 25. The processing circuitry 26 uses the display data generation function 26b to generate a plurality of contrast images for display based on the plurality of contrast images. The display 24 displays the plurality of contrast images for display.

[0051] (Step S303) The input interface 23 receives a user instruction to select one contrast image from the displayed plurality of contrast images. That is, one contrast image is selected from the plurality of contrast images in response to a user instruction.

[0052] (Step S304) The processing circuitry 26 uses the alignment function 26d to perform alignment between one contrast image among the plurality of contrast images and each of the plurality of mask images. Specifically, the alignment function 26d calculates a shift amount for each of the plurality of mask images relative to the single contrast image. Next, the alignment function 26d calculates a translation amount and a rotation amount for each of the plurality of mask images using the calculated shift amount. The alignment function 26d transforms each of the plurality of mask images using the translation amount and the rotation amount for each of the plurality of mask images to perform alignment with the single contrast image. The transformation of the mask image based on the calculated shift amount may be, for example, an affine transformation of multiple pixels in the mask image. Note that this transformation is not limited to an affine transformation.

[0053] (Step S305) The processing circuit 26 uses the matching calculation function 26e to calculate multiple matching degrees corresponding to the total number of the aligned mask images based on the aligned mask images and one contrast image. Specifically, the matching calculation function 26e calculates the difference between each of the aligned mask images and the one contrast image to generate multiple difference images corresponding to the total number of the aligned mask images. Next, the matching calculation function 26e calculates multiple matching degrees corresponding to each of the difference images based on each of the difference images.

[0054] (Step S306) The processing circuit 26 determines, by the determination function 26f, the difference image corresponding to the highest degree of matching among the plurality of degrees of matching as the difference image corresponding to the selected contrast image. Specifically, the determination function 26f determines the three difference images in descending order of degree of matching as the plurality of difference images.

[0055] (Step S307) The processing circuit 26 generates a plurality of difference images for display based on the determined plurality of difference images using the display data generation function 26b. The display 24 displays the generated plurality of difference images in an appropriate arrangement. At this time, the display 24 displays an average difference image D ave Alternatively, a difference image D1 using the registered mask image of the first frame may be displayed together with a plurality of difference images.

[0056] 4 is a diagram showing an example of a plurality of difference images Sub displayed on the display 24 in step S307. In FIG. 4, M(a), M(b), and M(c) indicate mask images in descending order of coincidence (similarity). Also, M(org) in FIG. 4 indicates the original mask image, for example, the mask image in the first frame or the average mask image M ave DE1 in Fig. 4 shows a display example in which three types of difference images Sub with high degrees of match (similarity) are displayed side by side in the display area of ​​the display 24. DE2 in Fig. 4 shows a display example in which three types of difference images Sub with high degrees of match (similarity) are displayed side by side in the display area of ​​the display 24, together with a difference image calculated using the aligned original mask image M(org).

[0057] (Step S308) When one of the displayed subtraction images is selected by a user's instruction via the input interface 23, the processing circuitry 26 stores the selected subtraction image as a DSA image in the memory 25. This completes the DSA image determination process.

[0058] The X-ray diagnostic apparatus 1 according to the embodiment described above performs registration between one contrast image and each of multiple mask images, calculates multiple degrees of match between the registered mask images and the one contrast image based on the registered mask images and the one contrast image, and determines a difference (difference image) between the mask image corresponding to the highest degree of match among the multiple degrees of match and the one contrast image as a difference image corresponding to the one contrast image. The X-ray diagnostic apparatus 1 also performs the registration by applying at least one of translation and rotation to the multiple mask images based on the one contrast image and each of the multiple mask images. The X-ray diagnostic apparatus 1 also determines differences (difference images) between a predetermined number of multiple mask images in descending order of degree of match among the multiple degrees of match and the one contrast image as a plurality of difference images, including one difference image, and displays the plurality of difference images.

[0059] As a result, the X-ray diagnostic apparatus 1 according to the embodiment can determine multiple difference images with a high degree of match in response to a contrast image selected by the user, and display the multiple difference images as candidates for the DSA image on the display 24. According to the present X-ray diagnostic apparatus 1, a DSA image can be determined by selecting a contrast image and a difference image, thereby reducing the user's work time. As described above, according to the present X-ray diagnostic apparatus 1, it is possible to improve the throughput of processing related to the determination and selection of DSA images and reduce the operational burden on the user.

[0060] Furthermore, according to the present X-ray diagnostic apparatus 1 of the embodiment, a transformation is applied to the mask image according to the deviation between the contrast image and the mask image to perform alignment, and the degree of match is calculated based on the difference image in which the deviation is minimized. This makes it possible to improve the image quality of multiple difference images, including the difference image associated with the highest degree of match, compared to conventional methods.

[0061] As described above, the X-ray diagnostic apparatus 1 can reduce the operational burden on the user and determine good DSA images with fewer registration errors, thereby improving the diagnostic efficiency for the subject P and the throughput of the examination.

[0062] (First Modification) In this modification, two mask images corresponding to frames before and after the mask image corresponding to the highest degree of match are used to determine the difference between the two mask images and one contrast image as two difference images for the two mask images of the previous and next frames, and the difference image corresponding to the highest degree of match and the determined two difference images are displayed. In this modification, the multiple mask images are a series of mask images generated at a predetermined frame rate. In the following description, the previous and next frames in this modification are described as one frame, but the previous and next frames are not limited to one frame and may be multiple frames.

[0063] The processing circuit 26 determines, by the determination function 26f, the difference (difference image) between the two mask images corresponding to the frames before and after the frame with the highest degree of match and one contrast image as two difference images for the two mask images of the frames before and after the frame. The two mask images are mask images that have been aligned by the alignment function 26d. The processing contents of the determination function 26f are executed in step S306 of FIG. 3 in the DSA image determination process.

[0064] The display 24 displays the difference image corresponding to the highest degree of match and the two determined difference images. The processing on the display 24 is executed in step S307 of Fig. 3 in the DSA image determination processing.

[0065] Fig. 5 is a diagram showing an example of a plurality of difference images Sub displayed on the display 24. M(a) in Fig. 5 is a mask image associated with the highest degree of match. M(a-1) in Fig. 5 is a mask image corresponding to the frame preceding the frame of the mask image associated with the highest degree of match. M(a+1) in Fig. 5 is a mask image corresponding to the frame following the frame of the mask image associated with the highest degree of match.

[0066] DE3 in Fig. 5 shows a display example in which three types of difference images Sub are displayed side by side in the frame order of the mask images, with the difference image Sub associated with the highest degree of match at the center, in the display area of ​​the display 24. DE5 in Fig. 5 shows a display example in which the difference image Sub associated with the highest degree of match and two difference images Sub using two mask images in frames before and after the mask image associated with the highest degree of match are displayed side by side in the display area of ​​the display 24, together with a difference image calculated using the original mask image M(org). The user selects a DSA image from the multiple displayed difference images via the input interface 23.

[0067] According to the X-ray diagnostic apparatus 1 of this modification, the multiple mask images are a series of mask images generated at a predetermined frame rate, and the differences (difference images) between two mask images corresponding to frames before and after the mask image with the highest degree of match and one contrast image are determined as two difference images for the two mask images, and the single difference image and the two difference images are displayed. As a result, according to this modification, multiple difference images for frames before and after the mask image with the highest degree of match can be displayed on the display 24 in relation to the mask image with the highest degree of match. Therefore, according to this X-ray diagnostic apparatus 1, it is possible to present to the user candidate difference images with fewer registration errors. Other effects are similar to those of the embodiment, and therefore description thereof will be omitted.

[0068] (Second Modification) The second variant involves determining difference images corresponding to the differences between two contrast images, which are frames before and after one contrast image selected by the user from among the multiple contrast images, and two mask images with the highest degree of matching for the two contrast images, as two difference images for the two contrast images, and displaying the one difference image with the highest degree of matching and the two determined difference images.

[0069] The processing circuitry 26 uses the registration function 26d to perform registration between two contrast images corresponding to frames before and after one contrast image selected by the user and multiple mask images. The processing performed by the registration function 26d is executed in step S304 of Fig. 3 during the DSA image determination process.

[0070] The processing circuitry 26 uses the coincidence calculation function 26e to calculate multiple degrees of coincidence between the aligned mask images and the two contrast images based on the aligned mask images and the two contrast images. That is, the coincidence calculation function 26e calculates multiple degrees of coincidence based on multiple difference images corresponding to the differences between the aligned mask images and the two contrast images. The processing content of the coincidence calculation function 26e is executed in step S305 of FIG. 3 in the DSA image determination process.

[0071] The processing circuit 26 determines, by the determination function 26f, the differences between the two contrast images and the two mask images corresponding to the maximum degrees of match between the two contrast images, as two difference images between the two contrast images of the previous and next frames. That is, the determination function 26f determines, for each of the two contrast images, the difference image corresponding to the maximum degree of match among a plurality of degrees of match as the difference image. The processing contents of the determination function 26f are executed in step S306 of FIG. 3 in the DSA image determination process.

[0072] The display 24 displays the difference image corresponding to the highest degree of match and the two determined difference images. The processing on the display 24 is executed in step S307 of Fig. 3 in the DSA image determination processing.

[0073] FIG. 6 is a diagram showing an example of a plurality of difference images Sub displayed on the display 24. M(a) in FIG. 6 represents one contrast image C selected by the user. j , the mask image with the highest matching score. M(d) in Figure 5 is a single contrast image C selected by the user. j Contrast image C of the previous frame j-1 , and M(e) is the mask image with the highest matching score. j Contrast image C of the next frame j+1 is the mask image with the highest degree of match.

[0074] DE5 in FIG. 6 is the contrast image C selected by the user. j 6 shows an example of a display in which three types of difference images Sub are displayed side by side in the display area of ​​the display 24 in the frame order of the contrast images, with the difference image relating to the contrast image C at the center. j Sub is a difference image and C is a contrast image of two frames before and after the frame. j-1 , C j+1 1 shows an example of a display in which two difference images Sub relating to the original mask image M(org) are displayed side by side in the display area of ​​the display 24, together with a difference image calculated using the original mask image M(org). The user selects a DSA image from the displayed plurality of difference images via the input interface 23.

[0075] According to the X-ray diagnostic apparatus 1 of this modification, alignment is performed between two contrast images corresponding to frames before and after one contrast image and multiple mask images, and multiple degrees of agreement between the aligned multiple mask images and the two contrast images are calculated based on the aligned multiple mask images and the two contrast images, and the differences between the two contrast images and the two mask images corresponding to the maximum degrees of agreement for the two contrast images are determined as two difference images for the two contrast images in the adjacent frames, and the one difference image and the two difference images are displayed.

[0076] As a result, the X-ray diagnostic apparatus 1 according to this modification can display on the display 24 a plurality of difference images relating to frames before and after the contrast image selected by the user, in relation to the highest degree of match. Therefore, the X-ray diagnostic apparatus 1 can present to the user candidate difference images that are adjacent (near) to the frame of the contrast image selected by the user and have few registration errors. Other effects are the same as those of the embodiment, and therefore description thereof will be omitted.

[0077] (Third Modification) The third modified example corresponds to a combination of the embodiment and the second modified example. Specifically, the processing in this modified example further executes the following processing in addition to the processing in the second modified example.

[0078] The processing circuitry 26 further determines, by the determination function 26f, differences between a predetermined number of mask images selected in descending order of the degree of matching among the plurality of degrees of matching, one contrast image selected by the user, and two contrast images corresponding to frames before and after the selected contrast image, as a plurality of difference images. That is, the determination function 26f determines, for each of the two contrast images corresponding to the preceding and following frames, the difference image corresponding to the greatest degree of matching among the plurality of degrees of matching as the difference image. In this modification, the predetermined number is assumed to be 3. The processing contents of the determination function 26f are executed in step S306 of FIG. 3 in the DSA image determination process.

[0079] The display 24 displays one difference image corresponding to the highest degree of match for one contrast image selected by the user, two difference images for the two contrast images of the previous and next frames, and the plurality of difference images. The processing on the display 24 is executed in step S307 of FIG. 3 in the DSA image determination processing.

[0080] FIG. 7 is a diagram showing a display example DE7 of a plurality of difference images Sub displayed on the display 24. M(a) in FIG. 7 represents one contrast image C selected by the user. j , the mask image with the highest matching score. M(a), M(b), and M(c) in Fig. 7 are the contrast images C j 7 shows the mask images in descending order of similarity (matching degree). Also, M(d) in FIG. 7 shows the mask images in descending order of similarity (matching degree) (similarity) (matching degree). j Contrast image C of the previous frame j-1 is the mask image with the highest degree of match.

[0081] M(d), M(f), and M(h) in Fig. 7 are the contrast images C j-1 The mask images in Fig. 7 are ordered by the degree of similarity (similarity) of the contrast image C j Contrast image C of the next frame j+1 7 are the mask images with the highest matching score. M(e), M(g), and M(i) in Fig. 7 are the mask images with the highest matching score. j+1 The mask images are shown in descending order of the degree of match (similarity) with respect to the DSA image. The user selects a DSA image from the plurality of difference images displayed on the DE 7 via the input interface 23.

[0082] According to the X-ray diagnostic apparatus 1 of this modification, the differences between a predetermined number of mask images in descending order of the degrees of coincidence among the plurality of mask images and one contrast image and two contrast images are further determined as a plurality of difference images, and the one difference image determined in the embodiment, the two difference images determined in the second modification, and the plurality of difference images are displayed. The effects of this modification correspond to the effects of the embodiment and the second modification, and therefore a description thereof will be omitted.

[0083] (Fourth Modification) The fourth modification corresponds to a combination of the first and second modifications. The mask images in this modification are a series of mask images generated at a predetermined frame rate. Specifically, the processing in this modification further executes the following processing in addition to the processing in the second modification.

[0084] The processing circuit 26 determines, by the determination function 26f, the differences between the two contrast images and the mask images corresponding to the frames before and after the one contrast image selected by the user that have the highest degree of similarity. That is, the determination function 26f determines, as the difference images, the difference images corresponding to the highest degree of similarity among the mask images corresponding to the two mask images corresponding to the frames before and after the one contrast image selected by the user. The processing contents of the determination function 26f are executed in step S306 of FIG. 3 in the DSA image determination process.

[0085] The display 24 displays one difference image corresponding to the highest degree of match for one contrast image selected by the user, two difference images for two contrast images in frames before and after the one contrast image, and the determined plurality of difference images. The processing on the display 24 is executed in step S307 of FIG. 3 in the DSA image determination processing.

[0086] FIG. 8 is a diagram showing a display example DE8 of a plurality of difference images Sub displayed on the display 24. M(a) in FIG. 8 is one contrast image C selected by the user. j , the mask image with the highest degree of matching. M(a-1) and M(a+1) in FIG. 8 correspond to two mask images in the frames before and after the mask image M(a). M(d) in FIG. 8 is one contrast image C selected by the user. j Contrast image C of the previous frame j-1 8 corresponds to the mask image with the highest degree of matching. M(d-1) and M(d+1) in FIG. 8 correspond to the two mask images in the frames before and after the mask image M(d). Also, M(e) in FIG. 8 corresponds to one contrast image C selected by the user. j Contrast image C of the next frame j+1 8 corresponds to the mask image M(e) in the frame before and after the mask image M(e). The user selects a DSA image from the multiple difference images displayed on the DE 8 via the input interface 23.

[0087] According to the X-ray diagnostic apparatus 1 of this modification, the multiple mask images are a series of mask images generated at a predetermined frame rate, and the differences between the multiple mask images corresponding to frames before and after the maximum degree of matching between the two contrast images and the two contrast images are determined as multiple difference images for the two mask images of the previous and next frames, and the one difference image determined in the embodiment, the two difference images determined in the second modification, and the multiple difference images are displayed. The effects of this modification correspond to the effects of the first and second modifications, and therefore will not be described here.

[0088] (Fifth Modification) In this modification, the DSA image determination process is applied to each of a plurality of regions of interest set in one contrast image selected by the user. The plurality of regions of interest are set in advance based on X-ray imaging conditions (e.g., imaging target region, lesion region, lesion name, etc.). The plurality of regions of interest may also be set by the region setting function 26c according to a user's instruction via the input interface 23.

[0089] The processing circuitry 26 uses the region setting function 26c to set multiple regions of interest based on the X-ray imaging conditions for the subject P. The processing content of the region setting function 26c is executed, for example, at any stage before step S303 in FIG. 3 in the DSA image determination process.

[0090] Fig. 9 is a diagram showing an example of a user interface for setting a region of interest and for setting a DSA image determination process. As shown in Fig. 9, the display 24 displays a dialog DL for selecting whether or not to perform alignment, along with a setting screen SS for setting a region of interest in one contrast image. When ROI setting is in the ON state, as shown in Fig. 9, it is possible to set an ROI by operating the cursor CS. Furthermore, when setting a region of interest is selected, the display 24 displays one difference image together with ROI1 (Org), as shown in Fig. 9.

[0091] On the display screen shown in Fig. 9, the user inputs ON / OFF of the region of interest setting and ON / OFF of the DSA image determination process setting via the input interface 23. In Fig. 9, the region of interest (ROI) setting is set to ON, and a second region of interest ROI2 is set for the normal region of interest ROI1 (org) set as the default. Also, as shown in Fig. 9, the optimal DSA display, which indicates the setting of the DSA image determination process, is set to ON.

[0092] The processing circuitry 26 uses the registration function 26d to perform registration between multiple regions of interest set in one contrast image selected by the user and each of multiple mask images. That is, the registration function 26d performs the registration using the regions of interest as target regions for registration. The processing content of the registration function 26d is executed, for example, in step S304 of FIG. 3 in the DSA image determination process.

[0093] The processing circuitry 26 uses the matching calculation function 26e to calculate multiple degrees of matching between the aligned mask images and the multiple region-of-interest images based on the aligned mask images and the multiple region-of-interest images corresponding to the multiple regions of interest. Specifically, the matching calculation function 26e calculates multiple difference images between the region-of-interest image and the multiple mask images according to the set region of interest. Next, the matching calculation function 26e calculates multiple degrees of matching for each region of interest, using the region of interest in the multiple difference images as the calculation target.

[0094] In other words, the matching calculation function 26e calculates multiple degrees of matching for multiple difference images showing the differences between multiple mask images aligned according to the region of interest and one contrast image, using the region of interest as the calculation range of the degree of matching. That is, the matching calculation function 26e calculates multiple degrees of matching for each of the multiple regions of interest based on the multiple difference images. The processing content of the matching calculation function 26e is executed, for example, in step S305 of FIG. 3 in the DSA image determination process.

[0095] The processing circuitry 26 determines, by the determination function 26f, the differences between the mask images corresponding to the highest degree of match for each of the regions of interest and the region-of-interest images as the subtraction images of interest corresponding to the regions of interest. That is, the determination function 26f determines, for each of the regions of interest, the difference image between the mask image corresponding to the highest degree of match and one contrast image as the subtraction image of interest. The processing contents of the determination function 26f are executed, for example, in step S306 of FIG. 3 in the DSA image determination process.

[0096] The display 24 displays one subtraction image determined in the embodiment and multiple subtraction images of interest. The processing on the display 24 is executed, for example, in step S307 of Fig. 3 in the DSA image determination processing.

[0097] FIG. 10 shows a plurality of ROIs (ROI1(org), ROI2, ROI3, ROI4) that have been set, a plurality of difference images displayed on the display 24 according to the plurality of ROIs, and an example RDSA. The difference image Sub(ROI1(Org)) shown in FIG. 10 shows a difference image between a mask image that corresponds to the highest degree of matching and is aligned with one contrast image for the region of interest ROI1(Org). The difference image Sub(ROI2) shown in FIG. 10 shows a difference image between a mask image that corresponds to the highest degree of matching and is aligned with one contrast image for the region of interest ROI2.

[0098] The difference image Sub(ROI3) shown in Fig. 10 shows the difference image between the mask image and one contrast image that are aligned and correspond to the highest degree of match for the region of interest ROI3. The difference image Sub(ROI4) shown in Fig. 10 shows the difference image between the mask image and one contrast image that are aligned and correspond to the highest degree of match for the region of interest ROI4. As shown in Fig. 10, the user selects a DSA image from the multiple difference images displayed on the RDSA via the input interface 23.

[0099] According to the X-ray diagnostic apparatus 1 of this modified example, alignment is performed between multiple regions of interest set in one contrast image and each of multiple mask images, and multiple degrees of match between the aligned multiple mask images and multiple region of interest images are calculated based on the aligned multiple mask images and multiple region of interest images corresponding to the multiple regions of interest, and the differences between the multiple mask images corresponding to the maximum degrees of match for each of the multiple regions of interest and one contrast image are determined as multiple difference images of interest corresponding to the multiple regions of interest, and the one difference image and the multiple difference images of interest are displayed.

[0100] As a result, the present X-ray diagnostic apparatus 1 can display, on the display 24, a difference image using a mask image corresponding to the highest degree of match in each of a plurality of regions of interest set in one contrast image. Therefore, the present X-ray diagnostic apparatus 1 can present to the user candidate difference images with fewer registration errors according to the region of interest. Other effects are the same as those of the embodiment, and therefore will not be described here.

[0101] (Sixth Modification) In this modification, a contrast region related to the contrast agent is extracted based on the difference image associated with the highest degree of match in the embodiment, and a DSA image determination process is applied to the extracted contrast region. That is, according to this modification, alignment is performed between a contrast partial image with the extracted contrast region as a region of interest and multiple mask images, and the degrees of match between the multiple mask images and the contrast partial images are calculated again.

[0102] Thereafter, in this modification, the recalculated degree of match is used to execute the DSA image determination process, as in the embodiment and modifications 1 to 5. In other words, in this modification, multiple degrees of match are recalculated based on multiple mask images and a contrast partial image corresponding to the contrast region extracted from the difference image associated with the maximum degree of match among the multiple degrees of match.

[0103] The processing circuitry 26 extracts a contrast region related to the contrast agent from a difference image based on the difference image between the mask image with the highest degree of match and one contrast image selected by the user, using the registration function 26d. The registration function 26d aligns the contrast partial image corresponding to the contrast region with the multiple mask images. For example, the registration function 26d performs registration by applying at least one of translation and rotation to the multiple mask images based on the contrast partial image and each of the multiple mask images. The processing content of the registration function 26d is executed, for example, after step S306 of FIG. 3 in the DSA image determination process.

[0104] The processing circuitry 26 uses the matching calculation function 26e to calculate multiple degrees of matching between the contrast partial image and the multiple mask images using the multiple mask images and the contrast partial image used for alignment with the contrast partial image. That is, the matching calculation function 26e recalculates multiple degrees of matching corresponding to the multiple mask images, respectively, for the extracted contrast region, based on multiple difference images between the aligned multiple mask images and the contrast partial image. The processing content of the matching calculation function 26e is executed, for example, in the DSA image determination process after the processing by the above-mentioned alignment function 26d in this modified example.

[0105] The processing circuit 26 determines, by the determination function 26f, the difference between the mask image corresponding to the highest degree of matching among the recalculated degrees of matching and one contrast image as one difference image corresponding to one contrast image. That is, the determination function 26f determines the difference image corresponding to the highest degree of matching among the plurality of difference images as the difference image. The processing contents of the determination function 26f are executed, for example, in the DSA image determination process after the processing by the degree-of-match calculation function 26e in this modified example. After the processing by the determination function 26f, the processing of step S307 in FIG. 3 is executed.

[0106] According to the X-ray diagnostic apparatus 1 of this modified example, based on the difference image and one contrast image, a contrast region related to the contrast agent is extracted from the difference image, the contrast partial image corresponding to the contrast region is aligned with multiple mask images, multiple degrees of agreement between the contrast partial image and the multiple mask images are recalculated using the multiple mask images and the contrast partial image used for alignment with the contrast partial image, and the difference between the mask image corresponding to the maximum degree of agreement among the recalculated degrees of agreement and one contrast image is determined as one difference image corresponding to one contrast image.

[0107] According to the X-ray diagnostic apparatus 1 of this modified example, based on the difference image corresponding to the maximum degree of matching determined in the embodiment and one contrast image, a contrast region related to the contrast agent is extracted from the difference image, the contrast partial image corresponding to the contrast region is aligned with multiple mask images, and multiple degrees of matching between the contrast partial image and the multiple mask images are recalculated using the multiple mask images and the contrast partial image used for alignment with the contrast partial image, and the difference (difference image) between the aligned mask image corresponding to the maximum degree of matching among the multiple degrees of matching calculated again and the one contrast image is determined as one difference image corresponding to the one contrast image.

[0108] As a result, the X-ray diagnostic apparatus 1 according to this modification uses the extracted contrast region as a region of interest, and therefore can present to the user candidate difference images with fewer registration errors according to the contrast region. Other effects are the same as those of the embodiment, and therefore will not be described here.

[0109] (Seventh Modification) In this modification, a contrast image selected by a user is divided into multiple regions, and a DSA image determination process is applied to each of the multiple contrast division images corresponding to the divided regions. The number of the multiple regions and the division method are set in advance. For the sake of concreteness, the following description assumes that the multiple regions are three regions, and that the division method is to divide one contrast image into three slices from bottom to top. Note that the number of regions can be changed as needed by a user's instruction via the input interface 23.

[0110] The processing circuitry 26 divides one contrast image into multiple regions using the alignment function 26d. The alignment function 26d aligns multiple contrast division images corresponding to the multiple regions with each of multiple mask images. Specifically, the alignment function 26d aligns ROIs set in each of the multiple contrast division images with the multiple mask images. The processing performed by the alignment function 26d is performed, for example, in step S304 of FIG. 3 during the DSA image determination process.

[0111] The processing circuitry 26 uses the coincidence calculation function 26e to calculate multiple degrees of coincidence between the aligned mask images and the aligned contrast division images based on the aligned mask images and the aligned contrast division images. Specifically, the coincidence calculation function 26e generates multiple difference images that indicate the differences between the aligned mask images and the aligned contrast division images. The coincidence calculation function 26e calculates multiple degrees of coincidence corresponding to the difference images for each of the regions based on the difference images. In other words, the coincidence calculation function 26e calculates multiple degrees of coincidence for each of the regions. The processing performed by the coincidence calculation function 26e is executed, for example, in step S305 of FIG. 3 during the DSA image determination process.

[0112] The processing circuit 26 uses the determination function 26f to determine, for each of the multiple regions, the differences between the mask image corresponding to the highest degree of match and the multiple contrast division images as multiple division difference images. That is, the determination function 26f determines, for each of the multiple regions, the difference image corresponding to the highest degree of match among the multiple degrees of match as the division difference image. In other words, the determination function 26f determines multiple division difference images corresponding to the multiple regions using the highest degree of match for each of the multiple regions among the multiple degrees of match. The determination function 26f stitches together the multiple division difference images to generate one difference image corresponding to one contrast image. The processing performed by the determination function 26f is executed, for example, in step S306 of FIG. 3 during the DSA image determination process.

[0113] The display 24 displays one difference image. FIG. 11 shows one contrast image C j 11 is a diagram showing an example of a plurality of regions (AR1, AR2, AR3) divided in the image and one difference image displayed on the display 24. In Fig. 11, a first region of interest ROI1 is set in the first region AR1, a second region of interest ROI2 is set in the second region AR2, and a third region of interest ROI3 is set in the third region AR3. Each of these regions of interest is used for registration with a plurality of mask images.

[0114] M(a) in FIG. 11 corresponds to the area corresponding to the first area AR1 and shows a mask image related to the highest degree of match with the first region of interest ROI1. M(b) in FIG. 11 corresponds to the area corresponding to the second area AR2 and shows a mask image related to the highest degree of match with the second region of interest ROI2. M(c) in FIG. 11 corresponds to the area corresponding to the third area AR3 and shows a mask image related to the highest degree of match with the third region of interest ROI3. As shown in FIG. 11, one difference image corresponding to one contrast image is displayed on the display 24 by stitching (combining) three difference images Sub.

[0115] According to the X-ray diagnostic apparatus 1 of this modified example, one contrast image selected by a user is divided into multiple regions, and alignment is performed between each of the multiple contrast division images corresponding to the multiple regions and each of the multiple mask images, and based on the aligned multiple mask images and the multiple contrast division images, multiple degrees of match between the aligned multiple mask images and the multiple contrast division images are calculated, and for each of the multiple regions, the differences (difference images) between the mask image and the multiple contrast division images corresponding to the greatest degree of match are determined as multiple divided difference images, and one difference image is generated by connecting the multiple divided difference images.

[0116] As a result, the present X-ray diagnostic apparatus 1 can stitch together divided difference images using mask images corresponding to the highest degree of matching in each of a plurality of regions of interest divided in one contrast image, and display one difference image on the display 24. Therefore, the present X-ray diagnostic apparatus 1 can present to the user candidate difference images with fewer registration errors according to the plurality of divided regions. Other effects are the same as those of the embodiment, and therefore will not be described here.

[0117] (Eighth Modification) This modification relates to application to DSA involving rapid intravenous injection (bolus injection, bolus administration) (hereinafter referred to as bolus DSA). In other words, this modification corresponds to application of the first modification to bolus DSA. Bolus DSA is used, for example, for X-ray imaging of the lower limb angiography of a subject P.

[0118] FIG. 12 is a diagram showing an example of an outline of imaging related to bolus DSA. As shown by CP in FIG. 12, the system control unit 22 performs a panning scan of the subject P by tracking the contrast agent along the flow of the contrast agent. At this time, the position data memory 21 stores the movement of the bed 7 when the contrast agent is imaged. The processing circuitry 26 also generates a series of contrast images along the flow of the contrast agent using the image calculation function 26a. That is, multiple contrast images in the series of contrast images are generated at a predetermined frame rate along the longitudinal direction of the subject P while the contrast agent is being rapidly injected into the subject P, and each of the contrast images includes one contrast image in this embodiment.

[0119] Next, the system control unit 22 performs a panning scan of the subject P without contrast agent using the movement of the bed 7 stored in the position data memory 21, as shown in the NCP in FIG. 12. At this time, the processing circuitry 26 generates a series of mask images following the flow of the contrast agent using the image calculation function 26a. That is, the multiple mask images in the series of mask images are generated at approximately the same frame rate as the series of contrast images, corresponding to the movement of the tabletop when the multiple contrast images are acquired. The imaging procedure for bolus DSA is not described here because known techniques can be applied.

[0120] The processing circuitry 26 uses the registration function 26d to perform registration between each of the multiple contrast images and one of the multiple mask images corresponding to the position of the tabletop for each of the multiple contrast images (hereinafter referred to as a position-corresponding mask image) and multiple mask images corresponding to a predetermined number of frames (hereinafter referred to as predetermined frames) before and after the frame of the position-corresponding mask image (hereinafter referred to as predetermined frame mask images). The number of predetermined frames in this modification is a number of frames that is set in advance before bolus DSA is performed and can be set and changed as appropriate via the input interface 23.

[0121] Specifically, the registration function 26d aligns the position-corresponding mask image and the predetermined frame mask image with each of the plurality of contrast images across a series of contrast images. The processing performed by the registration function 26d is executed in step S304 of the DSA image determination process shown in FIG. 3. As an application example of this modification, the registration function 26d may align the region of interest corresponding to the center of each of the plurality of contrast images.

[0122] The processing circuitry 26 uses the matching calculation function 26e to calculate multiple degrees of matching between each of the plurality of contrast images and the position-corresponding mask image, the predetermined frame mask image, and the predetermined number of mask images across the plurality of contrast images. Specifically, the matching calculation function 26e generates multiple difference images indicating the differences between each of the plurality of contrast images and the position-corresponding mask image and the predetermined frame mask image. Based on the multiple difference images, the matching calculation function 26e calculates multiple degrees of matching for each of the plurality of contrast images, each corresponding to the multiple difference images.

[0123] The processing contents of the coincidence calculation function 26e are executed in step S305 of Fig. 3 in the DSA image determination process. Note that, when alignment is executed for a region of interest corresponding to a central portion in each of a plurality of contrast images, the coincidence calculation function 26e may calculate the coincidence for the region of interest.

[0124] The processing circuit 26 determines, by the determination function 26f, a plurality of differences across the plurality of contrast images, which have differences between the mask image corresponding to the highest degree of matching among the plurality of degrees of matching and each of the plurality of contrast images, as a plurality of difference images corresponding to the plurality of contrast images. Specifically, the determination function 26f determines, as the difference image, the difference image associated with the highest degree of matching among the plurality of contrast images. The determination function 26f determines a plurality of difference images corresponding to the plurality of contrast images by executing the difference image determination across the plurality of contrast images.

[0125] The processing circuitry 26 generates a long image by stitching together the regions of interest in the plurality of subtraction images along the longitudinal direction based on the plurality of subtraction images determined by the determination function 26f. Specifically, the determination function 26f stitches together the regions of interest corresponding to the central portions of the plurality of subtraction images according to the position of the table of the bed 7, thereby generating a long image. Note that the stitching of the plurality of subtraction images may be performed by the image calculation function 26a. The above process by the determination function 26f is performed in step S306 of FIG. 3 in the DSA image determination process.

[0126] FIG. 13 is a diagram illustrating an example of the outline of generating a long image for bolus DSA. As shown in FIG. 13, a long image LI for bolus DSA is generated by stitching together multiple regions of interest RFB related to the stitching target in multiple subtraction images SUBS. As an application example of this modification, multiple long images may be generated in descending order of degree of match. In this case, the process in the determination function 26f is repeated from the highest degree of match to a predetermined degree of match. For the sake of convenience, background bones are depicted in the multiple subtraction images SUBS in FIG. 13, but in reality, the background bones are erased or attenuated by subtraction processing.

[0127] The display 24 displays the generated long image LI. Note that the display 24 may display multiple long images in descending order of degree of match. The above processing by the display 24 is executed in step S307 of FIG. 3 in the DSA image determination processing. When multiple long images are displayed on the display 24, the long image selected by the user in step S307 is stored in the memory 25 as an image related to bolus DSA.

[0128] In the X-ray diagnostic apparatus 1 according to this modification, one contrast image is included in a plurality of contrast images generated at a predetermined frame rate along the longitudinal direction of the subject P in association with rapid intravenous injection of a contrast agent into the subject P, and a plurality of mask images are generated at the same frame rate in response to the movement of the bed 7 when the plurality of contrast images are acquired. In this case, the X-ray diagnostic apparatus 1 according to this modification performs registration between each of the plurality of contrast images and one mask image among the plurality of mask images corresponding to the position of the tabletop for each of the plurality of contrast images, and a predetermined number of mask images for a predetermined number of frames before and after the frame related to the position of the tabletop.

[0129] Next, the X-ray diagnostic apparatus 1 according to this modification calculates multiple degrees of match between each of the multiple contrast images and one mask image and a predetermined number of mask images across the multiple contrast images, and determines multiple differences across the multiple contrast images, which have differences between the mask image corresponding to the largest degree of match among the multiple degrees of match and each of the multiple contrast images, as multiple difference images SUBS corresponding to the multiple contrast images. Next, the X-ray diagnostic apparatus 1 according to this modification stitches together the regions of interest of the multiple difference images along the longitudinal direction based on the multiple difference images SUBS to generate a long image LI.

[0130] As a result, in the X-ray diagnostic apparatus 1 according to this modification, in bolus DSA, Even if a misregistration occurs due to the state of the subject P or mechanical errors such as movement of the tabletop when collecting a series of contrast images and a series of mask images, a good DSA image can be generated, improving the diagnostic efficiency for the subject P and the throughput of the examination. Other effects are similar to those of the embodiment and the first modified example, and therefore will not be described.

[0131] (Ninth Modification) This modified example involves generating multiple interpolated images that fall within the time span between two chronologically adjacent mask images among multiple mask images, and then using the generated interpolated images to perform a DSA image determination process.

[0132] The processing circuitry 26 uses the alignment function 26d to generate multiple interpolated images within the time span between two temporally adjacent mask images. The number of interpolated images may be, for example, 10. For example, the alignment function 26d generates multiple interpolated images by inputting two temporally adjacent mask images into a trained model. Note that the generation of multiple interpolated images is not limited to trained models, and known techniques such as double-speed frame interpolation can be used as appropriate. Therefore, a description of the generation of multiple interpolated images will be omitted. The alignment function 26d further performs alignment between each of the multiple interpolated images and one contrast image. The processing performed by the alignment function 26d is performed, for example, in step S304 of FIG. 3 during the DSA image determination process.

[0133] The processing circuitry 26 further calculates, by the coincidence calculation function 26e, multiple coincidences between the aligned interpolated images and the one contrast image based on the aligned interpolated images and the one contrast image. That is, the coincidence calculation function 26e further generates multiple interpolated difference images based on the differences between the aligned interpolated images and the one contrast image. Next, the coincidence calculation function 26e calculates multiple coincidences corresponding to the multiple interpolated difference images using multiple pixels in the multiple interpolated difference images. The processing performed by the coincidence calculation function 26e is executed, for example, in step S305 of FIG. 3 during the DSA image determination process.

[0134] The processing circuitry 26 determines, by the determination function 26f, the difference between one contrast image and the mask image or the interpolated image corresponding to the highest degree of matching among the plurality of degrees of matching, as one difference image. The processing contents of the determination function 26f are executed, for example, in step S306 of FIG. 3 in the DSA image determination process.

[0135] According to the X-ray diagnostic apparatus 1 of this modified example, based on two mask images that are adjacent in time series among the multiple mask images, multiple interpolated images that fall within the time span between the two mask images are generated, alignment is further performed between each of the multiple interpolated images and one contrast image, and based on the aligned multiple interpolated images and one contrast image, multiple degrees of agreement between the aligned multiple interpolated images and the one contrast image are further calculated, and the difference (difference image) between the mask image or interpolated image corresponding to the maximum degree of agreement among the multiple degrees of agreement and the one contrast image is determined as one difference image.

[0136] It should be noted that three or more mask images may be used to create an interpolated image, which can improve the accuracy of the interpolation process compared to when two mask images are used.

[0137] As a result, the X-ray diagnostic apparatus 1 according to this modification increases the number of mask images that are the target of multiple degrees of match, making it possible to determine a good DSA image with fewer registration errors. Other effects are the same as those of the embodiment, and therefore will not be described here.

[0138] When the technical concept of the embodiments is realized by a medical image processing apparatus, the medical image processing apparatus has, for example, a configuration within a dotted frame 110 shown in Fig. 1. The medical image processing apparatus 110 performs registration between one contrast image generated by X-ray imaging of a subject P and each of multiple mask images generated by X-ray imaging, calculates multiple degrees of agreement between the registered multiple mask images and the one contrast image based on the registered multiple mask images and the one contrast image, and determines the difference between the mask image corresponding to the maximum degree of agreement among the multiple degrees of agreement and the one contrast image as a one difference image corresponding to the one contrast image. The processing procedure and effects of the DSA image determination process realized by the medical image processing apparatus 110 are similar to those of the embodiments, and therefore description thereof will be omitted.

[0139] When the technical idea of ​​the embodiment is realized by a medical image processing program, the medical image processing program causes a computer to perform alignment between one contrast image and each of multiple mask images, calculate multiple degrees of agreement between the aligned multiple mask images and the one contrast image based on the aligned multiple mask images and the one contrast image, and determine the difference between the mask image corresponding to the maximum degree of agreement among the multiple degrees of agreement and the one contrast image as one difference image corresponding to the one contrast image.

[0140] For example, the DSA image determination process can be realized by installing a medical image processing program in a computer such as a medical image processing device or server device and expanding the program in memory. In this case, the program that causes a computer to execute the DSA image determination process can also be stored and distributed on a storage medium such as a magnetic disk (e.g., a hard disk), an optical disk (e.g., a CD-ROM or DVD), or a semiconductor memory. The processing procedures and effects of the DSA image determination process realized by the medical image processing program are the same as those in the embodiment, and therefore will not be described here.

[0141] According to at least one of the embodiments described above, it is possible to determine a good DSA image while reducing the operational burden on the user.

[0142] Although several embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, modifications, and combinations of embodiments can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0143] 1 X-ray diagnostic equipment 3 X-ray generation unit 3a x-ray tube 3b X-ray constrictor 5 X-ray detector 7 berths 9 C-arm 11 X-ray controller 13 High voltage generator 13a X-ray control unit 13b High voltage generator 15 C-arm / Clinic mechanism control unit 21 Position data memory 22 System control section 23 Input Interface 24 displays 25 memory 26 Processing circuit 26a Image calculation function 26b Display data generation function 26c Area setting function 26d Alignment function 26e Matching calculation function 110 Medical image processing device

Claims

1. a registration unit that performs registration between one contrast image and each of a plurality of mask images; a matching degree calculation unit that calculates a plurality of matching degrees between the aligned mask images and the one contrast image based on the aligned mask images and the one contrast image; a determination unit that determines a difference between the mask image corresponding to the maximum degree of coincidence among the plurality of degrees of coincidence and the one contrast image as one difference image corresponding to the one contrast image; Equipped with the registration unit performs registration between a plurality of regions of interest set in the one contrast image and each of a plurality of mask images; the matching degree calculation unit calculates a plurality of matching degrees between the aligned mask images and a plurality of region of interest images corresponding to the plurality of regions of interest, based on the aligned mask images and the plurality of region of interest images; the determination unit determines differences between the plurality of mask images corresponding to the maximum degree of match for each of the plurality of regions of interest and the one contrast image as a plurality of difference images of interest corresponding to the plurality of regions of interest; a display unit that displays the one difference image and the plurality of difference images of interest; Medical imaging equipment.

2. An alignment unit that performs alignment between one contrast image and each of multiple mask images; a matching degree calculation unit that calculates a plurality of matching degrees between the aligned mask images and the one contrast image based on the aligned mask images and the one contrast image; a determination unit that determines a difference between the mask image corresponding to the maximum degree of coincidence among the plurality of degrees of coincidence and the one contrast image as one difference image corresponding to the one contrast image; Equipped with The alignment unit is Dividing the single contrast image into a plurality of regions; performing registration between a plurality of contrast division images corresponding to the plurality of regions and each of the plurality of mask images; the matching degree calculation unit calculates a plurality of matching degrees between the aligned mask images and the plurality of contrast division images based on the aligned mask images and the plurality of contrast division images; The determination unit determining, for each of the plurality of regions, differences between the mask image corresponding to the maximum degree of match and the plurality of contrast division images as a plurality of division difference images; stitching the plurality of divided difference images together to generate the single difference image; Medical imaging equipment.

3. An alignment unit that performs alignment between one contrast image and each of multiple mask images; a matching degree calculation unit that calculates a plurality of matching degrees between the aligned mask images and the one contrast image based on the aligned mask images and the one contrast image; a determination unit that determines a difference between the mask image corresponding to the maximum degree of coincidence among the plurality of degrees of coincidence and the one contrast image as one difference image corresponding to the one contrast image; Equipped with the one contrast image is included in a plurality of contrast images generated at a predetermined frame rate along a longitudinal direction of the subject by bolus injection of a contrast agent into the subject; the plurality of mask images are generated at the frame rate in response to a movement of the tabletop when the plurality of contrast images are acquired; the alignment unit performs alignment between each of the plurality of contrast images and one mask image among the plurality of mask images corresponding to the position of the tabletop for each of the plurality of contrast images, and the predetermined number of mask images corresponding to a predetermined number of frames before and after a frame related to the position of the tabletop; the matching degree calculation unit calculates, across the plurality of contrast images, a plurality of matching degrees between each of the plurality of contrast images and the one mask image and the predetermined number of mask images; The determination unit determining a plurality of differences across the plurality of contrast images as a plurality of difference images corresponding to the plurality of contrast images, the differences being between the mask image corresponding to the largest degree of matching among the plurality of degrees of matching and each of the plurality of contrast images; based on the plurality of difference images, stitching together the regions of interest of the plurality of difference images along the longitudinal direction to generate a long image; Medical imaging equipment.

4. the registration unit performs the registration by applying at least one of translation and rotation to the plurality of mask images based on the one contrast image and each of the plurality of mask images. The medical image processing device according to claim 1 .

5. The alignment unit is extracting a contrast region related to the contrast agent from the difference image based on the difference image and the one contrast image; performing registration of a contrast portion image corresponding to the contrast region with the plurality of mask images; the matching degree calculation unit recalculates a plurality of matching degrees between the contrast partial image and the plurality of mask images using the plurality of mask images and the contrast partial image that were used for alignment with the contrast partial image; the determination unit determines a difference between the mask image corresponding to the largest degree of matching among the recalculated plurality of degrees of matching and the one contrast image as a difference image corresponding to the one contrast image. The medical image processing device according to claim 1 .

6. a display unit that displays a dialog box for selecting whether or not to perform the alignment together with a setting screen for a region of interest in the one contrast image; the display unit displays the one difference image when the setting of the region of interest is selected. The medical image processing device according to claim 1 .

7. a registration unit that performs registration between one contrast image generated by X-ray imaging of a subject and each of a plurality of mask images generated by the X-ray imaging; a matching degree calculation unit that calculates a plurality of matching degrees between the aligned mask images and the one contrast image based on the aligned mask images and the one contrast image; a determination unit that determines a difference between the mask image corresponding to the maximum degree of coincidence among the plurality of degrees of coincidence and the one contrast image as one difference image corresponding to the one contrast image; Equipped with the registration unit performs registration between a plurality of regions of interest set in the one contrast image and each of a plurality of mask images; the matching degree calculation unit calculates a plurality of matching degrees between the aligned mask images and a plurality of region of interest images corresponding to the plurality of regions of interest, based on the aligned mask images and the plurality of region of interest images; the determination unit determines differences between the plurality of mask images corresponding to the maximum degree of match for each of the plurality of regions of interest and the one contrast image as a plurality of difference images of interest corresponding to the plurality of regions of interest; a display unit that displays the one difference image and the plurality of difference images of interest; X-ray diagnostic equipment.

8. An alignment unit that performs alignment between one contrast image generated by X-ray photography of a subject and each of multiple mask images generated by the X-ray photography; a matching degree calculation unit that calculates a plurality of matching degrees between the aligned mask images and the one contrast image based on the aligned mask images and the one contrast image; a determination unit that determines a difference between the mask image corresponding to the maximum degree of coincidence among the plurality of degrees of coincidence and the one contrast image as one difference image corresponding to the one contrast image; Equipped with The alignment unit is Dividing the single contrast image into a plurality of regions; performing registration between a plurality of contrast division images corresponding to the plurality of regions and each of the plurality of mask images; the matching degree calculation unit calculates a plurality of matching degrees between the aligned mask images and the plurality of contrast division images based on the aligned mask images and the plurality of contrast division images; The determination unit determining, for each of the plurality of regions, differences between the mask image corresponding to the maximum degree of match and the plurality of contrast division images as a plurality of division difference images; stitching the plurality of divided difference images together to generate the single difference image; X-ray diagnostic equipment.

9. An alignment unit that performs alignment between one contrast image generated by X-ray photography of a subject and each of multiple mask images generated by the X-ray photography; a matching degree calculation unit that calculates a plurality of matching degrees between the aligned mask images and the one contrast image based on the aligned mask images and the one contrast image; a determination unit that determines a difference between the mask image corresponding to the maximum degree of coincidence among the plurality of degrees of coincidence and the one contrast image as one difference image corresponding to the one contrast image; Equipped with the one contrast image is included in a plurality of contrast images generated at a predetermined frame rate along a longitudinal direction of the subject by bolus injection of a contrast agent into the subject; the plurality of mask images are generated at the frame rate in response to a movement of the tabletop when the plurality of contrast images are acquired; the alignment unit performs alignment between each of the plurality of contrast images and one mask image among the plurality of mask images corresponding to the position of the tabletop for each of the plurality of contrast images, and the predetermined number of mask images corresponding to a predetermined number of frames before and after a frame related to the position of the tabletop; the matching degree calculation unit calculates, across the plurality of contrast images, a plurality of matching degrees between each of the plurality of contrast images and the one mask image and the predetermined number of mask images; The determination unit determining a plurality of differences across the plurality of contrast images as a plurality of difference images corresponding to the plurality of contrast images, the differences being between the mask image corresponding to the largest degree of matching among the plurality of degrees of matching and each of the plurality of contrast images; based on the plurality of difference images, stitching together the regions of interest of the plurality of difference images along the longitudinal direction to generate a long image; X-ray diagnostic equipment.

10. On the computer, performing a registration between the contrast image and each of the plurality of mask images; calculating a plurality of match degrees between the registered plurality of mask images and the one contrast image based on the registered plurality of mask images and the one contrast image; determining a difference between the mask image corresponding to the maximum degree of matching among the plurality of degrees of matching and the one contrast image as a difference image corresponding to the one contrast image; To achieve this, performing the registration includes performing registration between a plurality of regions of interest set in the one contrast image and each of a plurality of mask images; calculating the degrees of match between the registered mask images and a plurality of region of interest images corresponding to the plurality of regions of interest based on the registered mask images and the plurality of region of interest images; determining the differences includes determining differences between the plurality of mask images corresponding to the maximum degree of match for each of the plurality of regions of interest and the one contrast image as a plurality of difference images of interest corresponding to the plurality of regions of interest; displaying the one difference image and the plurality of difference images of interest; A medical image processing program that makes this possible.

11. A computer comprising: performing a registration between the contrast image and each of the plurality of mask images; calculating a plurality of match degrees between the registered plurality of mask images and the one contrast image based on the registered plurality of mask images and the one contrast image; determining a difference between the mask image corresponding to the maximum degree of matching among the plurality of degrees of matching and the one contrast image as a difference image corresponding to the one contrast image; To achieve this, performing the alignment, Dividing the single contrast image into a plurality of regions; performing registration between a plurality of contrast division images corresponding to the plurality of regions and each of the plurality of mask images; calculating the degrees of match includes calculating a plurality of degrees of match between the registered plurality of mask images and the plurality of contrast division images based on the registered plurality of mask images and the plurality of contrast division images; Determining the difference comprises: determining, for each of the plurality of regions, differences between the mask image corresponding to the maximum degree of match and the plurality of contrast division images as a plurality of division difference images; stitching the plurality of split difference images together to generate the single difference image; A medical image processing program that makes this possible.

12. A computer comprising: performing a registration between the contrast image and each of the plurality of mask images; calculating a plurality of match degrees between the registered plurality of mask images and the one contrast image based on the registered plurality of mask images and the one contrast image; determining a difference between the mask image corresponding to the maximum degree of matching among the plurality of degrees of matching and the one contrast image as a difference image corresponding to the one contrast image; To achieve this, the one contrast image is included in a plurality of contrast images generated at a predetermined frame rate along a longitudinal direction of the subject by bolus injection of a contrast agent into the subject; the plurality of mask images are generated at the frame rate in response to a movement of the tabletop when the plurality of contrast images are acquired; The execution of the registration includes executing registration between each of the plurality of contrast images and one mask image among the plurality of mask images corresponding to the position of the tabletop for each of the plurality of contrast images, and the predetermined number of mask images for a predetermined number of frames before and after a frame related to the position of the tabletop; calculating the degree of match includes calculating, across the plurality of contrast images, a plurality of degrees of match between each of the plurality of contrast images and the one mask image and the predetermined number of mask images; Determining the difference comprises: determining a plurality of differences across the plurality of contrast images as a plurality of difference images corresponding to the plurality of contrast images, the differences being between the mask image corresponding to the largest degree of matching among the plurality of degrees of matching and each of the plurality of contrast images; based on the plurality of difference images, stitching together regions of interest in the plurality of difference images along the longitudinal direction to generate a long image; A medical image processing program that makes this possible.

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