Dynamic analysis device and program

Abstract

To efficiently calculate a V / Q ratio.SOLUTION: A control unit of a diagnostic console acquires, from among a plurality of frame images obtained by radiographing the dynamic state of the chest of a subject, a plurality of frame images for ventilation analysis and a plurality of frame images for perfusion analysis, selects a reference frame from among the plurality of acquired frame images, divides a lung field area in the reference frame image into a plurality of small areas, and tracks, in a frame image other than the reference frame image, each of the small areas in the reference frame image to identify a position corresponding to the small area in the frame image other than the reference frame image, thereby setting a plurality of small areas corresponding between the acquired frame images. For each of the set small areas, a V / Q ratio is calculated.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a dynamic analysis device and a program. [Background technology]

[0002] The functions of the lungs are ventilation and perfusion. Ventilation is the process of taking in oxygen as inhaled air and sending it to the alveoli, and expelling carbon dioxide from the alveoli as exhaled air. Blood flow is the process of sending blood from which carbon dioxide has been expelled from cells throughout the body to the alveoli, and sending blood that has absorbed oxygen through gas exchange in the alveoli to the heart. In other words, it is important for gas exchange that ventilation and perfusion function in a balanced manner, and if the function of either one is impaired, gas exchange will not work properly.

[0003] The relationship between ventilation (V) and perfusion (Q) is important for understanding the pathophysiology of respiratory diseases and is clinically assessed by the VQ ratio: VQ ratio = ventilation volume (V) / blood flow (Q)

[0004] For example, Patent Document 1 describes calculating the VQ ratio for each small region from the ventilation analysis results and blood flow analysis results for each small region of the same frame image in a series of frame images showing the dynamics of the chest. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-202208 Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology described in Patent Document 1, the VQ ratio is calculated from the ventilation analysis results and blood flow analysis results for each of the same small regions of the same frame image. In other words, the VQ ratio is calculated using the ventilation analysis results and blood flow analysis results for small regions located at the same pixel position.

[0007] However, there are cases where the VQ ratio is calculated using frame images taken during deep breathing or quiet breathing for ventilation analysis, and frame images taken during breath-holding for blood flow analysis. As shown in Figure 11, the same part of the lung field (indicated by R in Figure 11) is shown in different positions in the frame image (breathing image) for ventilation analysis and the frame image (breath-holding image) for blood flow analysis, so if the VQ ratio is calculated using the ventilation analysis results and blood flow analysis results for small areas at the same pixel position, an incorrect VQ ratio will be calculated.

[0008] Patent Document 1 also describes performing local matching and warping processing to correct positional shifts in lung field areas between frame images, then dividing the image into small areas and calculating the VQ ratio between small areas at the same pixel position. However, the warping process has a problem of being inefficient because it takes a long time to process.

[0009] An object of the present invention is to make it possible to efficiently calculate the VQ ratio. [Means for solving the problem]

[0011] Book The dynamic analysis device according to the present invention comprises: an acquisition means for acquiring a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamic state of the chest of a subject; a dividing means for selecting a reference frame image from the plurality of frame images for ventilation analysis and blood flow analysis acquired by the acquiring means, and dividing a lung field region in the reference frame image into a plurality of small regions; a tracking means for tracking each of the plurality of small regions of the reference frame image in other frame images other than the reference frame image and specifying a position corresponding to the corresponding small region in the other frame images, thereby setting a plurality of corresponding small regions between the frame images acquired by the acquisition means; a division and integration means for determining whether the aspect ratio of each of the plurality of small regions set by the tracking means falls within a reference range, and for dividing a small region determined not to fall within the reference range or integrating the small region into an adjacent small region; an analysis means for calculating an index value indicating ventilation volume using the plurality of frame images for ventilation analysis for each of the plurality of set small regions, and for calculating an index value indicating blood flow volume using the plurality of frame images for blood flow analysis; a ratio calculation means for calculating a ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume for each of the plurality of small regions calculated by the analysis means; Equipped with.

[0012] Furthermore, the dynamic analysis device according to the present invention comprises: an acquisition means for acquiring a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamic state of the chest of a subject; a dividing means for selecting a reference frame image from the plurality of frame images for ventilation analysis and blood flow analysis acquired by the acquiring means, and dividing a lung field region in the reference frame image into a plurality of small regions; a tracking means for tracking each of the plurality of small regions of the reference frame image in other frame images other than the reference frame image and specifying a position corresponding to the corresponding small region in the other frame images, thereby setting a plurality of corresponding small regions between the frame images acquired by the acquisition means; a deformation means for determining whether the aspect ratio of each of the plurality of small regions set by the tracking means falls within a reference range, and for deforming a small region determined not to fall within the reference range so that its aspect ratio falls within the reference range; an analysis means for calculating an index value indicating ventilation volume using the plurality of frame images for ventilation analysis for each of the plurality of set small regions, and for calculating an index value indicating blood flow volume using the plurality of frame images for blood flow analysis; a ratio calculation means for calculating a ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume for each of the plurality of small regions calculated by the analysis means; Equipped with.

[0014] In addition, the program according to the present invention is Computer, an acquisition means for acquiring a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamic state of the chest of the subject; a dividing means for selecting a reference frame image from the plurality of frame images for ventilation analysis and blood flow analysis acquired by the acquiring means, and dividing a lung field region in the reference frame image into a plurality of small regions; a tracking means for tracking each of the plurality of small regions of the reference frame image in other frame images other than the reference frame image and specifying a position corresponding to the corresponding small region in the other frame images, thereby setting a plurality of corresponding small regions between the frame images acquired by the acquisition means; a division and integration means for determining whether the aspect ratio of each of the plurality of small regions set by the tracking means falls within a reference range, and for dividing a small region determined not to fall within the reference range or integrating the small region into an adjacent small region; an analysis means for calculating an index value indicating ventilation volume using the plurality of frame images for ventilation analysis, and calculating an index value indicating blood flow volume using the plurality of frame images for blood flow analysis, for each of the plurality of set small regions; a ratio calculation means for calculating a ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume for each of the plurality of small regions calculated by the analysis means; to function as .

[0015] In addition, the program according to the present invention is Computer, an acquisition means for acquiring a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamic state of the chest of the subject; a dividing means for selecting a reference frame image from the plurality of frame images for ventilation analysis and blood flow analysis acquired by the acquiring means, and dividing a lung field region in the reference frame image into a plurality of small regions; a tracking means for tracking each of the plurality of small regions of the reference frame image in other frame images other than the reference frame image and specifying a position corresponding to the corresponding small region in the other frame images, thereby setting a plurality of corresponding small regions between the frame images acquired by the acquisition means; a deformation means for determining whether or not the aspect ratio of each of the plurality of small regions set by the tracking means falls within a reference range, and for deforming a small region determined not to fall within the reference range so that its aspect ratio falls within the reference range; an analysis means for calculating an index value indicating ventilation volume using the plurality of frame images for ventilation analysis, and calculating an index value indicating blood flow volume using the plurality of frame images for blood flow analysis, for each of the plurality of set small regions; a ratio calculation means for calculating a ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume for each of the plurality of small regions calculated by the analysis means; to function as . [Effects of the Invention]

[0027] According to the present invention, it is possible to efficiently calculate the VQ ratio. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is a diagram showing the overall configuration of a dynamic analysis system according to an embodiment of the present invention. [Figure 2] 2 is a flowchart showing an imaging control process executed by a control unit of the imaging console of FIG. 1. [Figure 3] 10 is a flowchart showing a VQ ratio calculation process executed by a control unit of the diagnostic console of FIG. [Figure 4] FIG. 10 is a diagram for explaining a breathing interval and a breath-holding interval. [Figure 5] FIG. 10 is a diagram for explaining the number of divisions of a lung field. [Figure 6] FIG. 10 is a diagram schematically illustrating a lung field region divided into small regions. [Figure 7] FIG. 10A is a diagram showing an example in which the lung field region is divided into equal widths according to the number of vertical and horizontal divisions, and FIG. 10B is a diagram showing an example in which the lower part of the lung field is divided at finer intervals than the upper part. [Figure 8] 4 is a flowchart showing the process of dividing and merging small regions executed in step S18 of FIG. 3. [Figure 9] FIG. 10 is a diagram illustrating the integration of small regions. [Figure 10] FIG. 10 is a diagram illustrating an example of an output of a VQ ratio. [Figure 11]FIG. 10 is a diagram showing changes in position within the lung region between a breathing image and a breath-holding image. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the scope of the invention is not limited to the illustrated examples.

[0030] Configuration of dynamic analysis system 100 First, the configuration of the embodiment of the present invention will be described. FIG. 1 shows the overall configuration of a dynamic analysis system 100 according to this embodiment. 1, the dynamic analysis system 100 is configured such that an imaging device 1 and an imaging console 2 are connected by a communication cable or the like, and the imaging console 2 and a diagnostic console 3 are connected via a communication network NT such as a LAN (Local Area Network). Each device constituting the dynamic analysis system 100 conforms to the DICOM (Digital Image and Communications in Medicine) standard, and communication between the devices is performed in accordance with DICOM.

[0031] <Configuration of the imaging device 1> The imaging device 1 is an imaging means for capturing periodic (cyclic) dynamics of the chest, such as changes in the shape of lung expansion and contraction due to breathing, and heartbeat. Dynamic imaging refers to obtaining multiple images showing the dynamics of a subject by repeatedly irradiating the subject with pulsed radiation such as X-rays at predetermined time intervals (pulse irradiation) or by continuously irradiating the subject with low dose rate radiation without interruption (continuous irradiation). A series of images obtained by dynamic imaging is called a dynamic image. Each of the multiple images that make up a dynamic image is called a frame image. Here, dynamic images include moving images, but do not include images obtained by capturing still images while displaying a moving image. In the following embodiment, a case where dynamic imaging is performed by pulse irradiation will be described as an example.

[0032] The radiation source 11 is disposed at a position facing the radiation detection unit 13 across the subject M, and irradiates the subject M with radiation (X-rays) under the control of the radiation irradiation control device 12. The radiation irradiation control device 12 is connected to the imaging console 2 and controls the radiation source 11 to perform radiation imaging based on radiation irradiation conditions input from the imaging console 2. The radiation irradiation conditions input from the imaging console 2 include, for example, a pulse rate, a pulse width, a pulse interval, the number of imaging frames per imaging, the value of the X-ray tube current, the value of the X-ray tube voltage, and the type of additional filter. The pulse rate is the number of radiation irradiations per second and corresponds to the frame rate described below. The pulse width is the radiation irradiation time per radiation irradiation. The pulse interval is the time from the start of one radiation irradiation to the start of the next radiation irradiation and corresponds to the frame interval described below.

[0033] The radiation detection unit 13 is composed of a semiconductor image sensor such as an FPD. The FPD has, for example, a glass substrate or the like, and a plurality of detection elements (pixels) are arranged in a matrix at predetermined positions on the substrate. The detection elements detect radiation emitted from the radiation source 11 and transmitted through at least the subject M according to its intensity, and convert the detected radiation into an electrical signal and store it. Each pixel is equipped with a switching unit such as a TFT (Thin Film Transistor). FPDs can be of an indirect conversion type, in which X-rays are converted into an electrical signal by a photoelectric conversion element via a scintillator, or a direct conversion type, in which X-rays are directly converted into an electrical signal, and either type may be used. The radiation detection unit 13 is disposed opposite the radiation source 11 with the subject M interposed therebetween.

[0034] The reading control device 14 is connected to the radiography console 2. The reading control device 14 controls the switching units of each pixel of the radiation detection unit 13 based on the image reading conditions input from the radiography console 2, switches the reading of the electrical signals accumulated in each pixel, and acquires image data by reading the electrical signals accumulated in the radiation detection unit 13. This image data is a frame image. The reading control device 14 then outputs the acquired frame image to the radiography console 2. The image reading conditions include, for example, the frame rate, frame interval, pixel size, image size (matrix size), etc. The frame rate is the number of frame images acquired per second and coincides with the pulse rate. The frame interval is the time from the start of acquisition of one frame image to the start of acquisition of the next frame image and coincides with the pulse interval.

[0035] The radiation irradiation control device 12 and the reading control device 14 are connected to each other and exchange synchronization signals with each other to synchronize the radiation irradiation operation and the image reading operation.

[0036] <Configuration of shooting console 2> The imaging console 2 outputs radiation irradiation conditions and image reading conditions to the imaging device 1 to control the radiation imaging and radiation image reading operations by the imaging device 1, and also displays dynamic images acquired by the imaging device 1 so that the imaging technician or other person performing the imaging can check the positioning and whether the images are suitable for diagnosis. As shown in FIG. 1, the radiography console 2 comprises a control unit 21, a storage unit 22, an operation unit 23, a display unit 24, and a communication unit 25, and each unit is connected by a bus .

[0037] The control unit 21 is composed of a CPU (Central Processing Unit), RAM (Random Access Memory), etc. In response to an operation of the operation unit 23, the CPU of the control unit 21 reads out a system program and various processing programs stored in the storage unit 22 and loads them into the RAM, and executes various processes including an imaging control process described below in accordance with the loaded programs, thereby centrally controlling the operation of each unit of the imaging console 2 and the radiation irradiation operation and reading operation of the imaging device 1.

[0038] The storage unit 22 is configured with a non-volatile semiconductor memory, a hard disk, etc. The storage unit 22 stores various programs executed by the control unit 21, parameters required for executing processes by the programs, data such as processing results, etc. For example, the storage unit 22 stores a program for executing the imaging control process shown in FIG. 2. The storage unit 22 also stores radiation irradiation conditions and image reading conditions corresponding to the imaging region (here, the chest). The various programs are stored in the form of readable program code, and the control unit 21 sequentially executes operations in accordance with the program code.

[0039] The operation unit 23 is configured with a keyboard having cursor keys, numeric input keys, various function keys, etc., and a pointing device such as a mouse, and outputs instruction signals input by operating the keys on the keyboard or the mouse to the control unit 21. The operation unit 23 may also have a touch panel on the display screen of the display unit 24, and in this case, outputs instruction signals input via the touch panel to the control unit 21.

[0040] The display unit 24 is composed of a monitor such as an LCD (Liquid Crystal Display) or CRT (Cathode Ray Tube), and displays input instructions and data from the operation unit 23 according to instructions of a display signal input from the control unit 21.

[0041] The communication unit 25 includes a LAN adapter, a modem, a TA (Terminal Adapter), etc., and controls data transmission and reception between each device connected to the communication network NT.

[0042] <Configuration of Diagnostic Console 3> The diagnostic console 3 is a dynamic analysis device that acquires dynamic images from the radiography console 2 and displays the acquired dynamic images and analysis results of the dynamic images to assist the doctor in making a diagnosis. In this embodiment, the diagnostic console 3 calculates the VQ ratio based on the dynamic images of the chest and displays the results. As shown in FIG. 1, the diagnostic console 3 comprises a control unit 31, a storage unit 32, an operation unit 33, a display unit , and a communication unit , and each unit is connected by a bus .

[0043] The control unit 31 is composed of a CPU, RAM, etc. In response to operations on the operation unit 33, the CPU of the control unit 31 reads out system programs and various processing programs stored in the storage unit 32, loads them into the RAM, and executes various processes such as the VQ ratio calculation process described below in accordance with the loaded programs, thereby centrally controlling the operations of each unit in the diagnostic console 3. The control unit 31 functions as an acquisition means, a division means, a tracking means, an analysis means, a ratio calculation means, a division and integration means, a transformation means, and an adjustment means.

[0044] The storage unit 32 is configured with a non-volatile semiconductor memory, a hard disk, etc. The storage unit 32 stores various programs, including a program for executing the VQ ratio calculation process in the control unit 31, parameters required for executing the processes by the programs, data such as processing results, etc. These various programs are stored in the form of readable program code, and the control unit 31 sequentially executes operations in accordance with the program code.

[0045] The operation unit 33 is configured with a keyboard having cursor keys, numeric input keys, various function keys, etc., and a pointing device such as a mouse, and outputs instruction signals input by operating the keys on the keyboard or the mouse to the control unit 31. The operation unit 33 may also have a touch panel on the display screen of the display unit 34, and in this case, outputs instruction signals input via the touch panel to the control unit 31.

[0046] The display unit 34 is configured with a monitor such as an LCD or CRT, and performs various displays according to instructions of a display signal input from the control unit 31. The display unit 34 functions as an output means.

[0047] The communication unit 35 includes a LAN adapter, a modem, a TA, etc., and controls data transmission and reception between each device connected to the communication network NT.

[0048] <Operation of Dynamic Analysis System 100> Next, the operation of the dynamic analysis system 100 will be described.

[0049] (Operation of imaging device 1 and imaging console 2) First, the imaging operation performed by the imaging device 1 and the imaging console 2 will be described. 2 shows an imaging control process executed in the control unit 21 of the imaging console 2. The imaging control process is executed by the control unit 21 in cooperation with a program stored in the storage unit 22.

[0050] First, the person performing the imaging operates the operation unit 23 of the imaging console 2 to input patient information (patient name, height, weight, age, sex, etc.) of the imaging target (subject M) and examination information (examination ID, imaging area (here, chest), breathing category (deep breathing / quiet breathing / breath holding / mixed, etc.)) (step S1).

[0051] Next, the radiation irradiation conditions are read out from the storage unit 22 and set in the radiation irradiation control device 12, and the image reading conditions are read out from the storage unit 22 and set in the reading control device 14 (step S2).

[0052] Next, the process waits for an instruction to irradiate radiation via operation of the operation unit 23 (step S3). Here, the person performing the imaging performs positioning by placing the subject M between the radiation source 11 and the radiation detection unit 13. When preparations for imaging are complete, the person operates the operation unit 23 to input an instruction to irradiate radiation.

[0053] When a radiation irradiation instruction is input via the operation unit 23 (step S3; YES), an imaging start instruction is output to the radiation irradiation control device 12 and the reading control device 14, and dynamic imaging is started (step S4). That is, radiation is irradiated from the radiation source 11 at pulse intervals set in the radiation irradiation control device 12, and frame images are acquired by the radiation detection unit 13. Note that, for example, the imaging device 1 may be equipped with an audio output unit and a display unit, and when an imaging start instruction is output, breathing guidance such as "take a breath in," "take a breath out," and "hold your breath" may be audibly or displayed. Then, after the imaging start instruction is given, radiation may be irradiated from the radiation source 11 at the timing when a predetermined breathing guidance (e.g., "take a breath in") is performed.

[0054] When the predetermined number of frames have been captured, the control unit 21 outputs an instruction to end the capture to the radiation irradiation control device 12 and the reading control device 14, and the capture operation is stopped. The number of frames to be captured is the number that can capture at least one respiratory cycle.

[0055] The frame images acquired by imaging are sequentially input to the imaging console 2, and are stored in the memory unit 22 in association with numbers (frame numbers) indicating the imaging order (step S5), and are also displayed on the display unit 24 (step S6). The imaging operator checks the positioning, etc., based on the displayed dynamic images, and determines whether an image suitable for diagnosis has been acquired by imaging (imaging OK) or whether reimaging is necessary (imaging NG). Then, the operator operates the operation unit 23 to input the determination result.

[0056] When a determination result indicating that imaging is OK is input by a predetermined operation of the operation unit 23 (step S7; YES), information such as an identification ID for identifying the dynamic image, patient information, examination information (examination ID, imaging region, radiation irradiation conditions, image reading conditions, breathing type (deep breathing / quiet breathing / breath holding / mixed, etc.)), and a number indicating the imaging order (frame number) is attached to each of the series of frame images acquired in the dynamic imaging (for example, written in the header area of the image data in DICOM format), and transmitted to the diagnostic console 3 via the communication unit 25 (step S8). Then, this process ends. Note that if a voice output or display of respiratory guidance is performed, the respiratory guidance information output when the frame image was captured may be attached to each frame image as auxiliary information. In the diagnostic console 3, the control unit 31 associates the dynamic images transmitted from the imaging console 2 with the auxiliary information and stores them in the memory unit 32. On the other hand, if a determination result indicating that photography is not possible is input by a predetermined operation of the operation unit 23 (step S7; NO), the series of frame images stored in the storage unit 22 is deleted (step S9), and this process ends. In this case, photography will need to be done again.

[0057] When calculating the VQ ratio, it is necessary to capture dynamic chest images including the respiratory state (deep breathing or quiet breathing) for ventilation analysis, and breath-holding or other chest dynamic images including the respiratory state for blood flow analysis. In the examination for calculating the VQ ratio, images may be taken separately for the respiratory state and the breath-holding state to obtain two dynamic images, or images may be taken consecutively for the respiratory state and the breath-holding state in one shot to obtain one dynamic image. Alternatively, one dynamic image may be taken in the respiratory state for both ventilation analysis and blood flow analysis.

[0058] (Diagnostic console 3 operation) Next, the operation of the diagnostic console 3 will be described. In the diagnostic console 3, for example, when a frame image of a dynamic image acquired by an examination is received from the radiography console 2 via the communication unit 35 and an instruction to calculate a VQ ratio is given by the operation unit 33, the VQ ratio calculation process shown in Fig. 3 is executed. The VQ ratio calculation process is executed by the control unit 31 in cooperation with a program stored in the storage unit 32.

[0059] In the VQ ratio calculation process, first, a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis are acquired from the received dynamic image (step S11).

[0060] Here, when images are taken separately in the breathing state and the breath-holding state, and two dynamic images are received as images taken during the examination, multiple frame images of the dynamic image taken in the breathing state are acquired as multiple frame images for ventilation analysis, and multiple frame images of the dynamic image taken in the breath-holding state are acquired as multiple frame images for blood flow analysis.

[0061] When a single dynamic image is received as an image captured during a single breath-holding test, a plurality of frame images from the breathing period (the period captured during the breath-holding period) are acquired as a plurality of frame images for ventilation analysis, and a plurality of frame images from the breath-holding period (the period captured during the breath-holding period) are acquired as a plurality of frame images for blood flow analysis. For example, as shown in FIG. 4, the diaphragm is extracted from each frame image of the dynamic image to acquire the temporal change in diaphragm position. A plurality of frame images from the period (breathing period) in which the displacement of the diaphragm position exceeds a predetermined threshold TH are acquired as a plurality of frame images for ventilation analysis, and a plurality of frame images from the period (breath-holding period) in which the displacement of the diaphragm position is equal to or less than the predetermined threshold are acquired as a plurality of frame images for blood flow analysis. The diaphragm position can be extracted using a known method, for example, as described in Japanese Patent Application Laid-Open No. 2018-148964. Furthermore, if the supplementary information of each frame image of a dynamic image includes information on respiratory guidance at the time of capturing the frame image, a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis may be acquired based on the information on respiratory guidance. Also, for example, a graph showing the change in diaphragm position over time may be displayed on the display unit 34, and the user may specify a section of frame images for ventilation analysis and a section of frame images for blood flow analysis using the operation unit 33.

[0062] When a single image is taken during breathing for both ventilation analysis and blood flow analysis, and one dynamic image is received as an image taken during the examination, the received dynamic image is acquired as multiple frame images for ventilation analysis and blood flow analysis.

[0063] It is sufficient that the frame images used for ventilation analysis correspond to one respiratory cycle, and the frame images used for blood flow analysis correspond to one cardiac cycle. In terms of the accuracy of analysis and calculation of the VQ ratio, it is preferable to use frame images taken in a breath-hold state as the frame images for blood flow analysis.

[0064] Next, lung fields are extracted from each of the plurality of frame images for ventilation analysis and blood flow analysis that have been acquired (step S12). The lung field region can be extracted using a known method such as the method using edge detection described in JP 2018-148964 A.

[0065] Next, a reference frame image is selected from the plurality of frame images for ventilation analysis and blood flow analysis that have been acquired (step S13). The reference frame image is preferably, for example, a frame image at the maximum respiratory level in which the area of the lung field region is the smallest. For example, the frame image at the maximum respiratory level can be extracted as the frame image at the maximum respiratory level in which the area (number of pixels) of the lung field region of each frame image is the smallest.

[0066] Next, the number of divisions of the lung field region when calculating the VQ ratio is set (step S14). In step S14, for example, as shown in Fig. 5, the number of divisions M in the vertical direction and the number of divisions N in the horizontal direction of the lung field region are set (M and N are positive integers). For example, the number of divisions may be set by a user selecting from a plurality of different combinations of M and N prepared in advance by operating the operation unit 33, or the numerical values of M and N input by the user may be set as the number of divisions. Alternatively, a predetermined combination of M and N may be set as the number of divisions.

[0067] Next, the lung field region of the reference frame image is divided into a plurality of small regions based on the division number set in step S14 (step S15). For example, a rectangular region circumscribing the lung field region is divided into a number of divisions M×N, thereby dividing the lung field region into a plurality of small regions. FIG. 6 shows how the lung field region is divided into small regions. As shown in FIG. 6, it is preferable to exclude small regions outside the lung field region and regions such as the cardiac region and bronchial tree region where gas exchange does not occur, for which calculation of the VQ ratio is not required. Note that in FIG. 6, the interior of the lung field region is not depicted in order to clearly show how the region is divided into small regions.

[0068] As shown in FIG. 7(a), the lung field region may be divided into equal widths according to the number of divisions, or into different widths depending on the position of the lung field region. For example, the upper and lower lung field regions may be divided into different widths. For example, because the lower lung field moves more significantly, the lower lung field may be divided into smaller subregions than the upper lung field, as shown in FIG. 7(b) (e.g., the lower one-third may be divided into smaller subregions). Furthermore, while blood vessels are densely concentrated near the center of the lung, the blood vessels in the peripheral regions may be too thin to visualize blood flow, making analysis meaningless. Therefore, the lung field may be divided into subregions larger in size in the peripheral (outer) regions than in the central (inner) regions. The size of the small region is preferably small (for example, about 1 cm×1 cm) when detailed evaluation is required, and large (for example, about 3 cm×3 cm) when priority is given to processing speed.

[0069] Next, a unique ID is assigned to each small region of the reference frame image (step S16). Each small area is assigned a unique ID according to a predetermined rule. For example, the fifth small area from the left on the first row is assigned an ID such as 1-5.

[0070] Then, each small region of the reference frame image is tracked in the other frame images (step S17). As a tracking method, for example, a method can be used in which the density information (brightness information) of each small region of a reference frame image is tracked in other frame images using optical flow or local matching. For example, for each small region of the reference frame image, a marker is set at the vertex or center of the small region to obtain density information around the marker, and in other frame images, a region having density information similar to the density information around the marker is searched for around a pixel position corresponding to the pixel position of the small region, and a position having similar density information is identified as the position to which the small region has moved (i.e., the position corresponding to the small region). This method makes it possible to track the same part within the lung field (e.g., a structure (such as a blood vessel shadow or a bronchial shadow)), thereby enabling accurate registration of small regions between frame images.

[0071] Alternatively, small areas may be tracked simply based on the lung field contour. For example, the lung field contour is tracked in another frame image, and the area between the top and bottom ends of the lung field contour is divided (evenly) by M divisions, and the area between the right and left ends of the lung field contour is divided by N divisions. Then, positions in the other frame image corresponding to each small area of the reference frame image (for example, the position corresponding to the small area at the top right of the reference frame image is the small area at the top right of the other frame image) are identified as the positions of the small areas after tracking. This tracking method allows small areas to be tracked quickly.

[0072] By tracking each small region of the reference frame image in the other frame images, the other frame images can be divided into the same number of divisions as the reference frame image, and corresponding small regions can be set among the multiple frame images acquired in step S11. Also, the number of small regions set in the multiple frame images for ventilation analysis and the multiple frame images for blood flow analysis can be the same.

[0073] Next, a process of dividing and integrating small regions is performed (step S18). 8 is a flowchart showing the flow of the small region dividing and merging process executed in step S 18. The small region dividing and merging process of FIG. 8 is executed by the control unit 31 in cooperation with a program stored in the storage unit 32.

[0074] First, a small region is selected and the aspect ratio is checked (step S181). Here, if either the length or width of a small region becomes extremely small due to movement and deformation of the lung field caused by breathing, the aspect ratio becomes extremely large or approaches zero. In such a case, it is considered that the small region has been compressed vertically or horizontally due to movement and deformation of the lung field caused by breathing. If ventilation analysis, blood flow analysis, and VQ ratio calculation are performed using this small region as is, the influence of artifacts will be significant, resulting in poor analysis accuracy and VQ ratio calculation accuracy. Furthermore, if either the length or width is extremely large, the aspect ratio will become extremely large or approaches zero, which is also undesirable in terms of analysis accuracy and VQ ratio calculation accuracy. Therefore, in step S181, the aspect ratio of each small region is checked.

[0075] The aspect ratio of the small region may be checked for each frame image acquired in step S11, but since the small region is deformed by breathing, it may be checked for frame images captured while breathing. Specifically, it is sufficient to check the frame image at the maximum inspiration position (at the resting inspiration position in the case of quiet breathing) where the change in shape of the lung field region from the reference frame image is greatest (for example, the frame image where the lung field area is largest or the diaphragm position is lowest). Therefore, in this embodiment, the frame image at the maximum inspiration position (at the resting inspiration position in the case of quiet breathing) is used as the check image for checking.

[0076] Next, it is determined whether the aspect ratio of the small region falls within a reference range (step S182). That is, it is determined whether the aspect ratio of the selected small area in the check image falls within a reference range.

[0077] If it is determined that the aspect ratio of the small region falls within the reference range (step S182; YES), the process proceeds to step S185.

[0078] If it is determined that the aspect ratio of the small region does not fall within the reference range (step S182; NO), the small region is divided or integrated (step S183). For example, if the size of a small area in the check image is smaller than a predetermined threshold, it is merged with an adjacent small area. For example, in the example shown in FIG. 9, the small areas with IDs 2 and 4 are smaller than the predetermined threshold, so they are merged with the adjacent small areas with IDs 1 and 3, respectively. If the size of a small area in the check image is equal to or larger than the predetermined threshold, that small area is divided into multiple small areas. After merging or division, IDs are provisionally reassigned according to predetermined rules. For example, in the case of merging, the smaller ID number is assigned. In the case of division, a branch number is assigned. For example, if a small area with ID 1 is divided into two, IDs 1-1, 1-2, etc. are assigned.

[0079] Once the small regions have been divided or integrated, the small regions of the other frame images with the same ID are similarly divided or integrated, and temporary IDs are reassigned (step S184), after which the process proceeds to step S185. In step S184, the number of small regions in all the acquired frame images is adjusted to be the same.

[0080] In step S185, it is determined whether or not the aspect ratio check for all small regions has been completed (step S185). If it is determined that the aspect ratio check has not been completed for all small regions (step S185; NO), the process returns to step S181, a small region for which the check has not yet been completed is selected, and the processes of steps S181 to S185 are repeatedly executed. If it is determined that all small regions have been checked (step S185; YES), the process proceeds to step S19 in FIG.

[0081] In this embodiment, the aspect ratio of all small regions is checked, but the aspect ratio of only some small regions may be checked. For example, because the lower lung field expands and contracts more rapidly than the upper lung field due to breathing, the aspect ratio of only the lower one-third of the lung field may be checked. This increases the processing speed.

[0082] In step S19 of FIG. 3, the small regions set in each acquired frame image are deformed so that the aspect ratio of each of the plurality of small regions falls within a reference range (step S19). For example, in each acquired frame image, it is determined whether the aspect ratio of each of the multiple set small regions falls within a standard range, and for small regions that are determined not to fall within the range, the vertices are adjusted and the small region is deformed so that the aspect ratio falls within the standard range.

[0083] Next, IDs are reassigned to each small region (step S20). For example, an ID is assigned to each small region of the reference frame image according to the same rule as in step S16, and the same ID is assigned to corresponding small regions of other frame images.

[0084] Next, ventilation analysis is performed using a plurality of frame images for ventilation analysis, and blood flow analysis is performed using a plurality of frame images for blood flow analysis (step S21).

[0085] In ventilation analysis, an index value indicating ventilation volume is calculated for each pixel of each frame image used for ventilation analysis. For example, the difference (absolute value of the difference, or a ratio is also acceptable) between the signal value of each pixel of each frame image used for ventilation analysis and the signal value of the corresponding pixel in the analysis reference frame image used as the reference for the analysis is calculated as an index value indicating ventilation volume for each pixel of each frame image. Corresponding pixels between frame images here refer to, for example, pixels that are located at the same position (coordinates within the small region) within a small region assigned the same ID. For example, the change in signal value over time for each corresponding pixel between frame images can be calculated, and the frame image with the lowest signal value (i.e., the frame image when the region is most contracted) can be used as the analysis reference frame image for that pixel.

[0086] In blood flow analysis, an index value indicating blood flow volume is calculated for each pixel of each frame image used for blood flow analysis. For example, the difference value (absolute value of the difference value, or a ratio) between the signal value of each pixel of each frame image used for blood flow analysis and the signal value of the corresponding pixel in the analysis reference frame image used as the reference for the analysis is calculated as an index value indicating blood flow volume for each pixel of each frame image. For example, the analysis reference frame image can be determined by calculating the time change in signal value for each corresponding pixel between frame images, and using the frame image with the highest signal value (i.e., the frame image with the least blood flow) as the analysis reference frame image for that pixel. Note that if the frame images used for blood flow analysis are images captured while breathing, the time change in signal value for each corresponding pixel between frame images is filtered with a time-direction high-pass filter (e.g., cutoff frequency 0.7 Hz) before calculating the analysis reference frame image and difference value. This removes low-frequency signal changes due to ventilation and extracts the time change in signal value due to blood flow.

[0087] In ventilation analysis and blood flow analysis, first, a representative value (e.g., average value) of the signal values of the pixels in each small region is calculated, and the signal value of each small region is set as the calculated representative value. The difference value between the signal value of each small region of each frame image for ventilation analysis (blood flow analysis) and the signal value of the corresponding small region of the analysis reference frame image that serves as the reference for the analysis may then be calculated as an index value indicating the ventilation volume (blood flow volume) for each small region of each frame image.

[0088] Next, a representative value of the index value indicating the ventilation volume and a representative value of the index value indicating the blood flow volume for each small region are calculated (step S22). For example, in each small region, the maximum value of the index values indicating ventilation calculated in step S21 is obtained for each pixel in the small region, and a representative value of the obtained maximum values in the small region (e.g., average, median, maximum, minimum, etc.) is calculated as an index value indicating ventilation for the small region. Also, in each small region, the maximum value of the index values indicating blood flow calculated in step S21 is obtained for each pixel in the small region, and a representative value of the obtained maximum values in the small region (e.g., average, median, maximum, minimum, etc.) is calculated as an index value indicating blood flow for the small region. In step S21, if the difference value between the signal value of each small region of each frame image and the representative value of the signal value of the corresponding small region of the analysis reference frame image that serves as the basis for the analysis is calculated as an index value indicating the ventilation volume (blood flow volume) for each small region of each frame image, then in step S22, the maximum value of these difference values is calculated as an index value indicating the ventilation volume (blood flow volume) for each small region.

[0089] Next, the VQ ratio is calculated between small areas with the same ID (step S23). Specifically, the VQ ratio, which represents the ratio of V to Q, is calculated by dividing the representative index value (V) indicating ventilation volume by the representative index value (Q) indicating blood flow volume for small areas with the same ID. The VQ ratio may be calculated by multiplying each of the V and Q values by a coefficient. For example, the V value may be multiplied by a coefficient α and the Q value by a coefficient β to calculate the VQ ratio as V×α / Q×β. The coefficients used are values verified through clinical experiments. Here, in a small area with sufficient ventilation and blood flow, the VQ ratio is close to 1, and this small area can be determined to be normal. In a small area where ventilation is sufficient but blood flow is insufficient, the VQ ratio becomes very large, and it can be determined that this small area has an abnormality such as pulmonary embolism. In a small area where ventilation and perfusion are insufficient, the VQ ratio is close to 1, and this small area can be judged to have a normal balance between ventilation and perfusion. In a small area with insufficient ventilation and sufficient blood flow, the VQ ratio approaches 0, and this small area can be determined to have an abnormality such as acute atelectasis.

[0090] Next, the calculated VQ ratio for each small region is mapped onto the image and output (step S24), and the VQ ratio calculation process ends. In step S24, for example, each small area of one frame image (for example, the reference frame image) is colored according to the calculation result of the VQ ratio calculated for that small area, and displayed on the display unit 34. This allows the user to easily grasp the VQ ratio for each small area, whether or not there are any small areas with poor VQ ratios, and if so, which areas they are. Alternatively, the lung field region of one frame image (e.g., a reference frame image) may be divided into multiple ROIs (regions of interest), and a representative value (such as an average value) of the VQ ratios of small regions within each ROI may be calculated for each ROI, and the calculation result (numerical value) may be displayed. Alternatively, as shown in FIG. 10(a), the sum (total) of the VQ ratios of small regions within each ROI may be calculated for each ROI, and the ratio of the sum of the VQ ratios for each ROI to the sum of the VQ ratios for all ROIs may be calculated, and the calculation result (numerical value) may be displayed in association with the ROI on the image. This allows the user to easily grasp the VQ ratio for each ROI. 10(b), when an ROI is specified by the operation unit 33 on a frame image (for example, a reference frame image) displayed on the display unit 34, a representative value (average value, etc.) of the VQ ratios of small areas within the specified ROI may be calculated and the calculation result (numerical value) may be displayed. This allows the user to easily check the VQ ratio of any ROI.

[0091] The control unit 31 may, for example, compare each of the ventilation analysis result, the blood flow analysis result, and the VQ ratio with a predetermined threshold value (a threshold value individually set for each of the ventilation analysis result, the blood flow analysis result, and the VQ ratio) to determine whether the value is abnormal, and if the comparison results in an abnormal value, automatically adjust the size (shape is constant) or shape (size is constant) of the small regions when dividing the lung field region of the reference frame image into small regions. The shape adjustment may, for example, adjust the vertices of the small regions so that the aspect ratio changes while the area of the small regions remains constant. For example, if a structure such as bone is included in a small region, the VQ ratio will be abnormally large, resulting in a value affected by artifacts. To avoid this, it is possible to make the small region larger so that the influence of bones, etc. is eliminated. Therefore, when an abnormal value is detected in the ventilation analysis result, the blood flow analysis result, or the VQ ratio, the control unit 31 adjusts the size or shape of the small region. The size or shape of all small regions may be adjusted collectively, or the size or shape of the small region in which an abnormal value was detected may be adjusted individually. The adjustment is performed little by little, and after the adjustment, the process returns to step S15 in FIG. 3 (or step S17 in the case of shape adjustment), and the processes of steps S15 (S17) to S24 are performed. This process is repeated until no abnormal values are detected (until the value becomes normal).

[0092] Furthermore, the control unit 31 may adjust the size or shape of the small region in response to an instruction to adjust the size or shape of the small region by a user's operation of the operation unit 33. As a result, for example, if the user wants to find a small disease, the size of the small region is adjusted to be small by setting the size of the small region small, making it possible to find a small disease. If the user wants to reduce artifacts, the size of the small region is adjusted to be large by setting the size of the small region large, making it possible to reduce the influence of the artifacts. The setting (adjustment) of the size of the small region by the user may be performed instead of setting the number of divisions in step S14, or the adjustment may be accepted after the VQ ratio calculation process is completed, and the lung field region of the reference frame image may be divided based on the adjusted size, and the processes of steps S16 to S24 may be performed. In addition, the user may adjust the shape of the small regions after dividing the lung field area of the reference frame image in step S3 by displaying the divided multiple small regions on the display unit 34 and accepting the user's adjustment of the shape of the small regions, or the adjustment may be accepted after the VQ ratio calculation process is completed, and the processes of steps S17 to S24 may be performed based on the adjusted shape.

[0093] As described above, according to the diagnostic console 3, the control unit 31 acquires a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamics of the chest of a subject, selects a reference frame image from the acquired plurality of frame images, divides the lung field region in the reference frame image into a plurality of small regions, and for each of the plurality of small regions in the reference frame image, tracks the small region in other frame images other than the reference frame image to identify the position corresponding to the small region in the other frame images, thereby setting a plurality of corresponding small regions among the acquired frame images. Then, for each of the set plurality of small regions, an index value indicating ventilation volume is calculated using the plurality of frame images for ventilation analysis, and an index value indicating blood flow volume is calculated using the plurality of frame images for blood flow analysis, and calculates the ratio (VQ ratio) of the index value indicating ventilation volume to the index value indicating blood flow volume for each of the calculated plurality of small regions. Therefore, by tracking the small area for calculating the VQ ratio of the reference frame image in other frame images for ventilation analysis and blood flow analysis, corresponding small areas are set between the frame images and the VQ ratio is calculated, making it possible to calculate the VQ ratio efficiently without performing warping processing.

[0094] Furthermore, for example, the control unit 31 acquires a plurality of frame images obtained by imaging in a breathing state as a plurality of frame images for ventilation analysis, and acquires a plurality of frame images obtained by imaging in a breath-holding state as a plurality of frame images for blood flow analysis. Therefore, it is possible to perform ventilation analysis and blood flow analysis with high accuracy and calculate the VQ ratio.

[0095] Furthermore, for example, the control unit 31 can accurately calculate the VQ ratio from each small area by setting the same number of small areas in the multiple frame images for ventilation analysis and the multiple frame images for blood flow analysis.

[0096] Furthermore, for example, the control unit 31 can set small regions with sizes according to the characteristics of the lung field region by dividing the reference frame image so that the sizes of the small regions differ depending on the position in the lung field region. For example, by dividing the reference frame image so that the size of the small areas in the peripheral areas is larger than the size of the small areas in the center of the lung field, the processing time for small areas in areas where accuracy is not guaranteed can be shortened, and the VQ ratio can be calculated efficiently. Also, for example, by dividing the reference frame image so that the size of the small region at the bottom of the lung field is smaller than the size of the small region at the top of the lung field, it becomes possible to perform division according to the movement of the lung field.

[0097] Furthermore, for example, the control unit 31 determines whether the aspect ratio of each of multiple small regions falls within a reference range, and divides or merges small regions that are determined not to fall within the range into adjacent small regions, thereby making it possible to suppress the influence of artifacts and accurately calculate the VQ ratio. Furthermore, for example, the control unit 31 can use frame images taken in a breathing state among the multiple acquired frame images to determine whether the aspect ratio of each of the multiple small regions falls within a standard range, thereby making it possible to efficiently determine whether the aspect ratio of each of the multiple small regions falls within a standard range.

[0098] Furthermore, for example, the control unit 31 can prevent the division or integration of small areas from causing correspondence between small areas between frame images to become inconsistent by adjusting the number of small areas in all acquired frame images so that they are the same after the division or integration of small areas.

[0099] Furthermore, for example, the control unit 31 determines whether the aspect ratio of each of multiple small regions falls within a standard range, and deforms the small regions that are determined not to fall within the standard range so that their aspect ratios fall within the standard range, thereby making it possible to suppress the influence of artifacts and calculate the VQ ratio with high accuracy.

[0100] Furthermore, when the control unit 31 determines that the calculated index value indicating the ventilation volume, the index value indicating the blood flow volume, or the ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume has become an abnormal value, it is possible to calculate an accurate VQ ratio by adjusting the size or shape of the small regions when dividing the lung field region of the reference frame image into multiple small regions.

[0101] In addition, the control unit 31 can adjust the size or shape of the small regions when dividing the lung field area of the reference frame image into multiple small regions in response to user operations, thereby making adjustments according to the user's needs, such as reducing the size of the small regions when it is desired to find small diseases, or increasing the size of the small regions when it is desired to suppress the effects of artifacts.

[0102] Furthermore, by allowing the user to select the number of divisions to be used when dividing the reference frame image into the plurality of small regions from a plurality of predetermined numbers of divisions, the user can easily set the number of divisions.

[0103] In addition, the control unit 31 sets a marker within each of multiple small areas of the reference frame image, and tracks the set marker in other frame images other than the reference frame image, thereby identifying the position corresponding to the small area in the other frame images, making it possible to accurately match the positions of small areas between frame images.

[0104] The description in this embodiment is an example of a suitable dynamic analysis device and program according to the present invention, and the present invention is not limited to this.

[0105] For example, in the above embodiment, an example has been described in which the VQ ratio is calculated from a plurality of frame images acquired by dynamic imaging, but the plurality of frame images in the present invention may be a plurality of images captured as still images. For example, two still images captured at the maximum expiratory position and the maximum inspiratory position may be used as the plurality of frame images for ventilation analysis, and two still images captured at the diastolic and systolic periods may be used as the frame images for blood flow analysis.

[0106] Furthermore, in the above embodiment, if the aspect ratio does not fall within the standard range and it is necessary to divide or combine small regions, they are divided or combined in steps S183 to S184 of FIG. 8, and IDs are reassigned in step S20 of FIG. 3. However, it is also possible to store information about the IDs of the small regions to be combined, or the IDs and number of divisions of the small regions to be divided in RAM or the like, and when calculating ventilation analysis, blood flow analysis, and VQ ratio, to treat the small regions with IDs designated to be combined as a single small region and perform calculations, or to treat the regions obtained by dividing the small regions with IDs designated to be divided based on the number of divisions as a single small region and perform calculations.

[0107] Furthermore, in the above embodiment, the output means for outputting the calculation result of the VQ ratio is a display unit, and an example has been described in which the calculation result of the VQ ratio is output by the display unit, but the calculation result of the VQ ratio may be output to an external device by the communication unit 35, or may be printed out by a printing device or the like.

[0108] Furthermore, for example, in the above description, examples have been disclosed in which a hard disk or a semiconductor nonvolatile memory is used as a computer-readable medium for the program according to the present invention, but the present invention is not limited to this example. Portable recording media such as CD-ROMs can also be used as other computer-readable media. Furthermore, carrier waves can also be used as a medium for providing data for the program according to the present invention via a communication line.

[0109] In addition, the detailed configuration and detailed operation of each device constituting the dynamic analysis system 100 may be modified as appropriate without departing from the spirit of the present invention. [Explanation of symbols]

[0110] 100 Dynamic Analysis System 1. Imaging device 11 Radiation source 12 Radiation exposure control device 13 Radiation detection unit 14 Reading control device 2. Filming console 21 Control Unit 22 Memory section 23 Control section 24 Display section 25 Communications Department 26 Bus 3 Diagnostic Console 31 Control Unit 32 Storage section 33 Operation section 34 Display section 35 Communications Department 36 Bus

Claims

1. an acquisition means for acquiring a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamic state of the chest of a subject; a dividing means for selecting a reference frame image from the plurality of frame images for ventilation analysis and blood flow analysis acquired by the acquiring means, and dividing a lung field region in the reference frame image into a plurality of small regions; a tracking means for tracking each of the plurality of small regions of the reference frame image in other frame images other than the reference frame image and specifying a position corresponding to the corresponding small region in the other frame images, thereby setting a plurality of corresponding small regions between the frame images acquired by the acquisition means; a division and integration means for determining whether the aspect ratio of each of the plurality of small regions set by the tracking means falls within a reference range, and for dividing a small region determined not to fall within the reference range or integrating the small region into an adjacent small region; an analysis means for calculating an index value indicating ventilation volume using the plurality of frame images for ventilation analysis for each of the plurality of set small regions, and for calculating an index value indicating blood flow volume using the plurality of frame images for blood flow analysis; a ratio calculation means for calculating a ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume for each of the plurality of small regions calculated by the analysis means; A dynamic analysis device comprising:

2. 2. The dynamic analysis device according to claim 1, wherein the splitting and integrating means uses frame images taken in a breathing state among the plurality of frame images acquired by the acquiring means to determine whether the aspect ratio of each of the plurality of small regions set by the tracking means falls within the reference range.

3. 3. The dynamic analysis device according to claim 1, wherein the dividing and integrating means adjusts the number of the plurality of small regions in all frame images acquired by the acquiring means after the dividing or integrating so that the number of the plurality of small regions is the same for all frame images acquired by the acquiring means.

4. an acquisition means for acquiring a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamic state of the chest of a subject; a dividing means for selecting a reference frame image from the plurality of frame images for ventilation analysis and blood flow analysis acquired by the acquiring means, and dividing a lung field region in the reference frame image into a plurality of small regions; a tracking means for tracking each of the plurality of small regions of the reference frame image in other frame images other than the reference frame image and specifying a position corresponding to the corresponding small region in the other frame images, thereby setting a plurality of corresponding small regions between the frame images acquired by the acquisition means; a deformation means for determining whether the aspect ratio of each of the plurality of small regions set by the tracking means falls within a reference range, and for deforming a small region determined not to fall within the reference range so that its aspect ratio falls within the reference range; an analysis means for calculating an index value indicating ventilation volume using the plurality of frame images for ventilation analysis for each of the plurality of set small regions, and for calculating an index value indicating blood flow volume using the plurality of frame images for blood flow analysis; a ratio calculation means for calculating a ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume for each of the plurality of small regions calculated by the analysis means; A dynamic analysis device comprising:

5. The dynamic analysis device according to any one of claims 1 to 4, wherein the acquisition means acquires a plurality of frame images obtained by taking images in a breathing state as a plurality of frame images for the ventilation analysis, and acquires a plurality of frame images obtained by taking images in a breath-holding state as a plurality of frame images for the blood flow analysis.

6. The dynamic analysis device according to any one of claims 1 to 5, wherein the number of small regions set in the plurality of frame images for ventilation analysis is the same as the number of small regions set in the plurality of frame images for blood flow analysis.

7. The dynamic analysis device according to any one of claims 1 to 6, wherein the dividing means divides the reference frame image so that the sizes of the plurality of small regions differ depending on the position of each of the small regions in the lung field region.

8. 8. The dynamic analysis device according to claim 7, wherein the dividing means divides the reference frame image so that the size of the small regions in the peripheral part of the lung field is larger than the size of the small regions in the central part of the lung field.

9. 8. The dynamic analysis device according to claim 7, wherein the dividing means divides the reference frame image so that a size of a small region in a lower part of the lung field region is smaller than a size of a small region in an upper part of the lung field region.

10. A dynamic analysis device according to any one of claims 1 to 9, further comprising an adjustment means for adjusting the size or shape of the small regions when the lung field region of the reference frame image is divided into the plurality of small regions by the division means.

11. The dynamic analysis device according to claim 10, wherein the adjustment means performs the adjustment when it determines that the calculated index value indicating the ventilation volume, the index value indicating the blood flow volume, or the ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume has become an abnormal value.

12. The dynamic analysis apparatus according to claim 10 , wherein the adjustment means performs the adjustment in response to a user operation.

13. A dynamic analysis device according to any one of claims 1 to 11, wherein the number of divisions when the division means divides the reference frame image into the plurality of small regions can be selected from a plurality of predetermined division numbers.

14. A dynamic analysis device according to any one of claims 1 to 13, wherein the tracking means sets a marker within each of the plurality of small regions of the reference frame image, and tracks the set marker in other frame images other than the reference frame image, thereby identifying a position corresponding to the small region in the other frame images.

15. The dynamic analysis apparatus according to any one of claims 1 to 14, further comprising an output means for outputting the calculation result by the ratio calculation means.

16. Computer, an acquisition means for acquiring a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamic state of the chest of the subject; Among the plurality of frame images for ventilation analysis and blood flow analysis acquired by the acquisition means, a dividing means for selecting a reference frame image from the reference frame image and dividing the lung field region in the reference frame image into a plurality of small regions; a tracking means for tracking each of the plurality of small regions of the reference frame image in other frame images other than the reference frame image and specifying a position corresponding to the corresponding small region in the other frame images, thereby setting a plurality of corresponding small regions between the frame images acquired by the acquisition means; a division and integration means for determining whether the aspect ratio of each of the plurality of small regions set by the tracking means falls within a reference range, and for dividing a small region determined not to fall within the reference range or integrating the small region into an adjacent small region; an analysis means for calculating an index value indicating ventilation volume using the plurality of frame images for ventilation analysis, and calculating an index value indicating blood flow volume using the plurality of frame images for blood flow analysis, for each of the plurality of set small regions; a ratio calculation means for calculating a ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume for each of the plurality of small regions calculated by the analysis means; A program to function as a

17. Computer, an acquisition means for acquiring a plurality of frame images for ventilation analysis and a plurality of frame images for blood flow analysis from a plurality of frame images obtained by radiographically capturing the dynamic state of the chest of the subject; a dividing means for selecting a reference frame image from the plurality of frame images for ventilation analysis and blood flow analysis acquired by the acquiring means, and dividing a lung field region in the reference frame image into a plurality of small regions; a tracking means for tracking each of the plurality of small regions of the reference frame image in other frame images other than the reference frame image and specifying a position corresponding to the corresponding small region in the other frame images, thereby setting a plurality of corresponding small regions between the frame images acquired by the acquisition means; a deformation means for determining whether or not the aspect ratio of each of the plurality of small regions set by the tracking means falls within a reference range, and for deforming a small region determined not to fall within the reference range so that its aspect ratio falls within the reference range; an analysis means for calculating an index value indicating ventilation volume using the plurality of frame images for ventilation analysis, and calculating an index value indicating blood flow volume using the plurality of frame images for blood flow analysis, for each of the plurality of set small regions; a ratio calculation means for calculating a ratio between the index value indicating the ventilation volume and the index value indicating the blood flow volume for each of the plurality of small regions calculated by the analysis means; A program to function as a

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