Dynamic analysis device and program

Abstract

To acquire information indicating a ventilation function of a whole lung easily and in a comparatively short time without being influenced by a movement or deformation of a part other than the lung positioned around the lung when analyzing a dynamic image I acquired by dynamically imaging the lung of a subject.SOLUTION: A dynamic analysis device 4 includes: measuring means 41 for measuring a change with time in a distance between a plurality of evaluation points P that move following the movement of a lung field area RL, which are arranged at a plurality of points of the lung field area RL in a dynamic image I composed of a plurality of frames F acquired by dynamically imaging the lung of a subject S; and output means for outputting information indicating a ventilation function of the lung of the subject S on the basis of the change with time in the distance between the evaluation points P measured by the measuring means 41.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Various techniques have been proposed to obtain information used for diagnosing a subject's lungs by analyzing dynamic images of the lung field. For example, Patent Document 1 describes an image processing device that includes a difference means for generating multiple difference images showing the difference in pixel values ​​between multiple images based on multiple images that constitute a dynamic image of an object, and a display means for sequentially switching between and displaying the multiple generated difference images. Patent document 2 also describes a dynamic analysis device that includes an index value measurement means for measuring changes over time in index values ​​related to the position and shape of blood vessels in multiple regions within a dynamic image obtained by radiographing a region of a subject that includes blood vessels, an elongation rate calculation means for calculating the elongation rate of blood vessels in each region based on the changes over time in the index values ​​of each measured region, and an elongation rate display means for displaying a list of the calculated elongation rates in each region. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4404291 [Patent Document 2] Japanese Patent Application Publication No. 2019-058368 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional image processing devices that capture changes in pixel values, such as those described in Patent Document 1, may produce artifact A due to movement or deformation of areas other than the lungs (e.g., ribs, breasts, fat, etc.) surrounding the lungs when quantifying (visualizing) the analysis results. For example, it is known that when breathing in an upright position, the upper lung fields receive less ventilation. However, when analyzing dynamic images obtained by dynamic imaging of the chest of a standing subject using a dynamic analysis device that captures changes in pixel values, artifacts A caused by movements or deformations of parts other than the lungs may occur in the upper lung field. This can cause the information indicating ventilation function output by this dynamic analysis device (conventional color map M C The dynamic image I) is shown in Figure 10. As described above, there may be cases where there appears to be no or little difference between the upper lung field region and the middle and lower lung field regions. Although it is relatively easy to remove ribs from dynamic images by performing image processing on the dynamic images, it is difficult to remove breasts and fat.

[0005] Furthermore, in order to accurately calculate the elongation rate using a conventional dynamic analysis device that captures changes in the distance of blood vessels, such as that described in Patent Document 2, it is necessary to detect the blood vessels in the dynamic image with high accuracy (to avoid mistakenly recognizing areas other than blood vessels as blood vessels). However, detecting blood vessels from dynamic images with high accuracy is difficult and time-consuming, so when using this dynamic analysis device, it takes a long time from the end of dynamic imaging to the start of diagnosis. Furthermore, dynamic analysis devices that capture changes in blood vessel distance cannot analyze the dynamics of peripheral areas where blood vessels are absent or too thin to be detected, making it difficult to obtain information on the ventilation function of the entire lung.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to enable, when analyzing dynamic images obtained by dynamic imaging of a subject's lungs, to easily and in a relatively short time obtain information indicating the ventilation function of the entire lungs without being affected by the movement or deformation of parts other than the lungs located around the lungs. [Means for solving the problem]

[0007] In order to solve the above problems, a dynamic analysis device according to the present invention comprises: Dynamic images consisting of multiple frames obtained by dynamic imaging of the subject's lungs In the above, evaluation points are arranged with respect to image data, and Lung area shown in to Placed The positions of the plurality of evaluation points in the frames other than the one frame are specified by estimating where a small area of ​​a specific density around the evaluation point will move in the next frame, and the distance between the plurality of evaluation points is calculated for each frame, and the distance between the plurality of evaluation points is calculated based on the distance between the plurality of evaluation points. a measuring means for measuring a change over time in the distance between a plurality of evaluation points; and an output means for outputting information indicating the pulmonary ventilation function of the subject based on the change over time in the distance between the evaluation points measured by the measurement means. 、 The measuring means calculates the area of ​​a polygon having two or more of the evaluation points arranged around the reference evaluation point and the reference evaluation point as vertices for each group of the evaluation points that have been divided in advance, and sets the area of ​​the polygon as distance information for the group. do.

[0008] In addition, the program according to the present invention is On the computer, Dynamic images consisting of multiple frames obtained by dynamic imaging of the subject's lungs In the above, evaluation points are arranged with respect to image data, and Lung area shown in to Placed The positions of the plurality of evaluation points in the frames other than the one frame are specified by estimating where a small area of ​​a specific density around the evaluation point will move in the next frame, and the distance between the plurality of evaluation points is calculated for each frame, and the distance between the plurality of evaluation points is calculated based on the distance between the plurality of evaluation points. a measurement process for measuring a change over time in distances between a plurality of evaluation points; and an output process for outputting information indicating the pulmonary ventilation function of the subject based on the change over time in the distance between the evaluation points measured in the measurement process. 、 The measurement process calculates the area of ​​a polygon having two or more evaluation points arranged around a reference evaluation point and the reference evaluation point as vertices for each group of the evaluation points that have been divided in advance, and uses the area of ​​the polygon as distance information for the group. do. [Effects of the Invention]

[0009] According to the present invention, when analyzing dynamic images obtained by dynamic imaging of a subject's lungs, information indicating the ventilation function of the entire lungs can be obtained easily and in a relatively short time without being affected by the movement or deformation of areas other than the lungs that are located around the lungs. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram illustrating an example of a radiation imaging system according to an embodiment of the present invention. [Figure 2] FIG. 10 is a block diagram showing another example of a radiation imaging system according to an embodiment of the present invention. [Figure 3]FIG. 3 is a block diagram showing a dynamic analysis device provided in the radiography system of FIGS. [Figure 4] 4 is a flowchart showing the flow of a dynamic analysis process executed by the dynamic analysis device of FIG. 3. [Figure 5] FIG. 10 is a diagram showing a frame in which evaluation points are arranged in a lung field region. [Figure 6] FIG. 10 is a diagram showing a group G of multiple evaluation points. [Figure 7] FIG. 10 is a diagram showing the movement of evaluation points in accordance with the movement of the lung field region. [Figure 8] FIG. 10 is a diagram illustrating an example of a method for calculating the amount of change in an area between evaluation points. [Figure 9] FIG. 4 is a diagram showing an example of information indicating ventilation function output by the dynamic analysis device of FIG. 3. [Figure 10] FIG. 10 is a diagram showing information indicating ventilation function output by a conventional dynamic analysis device. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention is based on the new finding that changes in the distance between multiple evaluation points placed at any location within the lung field region captured in a dynamic image show a correlation with ventilation function. "Ventilation" refers to the process by which air in the alveoli escapes into the trachea and enters the alveoli from the trachea due to the contraction and expansion of the alveoli that accompanies breathing. This fact has been confirmed by comparison with the results of clinical studies using lung ventilation scintigraphy.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the technical scope of the present invention is not limited to the following embodiments and illustrated examples.

[0013] <1. Radiography System> First, the schematic configuration of a radiation imaging system (hereinafter referred to as system 100) according to this embodiment will be described. FIG. 1 is a block diagram illustrating a system 100 .

[0014] As shown in FIG. 1, the system 100 includes a radiation imaging apparatus (hereinafter referred to as imaging apparatus 1) and a console 2. The system 100 according to this embodiment further includes a radiation generating device (hereinafter referred to as a generating device 3) and a dynamic analysis device 4. The devices 1 to 4 are capable of communicating with each other via, for example, a communication network N (such as a local area network (LAN), a wide area network (WAN), or the Internet).

[0015] The system 100 may be installed in an imaging room, or may be configured to be movable (for example, a medical examination cart). The system 100 also functions as a hospital information system (HIS), a radiology information system (RIS), and the like (not shown). Communication may be possible.

[0016] [1-1. Radiation Generator] The generating device 3 includes a generator 31, an irradiation instruction switch 32, and a radiation source 33 (a tube).

[0017] Based on the operation of the irradiation instruction switch 32, the generator 31 applies a tube voltage according to the preset imaging conditions to the radiation source 33 and also passes a tube current according to the imaging conditions to the radiation source 33.

[0018] When a tube voltage is applied from the generator 31 and a tube current flows, the radiation source 33 generates radiation X (e.g., X-rays) with a dose corresponding to the applied tube voltage and the flowing tube current.

[0019] Furthermore, the generating device 3 according to this embodiment is configured to generate radiation X in a manner that corresponds to the form of the radiation image to be generated (a still image, a dynamic image made up of a plurality of frames). In the case of a still image, radiation X is irradiated only once per depression of the irradiation instruction switch 32. In the case of dynamic images, each time the irradiation instruction switch 32 is pressed, the irradiation of pulsed radiation X is repeated multiple times per predetermined time (for example, 15 times per second), or the irradiation of radiation X is continued for a predetermined time.

[0020] [1-2. Radiography equipment] The imaging device 1 generates digital data of a radiation image showing an imaging region of a subject S. The imaging device 1 according to this embodiment is a portable FPD (Flat Panel Detector). do. Specifically, although not shown, the imaging device 1 according to this embodiment includes a sensor substrate on which image pickup elements that generate charges according to the radiation dose when exposed to radiation X and switch elements that store and release the charges are arranged two-dimensionally (in a matrix), a scanning unit that switches each switch element on and off, a readout unit that reads out the amount of charge released from each pixel as a signal value, a control unit that controls each unit and generates a radiographic image from the multiple signal values ​​read out by the readout unit, and a communication unit that transmits the generated radiographic image, various signals, etc. to other devices (the console 2, the generator 3, the dynamic analysis device 4, etc.) and receives various information, various signals, etc. from other devices.

[0021] The imaging device 1 stores and releases electric charges and reads out signal values ​​in synchronization with the timing at which radiation X is emitted from the generator 3, thereby generating a still image or a dynamic image. When a still image is to be generated, a radiographic image is generated only once per depression of the irradiation instruction switch 32. When a dynamic image is generated, the generation of frames constituting the dynamic image is repeated multiple times per predetermined time (for example, 15 times per second) for each depression of the irradiation instruction switch 32. Hereinafter, the operation of the imaging device 1 to generate a dynamic image showing the imaging target part of the subject will be referred to as dynamic imaging.

[0022] The imaging device 1 may be integrated with the generating device 3 (for example, a CT (Computed Tomography) device or the like). Furthermore, the imaging device 1 may be configured to display the generated dynamic image in real time on a display device connected to the imaging device 1 (for example, to perform fluoroscopy).

[0023] [1-3. Console] The console 2 sets various imaging conditions for at least one of the imaging device 1 and the generating device 3 . The console 2 is composed of a PC, a dedicated device, etc. The imaging conditions include, for example, conditions related to the subject S (imaged region, imaging direction, physique, etc.) and conditions related to irradiation of radiation X (tube voltage, tube current, irradiation time, current-time product (mAs value), etc.). The console 2 may set the imaging conditions automatically based on imaging order information obtained from other systems (HIS, RIS, etc.), or may set them (manually) based on operations performed on the operating unit by a user (e.g., a technician, etc.).

[0024] [1-4.Dynamic analysis device] The dynamic analysis device 4 analyzes the dynamic images generated by the imaging device 1 and outputs various information for assisting diagnosis (for example, information indicating the ventilation function of the lungs). The dynamic analysis device 4 is composed of a PC, a dedicated device, and the like. The dynamic analysis device 4 will be described in detail later.

[0025] [1-5. Shooting process] The imaging of the subject S using the system 100 configured as above is performed in the following manner. First, a user (technologist or the like) positions the subject S between the radiation source 33 of the generating device 3 and the imaging device 1, which are arranged facing each other with a gap therebetween, and performs positioning. When the user operates the irradiation instruction switch 32, the radiation generator 3 irradiates the region of the subject S to be imaged with radiation X. The imaging device 1 generates a radiographic image (still image, dynamic image) showing the imaging region at the timing when the radiation X is received from the generation device 3. When the generated radiographic image is a dynamic image, the imaging device 1 transmits the dynamic image to the dynamic analysis device 4 directly or via the console 2. The dynamic analysis device 4 analyzes the dynamics of the imaging region of the subject S using the received dynamic images, and outputs various information (information indicating the ventilation function of the lungs, etc.).

[0026] [1-6. Other] So far, the system 100 including the dynamic analysis device 4 has been described, but the dynamic analysis device 4 may also be implemented by another device constituting the system 100 (for example, the console 2). Specifically, for example, as shown in FIG. 2, a radiation imaging system 100A may be configured by the imaging device 1 and the generator 3, as well as a console 2A that also functions as a dynamic analysis device.

[0027] <2. Details of the dynamic analysis device> Next, details of the dynamic analysis devices 4 and 2A included in the systems 100 and 100A will be described using a single dynamic analysis device 4 as an example. FIG. 3 is a block diagram showing the dynamic analysis device 4, FIG. 4 is a flowchart showing the dynamic analysis process executed by the dynamic analysis device 4, and FIG. L Frame F where evaluation point P is placed FIG. 6 is a diagram showing a group G of multiple evaluation points P, and FIG. 7 is a diagram showing a lung field region R L Along with the movement of FIG. 8 is a diagram showing an example of a method for calculating the amount of change in the area between evaluation points P and P; and FIG. 9 is a diagram showing an example of information indicating ventilation function output by the dynamic analysis device 4 according to this embodiment.

[0028] [2-1. Configuration of dynamic analysis device] As shown in FIG. 3, the dynamic analysis device 4 includes a control unit 41, a storage unit 42, and a communication unit 43. The dynamic analysis device 4 according to this embodiment further includes a display unit 44 and an operation unit 45. The units 41 to 45 are electrically connected by a bus or the like.

[0029] The control unit 41 includes a CPU (Central Processing Unit), a RAM (Random Access Memory ), etc. The CPU reads out various programs stored in the ROM, loads them into the RAM, executes various processes in accordance with the loaded programs, and centrally controls the operations of each part of the dynamic analysis device 4.

[0030] The storage unit 42 is composed of a non-volatile memory, a hard disk, and the like. The storage unit 42 also stores various programs executed by the control unit 41, parameters required for executing the programs, and the like. The storage unit 42 may be capable of storing radiographic images acquired from other devices (such as the imaging device 1 and the dynamic analysis device 4). That's fine.

[0031] The communication unit 43 is composed of a communication module and the like. The communication unit 43 is configured to send and receive various signals, various data, etc. to and from other devices (such as the imaging device 1, the generating device 3, and the dynamic analysis device 4) connected via a communication network N by wire or wirelessly.

[0032] The display unit 44 is configured by, for example, an LCD (Liquid Crystal Display), a CRT (Cathode Ray Tube), or the like. The display unit 44 then displays a radiographic image or the like in accordance with the image signal received from the control unit 41 .

[0033] The operation unit 45 can be operated by the user. The operation unit 45 includes, for example, a keyboard (cursor keys, numeric input keys, various function keys, etc.), a pointing device (mouse, etc.), a touch panel laminated on the surface of the display unit 44, etc. Then, the operation unit 45 outputs a control signal to the control unit 41 in accordance with the operation performed by the user.

[0034] In addition, the dynamic analysis device 4 may not be equipped with a display unit 44 or an operation unit 45, and may be configured to receive control signals from an input device provided separately from the dynamic analysis device 4, for example, via a communication unit 43, or to output image signals to a display device (monitor) provided separately from the dynamic analysis device 4.

[0035] [2-2. Operation of the dynamic analysis device] The control unit 41 of the dynamic analysis device 4 configured as above is configured to execute a dynamic analysis process such as that shown in FIG. 4 when a predetermined condition is met. The specified conditions include, for example, that the dynamic analysis device 4 is turned on, that the imaging device 1 has started generating and transmitting a radiographic image, that a specified control signal has been received from another device, and that a specified operation has been performed on the operation unit 45.

[0036] (Acquisition process) In this dynamic analysis process, the control unit 41 first executes an acquisition process (step S1). In this acquisition process, the control unit 41 acquires, from the imaging device 1, a dynamic image I obtained by performing dynamic imaging of the imaging target part (lungs) of the subject. In the acquisition process according to this embodiment, the control unit 41 acquires the dynamic image I by causing the communication unit 43 to receive the data. In this acquisition process, the control unit 41 may acquire the dynamic image I by having a reading unit (not shown) read the data of the dynamic image I stored in a storage medium (for example, a USB memory, an SD card, etc.). Furthermore, if the acquisition of dynamic image I triggers the start of dynamic analysis processing, this acquisition processing is unnecessary.

[0037] (Placement processing) After acquiring the dynamic image I, the control unit 41 executes a placement process (step S2). In this arrangement process, the control unit 41 arranges the lung field region R in the dynamic image I as shown in FIG. L A plurality of evaluation points P are placed at a plurality of locations. In the placement process according to this embodiment, the control unit 41 assigns the evaluation point P to the lung field region R captured in a reference frame F among a plurality of frames F constituting the dynamic image I. L Place it in. In the placement process according to this embodiment, the control unit 41 sets the reference frame F to, for example, the lung field region R L Let's say the frame contains This reduces overlap of blood vessels in the depth direction, and therefore the tracking accuracy of the evaluation point P can be improved. In the placement process according to this embodiment, the control unit 41 also L in the left lung Evaluation points P are placed at at least 10 or more locations in the first region and at at least 10 or more locations in the right lung region.

[0038] In the placement process according to this embodiment, the control unit 41 places the evaluation points P so that they are distributed in a matrix. At this time, the control unit 41 arranges the evaluation points P so that the interval between two adjacent evaluation points P is larger than the size of a pixel (for example, about 0.4 mm). Specifically, the target region where the evaluation point P is placed is the lung field region R. L If so, the interval between evaluation points P is set to, for example, about 10 mm. Furthermore, when the target region in which the evaluation points P are to be placed is the cardiac region, the interval between the evaluation points P is set to, for example, about 5 mm. Furthermore, when the target region where the evaluation points P are to be placed is the throat region, the interval between the evaluation points P is set to, for example, about 2 mm.

[0039] Furthermore, in the placement process according to this embodiment, the control unit 41 divides the multiple evaluation points P arranged in a matrix into n (here, 3) rows vertically and m (here, 3) columns horizontally, as shown in FIG. 6, and each group of n × m (here, 9) evaluation points P forms one group G. The control unit 41 detects the lung field R L In the periphery, less than nine evaluation points P are grouped into one group. The loop G may be formed.

[0040] In this arrangement process, the control unit 41 may arrange the evaluation points P in a staggered manner or randomly. In addition, in this placement process, the control unit 41 assigns the evaluation point P to the lung field region R L Place it outside It may be like this. Furthermore, in this placement process, the control unit 41 may not automatically determine the placement location of the evaluation point P as described above, but may instead determine it in accordance with the operation performed on the operation unit 45 (user preference). Furthermore, after the control unit 41 automatically determines the placement locations of the evaluation points P, the placement of any evaluation points P may be adjusted in response to an operation performed on the operation unit 45.

[0041] In addition, when arranging the evaluation points P, the control unit 41 L Density of evaluation points P placed in For example, the lung field area R obtained by dynamic imaging in a standing position may be L For the dynamic image I, the lung field R L is divided into the upper lung field region and the lower lung field region (or the upper lung field region, the middle lung field region, and the lower lung field region), and more evaluation points P are placed in the lower lung field region than in other regions. This is because the lower lobes of the lungs move more significantly when breathing in an upright position. Furthermore, when placing evaluation points P, the control unit 41 may determine the placement density of the evaluation points P in accordance with the operation performed on the operation unit 45, rather than automatically determining the placement density of the evaluation points P as described above. The control unit 41 performs the above-described arrangement process, thereby serving as arrangement means in the systems 100 and 100A.

[0042] (Measurement processing) Lung field region R L After placing the evaluation point P, the control unit 41 executes the measurement process (step S3). In this measurement process, the control unit 41 first analyzes the movement of each evaluation point P. Specifically, the control unit 41 uses image processing (e.g., optical flow (dense optical flow)) on the dynamic image I to estimate where a small area of ​​a specific density around the evaluation point P will move to in the next frame F, thereby determining the amount and direction of movement of each evaluation point P in each frame F. As a result, each evaluation point P is located in the lung field region R on the dynamic image I. L It moves according to the movement of It becomes possible to move. For example, the evaluation score P (hereinafter referred to as the standard evaluation score P) located in the center of each group G C ) as a reference When the evaluation point P is fixed and observed, the surrounding evaluation points P are located in the lung field area R as shown in FIG. L When expanding, the standard evaluation point P C It moves radially away from the lung field area R L When contracting, the reference evaluation point P C Move closer to .

[0043] After analyzing the movement of the evaluation points P, the control unit 41 measures the change over time of the distances between the plurality of evaluation points P (hereinafter referred to as distance information) (the change accompanying the reproduction of the dynamic image I). In this measurement process, the control unit 41 measures the change over time in the distance information for each group G of evaluation points P that have been divided in advance. In the calculation process according to this embodiment, the control unit 41 assigns a reference evaluation point P C From the same Group G The average value of the distances to the other evaluation points P arranged around the group G is calculated, and the calculated average value is used as the distance information for the same group G in one frame F. Furthermore, the control unit 41 calculates the distance information for each group G for each of the multiple frames F. The distance information for one group G obtained from each frame F arranged in chronological order represents the change in the distance information for that group G over time.

[0044] In this measurement process, the control unit 41 calculates the reference evaluation score P C and its surroundings Alternatively, the area of ​​a polygon having other evaluation points P arranged in the vicinity as vertices may be calculated, and the calculated area may be used as distance information. In addition, in this measurement process, the control unit 41 compares all other evaluation points P in the group G with the reference evaluation point P C Even if the distance information is set to the average value of some of the distances between good. Also, all other evaluation points P and the standard evaluation point P in group G C Either of the distances The distance may be used to perform subsequent calculations (without calculating distance information). The control unit 41 performs the measurement process described above, thereby serving as a measurement means in the systems 100 and 100A.

[0045] (Calculation process) After measuring the change over time in the distance information, the control unit 41 executes a calculation process (step S4). In this calculation process, the control unit 41 calculates information indicating the ventilation function of the lungs based on the change over time in the measured distance information. In the calculation process according to this embodiment, the control unit 41 calculates the numerical value of at least one of the lung expansion volume and the lung ventilation volume as information indicating the ventilation function. Specifically, the lung field region R in the first state L The distance information in frame F, which shows the object, and the first state Lung field region R in a second state different from the L The difference between the distance information in frame F and It is calculated as the amount of change in distance information. In the calculation process according to the present embodiment, the control unit 41 sets the "first state" to, for example, the maximum expiratory level and the "second state" to the maximum inspiratory level. In this way, the maximum value of the amount of change can be calculated. Furthermore, the control unit 41 calculates the amount of change for each group G.

[0046] After calculating the amount of change, the control unit 41 sets each calculated amount of change as a reference evaluation point P C Distributed The amount of change at the location where the test piece was placed is calculated as the reference evaluation point P C Link to.

[0047] In the calculation process according to this embodiment, the control unit 41 calculates the area R where the evaluation point P is not located based on the calculated change amounts. S Calculate the amount of change in (pixel). Specifically, as shown in Fig. 8, for example, two reference evaluation points P C It is calculated by linear interpolation based on the distance (number of pixels) from

[0048] After calculating the amount of change, the control unit 41 calculates the value of at least one of the lung expansion volume and the lung ventilation volume based on the calculated amount of change. When calculating the amount of lung expansion, the control unit 41 sums up all the calculated amounts of change and sets the total value as the amount of lung expansion. On the other hand, when calculating the ventilation volume of the lungs, the control unit 41 sums up the values ​​obtained by multiplying each calculated change amount by a predetermined coefficient, and sets the sum as the ventilation volume. The coefficients are determined in advance based on the results of clinical experiments, for example.

[0049] In this calculation process, the control unit 41 may calculate the ventilation volume or ventilation rate of the left lung and the ventilation volume or ventilation rate of the right lung separately. In addition, when multiplying the amount of change by a coefficient in this calculation process, the control unit 41 may vary (weight) the coefficient to be multiplied depending on the part in the lung. For example, in the case of a lung field region R obtained by dynamic imaging in an upright position, L Regarding dynamic image I, the changes obtained from the upper lung field The coefficient multiplied by the amount obtained from the lower lung field is relatively small, and the coefficient multiplied by the change obtained from the lower lung field is large. This is because the ventilation volume in the upper lobes is small when breathing in an upright position. In this calculation process, the control unit 41 may calculate the rate of change of the distance from the amount of change. In this way, the ease with which the lungs expand and contract (pulmonary compliance) can be obtained as information indicating the ventilation function. The control unit 41 performs the calculation process described above, thereby serving as a calculation means in the systems 100 and 100A.

[0050] (Output processing) After calculating the value indicating the ventilation function, the control unit 41 executes an output process (step S5). In this output process, the control unit 41 outputs information indicating the calculated ventilation function of the lungs. That is, in this output process, the control unit 41 outputs the numerical value of at least one of the lung expansion volume and the lung ventilation volume based on the change over time of the measured distance information.

[0051] In the output process according to this embodiment, the control unit 41 causes the display unit 44 to display the numerical value of at least one of the expansion volume and ventilation volume in the form of an image using a color map M, as shown in FIG. Specifically, the control unit 41 makes the display color (for example, blue (a color that evokes air)) of areas with relatively small expansion or ventilation volumes relatively lighter, and makes the display color of areas with relatively large expansion or ventilation volumes relatively darker. In this case, the control unit 41 may compare the expansion volume or ventilation volume with a predetermined threshold value, and may not display the color indicating the expansion volume or ventilation volume for areas showing a ventilation volume below the threshold value. In addition, the lung field R L The evaluation point P is also placed in the outer area of When calculating the value of the expansion amount or ventilation amount, the control unit 41 masks the outer region and does not display the color indicating the expansion amount or ventilation amount in the region (the lung field region R where the expansion amount or ventilation amount is effective). L (only display) It may be as follows.

[0052] In this output process, the control unit 41 may display the evaluation score P on the dynamic image I in a superimposed manner. In this case, the control unit 41 divides one group G (group of evaluation points P) into one coarse block (for example, C The lung field area is defined as the area where the other evaluation points P surrounding the lung field are connected by lines. Area R L The shape of the block G changes according to the movement of the The area surrounded by the lines connecting the points is called the standard evaluation point P C The color corresponds to the amount of change associated with It may be designed to be filled in. In this output process, the control unit 41 may also display each calculated change amount as a vector (so that the direction of expansion can be seen). In this output process, the control unit 41 outputs the numerical value of at least one of the inflation volume and the ventilation volume in a graph (for example, the lung field region R L The three axes are the XY plane and the expansion volume and ventilation volume are the Z axis. The data may be displayed as a multi-dimensional bar graph or the like. The control unit 41 performs the output process described above, thereby serving as an output means in the systems 100 and 100A.

[0053] (Dynamic analysis processing, etc.) In the dynamic analysis process, the control unit 41 may be configured to execute the attenuation process before executing the placement process. In this case, the control unit 41 determines the lung field region R L This reduces the signal value components of bones that appear in the image. Then, in the placement process, the control unit 41 places the evaluation point P on the dynamic image I in which the signal value components of the bones are attenuated. In this way, the control unit 41 serves as an attenuation means in the systems 100 and 100A, and the tracking accuracy of the evaluation point P can be improved.

[0054] In the dynamic analysis process, the control unit 41 may be configured to execute the revealing process before executing the placement process. In this case, the control unit 41 determines the lung field region R L It makes visible blood vessels that are visible in the image. Examples of methods for making the blood vessels more visible include a method of emphasizing the blood vessel contours by edge enhancement processing, a method of reducing the influence of noise by smoothing processing, and a method of dividing an image into blood vessels and other parts by binarization processing. Then, in the placement process, the control unit 41 places an evaluation point P on the dynamic image I in which the blood vessels are visualized (for example, on the blood vessels). In this way, the control unit 41 serves as a revealing means in the system 100, 100A, and the tracking accuracy of the evaluation point P can be improved.

[0055] <3. Actions and Effects> The dynamic analysis device 4 according to the present embodiment described above analyzes the lung field region R of the subject captured in a dynamic image I consisting of a plurality of frames F. L are placed in multiple locations in the lung field area R L The device is equipped with a control unit 41 (measurement means, output means) that measures the change over time in the distance between multiple evaluation points P that move in accordance with the movement of the subject, and outputs information indicating the ventilation function of the subject's lungs based on the change over time in the measured distance between the evaluation points P.

[0056] For this reason, when this dynamic analysis device 4 is used to analyze a dynamic image I obtained by dynamic imaging of the chest of a subject S in a standing position, for example, the movement of the evaluation point P is captured (not a change in signal value), so no artifacts due to movement, deformation, etc. of parts other than the lungs occur in the upper lung field region. As a result, the information indicating the ventilation function output by the dynamic analysis device 4 accurately represents the actual ventilation function of the lungs, as shown in Figure 9 (the ventilation function of the upper lung field region (area surrounded by a circle) appears lower than the ventilation function of the middle and lower lung field regions). Furthermore, in the analysis using this dynamic analysis device 4, it is not necessary to detect with high accuracy the blood vessels that appear in the dynamic image I. Therefore, when this dynamic analysis device 4 is used, the time from the end of dynamic imaging to the start of diagnosis can be shortened compared to conventional methods. Furthermore, this dynamic analysis device 4 can analyze the dynamics even in peripheral areas where there are no blood vessels or where the blood vessels are so thin that they cannot be detected, by placing the evaluation point P. Therefore, when this dynamic analysis device 4 is used, information indicating the ventilation function of the entire lung can be obtained.

[0057] Therefore, according to the dynamic analysis device 4 of this embodiment, when analyzing the dynamic image I obtained by dynamic imaging of the lungs of the subject S, information indicating the ventilation function of the entire lungs can be obtained easily and in a relatively short time without being affected by the movement, deformation, etc. of parts other than the lungs.

[0058] <4.Other> It goes without saying that the present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present invention.

[0059] 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 these examples. Other computer-readable media include portable recording media such as CD-ROMs. Furthermore, carrier waves are also applicable as a medium for providing data for the program according to the present invention via a communication line. [Explanation of symbols]

[0060] 100,100A Radiography System 1. Imaging device 2 Console 2A Console (dynamic analysis device) 3 Generator 31 Generator 32 Irradiation instruction switch 33 Radiation source 4 Dynamic analysis device 41 Control Unit 42 Storage section 43 Communications Department 44 Display section 45 Operation section A. Artifact F Frame G Group I Dynamic Images M Colormap N Communication Network P rating P C Standard evaluation score R L lung field area R S small area S Subject X radiation

Claims

1. a measuring means for specifying the positions of evaluation points arranged in image data in a dynamic image consisting of a plurality of frames obtained by dynamic imaging of the lungs of a subject, the evaluation points being arranged in a lung field region captured in one frame, in frames other than the one frame by estimating where a small region of a specific density around the evaluation point will move in the next frame, calculating the distance between the plurality of evaluation points for each frame, and measuring the change over time in the distance between the plurality of evaluation points based on the distance between the plurality of evaluation points; and an output means for outputting information indicating the pulmonary ventilation function of the subject based on the change over time of the distance between the evaluation points measured by the measurement means, The measurement means calculates the area of ​​a polygon having two or more evaluation points arranged around a reference evaluation point and the reference evaluation point as its vertices for each group of evaluation points that have been divided in advance, and uses the area of ​​the polygon as distance information for the group.

2. 2. The dynamic analysis device according to claim 1, wherein the output means outputs a numerical value of at least one of a pulmonary ventilation volume and a pulmonary expansion volume as the information indicating the ventilatory function.

3. the measuring means measures a change over time in the distance between the plurality of evaluation points for each group of the evaluation points that has been divided in advance, 3. The dynamic analysis device according to claim 2, wherein the output means outputs a value of at least one of the expansion volume and the ventilation volume based on changes over time of the plurality of distances measured by the measurement means.

4. 4. The dynamic analysis device according to claim 2, wherein the output means outputs the numerical value of at least one of the expansion volume and the ventilation volume in the form of an image using a color map.

5. a calculation means for calculating a value of at least one of the expansion volume and the ventilation volume based on a change over time in the distance between the evaluation points measured by the measurement means; 5. The dynamic analysis device according to claim 2, wherein the output means outputs a numerical value of at least one of the expansion volume and the ventilation volume calculated by the calculation means.

6. The calculation means The evaluation point and its surroundings that serve as the reference in the frame in which the lung field region of the first state is captured are a difference between a distance between the evaluation point serving as a reference in a frame showing the lung field region in a second state different from the first state and a distance between the evaluation point serving as a reference and the other evaluation points arranged around the evaluation point in the frame, as a change in distance; The dynamic analysis device according to claim 5 , wherein a numerical value of at least one of the expansion volume and the ventilation volume is calculated based on the calculated change amount.

7. A dynamic analysis device as described in Claim 6, wherein the first state is maximum expiratory position.

8. The dynamic analysis device according to claim 1 , further comprising: a placement unit that places a plurality of the evaluation points in the lung field region.

9. further comprising attenuation means for attenuating signal value components of bones appearing in the lung field region; 9. The dynamic analysis device according to claim 8, wherein the positioning means positions the evaluation points on a dynamic image in which the signal value components of the bones have been attenuated by the attenuation means.

10. further comprising a visualization means for visualizing blood vessels in the lung field region; 10. The dynamic analysis device according to claim 8, wherein the arranging means arranges the evaluation points on a dynamic image in which the blood vessels are visualized by the visualization means.

11. The dynamic analysis device according to claim 8 , wherein the placement means automatically determines placement locations of the evaluation points.

12. Further provided with an operation unit operable by a user, 11. The dynamic analysis device according to claim 8, wherein the arranging means determines the location of the evaluation point in response to an operation performed on the operating unit.

13. On the computer, a measurement process in which, in a dynamic image consisting of a plurality of frames obtained by dynamic imaging of the lungs of a subject, evaluation points are arranged relative to image data, and the positions of a plurality of evaluation points arranged in a lung field region captured in one frame are identified in frames other than the one frame by estimating where a small region of a specific density around the evaluation point will move in the next frame, the distance between the plurality of evaluation points is calculated for each frame, and a change in the distance between the plurality of evaluation points over time is measured based on the distance between the plurality of evaluation points; an output process for outputting information indicating the pulmonary ventilation function of the subject based on the change over time in the distance between the evaluation points measured in the measurement process; The measurement process is a program that calculates the area of ​​a polygon having two or more evaluation points arranged around a reference evaluation point and the reference evaluation point as its vertices for each group of evaluation points that have been divided in advance, and uses the area of ​​the polygon as distance information for the group.

Images