JP2022081681A - Dynamic image analyzing system and dynamic image analyzing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to simply acquire a respiration function index such as residual volume, functional residual volume, total lung volume, and residual volume ratio.

SOLUTION: A radiation image analysis system 100 includes a control unit 31 that calculates the area of a lung field from a chest image obtained by performing radiography on the chest from one direction and, on the basis of the calculated area of the lung field, estimates the lung field's residual volume, functional residual volume, total lung volume, or residual volume ratio.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a dynamic image analysis device, a dynamic image analysis system, a dynamic image analysis program, and a dynamic image analysis method.

Respiratory function indicators (called respiratory function indices) such as residual volume, functional residual volume, total lung volume, and residual volume rate (residual volume / total lung volume) that can be calculated based on these are Although it is useful information for diagnosing lung diseases such as COPD, it cannot be easily measured by respiratory metering, and is usually used by methods such as helium closed circuit method, nitrogen washout open circuit method, and body plethysmograph method. Measurements are being made. However, in general, medical devices capable of these measurements are expensive and large, especially in small medical facilities such as clinics and small hospitals, such as residual volume, functional residual volume, and total lung volume. It is difficult to measure these values, and a method for easily measuring these values is desired.

Understanding the state of dynamic pulmonary hyperinflation is also very important in considering the cause of shortness of breath in COPD patients. Since dynamic pulmonary hyperinflation is recognized from an early stage of COPD, it is useful information for early diagnosis, and a method for easily measuring an index indicating a state of dynamic pulmonary hyperinflation is desired.

For example, Patent Document 1 describes the ventilation volume (vital capacity or tidal volume) from the maximum expiratory position to the maximum inspiratory position measured by spirometry or the like, and the lung field of the chest dynamic image that changes between the maximum expiratory position and the maximum inspiratory position. A method for calculating the estimated ventilation volume in each phase between the maximum inspiratory position and the maximum expiratory position based on the total signal change amount of the signal value in the region is described.

Japanese Unexamined Patent Publication No. 2009-153678

However, the technique described in Patent Document 1 is a method of estimating information that can be measured by spirometry from images, and has respiratory functions such as residual volume, functional residual volume, total lung volume, and residual volume. No method for estimating the index is described.

An object of the present invention is to make it possible to easily obtain respiratory function indexes such as residual volume, functional residual volume, total lung volume, and residual volume rate.

In order to solve the above problems, the dynamic image analysis apparatus of the present invention is used.
A lung field area calculation means for calculating the area of the lung field from a dynamic image obtained by performing a dynamic image of irradiating the chest of the subject with radiation, and
An estimation means for estimating at least one of the functional residual air amount and the residual air ratio of the lung field based on the area of the lung field calculated by the lung field area calculation means.
To prepare for.

Further, the dynamic image analysis system of the present invention is used.
A radiography device that acquires a dynamic image by performing dynamic imaging that irradiates the chest of the subject with radiation,
The dynamic image analysis apparatus according to any one of claims 1 to 11.
To prepare for.

Further, the dynamic image analysis program of the present invention is
It is a dynamic image analysis program that analyzes the dynamic image obtained by performing dynamic imaging by irradiating the chest of the subject with radiation.
On the computer
The first process of calculating the area of the lung field from the dynamic image obtained by performing dynamic imaging by irradiating the chest of the subject with radiation, and
A second process of estimating at least one of the functional residual air volume and residual air rate of the lung field based on the area of the lung field calculated by the first process.

Further, the dynamic image analysis method of the present invention is used.
It is a dynamic image analysis method that analyzes the dynamic image obtained by performing dynamic imaging by irradiating the chest of the subject with radiation.
The first step of calculating the area of the lung field from the dynamic image obtained by performing dynamic imaging in which the chest of the subject is irradiated with radiation, and
A second step of estimating at least one of the functional residual air amount and the residual air ratio of the lung field based on the area of the lung field calculated in the first step.
To prepare for.

According to the present invention, it is possible to easily obtain respiratory function indexes such as residual volume, functional residual volume, total lung volume, and residual volume.

It is a figure which shows the whole structure of the radiographic image analysis system in embodiment of this invention. It is a flowchart which shows the shooting control processing which is executed by the control part of the shooting console of FIG. FIG. 5 is a flowchart showing a respiratory function index estimation process A executed by the control unit of the diagnostic console of FIG. 1 in the first embodiment. (A) is a scatter diagram showing the relationship between the lung field area at the maximum inspiratory position (deep inspiratory position) and residual volume in the front chest image radiographed under deep breathing, and (b) is the lung at the deep inspiratory position. A scatter diagram showing the relationship between the field area and the functional residual volume, FIG. 4 (c) is a scatter diagram showing the relationship between the lung field area at the deep inspiratory position and the total lung volume. It is a figure which shows the lung field region extracted in 1st Embodiment. 2 is a flowchart showing a respiratory function index estimation process B executed by the control unit of the diagnostic console of FIG. 1 in the second embodiment. This is to explain the extraction method of the peripheral region of the lung field. It is a figure which shows typically the change by the breathing of the side surface at the position shown by AA'in the frame image (front chest image) of the front of the chest and the front image of the chest. (A) is a diagram schematically showing the output signal values in AA'of the three front chest images shown in FIG. 8, and (b) is a diagram schematically showing the difference signal values. (A) is a chair on which the subject can sit shallowly, and (b) is a mechanism on which the pelvis (waist) of the subject on the imaging device is fixed by sandwiching it from the left and right, FIG. 10 (a). c) is a diagram showing a mechanism of the imaging device for fixing the subject's pelvis (waist) to the imaging table afterwards. (a) is a graph of the time change of the position of the diaphragm of the left and right lungs calculated from the chest image taken during exercise load or tachycardia for a subject with obstructive lung disease, and (b) is obstructive. It is a graph of the time change of the lung field area of the left and right lungs calculated from the chest image taken at the time of exercise load or the process of tachycardia for a subject with lung disease.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

<First Embodiment>
[Configuration of Radiation Image Analysis System 100]
First, the configuration of the first embodiment of the present invention will be described.
FIG. 1 shows the overall configuration of the radiation image analysis system 100 according to the present embodiment.
As shown in FIG. 1, in the radiation image analysis system 100, the imaging device 1 and the imaging console 2 are connected by a communication cable or the like, and the imaging console 2 and the diagnostic console 3 are connected to a LAN (Local Area Network). It is configured to be connected via a communication network NT such as. Each device constituting the radiation image analysis system 100 conforms to the DICOM (Digital Image and Communications in Medicine) standard, and communication between the devices is performed according to DICOM.

[Structure of imaging device 1]
The imaging device 1 is an imaging means for photographing the dynamics of a subject having a periodicity (cycle), such as morphological changes in lung expansion and contraction associated with respiratory movements, and heartbeat. In dynamic imaging, radiation such as X-rays is pulsed and repeatedly irradiated at predetermined time intervals (pulse irradiation), or low dose rate is continuously irradiated (continuous irradiation). This means acquiring a plurality of images showing the dynamics of the subject. A series of images obtained by dynamic photography is called a dynamic image. Further, each of the plurality of images constituting the dynamic image is called a frame image. In the following embodiment, a case where dynamic imaging of the front of the chest is performed by pulse irradiation will be described as an example.

The radiation source 11 is arranged at a position facing the radiation detection unit 13 with the subject M (the chest of the subject) interposed therebetween, and is directed to the subject M in a state where the contrast agent is not administered under the control of the radiation irradiation control device 12. Irradiate the radiation (X-ray).
The radiation irradiation control device 12 is connected to the radiography console 2 and controls the radioactivity source 11 based on the radiation irradiation conditions input from the radiography console 2 to perform radiography. The radiation irradiation conditions input from the shooting console 2 are, for example, pulse rate, pulse width, pulse interval, number of shooting frames per shooting, X-ray tube current value, X-ray tube voltage value, additional filter type, etc. Is. The pulse rate is the number of irradiations per second, which is the same as the frame rate described later. The pulse width is the irradiation time per irradiation. The pulse interval is the time from the start of one irradiation to the start of the next irradiation, and is consistent with the frame interval described later.

The radiation detection unit 13 is composed of a semiconductor image sensor such as an FPD (Flat Panel Detector). The FPD has, for example, a glass substrate or the like, detects radiation emitted from a radiation source 11 and transmitted through at least the subject M at a predetermined position on the substrate according to its intensity, and detects the detected radiation as an electric signal. A plurality of detection elements (pixels) that are converted into and accumulated in a matrix are arranged in a matrix. Each pixel is configured to include, for example, a switching unit such as a TFT (Thin Film Transistor). The FPD has an indirect conversion type in which X-rays are converted into an electric signal by a photoelectric conversion element via a scintillator and a direct conversion type in which X-rays are directly converted into an electric signal, and either of them may be used.
The radiation detection unit 13 is held on the photographing table 15 (see FIGS. 10A to 10C) and is provided so as to face the radiation source 11 with the subject M interposed therebetween.

The read control device 14 is connected to the photographing console 2. The reading control device 14 controls the switching unit of each pixel of the radiation detection unit 13 based on the image reading condition input from the photographing console 2 to switch the reading of the electric signal stored in each pixel. Then, the image data is acquired by reading the electric signal stored in the radiation detection unit 13. This image data is a frame image. The read control device 14 outputs the acquired frame image to the shooting console 2. The image reading conditions are, for example, a frame rate, a frame interval, a pixel size, an image size (matrix size), and the like. The frame rate is the number of frame images acquired per second, and is consistent with the pulse rate. The frame interval is the time from the start of one frame image acquisition operation to the start of the next frame image acquisition operation, and coincides with the pulse interval.

Here, 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.

[Configuration of shooting console 2]
The photographing console 2 outputs radiation irradiation conditions and image reading conditions to the photographing device 1 to control the radiation photographing and the reading operation of the radiation image by the photographing device 1, and also captures the dynamic image acquired by the photographing device 1 as a camera operator. It is displayed for confirmation of positioning by the photographer and confirmation of whether or not the image is suitable for diagnosis.
As shown in FIG. 1, the photographing console 2 includes 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 26.

The control unit 21 is composed of a CPU (Central Processing Unit), a RAM (Random Access Memory), and the like. The CPU of the control unit 21 reads out the system program and various processing programs stored in the storage unit 22 and expands them in the RAM in response to the operation of the operation unit 23, and performs the shooting control processing described later according to the expanded program. Various processes such as the above are executed, and the operation of each part of the photographing console 2 and the irradiation operation and the reading operation of the photographing apparatus 1 are centrally controlled.

The storage unit 22 is composed of a non-volatile semiconductor memory, a hard disk, or the like. The storage unit 22 stores data such as parameters or processing results required for processing by various programs and programs executed by the control unit 21. For example, the storage unit 22 stores a program for executing the shooting control process shown in FIG. Further, the storage unit 22 stores the irradiation condition and the image reading condition in association with the subject portion (here, the chest). Various programs are stored in the form of a readable program code, and the control unit 21 sequentially executes an operation according to the program code.

The operation unit 23 is configured to include a keyboard equipped with cursor keys, number input keys, various function keys, and a pointing device such as a mouse, and controls an instruction signal input by key operation on the keyboard or mouse operation. Output to 21. Further, the operation unit 23 may be provided with a touch panel on the display screen of the display unit 24, and in this case, the instruction signal input via the touch panel is output to the control unit 21.

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

The communication unit 25 includes a LAN adapter, a modem, a TA (Terminal Adapter), and the like, and controls data transmission / reception with each device connected to the communication network NT.

[Configuration of diagnostic console 3]
The diagnostic console 3 is a radiographic image analysis device for acquiring a dynamic image from the imaging console 2 and displaying the acquired dynamic image and the analysis result of the dynamic image to support the diagnosis of a doctor.
As shown in FIG. 1, the diagnostic console 3 includes a control unit 31, a storage unit 32, an operation unit 33, a display unit 34, and a communication unit 35, and each unit is connected by a bus 36.

The control unit 31 is composed of a CPU, RAM, and the like. The CPU of the control unit 31 reads out the system program and various processing programs stored in the storage unit 32 and expands them in the RAM in response to the operation of the operation unit 33, and according to the expanded program, the breathing function described later. Various processes including the index estimation process A are executed, and the operation of each part of the diagnostic console 3 is centrally controlled. The control unit 31 functions as a lung field area calculation means and an estimation means.

The storage unit 32 is composed of a non-volatile semiconductor memory, a hard disk, or the like. The storage unit 32 stores data such as various programs including a program for executing the respiratory function index estimation process A in the control unit 31, parameters necessary for executing the process by the program, or the processing result. These various programs are stored in the form of a readable program code, and the control unit 31 sequentially executes an operation according to the program code.

Further, in the storage unit 32, the captured dynamic image contains patient information (for example, patient ID, patient's name, height, weight, age, gender, etc.), examination information (for example, examination ID, examination date, subject site (for example). Here, it is stored in association with the chest), the imaging direction (front, side), etc.).

Further, in the storage unit 32, a calculation formula for calculating an estimated value of residual air volume, functional residual air volume, and total lung air volume from the lung field area calculated from the front chest image or a lung calculated from the front chest image. The estimated value of the residual air rate is calculated from the table showing the correspondence between the field area and the residual air volume, the functional residual air volume, and the total lung air volume, and the rate of change ΔV% of the lung field area calculated from the front chest image. A table or the like showing the correspondence between the rate of change ΔV% of the lung field area and the residual air rate calculated from the calculation formula for this purpose or the front chest image is stored. Alternatively, for a large number of subjects, residual air volume, functional residual air volume, total lung air volume, residual air volume measured by a method such as a helium closed circuit method, a nitrogen wash-out release circuit method, or a body prestimogram method. Statistical data of the correspondence between each of the measured values of and the lung field area of the maximum inspiratory position (deep inspiratory position) calculated from the frontal chest image taken under deep breathing, or the rate of change ΔV% of the lung field area. , Or a scatter diagram, etc. are stored.

The operation unit 33 is configured to include a keyboard equipped with cursor keys, number input keys, various function keys, and a pointing device such as a mouse, and receives an instruction signal input by a user's key operation on the keyboard or mouse operation. Output to the control unit 31. Further, the operation unit 33 may include a touch panel on the display screen of the display unit 34, and in this case, the instruction signal input via the touch panel is output to the control unit 31.

The display unit 34 is composed of a monitor such as an LCD or a CRT, and performs various displays according to instructions of a display signal input from the control unit 31.

The communication unit 35 includes a LAN adapter, a modem, a TA, and the like, and controls data transmission / reception with each device connected to the communication network NT.

[Operation of radiation image analysis system 100]
Next, the operation of the radiation image analysis system 100 in the present embodiment will be described.

(Operation of shooting device 1 and shooting console 2)
First, the shooting operation by the shooting device 1 and the shooting console 2 will be described.
FIG. 2 shows a shooting control process executed by the control unit 21 of the shooting console 2. The photographing control process is executed in cooperation with the program stored in the control unit 21 and the storage unit 22.

First, the imaging operator operates the operation unit 23 of the imaging console 2, and inputs the patient information and the examination information of the subject (subject M) (step S1).

Next, the radiation irradiation condition is read from the storage unit 22 and set in the radiation irradiation control device 12, and the image reading condition is read out from the storage unit 22 and set in the reading control device 14 (step S2).

Next, the instruction of radiation irradiation by the operation of the operation unit 23 is waited for (step S3). Here, the photographer arranges the subject M between the radiation source 11 and the radiation detection unit 13 for positioning. In addition, the subject is instructed to breathe (here, deep breathing). When the shooting preparation is completed, the operation unit 23 is operated to input the irradiation instruction.

When the radiation irradiation instruction is input by the operation unit 23 (step S3; YES), the imaging start instruction is output to the radiation irradiation control device 12 and the reading control device 14, and the dynamic imaging is started (step S4). That is, radiation is irradiated by the radiation source 11 at the pulse interval set in the radiation irradiation control device 12, and a frame image is acquired by the radiation detection unit 13.

When the imaging of a predetermined number of frames is completed, the control unit 21 outputs an instruction to end the imaging to the radiation irradiation control device 12 and the reading control device 14, and the imaging operation is stopped. The number of frames to be photographed is the number of sheets that can be photographed for at least one breath cycle. The imaging is performed immediately before and during the imaging in a state where the contrast medium is not administered to the subject M.

The frame images acquired by shooting are sequentially input to the shooting console 2, stored in the storage unit 22 in association with a number (frame number) indicating the shooting order (step S5), and displayed on the display unit 24. (Step S6). The photographer confirms the positioning and the like from the displayed dynamic image, and determines whether the image suitable for the diagnosis is acquired by the image (shooting OK) or the re-shooting is necessary (shooting NG). Then, the operation unit 23 is operated to input the determination result.

When a determination result indicating that shooting is OK is input by a predetermined operation of the operation unit 23 (step S7; YES), an identification ID for identifying the dynamic image is assigned to each of the series of frame images acquired by the dynamic shooting. , Patient information, examination information, irradiation conditions, image reading conditions, numbers (frame numbers) indicating the shooting order, etc. are attached (for example, written in the header area of image data in DICOM format), and the communication unit 25 is It is transmitted to the diagnostic console 3 via (step S8). Then, this process ends. On the other hand, when a determination result indicating shooting NG is input by a predetermined operation of the operation unit 23 (step S7; NO), a series of frame images stored in the storage unit 22 is deleted (step S9), and this process is performed. finish. In this case, re-shooting is required.

(Operation of diagnostic console 3)
Next, the operation in the diagnostic console 3 will be described.
In the diagnostic console 3, when a series of frame images of dynamic images are received from the photographing console 2 via the communication unit 35, the received dynamic images are stored in the storage unit 32 and together with the control unit 31. The respiratory function index estimation process A shown in FIG. 3 is executed in cooperation with the program stored in the storage unit 32.

Here, the inventor of the present application uses a method such as a helium closure circuit method, a nitrogen wash-out release circuit method, or a body prestimograph method for a large number of subjects to obtain a residual air volume (RV) and a functional residual air volume (RV). FRC) and total lung air volume (TLC) are measured, and the lung field area is calculated from the frontal chest image. investigated.
FIG. 4 (a) is a spray diagram showing the relationship between the lung field area and residual volume at the maximum inspiratory position (deep inspiratory position) in the front chest image radiographed under deep breathing, and FIG. 4 (b) is deep. A scatter diagram showing the relationship between the lung field area in the inspiratory position and the functional residual air volume, FIG. 4 (c) is a scatter diagram showing the relationship between the lung field area in the deep inspiratory position and the total lung volume. As shown in FIGS. 4 (a) to 4 (c), the lung field area has a high correlation with residual air volume, functional residual air volume, and total lung air volume, and the residual air volume is based on the lung field area. It was found that functional residual volume and total lung volume can be estimated.
Similarly, the relationship between the rate of change in lung field area ΔV% ((lung field area in deep inspiratory position-lung field area in deep expiratory position) / lung field area in deep inspiratory position) and residual air rate was examined. As a result, it was found that the rate of change ΔV% in the lung field area correlates with the residual air rate, and the residual air rate can be estimated based on the rate of change ΔV% in the lung field area.
Respiratory function index estimation process A is a process for estimating residual volume, functional residual volume, total lung volume, and residual volume rate from the lung field area.

Hereinafter, the flow of the respiratory function index estimation process A will be described with reference to FIG.
First, from the received dynamic image, the lung field area in the frame images of the deep inspiratory position and the deep expiratory position is calculated (step S11).
For example, in step S11, first, the lung field region is extracted from each frame image of the dynamic image. Any known method may be used for extraction of the lung field region. For example, a threshold value is obtained by discriminant analysis from a histogram of the signal value (concentration value) of each pixel of the frame image, and a region having a signal higher than this threshold value is primarily extracted as a lung field region candidate. Next, edge detection is performed near the boundary of the primary extracted lung field region candidate, and if the point where the edge is maximum in the small block near the boundary is extracted along the boundary, the boundary of the lung field region (solid line in FIG. 5). The area R) surrounded by R can be extracted.
Next, the lung field area of each frame image is calculated. For example, the lung field area can be calculated by counting the pixel values in the lung field region of each frame image and multiplying by the pixel size. Of the lung field areas calculated from each frame image, the largest area is the lung field area in the deep inspiratory position, and the smallest area is the lung field area in the deep expiratory position.

Then, the residual volume, the functional residual volume, and the total lung volume are estimated based on the lung field area in the frame image of the deep inspiratory position or the deep expiratory position (step S12).
Here, in the storage unit 32, a frontal chest image of a deep inspiratory position or a deep expiratory position is taken for a large number of subjects to calculate the lung field area, and a helium closing circuit method and a nitrogen washing / releasing circuit method are used. , Or the anterior chest of the deep inspiratory or deep expiratory position determined based on statistical data obtained by measuring residual air volume, functional residual air volume, and total lung air volume by a method such as body prestimograph method. Residual air volume, functional residual air volume, estimated lung air volume calculation formula, or lung field area and residual air in the front chest image of deep inspiratory or deep expiratory position with the lung field area as a variable in the image. A table showing the correspondence between the amount, the functional residual air volume, and the estimated value of the lung air volume is stored. In step S12, residual volume, functional residual volume, and total lung volume are estimated based on these calculation formulas or tables stored in the storage unit 32.

Next, the rate of change ΔV% of the lung field area is calculated based on the following (Equation 1) (step S13).
ΔV% = (lung field area in deep inspiratory position-lung field area in deep expiratory position) / lung field area in deep inspiratory position ... (Equation 1)

Then, the residual air ratio is estimated based on the calculated ΔV% (step S14).
Here, the storage unit 32 captures frontal chest images of deep inspiratory and deep expiratory positions for a large number of subjects, and calculates the lung field area change rate ΔV% based on the lung field area. Residual volume (residual volume / total lung volume) is calculated based on residual volume and total lung volume measured by methods such as helium closure circuit method, nitrogen wash-out release circuit method, or body prestimograph method. A formula for calculating the estimated residual capacity with ΔV% as a variable, or a table showing the correspondence between ΔV% and the estimated residual capacity, which was determined based on the statistical data obtained by the above, is stored. ing. In step S14, the residual air ratio is estimated based on these calculation formulas or tables stored in the storage unit 32.

The residual air rate is estimated based on the amount of change in the lung field area of the chest front images of the deep inspiratory position and the deep expiratory position (lung field area in the deep inspiratory position-lung field area in the deep expiratory position). May be good. Further, the residual volume ratio may be obtained by dividing the residual volume estimated in step S12 by the total lung volume.

Then, the estimation results of the residual volume, the functional residual volume, the lung volume, and the residual volume rate are displayed on the display unit 34 (step S15), and the respiratory function index estimation process A ends. Alternatively, the residual air amount, the functional residual air amount, which is stored in the storage unit 32 and measured by a method such as a helium closing circuit method, a nitrogen wash-out release circuit method, or a body prestimograph method for a large number of subjects. The lung field area of the maximum inspiratory position (deep inspiratory position) calculated from each of the measured values of the total lung air volume and the residual air volume and the front image of the chest radiographed under deep breathing, or the rate of change in the lung field area ΔV. A vertical line is drawn at the position corresponding to the lung field area calculated in step S11 or the change rate ΔV% of the lung field area calculated in step S13 on the scatter diagram of the correspondence relationship with%. By displaying it in the part 34, the residual air amount, the functional residual air amount, the lung air amount, and the residual air rate may be estimated from the figure (the same applies to the second to fifth embodiments).

As described above, according to the first embodiment, it is possible to easily estimate the residual volume, the functional residual volume, the total lung volume, and the residual volume rate from the chest image.

<Second embodiment>
Hereinafter, a second embodiment of the present invention will be described.
Since the configuration of the radiographic imaging system 100 in the second embodiment is the same as that described in the first embodiment with reference to FIG. 1, the description is incorporated, and the radiographic image analysis in the second embodiment is hereinafter referred to. The operation of the system 100 will be described.

In the second embodiment, the subject M during tachypnea or exercise load is dynamically photographed by the imaging device 1, and the respiratory function index estimation process B shown in FIG. 6 is executed on the obtained dynamic image.

Hereinafter, the respiratory function index estimation process B will be described with reference to FIG. The respiratory function index estimation process B is executed in cooperation with the program stored in the control unit 31 and the storage unit 32.

First, the lung field area in the frame images of the deep inspiratory position and the deep expiratory position is calculated from the received dynamic image of the subject M during tachypnea or exercise load (step S21). Since the process of step S21 is the same as that described in step S11, the description is incorporated.

Next, the residual air amount or the functional residual air amount of the subject M is estimated based on the lung field area in the frame image of the deep inspiratory position or the deep expiratory position (step S22).
Here, as in the first embodiment, the storage unit 32 captures a front chest image of a deep inspiratory position or a deep expiratory position for a large number of subjects to calculate the lung field area and helium. Deep inspiratory or deep expiratory position determined based on statistical data obtained by measuring residual air volume or functional residual air volume by methods such as closed circuit method, nitrogen wash-out release circuit method, or body prestimograph method. Calculation formula of residual air volume or functional residual air volume with the lung field area as a variable in the chest front image of the position, or lung field area and residual air volume or functional in the deep inspiratory or deep expiratory position chest front image A table showing the correspondence with the estimated value of the residual air amount is stored. In step S22, the residual air amount or the functional residual air amount is estimated based on these calculation formulas or tables stored in the storage unit 32.

Then, the amount of residual air or the amount of functional residual air during tachypnea or exercise load is displayed on the display unit 34 as an index indicating dynamic lung hyperinflation (step S23), and the respiratory function index estimation process B ends.

Dynamic pulmonary hyperinflation is an early symptom of COPD. Dynamic pulmonary hyperinflation is a state in which when the respiratory rate increases due to tachypnea or exercise load, the lungs cannot be properly discharged from the lungs and the lungs swell too much, making it impossible to inhale air. That is, it is considered that patients with early COPD have increased residual air volume or functional residual air volume due to dynamic pulmonary hyperinflation during tachypnea or exercise load. Therefore, in the respiratory function index estimation process B, the chest front image of the deep inspiratory position or the deep expiratory position is taken during tachycardia or exercise load, and the residual air volume or the functional residual air volume is estimated based on the lung field area. However, this residual air volume or functional residual air volume is used as an index of dynamic pulmonary hyperinflation. The larger the residual air volume or the functional residual air volume, the higher the possibility of dynamic lung hyperinflation.

In the respiratory function index estimation process B shown in FIG. 6, dynamic imaging is performed during tachycardia or exercise load, and the lung field area calculated from the frame images of the deep inspiratory position and the deep expiratory position of the obtained dynamic image is used. The amount of residual air or functional residual air was estimated, and this amount of residual air or functional residual air was output as an index of dynamic pulmonary hyperinflation. ), And among the frame images of each dynamic image obtained, a calculation formula or table determined based on statistical data based on the lung field area calculated from the frame images of the deep inspiratory position and the deep expiratory position. Is used to estimate the amount of residual air or functional residual air before and after (or the process of tachycardia) when exercise load is applied, and the change (change or rate of change) is used as an index of dynamic pulmonary hyperinflation. It may be output. The larger the change in the amount of residual air or the amount of functional residual air, the higher the possibility of dynamic pulmonary hyperinflation.

As described above, in the second embodiment, it is possible to easily obtain an index of dynamic lung hyperinflation from the chest image.

<Third embodiment>
In step S11 of FIG. 3 in the first embodiment and step S21 of FIG. 6 in the second embodiment, the regions (regions R) of both lungs shown by the solid line in FIG. 5 are extracted as lung field regions. Based on the lung field area, it was explained as estimating respiratory function indicators such as residual air volume, functional residual air volume, total lung air volume, residual air rate, and dynamic lung hyperinflation index. Since lesions occur from the peripheral side (thoracic side) of the lung field, using the lung field area only on the peripheral side makes these respiratory function indicators more sensitive to COPD, and it is possible to detect COPD earlier. Is considered to be. Therefore, in the third embodiment, indices of residual volume, functional residual volume, total lung volume, residual volume rate, and dynamic lung hyperinflation are estimated based on the area of a part of the peripheral side of the lung field. An example of this will be described.

Since the configuration and imaging operation of the radiographic image analysis system 100 in the third embodiment are the same as those described in the first and second embodiments, the description is incorporated. Further, the flow of the calculation process of each respiratory function index in the diagnostic console 3 is substantially the same as that described in the first embodiment and the second embodiment, but the lung field region is obtained from each frame image of the dynamic image. After extraction, each respiration is based on the point where the peripheral region of the lung field is extracted and its area is calculated, and the peripheral region of the lung field calculated from the frame images of the deep inspiratory position and / or the deep expiratory position. Since the points for estimating the functional index are different, the method for extracting the peripheral region of the lung field and the method for estimating each respiratory function index based on the peripheral area of the lung field will be described below.

As a method for extracting the peripheral region of the lung field, for example, the lung field region is extracted from the front chest image (frame image) by the method described in the first embodiment, and as shown in FIG. 7, the lung apex The area surrounded by the vertical line L1 drawn from the apex P as the boundary between the central side and the peripheral side of the lung field and the contour L2 on the thoracic side of the lung field (that is, a part of the thoracic side of the lung field). Can be extracted as the peripheral region of the lung field. The area on the peripheral side of the lung field can be obtained by counting the pixel values of the extracted peripheral region of the lung field and multiplying by the pixel size. Alternatively, at a predetermined position (height) from the diaphragm, a horizontal line is drawn for each of the left and right lungs with the contours of the central side and the thoracic side of the lung field as end points, and the perpendicular line drawn from the midpoint of this horizontal line is drawn from the lung. It may be the boundary between the central side and the peripheral side of the field.

As a method for estimating residual volume, functional residual volume, total lung volume, and residual volume rate based on the area on the peripheral side of the lung field, the same method as the method described in the first embodiment is used. be able to.
That is, estimated values of residual volume, functional residual volume, and total lung volume determined based on statistical data, with the area of the peripheral side of the lung field as a variable in the front chest image of deep inspiratory or deep expiratory position. A table showing the correspondence between the peripheral area of the lung field in the front chest image of the deep inspiratory or deep expiratory position and the estimated values of residual volume, functional residual volume, and lung volume. Is stored in the storage unit 32, and the control unit 31 stores the peripheral part of the lung field calculated from the frame image of the deep inspiratory position or the deep expiratory position based on these calculation formulas or tables stored in the storage unit 32. Residual air volume, functional residual air volume, and total lung volume can be estimated from the side area.
In addition, a formula for calculating the residual air rate with the area change rate ΔV% of the area on the peripheral side of the lung field as a variable in the front chest image taken under deep breathing, which was determined based on statistical data, or deep breathing. A table showing the correspondence between the area change rate ΔV% of the area on the peripheral side of the lung field and the estimated value of the residual air rate in the front chest image taken below is stored in the storage unit 32, and the control unit 31 stores it. , Residual air from the area change rate ΔV% of the area on the peripheral side of the lung field calculated using the frame images of the deep inspiratory position and the deep expiratory position based on the above calculation formula or table stored in the storage unit 32. The rate can be estimated.

Thus, in the third embodiment, residual volume, functional residual volume, lung volume, residual volume rate, or motion based on the peripheral area of the lung field where COPD lesions occur. Since the index of target lung hyperinflation is calculated, it is possible to obtain an index of residual volume, functional residual volume, lung volume, residual volume rate, or dynamic lung hyperinflation that is highly sensitive to COPD.

<Fourth Embodiment>
In step S11 of FIG. 3 in the first embodiment and step S21 of FIG. 6 in the second embodiment, the regions of both lungs (regions R) shown by solid lines in FIG. 5 are extracted as lung field regions. Although described as estimating indices of residual volume, functional residual volume, total lung volume, residual volume, and dynamic lung hyperinflation based on the lung field area, it is generally described as stretching and contracting the lungs. Is larger on the dorsal side (see FIG. 8). Therefore, in the fourth embodiment, the dorsal lung floor end in the deep expiratory position or the deep inspiratory position is estimated from the dynamic image, and the estimated dorsal lung bottom end is used as the lower end of the lung field based on the lung field area. Indexes for residual volume, functional residual volume, total lung volume, residual volume, and dynamic lung hyperinflation are calculated.

Since the configuration and imaging operation of the radiation image analysis system 100 in the fourth embodiment are the same as those described in the first and second embodiments, the description is incorporated. Further, the flow of calculation processing of each respiratory function index in the diagnostic console 3 is substantially the same as that described in the first embodiment and the second embodiment, but the dorsal lung floor is obtained from each frame image of the dynamic image. The end is estimated, and the lung field area is calculated with the estimated dorsal bottom end as the lower end of the lung field. The difference is that each respiratory function index is estimated based on the area of the lung field at the lower end of the lung field. The estimation method of each respiratory function index based on the lung field area with the lower end of the lung field as the lower end will be described.

First, a method for estimating the dorsal lung floor and a method for calculating the area of the lung field will be described.
FIG. 8 is a diagram schematically showing a frame image (front chest image) of a dynamic image of the front of the chest and a change due to lateral respiration at the position indicated by AA'in the front chest image. 9 (a) is a diagram schematically showing the output signal values at the positions indicated by AA'of the three front chest images shown in FIG. 8, and FIG. 9 (b) schematically shows the difference signal values. It is a figure. In FIGS. 9 (a) and 9 (b), the line shown by the broken line indicates the output signal value at the deep expiratory position in FIG. 8, and the line indicated by the alternate long and short dash line indicates the output signal value in the intermediate phase of FIG. The inter-frame difference value between the intermediate phase and the deep expiratory position is shown, and the solid line shows the output signal value at the deep inspiratory position in FIG. 8 and the inter-frame difference value between the deep inspiratory position and the intermediate phase. There is. Further, in FIG. 9A, three lines of a deep expiratory position, an intermediate phase, and a deep inspiratory position are substantially overlapped between the GBs.

The respiratory cycle consists of an expiratory phase and an inspiratory phase. During the expiratory period, the raised diaphragm causes air to be expelled from the lungs, reducing the area of the lung field. In the deep exhalation position, the position of the diaphragm is the highest. During the inspiratory phase, the lowering of the diaphragm causes air to be taken into the lungs, increasing the area of the lung field in the thorax. In the deep inspiratory position, the position of the diaphragm is in the lowest position.
As described above, since the lung field region is a region where air enters and exits, the tissue density is lower and the radiation transmission amount is higher than that of the surrounding lung field region. Therefore, when X-ray photography is performed, the signal value in the lung field region becomes larger than that in the lung field region.

The position indicated by B in the side view of FIG. 8 is the upper end position of the diaphragm at the maximum expiratory position. The position indicated by C in the side view of FIG. 8 is the upper end position of the diaphragm in the intermediate phase. The position indicated by D in the side view of FIG. 8 is the upper end position of the diaphragm at the maximum inspiratory position. The upper end position of these diaphragms is a boundary where the signal value in the lung field region where the tissue density is thin shifts to the signal value in the lung field region, and is visually recognized as the lung bottom position in the front chest image of FIG. be able to.
On the other hand, the position indicated by E in the side view of FIG. 8 is the lower end position of the diaphragm in the intermediate phase. The position indicated by F in the side view of FIG. 8 is the lower end position of the diaphragm in the deep inspiratory position. As can be seen from the side view of FIG. 8, the diaphragm actually moves largely to the posterior side, and the lung field exists up to the lower end position of the posterior portion of the diaphragm. That is, the lower end position of the back surface of the diaphragm can be estimated to be the dorsal bottom end of the lung. The lower end position of the back surface of the diaphragm cannot be visually observed, but can be recognized by performing inter-frame difference processing between adjacent frame images.

When the inter-frame difference processing is performed between adjacent frame images, as shown in FIG. 9B, the upper end position L11 of the diaphragm has the maximum inter-frame difference value. Further, the lower end position L12 of the diaphragm is lower than the upper end position L11, and is the position of the boundary where the difference value between frames is substantially 0. The difference value between the frame images is calculated by, for example, subtracting the signal value of the same pixel of the n-1st frame image from the signal value of the pixel of the nth frame image. For the image of the first frame, the difference value obtained by subtracting the final frame image (for example, the ninth frame if there are nine frames) from the image of the first frame is calculated. Before performing the inter-frame difference processing, it is preferable to apply a low-pass filter processing in the time direction to the dynamic image to extract the time change of the signal value due to ventilation.

When the lower end of the lung field is estimated from the dorsal bottom end of the lung, the control unit 31 calculates the lung field area with the estimated dorsal bottom end of the lung as the lower end of the lung field. For example, the side end of the lung field region connecting the lower end of the side end of the lung field region extracted in step S11 of FIG. 3 and the dorsal lung bottom end of the diaphragm is obtained by interpolation, and the lung field region extracted in step S11 is obtained. The area obtained by adding the area of the lung field and the area of the lung field area and the area surrounded by the dorsal lung floor end is calculated as the lung field area. The lung field side end portion between the lung field region extracted in step S11 and the dorsal lung bottom end may be obtained by interpolation processing or the like as described above, or the dorsal lung of each frame image. The bottom end may be determined and the end on the lung field side may be estimated from the trajectories at both ends.

Next, we estimate indices for residual volume, functional residual volume, total lung volume, residual volume rate, and dynamic lung hyperinflation based on the area of the lung field with the dorsal bottom end of the lung as the lower end of the lung field. The method will be described.

A method for estimating residual volume, functional residual volume, total lung volume, and residual volume rate based on the area of the lung field with the dorsal bottom end of the lung as the lower end of the lung field will be described in the first embodiment. It is possible to use the same method as the above method.
That is, the residual air volume and the functional residual air volume determined based on the statistical data, with the lung field area as the variable with the dorsal lung floor end as the lower end of the lung field in the chest front image of the deep inspiratory position or the deep expiratory position. , Calculation formula of estimated value of total lung volume, or lung field area with the dorsal bottom end of the lung as the lower end of the lung field in the chest front image of the deep inspiratory position or the deep expiratory position, and the residual air volume and functional residual A table showing the correspondence between the air volume and the estimated value of the lung air volume is stored in the storage unit 32, and the control unit 31 is deep based on these calculation formulas or tables stored in the storage unit 32. The residual air volume, functional residual air volume, and total lung air volume can be estimated from the lung field area with the dorsal lung floor end as the lower end of the lung field calculated from the frame image of the inspiratory position or the deep expiratory position.
In addition, the estimation of the residual air rate using the area change rate ΔV% of the lung field area with the dorsal bottom end of the lung as the lower end of the lung field in the frontal chest image taken under deep breathing, which was determined based on statistical data, as a variable. Correspondence between the value calculation formula or the area change rate ΔV% of the lung field area with the dorsal lung floor end as the lower end of the lung field in the front chest image taken under deep breathing and the estimated value of the residual air rate. The table shown is stored in the storage unit 32, and the control unit 31 calculates using the frame images of the deep inspiratory position and the deep expiratory position based on the above calculation formula or table stored in the storage unit 32. The residual air rate can be estimated from the area change rate ΔV% of the lung field area with the dorsal bottom end of the lung as the lower end of the lung field.

Thus, in the fourth embodiment, the residual volume, the functional residual volume, the lung volume, the residual volume rate, or the residual volume based on the lung field area with the dorsal lung bottom end as the lower end of the lung field. Since the index of dynamic lung hyperinflation is calculated, it is possible to more accurately obtain the index of residual volume, functional residual volume, lung volume, residual volume rate, or dynamic lung hyperinflation.

<Fifth Embodiment>
In the first to fourth embodiments, the residual air volume, the functional residual air volume, the total lung air volume, the residual air rate, and the dynamic lung hyperinflation are based on the area of the lung field region of both lungs. Although it was explained as estimating the index of, the lung field area is calculated for each lung, and based on the calculated lung field area, the residual air volume, the functional residual air volume, and the total lung air volume for each lung are calculated. Alternatively, an index of dynamic pulmonary hyperinflation may be calculated.

Conventional tests such as spirometry can only obtain information on both lungs, but by using dynamic images, residual volume, functional residual volume, total lung volume, and residual volume for each lung can be obtained. It is possible to estimate rates and indicators of dynamic lung hyperinflation. This makes it possible to compare the left lung and the right lung. In addition, since it is possible to calculate an index of residual volume, functional residual volume, total lung volume, or dynamic lung hyperinflation of the operated side lung when one lung is operated, these values can be calculated. By calculating the time course, it is possible to calculate the time course of the lung after surgery.

As described above, according to the control unit 31 of the diagnostic console 3, the area of the lung field is calculated from the chest image obtained by radiography of the chest from one direction, and the area of the lung field is calculated based on the calculated area of the lung field. Then, the residual volume, functional residual volume, total lung volume, or residual volume rate of the lung field is estimated.
Therefore, it is possible to easily obtain respiratory function indices such as residual volume, functional residual volume, and total lung volume using chest images without the need for expensive and large-scale medical equipment as in the past. It will be possible.

The description in the above embodiment is a preferable example of the present invention, and is not limited thereto.

For example, in the first to fifth embodiments, based on the lung field area of the deep inspiratory position or the deep expiratory position calculated from the chest dynamic image obtained by kinematically photographing the chest from one direction in front of the chest. , Lung field residual air volume, functional residual air volume, total lung air volume, residual air rate, or respiratory function indicators such as dynamic lung hyperinflation index. Based on the lung field area of the deep inspiratory or deep expiratory position calculated from the chest dynamic image obtained by dynamic imaging, the residual air volume, functional residual air volume, total lung air volume, and residual air volume of the lung field. , Respiratory function indicators such as indicators of dynamic pulmonary hyperinflation may be created. However, from the viewpoint of reducing patient exposure, it is preferable to take a frontal chest image.

Further, in the above embodiment, a frame image of a deep inspiratory position or a deep expiratory position is specified from a chest dynamic image obtained by kinematically photographing the chest, and based on the lung field area calculated from the specified frame image, Although it was explained as creating an index of residual air volume, functional residual air volume, total lung air volume, residual air rate, dynamic lung hyperinflation, etc. in the lung field, the front of the chest in the deep inspiratory or deep expiratory position was described. The lung field area is calculated from the frontal image of the chest obtained by taking a still image, and based on the calculated lung field area, the residual air volume, functional residual air volume, total lung air volume, and residual air volume of the lung field are calculated. , An index of dynamic lung hyperinflation, etc. may be created.

Further, it is not necessary to estimate all of the residual volume, functional residual volume, total lung volume, and residual volume in the lung field, and for example, only the respiratory function index selected by the user may be estimated. .. In addition, the inventor of the present application has found that for a large number of subjects, the lung capacity at the maximum inspiratory position (deep inspiratory position) and the vital capacity measured by a respiratory function test (spirometry) in the frontal chest image taken under deep breathing (spirometry). As a result of examining the relationship of VC), it was found that there is a high correlation between the two, and based on the area of the lung field, the residual capacity of the lung field, the functional residual capacity, the total lung capacity, and the residual capacity are found. At the same time as estimating the spirometry, the vital capacity may be estimated based on the lung field area by using the same method. This makes it possible to easily estimate lung capacity using chest images, and users can easily estimate lung capacity from obstructive lung disease from estimated values of residual capacity, functional residual capacity, total lung capacity, residual capacity, and vital capacity. , It becomes possible to find out the characteristics of restrictive lung disease. Further, the estimated residual capacity may be calculated by subtracting the estimated lung capacity calculated based on the lung capacity area from the estimated total lung capacity calculated based on the lung field area.

Further, in the above embodiment, the estimated respiratory function index is displayed on the display unit 34, but the output of the respiratory function index is not particularly limited, and for example, it may be printed on paper by a printer. , It may be output by voice, or the data of the respiratory function index may be output to an external device via the communication network NT.

In addition, especially in dynamic imaging, since imaging is performed continuously for a long time (about 20 seconds), in order to suppress the body movement of the subject during imaging in a standing position, the imaging device 1 is used with the pelvis (waist). It is preferable to provide a mechanism for fixing the. For example, a chair 16 on which the subject (indicated by H in FIGS. 10 (a) to 10 (c)) can sit shallowly as shown in FIG. 10 (a), or a subject as shown in FIG. 10 (b). Mechanism 17 for fixing the person's pelvis (waist) from the left and right, mechanism 18 for fixing the subject's pelvis (waist) to the imaging table 15 afterwards as shown in FIG. 10 (c), etc. It is preferable to have. When taken in a perfect sitting position, the internal organs and diaphragm of the subject's digestive system rise, which hinders the subject's deep breathing. The body movement of the subject can be suppressed without disturbing the person's breathing. Similarly, the mechanism 17 that fixes the pelvis (waist) by sandwiching it from the left and right, and the mechanism 18 that fixes the pelvis (waist) by pressing it against the imaging table 15 afterwards also move the subject's breathing and thorax. The body movement of the subject can be suppressed without hindering. Further, when the mechanism 18 for fixing the pelvis (waist) to the imaging table 15 afterwards is provided, a mechanism (not shown) for fixing the pelvis (waist) to the ventral side of the subject is also provided at the same time, and the subject during imaging is provided. It is preferable to fix the subject's waist by sandwiching it from the front and back so that the movement of the waist portion of the subject is more suppressed. With these mechanisms, it is possible to suppress the body movement of the subject during dynamic imaging for about 20 seconds, and it becomes a noise component especially when quantifying or visualizing the amount of change in the signal value in the lung field. It is possible to suppress the amount of change in the signal value caused by body movement.

Further, the control unit 31 of the diagnostic console 3 may quantify and visualize the relationship between the movement of the structure in the lung field and the movement of the diaphragm in the chest dynamic image. For example, for each of a local region including the diaphragm in a certain frame image and a plurality of local regions in the lung field not including the diaphragm, using a technique such as template matching, in a frame image separated by a plurality of frames in time. The position of the corresponding area is obtained, and the movement amount and the movement direction for each local area are calculated. For each local region, the calculated movement amount is superimposed on the chest dynamic image as a numerical value and displayed, or the length according to the movement amount and the arrow pointing according to the movement direction are displayed on the chest dynamic image. Or, a color image in which each local region in the lung field is mapped with saturation according to the amount of movement and hue color according to the movement direction is superimposed and displayed on the chest dynamic image. This makes it possible to quantify and visualize the relationship between the movement of structures in the lung field and the movement of the diaphragm in chest dynamic images. As a result, the user can easily recognize the part where the movement in the lung field is poor with respect to the diaphragm, which is useful for grasping the pathological condition. For example, when the diaphragm is moving but the pulmonary blood vessels are not moving, it is possible to grasp that the contents of the lungs are not moving and gas exchange is not performed. Further, the above-mentioned movement amount and movement direction may be a value based on the movement amount and the movement direction of the local region including the diaphragm. For example, the movement amount and the movement direction of each local region in the lung field not including the diaphragm may be a value divided by the movement amount of the local region including the diaphragm, or an angle deviated from the movement direction of the local region including the diaphragm, respectively. .. This makes it possible to calculate the movement of the structure in the lung field based on the movement of the diaphragm as a quantitative value, and the user can better understand the relevance of the movement of the structure in the lung field based on the movement of the diaphragm. It will be easier.
In addition, before finding the position of the corresponding area in the frame image that is separated by multiple frames in time by using a technique such as template matching, the rib shadow is attenuated by using a known technique for each frame image. It is also possible to generate the generated frame image and calculate the position of the corresponding region in the frame image separated by a plurality of frames in time with respect to the generated frame image. In general, in the chest dynamic image under breathing, the ribs and pulmonary blood vessels move in opposite directions. Therefore, by diminishing the rib shadow in this way, the movement of the lung blood vessels in the lung field and the diaphragm in the chest dynamic image are performed. The relationship with movement can be quantified more accurately.
In the above, we decided to quantify and visualize the relationship between the movement of the structure in the lung field and the movement of the diaphragm in the chest dynamic image, but the same method was used to determine the movement of the structure in the lung field and the movement of the heart. The relationship between the two may be quantified and visualized. Similar to the movement of the diaphragm, this allows the user to easily recognize the part where the movement in the lung field is poor with respect to the movement of the heart, which is useful for grasping the pathological condition.

In addition, since the lung field of patients with diseases such as pneumonia and pulmonary fibrosis has a small amount of X-ray transmission, the signal value is lower in the X-ray image than in the lung field of a healthy person, and it is whitish (at a low concentration). ) It is reflected. When the lung field appears white, even if the amount of movement of the diaphragm is the same, the amount of change in the signal value in the lung field is large, so the dynamic image or the amount of change in the local signal value in the lung field In the image visualized by superimposing the color according to the quantitative value (numerical value) or the amount of change in the signal value on the dynamic image, the movement of the lung field seems to be good (healthy). Therefore, it is preferable that the control unit 31 of the diagnostic console 3 corrects the amount of change in the signal value based on the lung field concentration (signal value) in each frame image of the dynamic image. When calculating the amount of change in the signal value in the lung field, for example, a calculation formula showing the relationship between the feature amount (for example, the average signal value in the lung field) obtained from the signal value in the lung field and the correction coefficient, or the signal value in the lung field. A table or the like showing the correspondence between the feature amount obtained from the above and the correction coefficient is stored in the storage unit 32, and is obtained from the signal value in the lung field in the frame image to be calculated for the change amount of the signal value of the dynamic image. Based on the calculation formula or table stored in the above-mentioned storage unit 32, the correction coefficient corresponding to the feature amount is acquired, and the acquired correction coefficient is used for the calculated change amount of the signal value in the lung field. By multiplying, the amount of change in the corrected signal value in the lung field can be obtained. As a result, in patients with diseases such as pneumonia and pulmonary fibrosis, even when the lung field appears white, it is possible to suppress an increase in the amount of change in the signal value, and the user can more appropriately. Based on the amount of change in the signal value, it becomes possible to grasp the state of movement in the lung field. Further, the feature amount obtained from the above-mentioned signal value in the lung field is stored in the radiation irradiation condition and the storage unit 32 when the control unit 31 of the diagnostic console 3 receives the irradiation condition from the imaging device 1. It is preferable to calculate based on body shape information such as height and weight of the patient. The signal value in the lung field depends on the height, weight, and irradiation conditions of the patient. For example, even if the irradiation conditions are the same, if the patient has a large body shape, the amount of X-ray transmission is small and the signal value in the lung field is reduced. The signal value of is small. Therefore, by adjusting the value of the feature amount obtained from the above-mentioned signal value in the lung field by multiplying by a coefficient according to the size of the patient's body shape, the amount of change in the signal value in the lung field is corrected more accurately. Can be done.

Further, when displaying a plurality of chest images (dynamic images) taken at different times, the control unit 31 has the same position (height) at a specific part of the chest (for example, lung apex, hilar, same cervical spine, etc.). The image may be displayed in parallel on the display unit 34 by adjusting the position as described above. This makes it easier to compare multiple chest images and makes it easier to grasp changes at different times.

In addition, as an index showing the state of dynamic lung hyperinflation, for each frame image of the chest image taken during exercise load or in the process of tachycardia, for each of the left and right lungs, by a method such as edge recognition. The position (height) of the diaphragm is calculated, or the contour of the lung field is detected by the above-mentioned method to calculate the lung field area, and the calculated position of the diaphragm of the left and right lungs or the time change of the lung field area is displayed on the display unit 34. It may be displayed as a graph. In subjects with obstructive pulmonary disease such as COPD, as shown in FIGS. 11 (a) and 11 (b), the position of the diaphragm is lowered as time passes during exercise load or the tachycardia process. , The lung field area increases, and the amount of movement of the diaphragm position or the amount of change in the lung field area between the inspiratory position and the expiratory position decreases. Therefore, the user can grasp the degree of dynamic lung hyperinflation from the graph of the displayed diaphragm position or the time change of the lung field area. Furthermore, the time transition of the diaphragm position or lung field area in the expiratory position is calculated from the time change of the diaphragm position or lung field area of the left and right lungs, and the quantitative value indicating the degree of their increase or decrease is the state of dynamic lung hyperinflation. It may be calculated as an index indicating. For example, the parameters of the approximate expression when the time transition of the lung field area at the calculated expiratory position is linearly approximated or curvedly approximated (for example, the slope when linearly approximated) are calculated and used as an index showing the state of dynamic lung hyperinflation. indicate. When the degree of dynamic lung hyperinflation is strong, for example, the slope when linearly approximating the time transition of the lung field area in the expiratory position becomes large, so the user can more easily receive it by checking this quantitative value. The degree of dynamic lung hyperinflation of the examiner can be grasped. Furthermore, the diaphragm position or lung field area of the left and right lungs is calculated from the front chest image taken at the maximum inspiratory position or the frame image at the maximum inspiratory position of the dynamic image of the front of the chest, and the calculated maximum inspiratory position is calculated. Calculate the difference between the left and right lung diaphragm position or lung field area and the left and right lung diaphragm position or lung field area calculated from each frame image of the dynamic image of the front of the chest taken during exercise load or tachycardia process. Then, the time change of the calculated difference value may be displayed as a graph on the display unit 34. As a result, the time change of the respiratory function index corresponding to the maximum inspiratory volume (IC) is displayed, and the user confirms this time change to determine the exercise tolerance of the subject and dyspnea during exertion. It becomes easier to grasp the degree. Here, in calculating the lung field area, as described in the fourth embodiment, the dorsal lung bottom end is estimated from each frame image of the dynamic image, and the estimated dorsal lung bottom end is the lung field. The lung field area at the lower end may be calculated. This makes it possible to more accurately obtain an index of dynamic lung hyperinflation based on the movement of the dorsal side, which has a large expansion and contraction during respiration. Further, when photographing in the tachypnea process, it is preferable that the imaging device 1 has a breathing guidance mechanism for instructing the subject to inhale and exhale by voice or display by a monitor screen.

Further, for example, in the above description, an example in which a hard disk, a non-volatile memory of a semiconductor, or the like is used as a computer-readable medium of the program according to the present invention is disclosed, but the present invention is not limited to this example. As another computer-readable medium, a portable recording medium such as a CD-ROM can be applied. Further, a carrier wave is also applied as a medium for providing the data of the program according to the present invention via a communication line.

In addition, the detailed configuration and detailed operation of each device constituting the radiation image analysis system can be appropriately changed without departing from the spirit of the present invention.

100 Radiation image analysis system 1 Imaging device 11 Radiation source 12 Radiation irradiation control device 13 Radiation detection unit 14 Reading control device 2 Imaging console 21 Control unit 22 Storage unit 23 Operation unit 24 Display unit 25 Communication unit 26 Bus 3 Diagnostic console 31 Control unit 32 Storage unit 33 Operation unit 34 Display unit 35 Communication unit 36 Bus

The present invention relates to a dynamic image analysis system and a dynamic image analysis program .

In order to solve the above problems, the dynamic image analysis system of the present invention is used.
A lung field area calculation means for calculating the area of the lung field from a dynamic image obtained by performing a dynamic image of irradiating the chest of the subject with radiation, and
An estimation means for estimating at least one of the functional residual air amount and the residual air ratio of the lung field based on the area of the lung field calculated by the lung field area calculation means.
To prepare for.

Further, the dynamic image analysis program of the present invention is
It is a dynamic image analysis program that analyzes the dynamic image obtained by performing dynamic imaging by irradiating the chest of the subject with radiation.
On the computer
Based on the area of the lung field obtained from the dynamic image, a process of estimating at least one of the functional residual air amount and the residual air rate of the lung field is executed.

Claims (21)

A lung field area calculation means for calculating the area of the lung field from a dynamic image obtained by performing a dynamic image of irradiating the chest of the subject with radiation, and
An estimation means for estimating at least one of the functional residual air amount and the residual air ratio of the lung field based on the area of the lung field calculated by the lung field area calculation means.
A dynamic image analyzer equipped with. The estimation means is based on a calculation formula or table determined based on statistical data obtained from a large number of subjects other than the subject, and the area of the lung field of the subject. The dynamic image analysis apparatus according to claim 1, wherein at least one of the functional residual air amount and the residual air rate of the field is estimated. The statistical data is data obtained from a large number of subjects other than the subject, and the area of the lung field obtained by the dynamic imaging and the function obtained by a method different from the dynamic imaging. The dynamic image analysis apparatus according to claim 2, which includes data showing the relationship with the target residual air amount. The statistical data is data obtained from a large number of subjects other than the subject, and is obtained by a rate of change in the area of the lung field obtained by the dynamic imaging and a method different from the dynamic imaging. The dynamic image analysis apparatus according to claim 2 or 3, which includes data showing the relationship with the residual air ratio. The dynamic image analysis apparatus according to claim 3 or 4, wherein the method different from the dynamic imaging is a helium closing circuit method, a nitrogen wash-out release circuit method, or a body prestimograph method. The lung field area calculation means calculates the area of the lung field based on the frame image corresponding to the deep inspiratory position or the frame image corresponding to the deep expiratory position among the plurality of frame images constituting the dynamic image. The dynamic image analysis apparatus according to any one of claims 1 to 5. The dynamic image analysis apparatus according to any one of claims 1 to 6, wherein the area of the lung field calculated by the lung field area calculation means is a part of the area on the thoracic side. For the area of the lung field calculated by the lung field area calculation means, the dorsal lung bottom end of the lung field is estimated from the dynamic image, and the lung field with the dorsal lung bottom end as the lower end of the lung field. The dynamic image analysis apparatus according to any one of claims 1 to 6, which is an area. The dynamic image analysis apparatus according to any one of claims 1 to 6, wherein the area of the lung field calculated by the lung field area calculation means is the area of one lung of the lung field. The dynamic image is a dynamic image taken during tachypnea or exercise load.
The estimation means moves the functional residual air volume of the lung field estimated based on the area of the lung field calculated from the dynamic image taken by the tachypnea or exercise load by the lung field area calculation means. The dynamic image analyzer according to any one of claims 1 to 9, which is estimated as an index of pulmonary hyperinflation. The dynamic image is a dynamic image taken before and after exercise load or in the process of tachypnea.
The estimation means estimates and estimates the amount of functional residual air before and after exercise load or in the tachypnea process based on the area of the lung field calculated from the dynamic images taken before and after exercise load or in the tachypnea process. The dynamic image analyzer according to any one of claims 1 to 9, which estimates a change in the amount of functional residual air before and after loading or in the process of tachypnea as an index of dynamic pulmonary hyperinflation. A radiography device that acquires a dynamic image by performing dynamic imaging that irradiates the chest of the subject with radiation,
The dynamic image analysis apparatus according to any one of claims 1 to 11.
A dynamic image analysis system. It is a dynamic image analysis program that analyzes the dynamic image obtained by performing dynamic imaging by irradiating the chest of the subject with radiation.
On the computer
The first process of calculating the area of the lung field from the dynamic image obtained by performing dynamic imaging by irradiating the chest of the subject with radiation, and
A second process of estimating at least one of the functional residual air volume and residual air rate of the lung field based on the area of the lung field calculated by the first process.
A dynamic image analysis program that runs. The second process is based on a calculation formula or table determined based on statistical data obtained from a large number of subjects other than the subject, and the area of the lung field of the subject. The dynamic image analysis program according to claim 13, wherein at least one of the functional residual air amount and the residual air rate of the lung field is estimated. The statistical data is data obtained from a large number of subjects other than the subject, and the area of the lung field obtained by the dynamic imaging and the function obtained by a method different from the dynamic imaging. The dynamic image analysis program according to claim 14, which includes data showing the relationship with the target residual air amount. The statistical data is data obtained from a large number of subjects other than the subject, and is obtained by the rate of change in the area of the lung field obtained by the dynamic imaging and a method different from the dynamic imaging. The dynamic image analysis program according to claim 14 or 15, which comprises data showing the relationship with the residual air ratio. The dynamic image analysis program according to claim 15, wherein the method different from the dynamic imaging is a helium closure circuit method, a nitrogen wash-out release circuit method, or a body prestimograph method. In the first process, the area of the lung field is calculated based on the frame image corresponding to the deep inspiratory position or the frame image corresponding to the deep expiratory position among the plurality of frame images constituting the dynamic image. Item 6. The dynamic image analysis program according to any one of Items 13 to 17. The dynamic image is a dynamic image taken during tachypnea or exercise load.
In the second process, the amount of functional residual air in the lung field estimated based on the area of the lung field calculated from the dynamic image taken during tachypnea or exercise load by the first process is obtained. The dynamic image analysis program according to any one of claims 13 to 18, which is estimated as an index of dynamic pulmonary hyperinflation. The dynamic image is a dynamic image taken before and after exercise load or in the process of tachypnea.
In the second process, the amount of functional residual air before and after exercise load or in the tachypnea process is estimated and estimated based on the area of the lung field calculated from the dynamic images taken before and after exercise load or in the tachypnea process. The dynamic image analysis program according to any one of claims 13 to 18, which estimates a change in the amount of functional residual air before and after exercise load or during a tachypnea process as an index of dynamic pulmonary hyperinflation. It is a dynamic image analysis method that analyzes the dynamic image obtained by performing dynamic imaging by irradiating the chest of the subject with radiation.
The first step of calculating the area of the lung field from the dynamic image obtained by performing dynamic imaging in which the chest of the subject is irradiated with radiation, and
A second step of estimating at least one of the functional residual air amount and the residual air ratio of the lung field based on the area of the lung field calculated in the first step.
A dynamic image analysis method.

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