JP2015084821A - Diagnosis support information generation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide diagnosis support information correlated to a dynamic state of a subject part in real life.SOLUTION: A diagnosis support information generation method includes: applying a prescribed load to the chest as a subject site; capturing an image of the chest-part dynamic state in a loaded state affected by the loading, with an imaging device 1 and an imaging console 2 to generate a plurality of frame images related to the chest-part dynamic state in the loaded state; and calculating a prescribed feature quantity related to the chest-part dynamic state in the loaded state by a diagnostic console 3 on the basis of the plurality of generated frame images and generating the diagnosis support information related to the chest-part dynamic state on the basis of the calculated feature quantity.

Description

  The present invention relates to a diagnosis support information generation method.

  Instead of using conventional spirometers to measure lung ventilation, X-ray imaging of the subject's chest dynamics and attempts to apply it to the diagnosis of lung ventilation function (diagnosis of chest dynamics) It is coming.

  For example, Patent Document 1 discloses a value of a ratio of a feature quantity in the expiration period and a feature quantity in the inspiration period in each small region obtained by dividing the lung field region based on a series of frame images obtained by dynamic imaging of the chest. By creating and displaying a histogram, and displaying the average value and / or standard deviation of the ratio of the feature value of the expiration period and the feature quantity of the inspiration period in the entire lung field, the doctor can improve the ventilation function of the lung field. A technology for assisting in understanding such a disease state is described.

  Patent Document 2 describes a technique for calculating and outputting a feature amount indicating a degree of remaining power during rest breathing based on an image photographed during rest breathing and an image photographed during deep breathing.

International Publication No. 2012/026146 Pamphlet JP 2012-115581 A

  By the way, a normal person and a patient with a disease are living under a certain load such as holding a heavy object or going up stairs in real life. However, in the technique described in Patent Document 1, analysis focusing on resting breath (natural breathing) is performed, and in the technique described in Patent Document 2, analysis focusing on deep breathing and resting breathing is performed. Therefore, it was impossible to provide diagnosis support information correlated with the dynamics of the subject part in real life.

  An object of the present invention is to provide diagnosis support information correlated with the dynamics of a subject part in real life.

In order to solve the above-mentioned problem, the invention described in claim 1
Imaging means for generating a plurality of frame images by imaging the dynamics of the subject part; and diagnostic support for generating diagnostic support information related to the dynamics of the subject part by analyzing the plurality of frame images generated by the imaging means A diagnostic support information generation method using a diagnostic support system comprising information generation means,
A load applying step for applying a predetermined load to the subject region;
An imaging step of imaging the dynamics of the subject part in a loaded state affected by the load by the imaging unit;
Based on the plurality of frame images generated by the imaging unit in the imaging step, the diagnosis support information generation unit calculates a predetermined feature amount related to the dynamics of the subject part in the loaded state, and the calculated feature amount A diagnostic support information generating step for generating diagnostic support information related to the dynamics of the subject region based on
including.

The invention according to claim 2 is the invention according to claim 1,
The imaging step further images the dynamics of the subject part in an unloaded state without the influence of the load by the imaging means,
In the diagnosis support information generation step, the diagnosis support information generation means further includes a plurality of frame images generated by photographing dynamics of the subject part in the no-load state. Calculating a predetermined feature amount related to the dynamics of the subject region, and based on the calculated feature amounts related to the dynamics in the loaded state and the dynamics in the unloaded state, diagnostic support information related to the dynamics of the subject region Is generated.

The invention according to claim 3 is the invention according to claim 2,
The imaging step captures the dynamics of the subject part in the loaded state by performing first imaging by the imaging unit immediately after applying a load to the subject part, and is predetermined from the first imaging. By taking a second image after a lapse of time, the dynamics of the subject part in the unloaded state is imaged,
The diagnosis support information generation step calculates a first feature amount based on a plurality of frame images generated in the first imaging by the diagnosis support information generation means, and is generated in the second imaging A second feature amount is calculated based on a plurality of frame images, and diagnosis support information related to the dynamics of the subject part is generated based on a change between the first feature amount and the second feature amount.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the diagnostic assistance information correlated with the dynamics of the subject part in real life.

1 is a diagram showing an overall configuration of a chest diagnosis support system in an embodiment of the present invention. It is a flowchart which shows the flow of the production | generation of the diagnostic assistance information using the chest diagnostic assistance system of FIG. 3 is a flowchart illustrating a shooting control process executed by a control unit of the shooting console of FIG. 1. (A), (b) is the whole lung field of the frame image group obtained by photographing the chest dynamics after applying high load and low load to the chest of a normal person, or each block obtained by dividing this The figure which shows the waveform which shows the change of the average signal value for every, (c), (d), respectively, image | photographs a chest dynamics after applying high load and low load with respect to the patient of obstructive pulmonary disease, respectively. It is a figure which shows typically the waveform which shows the change of the average signal value for every block which divided | segmented the whole lung field of the frame image group obtained by this, or this. (A) is a graph of the characteristic amount corresponding to the ventilation amount from the loaded state immediately after the load to the return to the unloaded state at the rest, and (b) is the graph from the loaded state immediately after the load to the rested state. It is a graph of a respiratory cycle until it returns to a no-load state, (c) is the average value (standard deviation value) of the maximum flow velocity ratio until it returns to a no-load state at rest from a loaded state immediately after loading. It is a graph.

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

[Configuration of the chest diagnosis support system 100]
First, the configuration will be described.
In FIG. 1, the whole structure of the chest diagnosis assistance system 100 in this embodiment is shown.
As shown in FIG. 1, in the chest diagnosis support system 100, an imaging device 1 and an 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). Etc., and connected via a communication network NT. Each device constituting the chest diagnosis support system 100 conforms to the DICOM (Digital Image and Communications in Medicine) standard, and communication between the devices is performed in accordance with DICOM. In the case of a system that is self-contained within one chest diagnosis support system 100, in other words, when communication or the like is not performed directly with an external system, a configuration that does not conform to DICOM may be used.

[Configuration of the photographing apparatus 1]
The imaging device 1 is imaging means for imaging the dynamics of the chest having a periodicity (cycle), such as changes in the morphology of lung expansion and contraction associated with respiratory motion, heart pulsation, and the like. Dynamic imaging is performed by irradiating the chest of a human body with radiation such as X-rays continuously or in pulses to acquire a plurality of images (that is, continuous imaging). A series of images obtained by this continuous shooting is called a dynamic image. Each of the plurality of images constituting the dynamic image is called a frame image.
As shown in FIG. 1, the imaging apparatus 1 includes a radiation source 11, a radiation irradiation control device 12, a radiation detection unit 13, a reading control device 14, and the like.

The radiation source 11 is disposed at a position facing the radiation detection unit 13 with the subject part of the subject M interposed therebetween, and receives radiation (for the chest that is the subject part of the subject M) under the control of the radiation irradiation control device 12. X-rays).
The radiation irradiation control device 12 is connected to the imaging console 2 and controls the radiation source 11 based on the radiation irradiation conditions input from the imaging console 2 to perform radiation imaging. The radiation irradiation conditions input from the imaging console 2 are, for example, the irradiation time during continuous irradiation, the pulse rate during pulse irradiation, the pulse width, the pulse interval, the number of imaging frames per imaging, the value of the X-ray tube current, X-ray tube voltage value, filter type, and the like. The pulse rate is the number of times of radiation irradiation per second, and matches the frame rate described later. The pulse width is a radiation irradiation time per one irradiation. The pulse interval is the time from the start of one radiation irradiation to the start of the next radiation irradiation in continuous imaging, and coincides with a frame interval described later. In this embodiment, since the subject M is imaged a plurality of times, the radiation irradiation conditions include the number of times of imaging and the time interval between imaging (for example, from one continuous irradiation to the next continuous irradiation). Time interval).

The radiation detection unit 13 includes a semiconductor image sensor such as an FPD (Flat Panel Detector). The FPD has, for example, a glass substrate or the like, detects radiation that has been irradiated from the 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. A plurality of detection elements (pixels) that are converted into electrical signals and accumulated are arranged in a matrix. Each pixel includes a switching unit such as a TFT (Thin Film Transistor), and has a pixel size of 50 to 200 μm (micron). The FPD includes an indirect conversion type in which X-rays are converted into electric signals by a photoelectric conversion element via a scintillator, and a direct conversion type in which X-rays are directly converted into electric signals, either of which may be used.
The radiation detection unit 13 is provided so as to face the radiation source 11 with the subject M interposed therebetween.

The reading control device 14 is connected to the imaging 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 imaging console 2 to switch the reading of the electrical signal accumulated in each pixel. Then, the image data is acquired by reading the electrical signal accumulated in the radiation detection unit 13. This image data is a frame image. Then, the reading control device 14 outputs the acquired frame image to the photographing console 2. The image reading conditions include, for example, a frame rate, a frame interval, a binning size (how many pixels are handled as one block in a binning process described later), an image size (matrix size), and the like. The frame rate is the number of frame images acquired per second and matches 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 in continuous shooting, and coincides with the pulse interval. Further, as described above, in the present embodiment, since the subject M is imaged a plurality of times, the image reading conditions include the number of times of imaging, the time interval between the imaging (after the continuous reading, Time interval until continuous reading) is included.
The binning process divides the frame image into blocks of pixel units of the binning size, calculates a representative value (here, an average signal value) of the pixel signal value of each block, and calculates the signal value of the pixel in the block. This is a process of replacing the calculated representative value. The binning process may be performed by the imaging console 2, but is performed by the radiation detection unit 13. For example, image data (binning image data) obtained by compressing 10 pixels × 10 pixels into one block is used for imaging described later. When it is determined that re-shooting is necessary and the engineer can determine whether re-shooting is necessary or not, that is, it can be used for dynamic analysis, the binning image data is transferred to the diagnostic console 3 for analysis. Can be used for That is, it is preferable to use the binning image data for both the preview display for re-examination necessity confirmation and the dynamic analysis.

  Here, the radiation irradiation control device 12 and the reading control device 14 are connected to each other so as to synchronize the radiation irradiation operation and the image reading operation in synchronization with each other. As a method of synchronization, in addition to a method in which the radiation irradiation control device 12 and the reading control device 14 communicate synchronization signals, a method in which the radiation irradiation control device 12 detects the start and end of irradiation by itself can be used. .

[Configuration of the shooting console 2]
The imaging console 2 outputs radiation irradiation conditions and image reading conditions to the imaging apparatus 1 to control radiation imaging and radiographic image reading operations by the imaging apparatus 1, and also captures dynamic images acquired by the imaging apparatus 1. Displayed for confirmation of whether the image is suitable for confirmation of positioning or diagnosis.
As shown in FIG. 1, the imaging 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 includes a CPU (Central Processing Unit) and a RAM (Random Access Memory).
) Etc. The CPU of the control unit 21 reads the system program and various processing programs stored in the storage unit 22 in accordance with the operation of the operation unit 23, expands them in the RAM, and performs shooting control processing described later according to the expanded programs. Various processes including the beginning are executed to centrally control the operation of each part of the imaging console 2 and the radiation irradiation operation and the reading operation of the imaging apparatus 1.

  The storage unit 22 is configured by a nonvolatile semiconductor memory, a hard disk, or the like. The storage unit 22 stores various programs executed by the control unit 21 and data such as parameters necessary for execution of processing by the programs or processing results. 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 radiation irradiation condition and the image reading condition in association with the day subject part. Various programs are stored in the form of readable program code, and the control unit 21 sequentially executes operations according to the program code.

  The operation unit 23 includes a keyboard having a cursor key, numeric input keys, various function keys, and the like, and a pointing device such as a mouse. The control unit 23 controls an instruction signal input by key operation or mouse operation on the keyboard. To 21. In addition, the operation unit 23 may include a touch panel on the display screen of the display unit 24. In this case, the operation unit 23 outputs an instruction signal input via the touch panel to the control unit 21.

  The display unit 24 is configured by a monitor such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube), and displays an input instruction, data, or the like from the operation unit 23 in accordance with an instruction of a display signal input from the control unit 21. To do. In addition, a binning image is displayed in order to determine whether or not re-shooting is necessary (whether it can be used for dynamic analysis).

  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 diagnostic support information generation means for acquiring a dynamic image from the imaging console 2, analyzing the acquired dynamic image, and generating and displaying diagnostic support information for a doctor to make an interpretation diagnosis.
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 includes a CPU, a 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 in accordance with the operation of the operation unit 33, expands them in the RAM, and generates diagnostic support information according to the expanded programs. Various processes including the process are executed to centrally control the operation of each part of the diagnostic console 3.

  The storage unit 32 is configured by a nonvolatile semiconductor memory, a hard disk, or the like. The storage unit 32 stores various programs such as a program for executing diagnosis support information generation processing by the control unit 31 and data such as parameters necessary for execution of processing by the program or processing results. These various programs are stored in the form of readable program codes, and the control unit 31 sequentially executes operations according to the program codes.

  The operation unit 33 includes a keyboard having cursor keys, numeric input keys, various function keys, and the like, and a pointing device such as a mouse. The control unit 33 controls an instruction signal input by key operation or mouse operation on the keyboard. To 31. The operation unit 33 may include a touch panel on the display screen of the display unit 34, and in this case, an instruction signal input via the touch panel is output to the control unit 31.

  The display unit 34 is configured by a monitor such as an LCD or a CRT, and displays an input instruction, data, or the like from the operation unit 33 in accordance with an instruction 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 Chest Diagnosis Support System 100]
Next, the operation in the chest diagnosis support system 100 will be described.

(Flow of diagnostic support information generation)
With reference to FIG. 2, the flow of generating diagnosis support information using the chest diagnosis support system 100 will be described.
First, the subject M is caused to perform a predetermined exercise, and a load is applied to the chest that is the subject part of the subject M (step T1). This step is performed in order to acquire the influence by the load which the subject M receives in real life. For example, if a high load is applied, the subject M is caused to perform exercises such as stepping up and down 20 times, and if a low load is applied, the stepping up and down 10 times. The load level is not limited to this, and may be set as appropriate according to the sex, age, past medical history, etc. of the subject M.

なお、単位時間あたりの呼吸数が増加することは、各呼吸の周期が小さくなることを意味している。
体力測定等で広く用いられている踏み台昇降に於いては、高負荷とは、例えば、踏台昇降２０回、低負荷とは、例えば、踏台昇降１０回程度の負荷である。 Here, it is known that in the case of a normal person who does not have a disease in the chest including the lungs and the heart, when a load is applied to the chest by exercising, in general, respiration and heart rate change as shown in [Table 1]. It has been.

An increase in the number of breaths per unit time means that the cycle of each breath is reduced.
In the step raising / lowering step widely used in physical strength measurement or the like, the high load is, for example, 20 times of step raising / lowering, and the low load is, for example, a load of about ten times of step raising / lowering.

When exercise such as stepping up and down is performed, lactic acid is produced in the body, and the produced lactic acid is released into the blood. Lactic acid released into the blood is neutralized into water and carbon dioxide. An internal mechanism that increases the amount of ventilation in order to discharge this carbon dioxide outside the body with breathing is known. In a normal person, immediately after applying a load, according to this internal mechanism, as shown in [Table 1], the respiratory cycle is significantly shortened (that is, the respiratory rate per unit time is increased), and one respiratory cycle The per-ventilation volume also increases greatly, and after a predetermined time elapses, a transition to a resting breathing state occurs.
On the other hand, in the case of patients with disease (especially in the case of obstructive pulmonary disease), there is less change in the respiratory cycle immediately after applying the load and at rest compared to normal subjects, and immediately after applying the load and at rest. It is known that there is little change in ventilation volume per respiratory cycle. Moreover, it takes a longer time to restore a resting breathing state after applying a load than a normal person. In addition, at rest, the respiratory cycle is shorter than that of normal subjects, and the ventilation volume per respiratory cycle is small.
That is, in a normal person and a diseased patient, a state immediately after the load is applied (referred to as a loaded state) from a state in which the load on the chest dynamics is affected (referred to as a no-load state). It is the same as the resting breathing state.) The difference in the change of the respiratory cycle and the ventilation volume until returning to the rest is larger, and discriminating both based on these distinguishes both based on the breathing cycle and ventilation volume in the resting breathing state In other words, the diagnosis capability is high and the diagnosis can be performed with high accuracy. In addition, normal people and diseased patients are subject to some kind of load in real life, and it is considered that generation of diagnosis support information more correlated with real life is possible when the load is applied.
Therefore, in the present embodiment, a load is applied to the chest of the subject M before dynamic imaging.

  After applying the load, the subject M is subjected to dynamic imaging of the chest, which is the subject region (step T2). Specifically, step T2 is performed by the imaging console 2 executing the imaging control process shown in FIG. The photographing control process is executed in cooperation with the control unit 21 and a program stored in the storage unit 22.

  In the imaging control process of FIG. 3, first, the operation unit 23 of the imaging console 2 is operated by an imaging engineer, and patient information of the subject M (name, height, weight, age, sex, etc. of the subject M). Is input (step S1).

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

  Next, a radiation irradiation instruction by the operation of the operation unit 23 is waited (step S3). Here, the imaging operator such as an imaging engineer positions the subject part of the subject M. That is, the subject part of the subject M is disposed between the radiation source 11 and the radiation detection unit 13. When preparation for imaging is completed, the operation unit 23 is operated to input a radiation irradiation instruction.

  When a radiation irradiation instruction is input by the operation unit 23 (step S3; YES), a photographing start instruction is output to the radiation irradiation control device 12 and the reading control device 14, and dynamic photographing is started (step S4). That is, radiation is emitted from the radiation source 11 at a pulse interval set in the radiation irradiation control device 12, and a frame image is acquired by the radiation detection unit 13. When imaging of a predetermined number of frames (or time) is completed, the control unit 21 instructs the radiation irradiation control device 12 and the reading control device 14 to wait for a predetermined time interval (time interval between imaging). The image is output and shooting is waited. When a predetermined time interval elapses, the next dynamic imaging is performed. When the predetermined number of times of dynamic imaging is completed, the control unit 21 outputs an instruction to end imaging to the radiation irradiation control device 12 and the reading control device 14, and the imaging operation is stopped. The number of frames per shot is the number of frames that can be taken at least for one respiratory cycle.

Here, a plurality of dynamic imaging is performed when the imaging is continued over the entire period from when the load is applied until the state returns to a resting state (continuation of radiation or pulse irradiation). This is to prevent this because the exposure dose increases. Therefore, first, immediately after applying a load on the chest of the subject M (immediately after the load), a time width including multiple cycles of breathing, for example, dynamic imaging (first imaging) for 8 seconds is performed. After a predetermined time, for example, 30 seconds has elapsed, dynamic imaging is performed for a time width including a plurality of cycles of breathing at rest, for example, 10 seconds (second imaging). The time interval between the first imaging and the second imaging may be set to a time (experimental or empirical time) that would return to a resting breathing state in consideration of the load of a normal person. preferable.
Note that if necessary, the time interval between photographings is shortened and photographing between the first photographing and the second photographing indicates the state of the chest in the transition period until the state returns from the loaded state to the unloaded state. It is good also as implementing. This is preferable because information on the transition period from when the loaded state returns to the unloaded state can be obtained.
The irradiation time of radiation and the time interval between imaging can be appropriately set according to the magnitude of the load.

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

  When a determination result indicating photographing OK is input by a predetermined operation of the operation unit 23 (step S7; YES), an identification ID for identifying a dynamic image or each of a series of frame images acquired by dynamic photographing is displayed. Patient information, subject part, radiation irradiation condition, image reading condition, information indicating the number of times of imaging, information indicating the order of imaging (frame number), date of imaging, etc. are attached (for example, image data in DICOM format) Is transmitted to the diagnostic console 3 via the communication unit 25 (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 shooting control processing is performed. Ends.

  In order to perform a more accurate diagnosis, it is preferable to perform imaging while applying a plurality of loads with different levels to the subject M. When performing imaging with a different load, it is necessary to perform imaging with the next load after the influence of the applied load disappears and the subject M returns to a resting breathing state.

  When the dynamic imaging is completed, the diagnostic support information is generated in the diagnostic console 3 based on the plurality of frame image groups obtained by the multiple dynamic imaging (step T3).

−Generation of diagnostic support information for ventilation function−
Here, one respiratory cycle is composed of an expiration period and an inspiration period. During the exhalation period, air is expelled from the lungs by raising the diaphragm, and the area of the lung field is reduced. Along with this, the density of the lung field increases, so that the amount of radiation transmitted through the lung field and the signal value of the image indicating this decrease. During the inspiration period, air is taken into the lungs when the diaphragm is lowered, and the area of the lung field in the thorax is enlarged. Along with this, the density of the lung field decreases, so the amount of radiation transmitted through the lung field and the signal value indicating this increase. Therefore, the horizontal axis represents the elapsed time from the start of imaging for the entire lung field of a series of frame images obtained by dynamic imaging of the chest or for each block obtained by dividing the entire lung field (for example, a block of a plurality of pixels obtained by binning processing). , Create a coordinate plane with the vertical axis as the average signal value of the pixels, and plot the point where the elapsed time from the start of capturing each frame image and the average signal value calculated for that area intersect, to maximize the maximum inspiratory position A waveform having the signal value and the maximum expiratory level as the minimum signal value can be obtained. The amplitude which is the difference between the maximum signal value and the minimum signal value is an index value indicating the ventilation volume.

  FIG. 4 (a) shows the average signal value for the entire lung field of the frame image group obtained by photographing the chest dynamics after applying a high load to the chest of a normal person or for each block obtained by dividing this. The waveform which shows a change is shown typically. FIG. 4 (b) shows the change in the average signal value for the entire lung field of the frame image group obtained by imaging the chest dynamics after applying a low load to a normal person or for each block obtained by dividing this. The waveform to show is shown typically. 4 (a) and 4 (b), the waveform of the signal value shows only a part of the loaded state immediately after the high load is applied and the unloaded state at the time of returning to the resting breathing state. The signal value is obtained by performing a low-pass filter process in the time axis direction in order to extract a time change of the signal value due to ventilation.

  As shown in FIGS. 4 (a) and 4 (b), when a normal person exercises and gives a load, the period of change in the signal value becomes shorter immediately after the load than in the rest, and the amplitude of the signal value Will increase. When a predetermined time elapses from this state, the period and amplitude of the resting breathing state are restored. It takes less time to transition to a resting breathing state when the load is low.

  FIG. 4 (c) shows an average signal for the entire lung field of the frame image group obtained by photographing the chest dynamics after applying a high load to a patient with obstructive pulmonary disease, or for each block obtained by dividing this. The waveform which shows the change of a value is shown typically. FIG. 4D shows an average signal for the entire lung field of the frame image group obtained by photographing the chest dynamics after applying a low load to a patient with obstructive pulmonary disease or for each block obtained by dividing this. The waveform which shows the change of a value is shown typically. 4 (c) and 4 (d), the waveform of the signal value shows only a part of the loaded state immediately after the high load is applied and the unloaded state at the time of returning to the resting breathing state. The signal value is obtained by performing a low-pass filter process in the time axis direction in order to extract a time change of the signal value due to ventilation.

  As shown in FIGS. 4 (c) and 4 (d), when a patient with obstructive pulmonary disease is exercised to give a load, the signal value changes immediately after the load is applied as compared with a normal person, as in a normal person. And the amplitude of the signal value increases. However, as can be seen by comparing FIGS. 4A to 4D, changes in the period and amplitude of the signal value during loading and at rest are smaller than those of normal persons. Further, in the case of a patient with obstructive pulmonary disease, it takes longer to return to a resting breathing state than a normal person.

  Therefore, the control unit 31 of the diagnostic console 3 executes diagnostic support information generation processing in cooperation with the program stored in the storage unit 32, and the frames obtained by each of the plurality of times of photographing at step T2. Based on the image group, a plurality of feature amounts corresponding to each of the plurality of photographings are calculated, and diagnosis support information is generated based on the plurality of feature amounts. That is, a predetermined feature amount is calculated based on at least a plurality of frame images generated in the first shooting (the calculated feature amount is referred to as a first feature amount), and is generated in the second shooting. A predetermined feature amount is calculated based on the plurality of frame images (the calculated feature amount is referred to as a second feature amount), and the ventilation of the subject M is performed based on the first feature amount and the second feature amount. Generate diagnosis support information related to the function. When the third, fourth,..., N-th shooting is performed between the first shooting and the second shooting as required, a predetermined feature amount is based on a plurality of frame images generated in each shooting. And the diagnosis support information is generated based on the plurality of calculated feature amounts.

In calculating the feature amount, it is necessary to associate the lung field regions of a series of frame images obtained from the imaging apparatus 1 with each other. For example, as described in Japanese Patent Application Laid-Open No. 2012-110400, this association is performed by a pixel at the same position in the lung field region of each frame image (a pixel indicating the output of the detection element at the same position in the radiation detection unit 13). Can be performed by associating the frame images with each other. Specifically, a lung field region is extracted using one frame image in the frame image group as a reference image, and pixels in the same position as each pixel in the lung field region of the reference image are extracted from the other frame images. Correspond to each pixel in the field.
The reference image is preferably an image of the maximum expiratory position in which the area of the lung field region is minimum. This is because the pixels in the lung field area of the reference image are not associated outside the lung field areas of other frame images. Any method may be used to extract the lung field region. For example, a threshold is obtained by discriminant analysis from a histogram of signal values (density values) of each pixel of the reference image, and a region having a signal higher than this threshold is primarily extracted as a lung field region candidate. Next, by performing edge detection near the boundary of the first extracted lung field region candidate and extracting along the boundary the point where the edge is maximum near the boundary, the boundary of the lung field region can be extracted.
As described above, it is preferable to associate pixels at the same position among a plurality of frame images because the processing time can be shortened.
Further, for example, the position of the lung field region between the frame images may be associated by performing known local matching processing and warping processing described in Japanese Patent Application Laid-Open No. 2012-5729.

  In addition, since the signal change of the dynamic image of the chest includes not only the signal change due to ventilation but also the signal change due to blood flow, when calculating the feature amount related to the ventilation function, It is necessary to perform low-pass filter processing in the time axis direction (for example, a high-frequency cutoff frequency of 1.0 Hz) on the signal value to remove signal changes due to blood flow.

  The feature amount may be calculated for the entire lung field, or may be calculated for an area designated by the user using the operation unit 33 in the lung field area. For example, when it is known in advance by a stethoscope or the like that a part of the lung field region is suspicious, the feature amount calculation process is performed only on the necessary region by calculating only the specified region. Therefore, the processing time can be shortened. The ventilation amount measurement using a spirometer cannot measure only a specific region, but in the present embodiment, it is preferable because the feature amount of only the designated region can be calculated. In addition, it is preferable to calculate the feature amount for each block obtained by dividing the lung field region into a plurality of blocks (for example, in the case of a 200 μm pixel size, 2 mm × 2 mm square composed of 10 × 10 pixels). This is because, as described above, data of a 2 mm × 2 mm square block subjected to binning processing can be used for both preview display and feature amount analysis. Of course, when priority is given to the accuracy of the feature amount over the processing time, the feature amount analysis may be performed for each pixel.

As the predetermined feature amount to be calculated, for example, any feature amount relating to the ventilation function of the lung field, such as a feature amount corresponding to the ventilation amount, a respiratory cycle, an average value or a standard deviation value of the maximum flow velocity ratio, is calculated. Also good. However, the same feature amount is calculated for all of the first to n-th shooting.
As the feature amount corresponding to the ventilation amount, for example, the difference between the signal amount of the maximum inspiratory position and the maximum expiratory position in one respiratory cycle described in JP-A-2009-153678 can be used. For the maximum inspiratory level and the maximum expiratory signal level, for example, a histogram of the maximum inspiratory position signal value and the maximum expiratory signal level in the feature amount calculation target area is generated, and each signal value is multiplied by the frequency. Can be calculated.
In addition, the respiratory cycle calculates an average signal value of signal values in the feature quantity calculation target region, generates a signal waveform indicating a temporal change of the average signal value, and generates the length (time) of one cycle of the generated waveform. ) Can be obtained.
In addition, the average value and standard deviation value of the maximum flow rate ratio are calculated between adjacent (temporally adjacent) frame images for each block into which the lung field region is divided, and between expiratory frames. Divide the maximum absolute value of the difference value by the maximum absolute value of the difference value between frames during the expiration period to obtain the maximum flow rate ratio, and calculate the average value and the standard deviation value of the maximum flow rate ratio of the entire lung field Can be obtained. The average value and the standard deviation value of the maximum flow velocity ratio are calculated for the entire lung field.

  When the feature amount corresponding to each photographing is calculated, diagnosis support information is generated based on the calculated plurality of feature amounts. For example, a graph is generated by plotting each feature amount calculated on the coordinate space with the feature amount on the vertical axis and the elapsed time from the start of imaging on the horizontal axis, and this graph is used as diagnosis support information. The graph may display an approximate curve generated based on a plurality of feature amounts at different points in time. In addition, for example, a change rate of a feature amount (for example, a first feature amount immediately after loading and a second feature amount at rest) in a plurality of photographings may be calculated and used as diagnosis support information. Further, the numerical value of the feature amount corresponding to the first photographing immediately after the load may be used as the diagnosis support information.

FIG. 5A schematically shows a graph of feature amounts corresponding to the ventilation amount from the loaded state immediately after the load to the return to the unloaded state at rest. For the sake of explanation, in FIG. 5A, a subject who is normal and has a good ventilation function (solid line) and a subject who is classified as a normal person but whose ventilation function is slightly degenerate (one point) A graph shows the characteristic quantities of subjects who are classified as normal persons (chain lines), but whose ventilation function is degenerated to some extent (two-dot chain lines), and those who develop obstructive pulmonary disease (thick solid lines).
As shown to Fig.5 (a), the normal person with a favorable ventilation function increases the ventilation volume immediately after a load significantly compared with the time of rest, and returns to the state close | similar to a resting breathing state immediately. Even if the person is classified as a normal person, if the ventilation function is slightly degenerate, the ventilation volume immediately after the load is large, but it takes time to reach a state of resting breathing. If the ventilation function is degenerated to some extent, the ventilation volume immediately after the load is smaller than that of a person with good ventilation function, and it takes more time to reach a state of resting breathing, but it is more than the affected person. The onset of obstructive pulmonary disease has a much smaller change in ventilation volume immediately after the load than at the normal time, and the value immediately after the load is considerably smaller than the normal value.

FIG. 5 (b) schematically shows a graph of the respiratory cycle from the loaded state immediately after loading to the return to the unloaded state at rest. For the sake of explanation, in FIG. 5B, the respiration cycle of a normal person (solid line) and an onset of obstructive pulmonary disease (thick solid line) is shown in one graph.
As shown in FIG. 5 (b), the breathing cycle immediately after a normal person's load is significantly shorter than that at rest, and the breathing cycle becomes longer as the person returns at rest. On the other hand, in the onset, the fluctuation of the respiratory cycle immediately after the load and at rest is much smaller than that of the normal person, and the respiratory cycle immediately after the load is considerably longer than that of the normal person.

FIG. 5 (c) schematically shows a graph of the average value (or standard deviation value) of the maximum flow rate ratio from the loaded state immediately after loading to the unloaded state at rest. For the sake of explanation, in FIG. 5C, the average value (or standard deviation value) of the maximum flow rate ratio of a normal person (solid line) and an onset of obstructive pulmonary disease (thick solid line) is shown in one graph. ing.
As shown in FIG.5 (c), the average value (standard deviation value) of the maximum flow velocity ratio immediately after a normal person's load is substantially the same as at rest, and there is almost no fluctuation | variation. On the other hand, in the hyperventilation state after exercise load, since the time of exhalation increases and air trapping that captures air without being able to be called increases, the average value (standard deviation value) of the maximum flow rate ratio at rest is There is a tendency to increase. The higher the severity, the greater the value immediately after loading.

  In normal life, both normal persons and diseased patients are living under a load such as holding heavy objects or going up stairs. Therefore, by performing dynamic imaging of the chest under a load, calculating a feature value of the ventilated function in a loaded state, and providing it as diagnosis support information, the ventilation function in the real life of the subject M can be further improved. Correlated diagnosis support information can be provided. In addition, as shown in FIGS. 5A to 5C, the graph has various patterns depending on the feature amount. In any feature amount, the difference between the feature amount of the normal person and the onset person is immediately after the load. It can be seen that it is larger than at rest. Therefore, by providing at least the feature amount immediately after the load to the doctor, the doctor can easily discriminate whether or not the ventilation function of the subject M is normal. Further, by graphing the change in the feature amount from the loaded state immediately after the load to the return to the no-load state of the resting breathing state as shown in FIGS. It is possible to provide the doctor with a transient change in the feature amount from the loaded state to the resting breathing state, and the doctor can discriminate whether or not the ventilation function of the subject M is normal. It becomes even easier. In addition, it is possible for the doctor to give guidance to the patient on how long it is necessary to take a break when a load such as exercise is applied.

-Generation of diagnostic support information related to blood flow-
In the above description, generation of diagnosis support information for the ventilation function of the lung has been described. However, diagnosis support information related to the blood flow of the lung may be generated. Since it is heartbeat cycle >> respiratory cycle, if imaging is performed for one or more respiratory cycles for each imaging, both ventilation and blood flow are obtained using a frame image group obtained by imaging for generating ventilation diagnosis support information. Diagnosis support information can be generated.

  In the lung field, blood is rapidly discharged from the right ventricle through the aorta due to the contraction of the heart, thereby expanding the lung blood vessels. When a blood vessel dilates in the lung field, the radiation transmission amount in the area where the pulmonary blood vessel has expanded is relatively smaller than the radiation transmission amount that passes through the lung field (alveolar region), so the radiation detection unit corresponding to this region The signal value of 13 decreases. That is, for each corresponding pixel (or the above-mentioned block) between frame images, a high-pass filter process in the time axis direction (low-frequency cutoff frequency 0.7 Hz) is performed to extract a signal change related to blood flow, and the horizontal axis Create a coordinate plane with the elapsed time from the start of shooting and the vertical axis as the average signal value of the pixels, and plot the points where the elapsed time from the start of shooting of each frame image and the average signal value calculated for that area intersect Then, it is possible to obtain a waveform (blood flow signal waveform) indicating a change in which the pulmonary blood vessels expand or contract due to blood flow.

As shown in [Table 1], it is known that, by causing the subject M to exercise and applying a load, the heart rate per unit time and the heart rate per stroke increase physiologically. Therefore, changes in blood flow signal waveforms when a load (high load, low load) is applied to a normal person and a sick patient are substantially the same as those shown in FIGS. 4 (a) to 4 (d). . That is, when the load is applied, the difference in blood flow signal waveform between the normal person and the disease patient becomes more prominent.
Therefore, by calculating and providing characteristic information such as the amplitude and period of the blood flow signal from the loaded state immediately after the load to the unloaded state at rest, the doctor can receive the diagnosis support information. It becomes possible to easily discriminate whether or not the examiner's M pulmonary blood flow is normal.

  The association of the lung field regions between the respective frame images as a premise for calculating the feature value related to the blood flow can be performed by the same method as the calculation of the feature value of ventilation. Further, in order to extract a component of a signal value due to blood flow, it is necessary to calculate a feature amount after performing high-pass filter processing in the time axis direction on each associated pixel (block).

  Any feature amount related to blood flow may be used as the feature amount. For example, the amplitude and period of the blood flow signal waveform can be used. Further, for example, as described in Japanese Patent Application Laid-Open No. 2009-136573, a low signal portion of each frame image is detected as a pulsation portion, and a movement amount (blood flow rate) per unit time of the centroid of the pulsation portion is a feature amount. It is good.

  In addition, as in the case of ventilation, a graph showing the change in the feature amount from the loaded state immediately after loading to the unloaded state at rest, and the feature amount in each shooting (for example, immediately after loading and at rest) A rate of change, a numerical value of a feature amount immediately after loading, and the like can be generated as diagnosis support information. The effect of providing diagnosis support information related to blood flow to a doctor is the same as that described in the ventilation.

  Further, as described above, since the amount of change in blood flow signal value (the amplitude of the blood flow signal waveform) is greater immediately after the load than at rest, the region where the blood flow increases (with blood flow) immediately after the load. The signal value difference between the region) and the region where the blood flow volume does not increase (region without blood flow) increases. Therefore, for example, a series of frame images taken with a load applied to the chest are sequentially displayed as diagnosis support information, or a color corresponding to the sum of signal values of corresponding pixels and blocks of the series of frame images Is used as diagnosis support information, or as described in JP 2012-5729 A, the difference value between the signal values of the corresponding pixels or small regions (blocks) between adjacent frame images (in the case of small regions) (Difference value of representative value such as average signal value) is calculated, and an inter-frame difference image in which a color corresponding to the signal value is added to the image is generated, and this is sequentially displayed (moving image display) to relate to blood flow Even in the case of generating diagnostic support information or the like, the region with and without blood flow becomes clearer, so that it is possible to provide diagnostic support information with high visibility. In particular, the peripheral blood vessels near the rib cage and the apex of the lung where the blood flow volume is low when resting increases the blood flow volume by applying a load, so the visibility of the presence or absence of blood flow in these areas is increased, and the blood flow volume decreases. It is easier to see the diseased part. For example, when the subject M has a region with a thrombus (a blood vessel region without blood flow), the visibility of the thrombus region is improved, which is preferable because it is easy for a doctor to recognize. In addition, diagnosis support information with a color corresponding to the blood flow signal of the frame image taken under load and the inter-frame difference value is used to check the improvement status of the thrombus when drug treatment is performed on the thrombus Can also be used. Since it is a heartbeat cycle >> respiration cycle, it is preferable because imaging can be completed in a short time and the exposure dose can be reduced. Further, it is preferable because the burden on the patient is less than in the case of using a contrast agent.

  When the generation of the diagnostic support information is completed, the diagnostic support information is displayed on the display unit 34 by the control unit 31 of the diagnostic console 3 (step T4).

  As described above, according to the present embodiment, a predetermined load is applied to the chest, which is the subject region, and the chest dynamics in a loaded state affected by the load are imaged by the imaging device 1 and the imaging console 2. A plurality of frame images related to the chest dynamics in the loaded state are generated, and a predetermined state related to the chest dynamics in the loaded state, for example, the ventilation function of the lung field and the blood flow is generated by the diagnostic console 3 based on the generated plurality of frame images And the diagnostic support information related to the chest dynamics is generated based on the calculated feature amount.

  Accordingly, since the doctor can grasp the state of the ventilation function and blood flow of the lungs of the subject M when receiving a load as in real life, the ventilation of the subject M in real life. It becomes possible to provide diagnosis support information correlated with functions and blood flow. Further, immediately after the load, the difference in the feature amount between the normal person and the diseased patient is larger than that at rest. Therefore, by providing the feature amount of the load straightness as diagnosis support information, the ventilation function of the subject M by the doctor is provided. And whether the blood flow is normal or not can be easily discriminated.

  Further, the chest dynamics of the unloaded subject M that is not affected by the load is further photographed by the photographing apparatus 1 and the photographing console 2, and the chest of the unloaded subject M is photographed by the diagnostic console 3. Calculates predetermined feature values related to dynamics, and generates diagnosis support information related to the chest dynamics of subject M based on the calculated feature values related to the dynamics in the loaded state and the dynamics in the unloaded state By doing so, it becomes possible for the doctor to easily understand how the chest dynamics change when subjected to a load compared to the unloaded state.

  For example, by performing a first imaging after applying a load on the subject M, imaging the chest dynamics in a loaded state, and performing a second imaging after a predetermined time has elapsed since the first imaging. The chest dynamics in an unloaded state are photographed, the first feature amount is calculated based on the plurality of frame images generated in the first photographing, and the plurality of frame images generated in the second photographing is calculated. Resting from the loaded state immediately after the load by calculating the second feature amount and generating diagnosis support information related to the dynamics of the subject region based on the change between the first feature amount and the second feature amount It becomes possible for the doctor to grasp the change in the function of the chest dynamics until returning to the respiratory state at the time.

  In addition, the description in the said embodiment is an example of the suitable chest diagnosis assistance system which concerns on this invention, and is not limited to this.

  For example, in the above embodiment, the case where the subject region is the chest has been described as an example, but the present invention is not limited to this. In addition, although an imaging apparatus that captures dynamics and generates a dynamic image is an X-ray imaging apparatus, it is not limited to this.

For example, in the above description, an example in which a hard disk, a semiconductor nonvolatile memory, 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. CD-ROM as other computer-readable medium
It is possible to apply a portable recording medium such as the above. Further, a carrier wave is also applied as a medium for providing program data according to the present invention via a communication line.

  In addition, the detailed configuration and detailed operation of each device constituting the chest diagnosis support system 100 can be changed as appropriate without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 Chest diagnosis support 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 Diagnosis console 31 Control unit 32 Storage unit 33 Operation unit 34 Display unit 35 Communication unit 36 Bus

Claims (3)

Imaging means for generating a plurality of frame images by imaging the dynamics of the subject part; and diagnostic support for generating diagnostic support information related to the dynamics of the subject part by analyzing the plurality of frame images generated by the imaging means A diagnostic support information generation method using a diagnostic support system comprising information generation means,
A load applying step for applying a predetermined load to the subject region;
An imaging step of imaging the dynamics of the subject part in a loaded state affected by the load by the imaging unit;
Based on the plurality of frame images generated by the imaging unit in the imaging step, the diagnosis support information generation unit calculates a predetermined feature amount related to the dynamics of the subject part in the loaded state, and the calculated feature amount A diagnostic support information generating step for generating diagnostic support information related to the dynamics of the subject region based on
Diagnostic support information generation method including The imaging step further images the dynamics of the subject part in an unloaded state without the influence of the load by the imaging means,
In the diagnosis support information generation step, the diagnosis support information generation means further includes a plurality of frame images generated by photographing dynamics of the subject part in the no-load state. Calculating a predetermined feature amount related to the dynamics of the subject region, and based on the calculated feature amounts related to the dynamics in the loaded state and the dynamics in the unloaded state, diagnostic support information related to the dynamics of the subject region The method for generating diagnosis support information according to claim 1. The imaging step captures the dynamics of the subject part in the loaded state by performing first imaging by the imaging unit immediately after applying a load to the subject part, and is predetermined from the first imaging. By taking a second image after a lapse of time, the dynamics of the subject part in the unloaded state is imaged,
The diagnosis support information generation step calculates a first feature amount based on a plurality of frame images generated in the first imaging by the diagnosis support information generation means, and is generated in the second imaging A second feature amount is calculated based on a plurality of frame images, and diagnosis support information related to the dynamics of the subject part is generated based on a change between the first feature amount and the second feature amount. Item 3. The diagnostic support information generation method according to Item 2.

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