JP2011125385A - X-ray equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide X-ray equipment capable of providing information suitable for diagnosis of the heart. <P>SOLUTION: An image acquisition part 1 acquires X-ray image data of a plurality of frames by applying X rays a plurality of times. A contour extraction part 41 specifies the contour of the lungs of a subject based on the X-ray image data of respective frames. A width calculation part 42 calculates the width of the lungs and the width of the heart in each frame based on the contour of the lungs in the respective frames. A cardiothoracic ratio calculation part 43 calculates the cardiothoracic ratio, the ratio of the lung width to the heart width, for each frame. A display control part 5 displays the cardiothoracic ratio in each frame in a display part 61. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an X-ray imaging apparatus that images a subject with X-rays and generates information used for heart diagnosis based on an X-ray image obtained by the imaging.

  For example, when diagnosing cardiac hypertrophy or hypertrophic cardiomyopathy, the chest of the subject is imaged with X-rays, and the width of the lung and the width of the heart are obtained using the X-ray images obtained by the imaging. The ratio (cardiothoracic ratio = heart width / lung width) (CTR) is calculated. This cardiothoracic ratio (CTR) indicates the degree of expansion of the heart.

  Conventionally, the cardiothoracic ratio (CTR) has been obtained from the shadow of the heart represented in a still image obtained by X-ray imaging. Further, a method for automatically calculating a cardiothoracic ratio (CTR) based on an X-ray still image has been proposed (for example, Patent Document 1).

JP 2002-109550 A

  However, in the method for obtaining the cardiothoracic ratio (CTR) from the X-ray still image, since the movement due to the heartbeat is not taken into consideration, only the cardiothoracic ratio (CTR) at the time of X-ray imaging is calculated. Is done. Therefore, when X-ray imaging is performed when the heart is in a contracted state and an X-ray image representing the contracted heart is obtained, a cardiothoracic ratio (CTR) in the contracted state is obtained. . In this case, since the heart represented in the X-ray image is in a contracted state, if diagnosis is performed using the cardiothoracic ratio (CTR) obtained from the X-ray image, symptoms such as cardiac hypertrophy are appropriately diagnosed. There was a risk of not being able to.

  An object of the present invention is to solve the above-described problems, and to provide an X-ray imaging apparatus capable of providing information suitable for heart diagnosis as compared with the prior art.

  According to the first aspect of the present invention, the X-ray generation unit that emits X-rays and the X-rays that are disposed at a position facing the X-ray generation unit with a subject interposed therebetween are irradiated from the X-ray generation unit. X-ray detection means for detecting the X-ray, X-ray image generation means for generating X-ray image data based on the X-rays detected by the X-ray detection means, and a plurality of times within a predetermined period in the X-ray generation means, Based on each of the control means for generating X-ray image data of a plurality of frames by the X-ray image generation means by irradiating X-rays and the X-ray image data of the plurality of frames, the object Image processing means for obtaining a cardiothoracic ratio, which is a ratio between the lung width and the heart width, for each frame; and display control means for displaying information representing temporal changes in the cardiothoracic ratio on the display means. X-ray imaging device .

  According to the present invention, it is possible to provide cardiothoracic ratios at a plurality of time points by acquiring X-ray image data of a plurality of frames and obtaining a cardiothoracic ratio for each frame. This makes it possible to perform diagnosis while comparing cardiothoracic ratios at a plurality of time points. Thus, according to the present invention, it is possible to provide information that is more suitable for heart diagnosis than before.

1 is a block diagram showing an X-ray imaging apparatus according to an embodiment of the present invention. It is a schematic diagram which shows the outline of a lung. It is a graph which shows the change of the cardiothoracic ratio (CTR) with respect to time.

  An X-ray imaging apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing an X-ray imaging apparatus according to an embodiment of the present invention.

  The X-ray imaging apparatus according to this embodiment includes an image acquisition unit 1, a storage unit 2, a subject information acquisition unit 3, an image processing unit 4, a display control unit 5, a user interface (UI) 6, A main control unit 7 and a high voltage control unit 8 are provided.

(Image acquisition unit 1)
The image acquisition unit 1 includes a high voltage generation unit 11, an X-ray generation unit 12, a standing imaging device 13, a standing plane detector 14, a supine imaging device 15, and a supine plane detector 16. And an X-ray image generation unit 17. The X-ray generator 12 includes an X-ray tube (not shown) that generates X-rays and an X-ray diaphragm (not shown) that forms an X-ray irradiation field. A high voltage generator 11 is connected to the X-ray generator 12. Under the control of the high voltage control unit 8, the high voltage generation unit 11 applies a tube voltage to the X-ray tube of the X-ray generation unit 12 and supplies a tube current. As a result, X-rays are generated from the X-ray tube of the X-ray generator 12. The standing position imaging device 13 is provided with a standing plane detector 14, and the lying position imaging device 15 is provided with a lying position plane detector 16. The standing plane detector 14 and the lying plane detector 16 are connected to the X-ray image generation unit 17. Image information from the standing plane detector 14 and the lying plane detector 16 is output to the X-ray image generation unit 17. In addition, the arrow shown with the broken line in a figure typically represents the X-ray | X_line to be exposed, and it is according to an operator's instruction | indication with respect to the standing position imaging device 13 and the supine position imaging device 15. Control exposure. The X-ray generator 12 corresponds to an example of the “X-ray generator” of the present invention. Further, the standing plane detector 14 or the lying plane detector 16 corresponds to an example of the “X-ray detection means” of the present invention.

  The main control unit 7 is connected to a user interface (UI) 6. When the operator gives an X-ray irradiation instruction using the user interface 6, the X-ray irradiation instruction is output from the user interface 6 to the main control unit 7. The main control unit 7 continuously generates an X-ray generation trigger signal in accordance with the X-ray irradiation instruction. The high voltage control unit 8 repeatedly applies a pulsed tube voltage to the X-ray tube of the X-ray generation unit 12 from the high voltage generation unit 11 while receiving the X-ray generation trigger signal from the main control unit 7. A control signal for generating That is, the high voltage control unit 8 captures an X-ray irradiation time interval and an X-ray image data collection time interval, a tube voltage value, and a tube current during the period of receiving the X-ray generation trigger signal. A control signal including a value is generated. The high voltage generator 11 applies a tube voltage to the X-ray tube of the X-ray generator 12 according to the imaging rate indicated by the control signal output from the high voltage controller 8. As a result, the X-ray generator 12 emits X-rays at a constant cycle according to the imaging rate, and a plurality of frames of X-ray image data are generated. The operator can change the photographing rate, the tube voltage value, and the tube current value by using the operation unit 62.

  The main control unit 7 determines the timing of X-ray irradiation by the X-ray generation unit 12 according to an electrocardiogram waveform output from an electrocardiograph 31 described later or a signal indicating a respiratory state output from a respiratory detector 32 described later. May be controlled.

  X-rays that have passed through the subject are detected by the standing plane detector 14 or the lying plane detector 16. The main control unit 7 controls the standing plane detector 14 or the lying plane detector 16 and the X-ray image generation unit 17 in synchronization with the generation of X-rays. The X-ray image generation unit 17 generates X-ray image data of one frame for one X-ray irradiation in synchronization with the X-ray irradiation by the X-ray generation unit 12. The X-ray image generation unit 17 outputs the X-ray image data to the storage unit 2. The X-ray image generation unit 17 corresponds to an example of “X-ray image generation means” of the present invention.

  In this embodiment, X-ray image data on the chest is acquired by imaging the chest of the subject using an X-ray imaging apparatus as an example. For example, the image acquisition unit 1 generates X-ray image data of a plurality of frames on the chest of the subject by performing X-ray irradiation a plurality of times in accordance with the X-ray irradiation control by the main control unit 7. Then, the image acquisition unit 1 outputs X-ray image data of a plurality of frames in the chest to the storage unit 2.

  For example, when the operator uses the operation unit 62 to specify the length of time for shooting (hereinafter referred to as “shooting period”), information indicating the shooting period is displayed from the user interface (UI) 6 to the main control unit 7. Is output. The main control unit 7 causes the X-ray generation unit 12 to irradiate X-rays according to the imaging rate during the designated imaging period. Thereby, the image acquisition unit 1 generates X-ray image data of a plurality of frames in the imaging period by irradiating X-rays at a constant time interval according to the imaging rate during the imaging period designated by the operator. The main control unit 7 corresponds to an example of “control means” of the present invention.

  Further, the operator may specify the number of times of shooting using the operation unit 62. In this case, the image acquisition unit 1 generates X-ray image data of a plurality of frames by irradiating X-rays a specified number of times at a constant time interval according to the imaging rate.

(Storage unit 2)
The storage unit 2 stores the X-ray image data output from the X-ray image generation unit 17. In this embodiment, X-ray image data on the chest of the subject is stored in the storage unit 2.

(Subject information acquisition unit 3)
The subject information acquisition unit 3 includes an electrocardiograph 31 and a respiration detector 32. Note that the subject information acquisition unit 3 may include only the electrocardiograph 31 or may include only the respiration detector 32.

  The electrocardiograph 31 acquires an electrocardiographic waveform (ECG signal) of the subject and outputs the electrocardiographic waveform to the main control unit 7 and the display control unit 5. As the electrocardiograph 31, a known electrocardiograph can be used. The respiratory detector 32 acquires a signal indicating the respiratory state of the subject and outputs a signal indicating the respiratory state to the main control unit 7 and the display control unit 5. A known respiratory detector can be used as the respiratory detector 32. For example, the respiration detector 32 includes a sensor such as a thermistor or an acceleration sensor, and acquires a signal indicating the respiration state of the subject by detecting a change in temperature or pressure due to a nasal airflow or mouth airflow. For example, a time change in pressure due to a nasal airflow or mouth airflow corresponds to a signal indicating a respiratory state. A signal indicating an electrocardiogram waveform or a respiratory state is an example of subject information.

(Image processing unit 4)
The image processing unit 4 includes a contour extraction unit 41, a width calculation unit 42, and a cardiothoracic ratio calculation unit 43.

(Outline extraction unit 41)
The contour extraction unit 41 reads out X-ray image data of the chest from the storage unit 2 and identifies the lung contour represented in the X-ray image data. For example, the contour extraction unit 41 specifies the position of the lung contour represented in the X-ray image data based on the pixel value (luminance value) of the X-ray image data. In this embodiment, the image acquisition unit 1 acquires a plurality of frames of X-ray image data, and the storage unit 2 stores a plurality of frames of X-ray image data. The contour extraction unit 41 reads X-ray image data of a plurality of frames from the storage unit 2 and specifies the position of the lung contour represented in the X-ray image data of each frame. That is, the contour extraction unit 41 specifies the position of the lung contour in each frame.

  The width calculation unit 42 obtains a lung width (lung width) and a heart width (heart width) based on the lung contour specified by the contour extraction unit 41. In this embodiment, since the contour of the lung in each frame is specified by the contour extraction unit 41, the width calculation unit 42 obtains the lung width and the heart width in each frame based on the lung contour in each frame.

  Here, the lung width and the heart width will be described with reference to FIG. FIG. 2 is a schematic diagram showing an outline of a lung. Contours Pa and Pb shown in FIG. 2 are contours of the lung specified by the contour extraction unit 41. As an example, the width calculation unit 42 determines the lung width and the heart width based on the contours Pa and Pb of the lung shown in FIG.

  The heart width is defined as a length D1 between a contour position a inside one contour Pa and a contour position b inside the other contour Pb. That is, the lateral width of the inner space surrounded by the lung contour Pa and the contour Pb corresponds to the heart width. The lung width is defined as a length D2 between a contour position c outside one contour Pa and a contour position d outside the other contour Pb. In other words, the horizontal width of the contour combining the lung contour Pa and the contour Pb corresponds to the lung width.

  For example, the operator may use the operation unit 62 to specify a location where the heart width is measured and a location where the lung width is measured. In the example shown in FIG. 2, the reference line L1 is a reference line for designating a location where the heart width D1 is measured. Further, the reference line L2 is a reference line for designating a location where the lung width D2 is measured. The reference line L1 and the reference line L2 are lines that penetrate the lung contour Pa and the contour Pb in the lateral direction. The intersection between the reference line L1 and the contour Pa corresponds to the contour position a, and the intersection between the reference line L1 and the contour Pb corresponds to the contour position b. Further, the intersection of the reference line L2 and the contour Pa corresponds to the contour position c, and the intersection of the reference line L2 and the contour Pb corresponds to the contour position d. That is, the contour position inside the contours Pa and Pb is designated by the reference line L1, and the contour position outside the contours Pa and Pb is designated by the reference line L2. The operator can designate a position where the heart width is measured by designating the position of the reference line L1 using the operation unit 62. In addition, the operator can designate the position where the lung width is measured by designating the position of the reference line L2 using the operation unit 62.

  The contour position a in the contour Pa may be defined as the innermost contour position in the contour Pa. The contour position c in the contour Pa may be defined as the outermost contour position in the contour Pa. Similarly, the contour position b in the contour Pb may be defined as the innermost contour position in the contour Pb. The contour position d in the contour Pb may be defined as the outermost contour position in the contour Pb.

  Here, a case where the operator designates a location where the heart width is measured and a location where the lung width is measured will be described. In this case, when the contour extraction unit 41 specifies the contour of the lung based on the X-ray image data, the contour extraction unit 41 outputs contour image data representing the contour of the lung to the display control unit 5. The display control unit 5 causes the display unit 61 to display the lung contour Pa and the contour Pb based on the contour image data. In addition, the display control unit 5 causes the display unit 61 to display the reference line L1 and the reference line L2 so as to overlap the contour Pa and the contour Pb. The display control unit 5 stores in advance image data representing the reference line L1 and image data representing the reference line L2. The display control unit 5 causes the display unit 61 to display the reference line L1 and the reference line L2 on the contour Pa and the contour Pb based on the image data.

  The operator refers to the contour of the lung displayed on the display unit 61 and uses the operation unit 62 to designate a location where the heart width is measured and a location where the lung width is measured. Specifically, the operator designates a position where the heart width is measured by designating the position of the reference line L1 using the operation unit 62. Further, the operator designates a position where the lung width is measured by designating the position of the reference line L2 using the operation unit 62. When the position of the reference line L1 and the position of the reference line L2 are specified by the operator, coordinate information indicating the position of the reference line L1 and coordinate information indicating the position of the reference line L2 are displayed in the user interface (UI) 6. To the width calculation unit 42 via the display control unit 5.

  The width calculation unit 42 receives the coordinate information of the reference line L1, determines the position of the intersection between the contour Pa and the reference line L1, and determines the position of the intersection between the contour Pb and the reference line L1. That is, the width calculation unit 42 obtains the contour position a that is the intersection of the contour Pa and the reference line L1, and obtains the contour position b that is the intersection of the contour Pb and the reference line L1. Although there are two intersections between the contour Pa and the reference line L1, the width calculation unit 42 obtains the position of the intersection inside the contour Pa as the contour position a among the two intersections. Similarly, although there are two intersections between the contour Pb and the reference line L2, the width calculation unit 42 obtains the position of the intersection inside the contour Pb as the contour position b among the two intersections. For example, the width calculation unit 42 defines a virtual line T serving as a reference between the contour Pa and the contour Pb. The width calculation unit 42 obtains, as the contour position a, the position of the intersection that is close to the virtual line T among the two intersections where the contour Pa and the reference line L1 intersect. Similarly, the width calculation unit 42 obtains, as the contour position b, the position of the intersection that is close to the virtual line T among the two intersections where the contour Pb and the reference line L1 intersect.

  Further, the width calculation unit 42 receives the coordinate information of the reference line L2, obtains the position of the intersection between the contour Pa and the reference line L2, and obtains the position of the intersection between the contour Pb and the reference line L2. That is, the width calculation unit 42 obtains a contour position c that is an intersection of the contour Pa and the reference line L2, and obtains a contour position d that is an intersection of the contour Pb and the reference line L2. Although there are two intersections between the contour Pa and the reference line L2, the width calculation unit 42 obtains the position of the intersection outside the contour Pa as the contour position c among the two intersections. Similarly, there are two intersections between the contour Pb and the reference line L2, but the width calculation unit 42 obtains the position of the intersection outside the contour Pb as the contour position d among the two intersections. For example, the width calculation unit 42 obtains, as the contour position c, the position of the intersection far from the virtual line T among the two intersections where the contour Pa and the reference line L2 intersect. Similarly, the width calculation unit 42 obtains, as the contour position d, the position of the intersection far from the virtual line T among the two intersections where the contour Pb and the reference line L2 intersect.

  Then, the width calculating unit 42 obtains the distance D1 between the contour position a and the contour position b as the heart width, and obtains the distance D2 between the contour position c and the contour position d as the lung width.

  The width calculation unit 42 determines the heart width and the lung width in each frame based on the contour Pa and the contour Pb in each frame. For example, when the reference line L1 and the reference line L2 are designated by the operator, the width calculation unit 42 determines the heart in each frame based on the contour Pa and the contour Pb in each frame and the reference line L1 and the reference line L2. The width D1 and the lung width D2 are obtained.

  Note that the operator may designate the reference line L1 and the reference line L2 for each frame using the operation unit 62. In this case, the width calculation unit 42 obtains the heart width D1 and the lung width D2 in each frame using the reference line L1 and the reference line L2 designated for each frame.

  Alternatively, once the reference line L1 and the reference line L2 are designated by the operator, the width calculating unit 42 uses the once designated reference line L1 and the reference line L2, and uses the heart width D1 and the lung width in each frame. D2 may be obtained. In this case, the width calculation unit 42 obtains the heart width D1 and the lung width D2 in each frame using the same reference line L1 and reference line L2.

  The width calculation unit 42 outputs the value of the heart width D1 and the value of the lung width D2 in each frame to the cardiothoracic ratio calculation unit 43.

The cardiothoracic ratio calculation unit 43 receives the value of the heart width D1 and the value of the lung width D2 from the width calculation unit 42, and obtains a cardiothoracic ratio (CTR) that is a ratio of the heart width D1 and the lung width D2. The cardiothoracic ratio (CTR) is obtained by the following equation.
CTR (%) = (heart width D1 / lung width D2) × 100
The cardiothoracic ratio calculating unit 43 receives the value of the heart width D1 and the value of the lung width D2 in each frame from the width calculating unit 42, and calculates the cardiothoracic ratio in each frame according to the above formula.
The cardiothoracic ratio calculation unit 43 outputs the cardiothoracic ratio in each frame to the display control unit 5.
The image processing unit 4 corresponds to an example of “image processing means” of the present invention.

(Display control unit 5)
The display control unit 5 includes a graph creation unit 51. The display control unit 5 reads X-ray image data from the storage unit 2 and causes the display unit 61 to display an X-ray image based on the X-ray image data. Further, the display control unit 5 receives the cardiothoracic ratio from the cardiothoracic ratio calculating unit 43 and causes the display unit 61 to display the cardiothoracic ratio. The display control unit 5 corresponds to an example of “display control means” of the present invention.

  The display control unit 5 may display an X-ray image on the display unit 61 as a still image, or may display a moving image on the display unit 61 using a plurality of X-ray images. For example, when the operator designates X-ray image data of a desired frame using the operation unit 62, the display control unit 5 reads the X-ray image data of the frame designated by the operator from the storage unit 2, and An X-ray image based on the X-ray image data is displayed on the display unit 61 as a still image. When the operator designates a desired period using the operation unit 62, the display control unit 5 reads X-ray image data of a plurality of frames acquired during the designated period from the storage unit 2, and reads each frame. X-ray images based on the X-ray image data are displayed on the display unit 61 in time order. Thereby, a plurality of X-ray images are displayed on the display unit 61 as moving images.

(Graph creation unit 51)
Based on the cardiothoracic ratio in each frame output from the cardiothoracic ratio calculating unit 43 of the image processing unit 4, the graph creating unit 51 creates a graph showing the change in the cardiothoracic ratio with respect to time. The display control unit 5 causes the display unit 61 to display a graph indicating changes in the cardiothoracic ratio.

  Further, the display control unit 5 may cause the display unit 61 to display the value of the heart width D1 and the value of the lung width D2 in each frame. In this case, the width calculation unit 42 outputs the value of the heart width D1 and the value of the lung width D2 in each frame to the display control unit 5. Based on the output from the width calculation unit 42, the graph creation unit 51 creates a graph showing a change in the heart width D1 with respect to time and a graph showing a change in the lung width D2 with respect to time. The display control unit 5 causes the display unit 61 to display a graph indicating changes in the heart width D1 and a graph indicating changes in the lung width D2.

  An example of each graph is shown in FIG. FIG. 3 is a graph showing changes in the cardiothoracic ratio (CTR) with respect to time. The horizontal axis represents time, one vertical axis represents the cardiothoracic ratio (CTR), and the other vertical axis represents the width (cm) of the heart and lungs. Graph 100 shows the change in cardiothoracic ratio (CTR) over time. The graph 200 shows the change of the lung width D2 with respect to time. The graph 300 shows the change of the heart width D1 with respect to time. The display control unit 5 may display only the graph 100 indicating the change of the cardiothoracic ratio on the display unit 61, or may display the graph 100, the graph 200, and the graph 300 on the display unit 61 at the same time.

(Display of ECG waveform, etc.)
The display control unit 5 may receive the electrocardiogram waveform from the electrocardiograph 31 and cause the display unit 61 to display the electrocardiogram waveform. The display control unit 5 may receive a signal indicating the respiratory state from the respiratory detector 32 and cause the display unit 61 to display a waveform indicating the respiratory state. The display control unit 5 may display the electrocardiogram waveform and the waveform indicating the respiratory state on the display unit 61 at the same time, or may display one of the waveforms on the display unit 61.

  The display control unit 5 may display the graph 100 indicating the change of the cardiothoracic ratio and the electrocardiographic waveform on the display unit 61 at the same time, or display the graph 100 and the waveform indicating the respiratory state on the display unit 61 at the same time. You may let them. Further, the display control unit 5 may cause the display unit 61 to simultaneously display the graph 100, the electrocardiogram waveform, and the waveform indicating the respiratory state. The display control unit 5 may cause the display unit 61 to simultaneously display the graphs 100 to 300, the electrocardiogram waveform, and the waveform indicating the respiratory state. The operator may use the operation unit 62 to specify a graph to be displayed or an electrocardiogram waveform. In this case, the display control unit 5 receives an operator's instruction from the user interface (UI) 6 and causes the display unit 61 to display a graph, an electrocardiogram waveform, or the like designated by the operator.

(Display of maximum value)
The display control unit 5 may specify the maximum value of the cardiothoracic ratio (CTR) in each frame and display the maximum value on the display unit 61. For example, as illustrated in FIG. 3, the display control unit 5 specifies the maximum value 110 of the graph 100 and causes the display unit 61 to display the maximum value 110. Further, the display control unit 5 reads out the X-ray image data acquired when the cardiothoracic ratio becomes the maximum value from the storage unit 2 and causes the display unit 61 to display the X-ray image based on the X-ray image data. May be. For example, the display control unit 5 causes the display unit 61 to simultaneously display the maximum value of the cardiothoracic ratio and the X-ray image acquired when the cardiothoracic ratio reaches the maximum value. Further, the display control unit 5 may cause the display unit 61 to display the heart width D1 and the lung width D2 at the time when the cardiothoracic ratio becomes the maximum value.

  As described above, it is possible to display cardiothoracic ratios at a plurality of time points by acquiring X-ray image data of a plurality of frames and obtaining a cardiothoracic ratio in each frame. That is, the cardiothoracic ratio in various states can be displayed. This makes it possible to make a comprehensive diagnosis by comparing cardiothoracic ratios in various states. Further, obtaining the maximum value of the cardiothoracic ratio has the effect of reducing the possibility of overlooking symptoms such as cardiac hypertrophy.

(Photographing based on subject information)
The main control unit 7 may control the timing of X-ray irradiation by the X-ray generation unit 12 based on the subject information acquired by the subject information acquisition unit 3. For example, the main control unit 7 receives an electrocardiogram waveform from the electrocardiograph 31 and controls the timing of X-ray irradiation by the X-ray generation unit 12 according to the electrocardiogram waveform. Alternatively, the main control unit 7 receives a signal indicating the respiratory state from the respiratory detector 32, and controls the timing of X-ray irradiation by the X-ray generation unit 12 according to the signal indicating the respiratory state. Hereinafter, a specific example of timing control of X-ray irradiation will be described.

(Timing control of X-ray irradiation based on heart rate)
For example, the main control unit 7 may control the timing of X-ray irradiation according to the heart rate of the subject. That is, the main control unit 7 causes the X-ray generation unit 12 to irradiate X-rays during an arbitrary number of heartbeats according to the electrocardiogram waveform. For example, when the operator designates a heart rate for irradiating X-rays using the operation unit 62, information indicating the designated heart rate is output from the user interface (UI) 6 to the main control unit 7. Based on the electrocardiographic waveform, the main control unit 7 causes the X-ray generation unit 12 to irradiate X-rays at a constant time interval according to the imaging rate during a period corresponding to the heart rate specified by the operator. For example, the main control unit 7 counts the heart rate with a counter, and causes the X-ray generation unit 12 to emit X-rays at a constant time interval during a period corresponding to the designated heart rate. As a result, the image acquisition unit 1 emits X-rays at a constant time interval according to the imaging rate during a period corresponding to the heart rate specified by the operator, so that X-ray image data of a plurality of frames in the period can be obtained. Generate. The image processing unit 4 obtains the heart width D1 and the lung width D2 in each frame, and further obtains the cardiothoracic ratio in each frame. That is, the image processing unit 4 obtains a cardiothoracic ratio at each time point included in a period corresponding to the designated heart rate. Then, the display control unit 5 creates a graph indicating a change in the cardiothoracic ratio with respect to time, and causes the display unit 61 to display the graph. Thereby, a graph of the cardiothoracic ratio in a period corresponding to the designated heart rate is displayed on the display unit 61. Further, the display control unit 5 may obtain the maximum value of the cardiothoracic ratio in a period corresponding to the designated heart rate, and display the maximum value on the display unit 61.

  For example, when the operator designates one heartbeat using the operation unit 62, information indicating one heartbeat is output from the user interface (UI) 6 to the main control unit 7. The main control unit 7 counts one heartbeat based on the electrocardiogram waveform, and causes the X-ray generation unit 12 to irradiate X-rays at a constant time interval according to the imaging rate during a period corresponding to the one heartbeat. Thereby, the image acquisition unit 1 generates X-ray image data of a plurality of frames in a period corresponding to one heartbeat by irradiating X-rays at a constant time interval according to the imaging rate during a period corresponding to one heartbeat. . Then, the image processing unit 4 obtains a cardiothoracic ratio at each time point included in a period corresponding to one heartbeat. The display control unit 5 creates a graph of the cardiothoracic ratio in a period corresponding to one heartbeat, and causes the display unit 61 to display the graph. Further, the display control unit 5 may obtain the maximum value of the cardiothoracic ratio during a period corresponding to one heartbeat and display the maximum value on the display unit 61.

(X-ray irradiation in the diastole of the heart)
Further, the main control unit 7 may cause the X-ray generation unit 12 to emit X-rays during the diastole or systole of the heart. For example, the operator uses the operation unit 62 to designate the diastole of the heart as a period for obtaining the cardiothoracic ratio. Information indicating the expansion period is output from the user interface (UI) 6 to the main control unit 7. The main control unit 7 specifies the diastole of the heart based on the electrocardiogram waveform, and causes the X-ray generation unit 12 to emit X-rays at a constant time interval according to the imaging rate during the diastole. As a method for specifying the diastole, a conventional method can be used. Thereby, the image acquisition unit 1 generates X-ray image data of a plurality of frames in the diastole by irradiating X-rays at a constant time interval according to the imaging rate during the diastole. The image processing unit 4 obtains a cardiothoracic ratio at each time point included in the diastole. Then, the display control unit 5 creates a graph showing the change of the cardiothoracic ratio in the diastole, and displays the graph on the display unit 61. Thereby, a graph of the cardiothoracic ratio in the diastole is displayed on the display unit 61. Further, the display control unit 5 may obtain the maximum value of the cardiothoracic ratio in the diastole and display the maximum value on the display unit 61.

  As described above, it is possible to provide information suitable for diagnosis of cardiac hypertrophy, hypertrophic cardiomyopathy, etc. by performing imaging in the diastole of the heart and displaying the cardiothoracic ratio in the diastole.

  The operator may use the operation unit 62 to specify the systole of the heart as a period for obtaining the cardiothoracic ratio. In this case, the image acquisition unit 1 acquires X-ray image data of a plurality of frames in the systole. The image processing unit 4 obtains a cardiothoracic ratio at each time point included in the systole. Then, the display control unit 5 creates a graph of the cardiothoracic ratio in the systole and causes the display unit 61 to display the graph. The display control unit 5 may obtain the maximum value of the cardiothoracic ratio in the systole and display the maximum value on the display unit 61.

(Timing control of X-ray irradiation based on respiratory rate)
The main control unit 7 may control the timing of X-ray irradiation according to the breathing state of the subject. That is, the main control unit 7 causes the X-ray generation unit 12 to irradiate X-rays during an arbitrary number of breaths in accordance with a signal indicating the breathing state. For example, when the operator designates the respiration rate for irradiating X-rays using the operation unit 62, information indicating the designated respiration rate is output from the user interface (UI) 6 to the main control unit 7. The main control unit 7 causes the X-ray generation unit 12 to irradiate X-rays at a constant time interval according to the imaging rate during a period corresponding to the respiration rate designated by the operator based on a signal indicating the breathing state. For example, the main control unit 7 counts the respiration rate with a counter, and causes the X-ray generation unit 12 to irradiate X-rays at regular time intervals during a period corresponding to the designated respiration rate. As an example, the main control unit 7 counts the number of breaths by a counter based on a signal indicating a breathing state (as an example, a temporal change in pressure due to a nasal airflow or a mouth airflow). As a result, the image acquisition unit 1 emits X-rays at a certain time interval according to the imaging rate during a period corresponding to the respiration rate specified by the operator, so that a plurality of frames of X-ray image data in that period can be obtained. Generate. The image processing unit 4 obtains the heart width D1 and the lung width D2 in each frame, and further obtains the cardiothoracic ratio in each frame. That is, the image processing unit 4 obtains a cardiothoracic ratio at each time point included in a period corresponding to the designated respiration rate. Then, the display control unit 5 creates a graph indicating a change in the cardiothoracic ratio with respect to time, and causes the display unit 61 to display the graph. As a result, a graph of the cardiothoracic ratio in a period corresponding to the designated respiration rate is displayed on the display unit 61. In addition, the display control unit 5 may obtain the maximum value of the cardiothoracic ratio during a period corresponding to the designated respiration rate and display the maximum value on the display unit 61.

  For example, when the operator designates one breath using the operation unit 62, information indicating one breath is output from the user interface (UI) 6 to the main control unit 7. The main control unit 7 counts one breath based on the signal indicating the breathing state, and causes the X-ray generation unit 12 to emit X-rays at a constant time interval according to the imaging rate during a period corresponding to the one breath. Thereby, the image acquisition unit 1 generates X-ray image data of a plurality of frames in a period corresponding to one breath by irradiating X-rays at a constant time interval according to the imaging rate during a period corresponding to one breath. . And the image acquisition part 1 calculates | requires the cardiothoracic ratio in each time point included in the period corresponded to 1 respiration. The display control unit 5 creates a graph of the cardiothoracic ratio in a period corresponding to one breath and causes the display unit 61 to display the graph. Further, the display control unit 5 may obtain a maximum value of the cardiothoracic ratio in a period corresponding to one breath and display the maximum value on the display unit 61.

(X-ray irradiation during the inspiration period of breathing)
Further, the main control unit 7 may cause the X-ray generation unit 12 to irradiate X-rays during the inspiration period or expiration period of breathing of the subject. The inspiration period is a period during which the subject inhales air. The expiration period is a period during which the subject exhales air. For example, the operator uses the operation unit 62 to designate a breathing inspiration period as a period for obtaining a cardiothoracic ratio. Information indicating the intake period is output from the user interface (UI) 6 to the main control unit 7. The main control unit 7 specifies an inspiration period based on a signal indicating a breathing state, and causes the X-ray generation unit 12 to irradiate X-rays at a constant time interval according to an imaging rate during the inspiration period. For example, the main control unit 7 specifies an inspiration period based on a signal indicating a respiration signal (for example, a temporal change in pressure due to a nasal airflow or a mouth airflow), and during the inspiration period, the main control unit 7 X-rays are irradiated at regular time intervals. Thereby, the image acquisition unit 1 obtains the cardiothoracic ratio at each time point included in the inspiration period by irradiating X-rays at a constant time interval according to the imaging rate during the inspiration period. Then, the display control unit 5 creates a graph indicating the change in the cardiothoracic ratio during the inspiration period, and causes the display unit 61 to display the graph. As a result, a graph of the cardiothoracic ratio during the inspiration period is displayed on the display unit 61. The display control unit 5 may obtain the maximum value of the cardiothoracic ratio during the inspiration period and display the maximum value on the display unit 61.

  As described above, it is possible to provide information suitable for diagnosis of cardiac hypertrophy, hypertrophic cardiomyopathy, etc. by performing imaging during the inspiratory period and displaying the cardiothoracic ratio during the inspiratory period. The display control unit 5 may obtain the maximum value of the cardiothoracic ratio during the expiration period and display the maximum value on the display unit 61.

  In addition, the operator may use the operation unit 62 to designate a breathing expiration period as a period for obtaining the cardiothoracic ratio. In this case, the image acquisition unit 1 acquires X-ray image data of a plurality of frames in the expiration period. The image processing unit 4 obtains a cardiothoracic ratio at each time point included in the expiration period. Then, the display control unit 5 creates a graph of the cardiothoracic ratio in the expiration period and causes the display unit 61 to display the graph.

(User interface 6)
The user interface (UI) 6 includes a display unit 61 and an operation unit 62. The display unit 61 includes a monitor such as a CRT or a liquid crystal display, and displays an X-ray image and a cardiothoracic ratio. The operation unit 62 includes a pointing device such as a joystick or a trackball, a switch, various buttons, or a keyboard. The operator can use the operation unit 62 to specify a shooting period and a shooting rate.

  Note that the image processing unit 4, the display control unit 5, and the main control unit 7 may be configured by a CPU (not shown) and a storage device (not shown) such as a ROM and a RAM as an example. The storage device includes an image processing program for executing the function of the image processing unit 4, a display control program for executing the function of the display control unit 5, and a main control program for executing the function of the main control unit 7. Is remembered. Further, the image processing program executes a contour extraction program for executing the function of the contour extraction unit 41, a width calculation program for executing the function of the width calculation unit 42, and a function of the cardiothoracic ratio calculation unit 43. A cardiothoracic calculation program is included. The display control program includes a graph creation program for executing the function of the graph creation unit 51. Then, the function of each unit is executed by the CPU executing each program.

(Operation)
Next, an example of the operation by the X-ray imaging apparatus having the above configuration will be described.

(Step S01)
First, the operator designates a shooting period using the operation unit 62. The operator may specify a desired heart rate as an imaging period, or may specify a desired respiration rate. Alternatively, the operator may specify the diastole or systole of the heart, or may specify the breathing inspiration period or expiration period. Alternatively, the operator may set an arbitrary length of time as the shooting period.

  When the shooting period is designated by the operator, information indicating the shooting period is output from the user interface (UI) 6 to the main control unit 7.

(Step S02)
The main control unit 7 causes the X-ray generation unit 12 to emit X-rays according to the imaging rate during the imaging period designated by the operator. Accordingly, the image acquisition unit 1 generates X-ray image data of a plurality of frames in the imaging period by irradiating X-rays at a constant time interval according to the imaging rate during the imaging period.

  For example, when the cardiac diastole is designated by the operator, the main control unit 7 specifies the cardiac diastole based on the electrocardiographic waveform acquired by the electrocardiograph 31, and the imaging rate is set during the diastole. Accordingly, the X-ray generator 12 is irradiated with X-rays at regular time intervals. Thereby, the image acquisition unit 1 generates X-ray image data of a plurality of frames in the diastole by irradiating X-rays at a constant time interval during the diastole. When the systole of the heart is designated by the operator, the image acquisition unit 1 generates X-ray image data of a plurality of frames in the systole by photographing during the systole.

  When the breathing inspiration period is designated by the operator, the main control unit 7 performs the breathing inspiration based on the signal indicating the breathing state acquired by the breathing detector 32 (for example, time change in pressure). The period is specified, and the X-ray generation unit 12 is irradiated with X-rays at regular time intervals according to the imaging rate during the inspiration period. Thereby, the image acquisition unit 1 generates X-ray image data of a plurality of frames in the inhalation period by irradiating X-rays at a constant time interval during the inhalation period. When the expiration period of breathing is designated by the operator, the image acquisition unit 1 generates X-ray image data of a plurality of frames in the expiration period by capturing images during the expiration period.

(Step S03)
The X-ray image data of a plurality of frames acquired in step S02 is stored in the storage unit 2. The contour extraction unit 41 of the image processing unit 4 reads X-ray image data of a plurality of frames from the storage unit 2 and specifies the lung contour in each frame. The width calculation unit 42 obtains the heart width D1 and the lung width D2 in each frame based on the contour in each frame. Then, the cardiothoracic ratio calculation unit 43 obtains a cardiothoracic ratio (CTR) in each frame based on the heart width D1 and the lung width D2 in each frame.

  As an example, when a plurality of frames of X-ray image data in the diastole of the heart are acquired, the image processing unit 4 obtains the cardiothoracic ratio at each time point included in the diastole. As another example, when a plurality of frames of X-ray image data are acquired during the inspiration period of respiration, the image processing unit 4 obtains a cardiothoracic ratio at each time point included in the inspiration period.

(Step S04)
When the cardiothoracic ratio in each frame is obtained in step S03, the display control unit 5 causes the display unit 61 to display the cardiothoracic ratio. Specifically, the graph creation unit 51 of the display control unit 5 creates a graph indicating the change of the cardiothoracic ratio with respect to time based on the cardiothoracic ratio in each frame, and causes the display unit 61 to display the graph. For example, as shown in FIG. 3, the display control unit 5 causes the display unit 61 to display a graph 100 indicating changes in the cardiothoracic ratio with respect to time. The display control unit 5 may specify the maximum value of the cardiothoracic ratio in each frame and display the maximum value on the display unit 61.

  As an example, when the cardiothoracic ratio in the diastole of the heart is obtained, the display control unit 5 creates a graph showing the change in the cardiothoracic ratio in the diastole and displays the graph on the display unit 61. Further, the display control unit 5 may specify the maximum value of the cardiothoracic ratio in the diastole and display the maximum value on the display unit 61. As another example, when the cardiothoracic ratio in the inspiratory period of breathing is obtained, the display control unit 5 creates a graph showing the change in the cardiothoracic ratio in the inspiratory period, and displays the graph on the display unit 61. Let Further, the display control unit 5 may specify the maximum value of the cardiothoracic ratio in the inspiratory period and display the maximum value on the display unit 61.

  Further, the display control unit 5 may create a graph of the heart width D1 and a graph of the lung width D2 and display these graphs on the display unit 61. Further, the display control unit 5 may cause the display unit 61 to display a signal indicating an electrocardiogram waveform or a respiratory state.

  As described above, it is possible to provide cardiothoracic ratios at a plurality of time points by acquiring X-ray image data of a plurality of frames by performing imaging during the imaging period and obtaining cardiothoracic ratios in the plurality of frames. It becomes. This makes it possible to make a comprehensive diagnosis with reference to cardiothoracic ratios in various states. As a result, the possibility of overlooking symptoms such as cardiac hypertrophy can be reduced.

DESCRIPTION OF SYMBOLS 1 Image acquisition part 2 Memory | storage part 3 Subject information acquisition part 4 Image processing part 5 Display control part 6 User interface (UI)
7 Main control unit 8 High voltage control unit 41 Contour extraction unit 42 Width calculation unit 43 Cardiothoracic ratio calculation unit 51 Graph creation unit

Claims (11)

X-ray generation means for irradiating X-rays;
An X-ray detection unit that is disposed at a position facing the X-ray generation unit with a subject interposed therebetween, and detects X-rays emitted from the X-ray generation unit;
X-ray image generation means for generating X-ray image data based on the X-rays detected by the X-ray detection means;
Control means for causing the X-ray image generation means to generate X-ray image data of a plurality of frames by causing the X-ray generation means to emit X-rays a plurality of times within a predetermined period;
Image processing means for determining, for each frame, a cardiothoracic ratio, which is a ratio of the subject's lung width and heart width, based on each of the plurality of frames of X-ray image data;
Display control means for displaying information representing temporal changes in the cardiothoracic ratio on a display means;
An X-ray imaging apparatus comprising:   2. The control unit according to claim 1, wherein the control unit receives the electrocardiogram waveform of the subject and controls the predetermined period in which the X-ray generation unit irradiates the X-ray based on the electrocardiogram waveform. X-ray imaging equipment.   The X-ray imaging apparatus according to claim 2, wherein the control unit specifies a diastole of the heart based on the electrocardiogram waveform and sets the diastole as the predetermined period.   The X-ray imaging apparatus according to claim 2, wherein the display control unit displays the electrocardiographic waveform and the cardiothoracic ratio on the display unit.   The control means receives a signal indicating the breathing state of the subject and controls the predetermined period of time during which the X-ray generation means irradiates the X-ray based on the signal indicating the breathing state. Item 2. The X-ray imaging apparatus according to Item 1.   The X-ray imaging apparatus according to claim 5, wherein the control unit specifies an inspiration period based on a signal indicating the breathing state, and sets the inspiration period as the predetermined period.   The X-ray imaging apparatus according to claim 5, wherein the display control unit displays the respiratory state and the cardiothoracic ratio on the display unit.   The X-ray imaging apparatus according to claim 1, wherein the display control unit displays the cardiothoracic ratio, the lung width, and the heart width on the display unit.   8. The display control unit according to claim 1, wherein the display control unit specifies a maximum value of the cardiothoracic ratio obtained for each frame and causes the display unit to display the maximum value. X-ray imaging apparatus according to the above.   The display control means causes the display means to display a maximum value of the cardiothoracic ratio and an X-ray image based on X-ray image data acquired when the cardiothoracic ratio becomes maximum. The X-ray imaging apparatus according to claim 9.   The display control means causes the display means to display a cardiothoracic ratio obtained based on X-ray image data acquired at a time point designated by an operator. X-ray imaging apparatus described in 1.

Images