Body movement display device, method for operating body movement display device, and image diagnosis system

Abstract

The invention provides a body movement display device, a method for operating the body movement display device, and an image diagnosis system, which can further suppress the movement of the sight line of a subject and enable the subject to favorably recognize the body movement of the subject. A body movement display device (200) is provided with: a processor (210); a projector (230) that displays an image so that the subject can be visually recognized during the examination of the subject by the MRI device (100); and a body movement detection sensor including a first camera (220A) and a second camera (220B) for detecting body movement of the subject, in which the processor (210) generates a rotationally symmetrical first pattern having a fixed center, the size of which changes in accordance with the amplitude of the body movement of the subject detected by the body movement detection sensor, and generates a second pattern that changes in accordance with the amplitude of the body movement of the subject detected by the body movement detection sensor. The generated first pattern is projected as an image by a projector (230) into a scanning hole of an MRI device (100).

Description

TECHNICAL FIELD

[0001] The present application relates to a body motion display device, a method for operating a body motion display device, and an image diagnosis system, and particularly relates to a technology in which a subject can recognize his or her own body motion well. BACKGROUND

[0002] A magnetic resonance imaging device (MRI device) used in image diagnosis is capable of non-invasively acquiring information from a living body, and is therefore widely used in the medical field.

[0003] A 1-time imaging time of an MRI device having such a feature is long, and is easily affected by a subject's movement during data acquisition. The subject's body motion during imaging has an influence on image quality. Therefore, it is necessary to reduce the subject's body motion during data acquisition. In a case where the subject is informed of his or her own body motion, the subject himself or herself will pay attention to the body motion, and thus an effect of reducing the body motion during imaging can be expected.

[0004] As a method for informing a subject of his or her own body motion, a method based on graphics is proposed (Patent Literature 1).

[0005] In the MRI device described in Patent Literature 1, in order to effectively perform breath-synchronized photography, a breath state is displayed in a manner that the subject can visually recognize, and in particular, a depth of breath is displayed by a light emission position of a scale or a light point. Thereby, the subject can adjust his or her own breath state.

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2006-158762

[0007] In the case of the MRI device described in Patent Literature 1, the subject moves his or her line of sight when confirming the light emission position of the scale or the light point indicating the depth of breath, and thus there is a problem in that a possibility that the movement of the line of sight induces movement of the head and movement of other imaging target portions other than the head becomes high. SUMMARY

[0008] The present application has been achieved in view of such a situation, and an object thereof is to provide a body motion display device, a method for operating a body motion display device, and an image diagnosis system, in which a subject can recognize his or her own body motion well and movement of the subject's line of sight is further suppressed.

[0009] The invention involved in the first aspect is a motion display device comprising: a processor; a display for displaying images in a manner that the examinee can visually recognize during an examination of a subject based on an image diagnostic device; and a motion detection sensor for detecting the subject's motion. In this motion display device, the processor generates a first image that is fixed at the center and rotated symmetrically, the size of which changes according to the amplitude of the subject's motion detected by the motion detection sensor, and displays the generated first image as an image on the display.

[0010] According to a first aspect of the present invention, during an examination based on an image diagnostic device, the examinee can confirm their body movement range by observing a rotationally symmetrical first image whose size changes according to their own range of motion and whose center remains fixed. In particular, the center of the first image (the center of rotational symmetry) does not move, thus allowing the examinee to fix their gaze while observing the first image. That is, it can further suppress the examinee's gaze movement and reduce head movement induced by gaze movement, as well as movement of other parts of the imaged object besides the head.

[0011] In the first embodiment of the present invention, the body movement display device according to the second embodiment preferably converts the amplitude of the subject's body movement into the size of the first graphic and generates a first graphic corresponding to the size of the converted first graphic.

[0012] In the second embodiment, the body movement display device according to the third aspect of the present invention preferably converts the amplitude of the subject's body movement into the size of the first graphic using either a linear or non-linear conversion. In the case of a linear conversion, the size of the first graphic changes according to the amplitude of the body movement in a predetermined relationship, thus making the method for displaying the body movement state readily understandable. On the other hand, in the case of a non-linear conversion, for body movement amplitudes where further suppression of body movement is desired, the sensitivity of the first graphic can be increased, prompting the subject to adjust their body movement.

[0013] In the second or third embodiment of the present invention, the conversion of the subject's body movement amplitude to the size of the first graphic is preferably a weighted conversion, which corresponds to the magnitude of the impact of the subject's body movement on the imaging of the image diagnostic device.

[0014] In the fifth aspect of the present invention, the body movement display device, in the fourth aspect, varies the magnitude of the impact of the subject's body movement on the imaging of the image diagnostic device by at least one of the subject's imaging target area, the imaging sequence, and the k-space filling method of the image diagnostic device. When converting the subject's body movement amplitude into the size of the first image, the conversion is performed by assigning weights to the imaging conditions of the imaging target area, the imaging sequence, and the k-space filling method, thereby enabling a conversion that is more suitable for displaying the state of body movement caused by the imaging.

[0015] In any of the first to fifth embodiments of the present invention, the body movement display device preferably has a boundary value set. This boundary value is the boundary value allowed by the image diagnostic device for the range of body movement of the subject, and it indicates the correlation between the size of the first graphic and the first graphic. The processor displays a second graphic on the display with its center aligned with the first graphic. The second graphic has a size corresponding to the boundary value and a shape similar to the first graphic. By displaying the second graphic, which has a size corresponding to the boundary value, on the display, the subject can adjust their body movement so that the movement does not exceed the second graphic. Since the shape of the second graphic is similar to the first graphic and its center is aligned with the first graphic, the subject can visually identify both the first and second graphics simultaneously without moving their gaze.

[0016] In the seventh aspect of the present invention, the body motion display device preferably sets boundary values ​​based on at least one of the subject's image-captured area, the image sequence, and the k-space filling method of the image diagnostic device. When the range of body motion of the subject, as allowed by the image diagnostic device, can change due to image conditions such as the subject's image-captured area, the image sequence, and the k-space filling method, it is preferable to set the boundary values ​​according to the image conditions.

[0017] In the eighth aspect of the present invention, the motion display device preferably displays the first graphic and the second graphic on the display screen differently in at least one of color, line type and brightness in the sixth or seventh aspect.

[0018] In any of the sixth to eighth embodiments of the present invention, the body movement display device according to the ninth embodiment preferably issues a warning when the subject's body movement amplitude exceeds a threshold and approaches or exceeds a boundary value. This further encourages the subject to suppress body movement.

[0019] In the ninth embodiment, the motion display device according to the tenth aspect of the present invention preferably provides a warning by one or more of the following: a warning sound generator, a display, an illumination device in the frame of an image diagnostic device, and a vibration generator.

[0020] In any of the first to tenth embodiments of the present invention, the body motion display device according to the eleventh embodiment preferably includes a body motion detection sensor comprising: a camera that captures images of a subject and outputs an image of the subject; and an image processing unit that processes the image to detect the body motion of the subject. The image processing unit extracts the image object portion of the subject contained in the image based on the image diagnostic device, obtains the movement between consecutive frames of the extracted image object portion as the body motion vector of the image object portion, and detects the amplitude of the body motion of the subject based on the body motion vector.

[0021] In any of the first to eleventh embodiments of the present invention, the shape of the first graphic is preferably circular or a regular polygon.

[0022] The invention involved in the 13th aspect is an image diagnostic system, which includes an image diagnostic device and a motion display device of any one of the 1st to 12th aspects.

[0023] In the 13th embodiment, the image diagnostic system according to the 14th embodiment of the present invention preferably includes a magnetic resonance imaging device or an X-ray CT device.

[0024] The invention involved in the 15th aspect is a method of operating a motion display device, the motion display device comprising: a processor; a display for displaying images in a manner that the examinee can visually recognize during an examination of a subject based on an image diagnostic device; and a motion detection sensor for detecting the body movements of the examinee, the method of operating the motion display device comprising the following steps: the processor acquiring the amplitude of the examinee's body movements from the motion detection sensor; the processor generating a first image that is fixed at its center and rotated symmetrical, the size of the first image changing according to the acquired amplitude of the examinee's body movements; and the processor displaying the generated first image as an image on the display.

[0025] Invention Effects

[0026] According to the present invention, during an examination based on an image diagnostic device, the examinee can observe a rotationally symmetrical first image whose size changes according to the amplitude of their own body movements and whose center is fixed, allowing the examinee to clearly identify their own body movements. In particular, by observing the rotationally symmetrical first image with a fixed center, it is possible to further suppress the examinee's gaze movement and reduce head movements and movements of other parts of the body induced by gaze movement. Attached Figure Description

[0027] Figure 1 This is a perspective view showing the appearance of a magnetic resonance imaging (MRI) device to which the respiratory action display device of the present invention is applicable.

[0028] Figure 2 It means Figure 1 A diagram showing the schematic structure inside an MRI device.

[0029] Figure 3 This is a diagram showing the external structure of the main parts of the motion display device involved in the present invention.

[0030] Figure 4 This is a block diagram illustrating an embodiment of the image diagnostic system according to the present invention.

[0031] Figure 5 This is a diagram showing an example of an image projected by a projector, and in particular, a diagram showing an image composed of a first graphic C1 and a second graphic C2.

[0032] Figure 6 This is an example of a graph showing the relationship between the subject's range of motion and the size of the object (Figure 1).

[0033] Figure 7 This is another example of a graph showing the relationship between the subject's range of motion and the size of the object (Figure 1).

[0034] Figure 8 It is a diagram showing the relationship between the changes in the size of the object (Figure 1) that accompanies the changes in the body movements of the examinee and the changes in the object displayed to the examinee.

[0035] Figure 9 This is a flowchart illustrating an embodiment of the working method of the motion display device according to the present invention.

[0036] Figure 10 It is a diagram that represents a portion of a graphic projected by a projector, especially a diagram that shows a fixed line of sight.

[0037] Figure 11 It is a diagram representing the composite of the first graphic H1 and the second graphic H2.

[0038] Symbol Explanation

[0039] 100-MRI device, 102-Subject, 104-Genius magnet, 106-Inclined magnetic field coil, 108-Transmitting coil, 110-Rack, 112-High-frequency magnetic field generator, 114-Receiver, 116-Inclined magnetic field power supply, 118-Signal processing unit, 120-Scanning aperture, 130-Bed, 130A-Top plate, 140-Receiver coil, 142-Signal cable, 150-Control unit, 160-Operator unit, 170-Display, 200-Motion display device, 210-Processor, 220A-First camera, 220B-Second camera, 222A-Breathing belt, 230-Projector, C1, H1-First image, C2, H2-Second image, Im-Image, M-Mark, S10~S70-Indicates the steps of operating the motion display device. Detailed Implementation

[0040] Hereinafter, preferred embodiments of the motion display device, the working method of the motion display device, and the image diagnostic system related to the present invention will be described with reference to the accompanying drawings.

[0041] Figure 1 This is a perspective view showing the appearance of a magnetic resonance imaging (MRI) device to which the motion display device of the present invention is applicable.

[0042] Figure 1 The MRI apparatus 100 shown includes a frame 110 and a bed 130, the bed 130 having a top plate 130A disposed in front of the cylindrical imaging space, i.e., the scanning aperture 120, provided on the frame 110.

[0043] [Internal structure of an MRI device]

[0044] Figure 2 It means Figure 1 A diagram showing the schematic structure inside an MRI device.

[0045] like Figure 2 As shown, the MRI device 100 includes a static magnetic field generating magnet 104 that generates a uniform static magnetic field in the imaging space where the subject 102 is placed, a gradient magnetic field coil (GC) 106, an RF (Radio Frequency) coil (transmitting coil) 108, a receiving coil 140, a high-frequency magnetic field generator 112, a receiver 114, and a gradient magnetic field power supply 116.

[0046] The tilting magnetic field coil 106 is composed of tilting magnetic field coils in the X, Y, and Z directions, and generates tilting magnetic field pulses in the imaging space based on the signal from the tilting magnetic field power supply 116. The transmitting coil 108 generates a high-frequency magnetic field based on the signal from the high-frequency magnetic field generator 112, which causes the atomic nuclei of the atoms constituting the tissue of the subject 102 to produce nuclear magnetic resonance (NMR) signals.

[0047] The receiving coil 140 detects the NMR signal generated from the subject 102. The detected NMR signal is transmitted to the receiver 114 via the signal cable 142. The A / D conversion is performed by the AD (analog-to-digital) converter located in the receiver 114 to generate measurement data (Raw data).

[0048] Furthermore, the MRI device 100 also includes a signal processing unit 118, a control unit 150, an operation unit 160, and a display 170.

[0049] The signal processing unit 118 performs an inverse Fourier transform on the measurement data generated by the receiver 114 to reconstruct the image, and outputs the reconstructed image signal to the control unit 150 and the display 170.

[0050] In addition, Figure 2 The example described is of the receiving coil 140 being connected to the signal processing unit 118 and the control unit 150 via the signal cable 142. However, the connection between the receiving coil 140 and the signal processing unit 118 and / or the control unit 150 is not limited to wired connection and can also be wireless. As an example of wireless connection, the receiving coil 140 also includes an AD converter and a wireless communication module. Digital data (e.g., measurement data) generated by the receiving coil 140 is wirelessly transmitted to the wireless communication module within the signal processing unit 118 and / or the control unit 150.

[0051] The control unit 150 includes a measurement control unit and an arithmetic unit (not shown), and performs overall control of the device, including the high-frequency magnetic field generator 112, the tilting magnetic field power supply 116, and the display 170. The display 170 displays the reconstructed image and... Figure 3 The images of the subject 102 captured by the first camera 220A and the second camera 220B shown herein function as part of the user interface when the operator inputs various parameters, etc.

[0052] The control unit 150 sends commands to the high-frequency magnetic field generator 112 and the tilting magnetic field power supply 116 according to the subject's camera object location (position or size of a specific area) and camera sequence (examination protocol (camera plan), pulse sequence corresponding to the camera plan) caused by the operator operating the operation unit 160, thereby generating a high-frequency magnetic field and a tilting magnetic field respectively.

[0053] There are multiple k-space filling methods that fill the k-space (Fourier space) with the data required for image reconstruction, but appropriate k-space filling methods are also available. Furthermore, details regarding k-space filling methods will be described later.

[0054] Furthermore, the control unit 150 generates a file in a medical image format from the image signal specified by the operation unit 160 from the image signal processed by the signal processing unit 118, and registers it in an image database (not shown).

[0055] The aforementioned signal processing unit 118 and control unit 150 can be implemented, for example, by a program executed by a computer for calculation or control. The computer has a processor such as a CPU (Central Processing Unit) and a memory that stores control programs and parameters.

[0056] Figure 3 This is a diagram showing the external structure of the main parts of the motion display device according to the present invention. Additionally, in Figure 3 In the middle, to and Figure 1 and Figure 2 Identical parts are marked with the same symbols, and their detailed descriptions are omitted.

[0057] exist Figure 3 In this device, a first camera 220A and a second camera 220B are mounted on the frame 110, which captures images of the subject 102 within the scanning port 120. The first camera 220A and the second camera 220B function as part of a motion detection sensor for detecting the body movements of the subject 102.

[0058] That is, the body movement detection sensor in this example includes: a first camera 220A and a second camera 220B; and an image processing unit that detects the body movement of the subject 102 in the image captured by at least one of the first camera 220A and the second camera 220B.

[0059] The image processing unit extracts the subject area of ​​the subject 102 captured by the MRI device 100 in the image captured by at least one of the first camera 220A and the second camera 220B, obtains the movement between consecutive frames of the extracted subject area as the body motion vector (displacement vector) of the subject area, and detects the subject's body motion amplitude based on the obtained body motion vector.

[0060] Furthermore, when the subject is the chest and / or abdomen, the breathing belts 222A and 222B installed on the chest and / or abdomen of the subject 102 function as part of a body movement detection sensor for detecting the body movement (breathing movements) of the chest and / or abdomen of the subject 102.

[0061] Furthermore, the number of cameras is not limited to two; it can be one or more. Also, the camera placement is not limited to the upper part of the subject or the scanning aperture 120. Moreover, the cameras are not limited to visible light cameras; for example, infrared cameras can also be used.

[0062] Furthermore, the body movement detection sensor can also use a sheet with multiple pressure sensors built-in and placed below the subject. The subject's body movement information can be obtained based on the pressure signals detected by the pressure sensors within the sheet as the subject moves.

[0063] The projector 230 projects images into the scanning aperture 120 and functions as a display that shows images in a way that the examinee 102 can visually recognize during the examination of the examinee 102.

[0064] [Image Diagnostic System]

[0065] Figure 4 This is a block diagram illustrating an embodiment of the image diagnostic system according to the present invention.

[0066] Figure 4 The illustrated image diagnostic system includes an MRI device 100 as an image diagnostic apparatus and a motion display device 200. Furthermore, the structure of the MRI device 100 is as follows: Figure 1 and Figure 2 specifically shown in .

[0067] The motion display device 200 consists of a processor 210, a first camera 220A and a second camera 220B, and a projector 230.

[0068] Alternatively, the first camera 220A and the second camera 220B can be cameras originally provided by the MRI device 100 for capturing the state of the subject 102. Furthermore, cameras using breathing belts 222A and 222B, or other motion detection sensors, can be used instead of the first camera 220A and the second camera 220B.

[0069] The processor 210, consisting of a CPU or the like, centrally controls the various parts of the motion display device 200 and performs various processes, including generating images projected from the projector 230.

[0070] The processor 210 and the control unit 150 of the MRI device 100 can communicate with each other. During the examination based on the MRI device 100, the processor 210 projects an image representing the body movement of the subject 102 from the projector 230 into the scanning aperture 120.

[0071] Furthermore, as described above, when the signal processing unit 118 and control unit 150 of the MRI apparatus 100 are configured as a computer equipped with a processor and memory, the processor of the MRI apparatus 100 can function as the processor 210 of the motion display device 200.

[0072] <First Embodiment of the Motion Display Device>

[0073] Next, a first embodiment of the motion display device according to the present invention will be described.

[0074] If the subject 102 enters the examination room equipped with the MRI device 100 and lies on the bed 130 of the MRI device 100, the top plate 130A of the bed 130 is controlled so that the subject 102's imaging target area is located in the center of the imaging area within the scanning aperture 120. Then, the MRI device 100 begins to photograph the subject 102's imaging target area according to the imaging sequence.

[0075] Figure 4 The processor 210 of the motion display device 200 shown acquires images captured by at least one of the first camera 220A and the second camera 220B during imaging (in inspection) based on the MRI device 100.

[0076] The processor 210 analyzes the acquired images of the subject 102 and extracts images representing the camera target area of ​​the subject 102 or the area surrounding the camera target area. For example, if the camera target area of ​​the subject 102 is the abdomen, images of the abdomen or the area surrounding the abdomen are extracted from images captured by at least one of the first camera 220A and the second camera 220B. Similarly, if the camera target area of ​​the subject 102 is the head, images of the head or the area surrounding the head are extracted from images captured by at least one of the first camera 220A and the second camera 220B. Furthermore, when the camera target area is the head, the receiving coil is of course a receiving coil that detects NMR signals generated from the head of the subject 102. Additionally, the camera target area of ​​the subject 102 can be obtained from the examination information of the subject 102.

[0077] Next, the processor 210 uses the optical flow of the extracted image to obtain the motion vector of the camera object. That is, the processor 210 obtains the displacement vector of the camera object between adjacent frames of the image or the surrounding area of ​​the camera object containing the camera object as the motion vector (motion information).

[0078] Then, the processor 210 detects the amplitude of the subject's body movement based on the body movement vector. Specifically, the amplitude of the subject's body movement is detected as the integral value (area) of the body movement vector over a predetermined time. The predetermined time can be set to the time of receiving the NMR signal within the TR (time to repeat) period, but is not limited to this and can be set appropriately.

[0079] In this example, processor 210 functions as an image processing unit that analyzes the acquired images of subject 102 and detects the subject's body movement amplitude. However, it could also be configured as an image processing unit different from processor 210 that acquires images of subject 102 from at least one of the first camera 220A and the second camera 220B, and analyzes the acquired images to detect the subject's body movement amplitude. Furthermore, it is preferable to continuously detect the subject's body movement amplitude frame by frame of each acquired image.

[0080] The processor 210 generates a rotationally symmetrical object (first image C1) whose size changes according to the detected body movement amplitude of the subject 102 and whose center is fixed, and projects the generated first image C1 as an image from the projector 230 into the scanning aperture 120 (reference). Figure 5 ).

[0081] That is, the processor 210 converts the subject's body movement amplitude into the size of the first pattern C1, and generates a first pattern C1 corresponding to the converted size of the first pattern C1. Further details regarding the conversion of the subject's body movement amplitude into the size of the first pattern C1 will be described later.

[0082] Figure 5 This is a diagram showing an example of an image projected by a projector, and in particular, a diagram showing an image composed of a first graphic C1 and a second graphic C2.

[0083] A boundary value is set, which is the allowable limit for the range of body movement of the subject 102 by the MRI device 100, and its relationship with the size of the first image is indicated. Preferably, the boundary value is set to a range of body movement amplitude that is at the level of body movement artifacts (affecting the imaging). Therefore, as long as the range of body movement of the subject 102 does not exceed the boundary value, the image quality of the image captured by the MRI device 100 is acceptable.

[0084] The second figure C2 is a figure with a size corresponding to the boundary value and a shape similar to the first figure C1; in this example, it is a circle.

[0085] The processor 210 can obtain the second graphic C2 from the memory within the processor 210 or the external memory, and generate the projected image Im by combining the generated first graphic C1 and the obtained second graphic C2.

[0086] Figure 5 The size of the image Im shown (the size of the projection area from the projector 230 to the scanning hole 120) can be set to approximately 20cm × 30cm, for example.

[0087] With an image size of 20cm × 30cm, the diameter of the second image C2 can be set to approximately 15cm. While patients typically remove their glasses during MRI scans, even those with poor vision who cannot wear glasses can visually identify the second image C2 of the aforementioned size.

[0088] Preferably, at least one of the colors, line types, and brightness of the first graphic C1 and the second graphic C2 contained in the image Im generated by the processor 210 is different. Figure 5 The first graphic C1 shown is filled with a different color and / or brightness than the second graphic C2.

[0089] in addition, Figure 3 The subject 102 shown is in a supine position. Therefore, the image projected from the projector 230 is projected onto the top of the scanning aperture 120 in a manner that the subject 102 can visually recognize. However, if the subject is positioned in a lateral decubitus position, it is preferable to project the image onto the side of the scanning aperture 120 in a manner that the lateral decubitus subject can visually recognize. That is, the processor 210 preferably projects the image onto a position within the scanning aperture 120 that is easily visually recognizable by the subject, based on the subject's position information.

[0090] <First Implementation Method for Converting the Subject's Body Movement Range to the Size of the First Graph>

[0091] The processor 210 converts the subject's body movement amplitude into the size of the first pattern C1 and generates a first pattern C1 corresponding to the converted size of the first pattern C1. Therefore, the greater the subject's body movement amplitude, the larger the generated first pattern C1 will be.

[0092] Figure 6 This is an example of a graph showing the relationship between the subject's range of motion and the size of the object (Figure 1).

[0093] The processor 210 detects the subject's body movement amplitude from the captured image of the subject, and converts the detected body movement amplitude into the size of the object (first graphic C1) (the diameter of a circle or the area of ​​a circle) by... Figure 6 The parameters shown in the single-dotted line curve are linearly transformed, or by... Figure 6 The parameters shown in the solid line curve are subjected to nonlinear transformation.

[0094] Now, if the size (diameter or area) of the first pattern when the subject's body movement amplitude (the integral value of the body movement vector over a specified time) becomes the boundary value allowed by the MRI device 100 is set to Cmax, then the processor 210 performs a linear or nonlinear transformation in such a way that the size of the first pattern varies from 0 to Cmax when the subject's body movement amplitude varies within the range of 0 to the boundary value.

[0095] In the case of linear transformation, Figure 5 The size of the first figure C1 shown changes according to the amplitude of body movement in a prescribed relationship, so it is easy to understand as a method for displaying the state of body movement. On the other hand, in the case of nonlinear transformation, for the amplitude of body movement that is to be further suppressed, the sensitivity of the first figure C1 can be increased, which can prompt the subject to adjust the body movement.

[0096] exist Figure 6 In the case of a solid line curve representing a nonlinear transformation, the closer the body motion amplitude is to the boundary value, the more drastic the change in the size of the first graph becomes (the sensitivity increases).

[0097] Figure 7 This is another example of a graph showing the relationship between the subject's range of motion and the size of the object (Figure 1).

[0098] exist Figure 7 In the case of a solid line graph representing a nonlinear transformation, within a small range of body motion amplitude, the change in the size of the first graph relative to the change in body motion amplitude is small (low sensitivity). Within a medium range of body motion amplitude, the change in the size of the first graph relative to the change in body motion amplitude becomes rapid (higher sensitivity). Within a large range of body motion amplitude, the change in the size of the first graph relative to the change in body motion amplitude is roughly consistent with the case of a dashed line graph representing a linear transformation.

[0099] exist Figure 6 In the case of a solid line graph representing a nonlinear transformation, the closer the amplitude of body movement is to the boundary value, the more drastic the change in the size of the first graph becomes, thus making it easier for the subject to realize they want to stop moving. On the other hand, in Figure 7 In the case of a solid line graph representing a nonlinear transformation (where the change in the first graph becomes abrupt midway), even body movements that are not large enough to reach the boundary value will appear larger in the first graph, thus enabling the subject to maintain focus and keep their body still.

[0100] Figure 8 It is a diagram showing the relationship between the changes in the size of the object (Figure 1) that accompanies the changes in the body movements of the examinee and the changes in the object displayed to the examinee.

[0101] exist Figure 8 In the process, processor 210 converts motion information into the size of the object (first graphic C1). Figure 8 (A) and Figure 8 (B)). In Figure 8 In (B), the size of the first graph C1 in states A, B, and C is shown as a bar chart.

[0102] Here, state A represents the state before the body motion increases, state B represents the state after state A where the body motion increases, and state C represents the state after state B where the body motion decreases.

[0103] Processor 210 generation and Figure 8 (B) The processor 210 generates images in states A, B, and C by combining the first image C1 corresponding to the size of the first image C1 in states A, B, and C with the second image C2 corresponding to the size of the boundary value. Then, the processor 210 projects the generated images (images in states A, B, and C, etc.) from the projector 230 into the scanning aperture 120. Figure 8 (C)).

[0104] The subject 102 is able to observe the images of the object (first image C1) in state A → state B → state C during the examination performed by the MRI device 100. Figure 8 (C) When the subject observes the object display in state A, if there is body movement in the object area being filmed, the object display transitions to state B. The subject observes this object display to adjust their body movement to prevent the object area from moving. Then, if the subject's movement is suppressed and the object display transitions from state B to state C, the subject can confirm that the movement of the object area has decreased by observing the object display in state C.

[0105] in addition, Figure 8 The objects shown in states A, B, and C indicate changes in the body movement of the subject 102. However, the images projected from the projector 230 into the scanning aperture 120 are actually dynamic images that change continuously according to the movement of the body. For example, they are preferably dynamic images that change continuously in accordance with the frame rate of the dynamic image (30 frames / second or 60 frames / second).

[0106] By observing the image projected into the scanning aperture 120, the subject 102 can monitor their body movement amplitude in real time and suppress body movement as needed. Furthermore, the first graphic C1 representing the body movement amplitude within the image Im is a rotationally symmetric graphic with a fixed center (in this example, its shape is circular), which only changes in size without moving. Therefore, the subject 102 can view the display without moving their gaze, thus minimizing eye movement and reducing head movement and other body movements that are induced by eye movement.

[0107] Furthermore, in addition to the first graphic C1 representing the amplitude of body movement, a second graphic C2 representing the magnitude of the boundary value is also displayed concentrically with the first graphic C1, allowing the subject 102 to compare the first graphic C1 and the second graphic C2. Thus, the subject 102 can grasp the current level of their body movement and suppress it so that the first graphic C1 does not exceed the second graphic C2.

[0108] <Second Implementation Method for Converting the Subject's Body Movement Range to the Size of the First Graph>

[0109] The magnitude of the subject's body movement and the resulting impact on the MRI device 100's imaging are not necessarily one-to-one.

[0110] That is, the magnitude of the effect of the subject's body movement on the imaging of the MRI device 100 varies, for example, based on the subject's imaging target area, imaging sequence, and k-space filling method of the MRI device 100. For example, even if the subject's body movement amplitude is the same, the effect on the imaging of the MRI device 100 will change depending on the subject's imaging target area, imaging sequence, or k-space filling method.

[0111] Therefore, the processor 210 preferably performs a weighted conversion when converting the amplitude of the subject 102's body movement into the size of the first pattern C1, the weight corresponding to the magnitude of the effect of the subject 102's body movement on the imaging of the MRI device 100.

[0112] The processor 210 acquires imaging conditions such as the imaging subject area, imaging sequence, and k-space filling method of the subject 102 from the MRI device 100. When converting the body movement amplitude of the subject 102 into the size of the first pattern C1, it determines the weight corresponding to at least one of the above imaging conditions (the weight corresponding to the magnitude of the influence on the imaging of the MRI device 100) and performs the conversion with the determined weight.

[0113] For example, compared to the high-frequency region of k-space, it is more necessary to reduce the body movement of the object being photographed during the collection period in the low-frequency region. Therefore, it is preferable to perform weighting that makes the size of the circle area of ​​the first pattern C1 change more sensitively during the collection of signals in the low-frequency region. Furthermore, the collection period in k-space varies depending on the camera sequence or the k-space filling method, so it is preferable to determine the spatial frequency level at a certain moment based on the parameters of the camera sequence or the k-space filling method.

[0114] The following is a detailed explanation.

[0115] In k-space, there exist low-frequency and high-frequency regions, with strong signals present in the low-frequency region. If body movement occurs during signal collection in the low-frequency region, artifacts during the inverse Fourier transform will affect the overall image. Therefore, it becomes more important to avoid moving the camera position during signal collection in the low-frequency region. Thus, when converting the amplitude of body movement into the size of the first pattern C1, the conversion coefficients are weighted according to the spatial frequency of the collected signal. This allows the size (area of ​​the circle) of the first pattern C1 representing the subject's body movement to change more sensitively with body movement during the collection period in the low-frequency region of k-space (compared to the collection period in the high-frequency region). If the display of body movement during periods prone to artifacts is particularly emphasized, the subject can be encouraged to further suppress body movement during those periods.

[0116] Furthermore, in the first embodiment of the conversion of the subject's body movement amplitude to the size of the first pattern, such as Figure 6 and Figure 7 As shown in the graph, the subject's body movement amplitude is linearly or nonlinearly converted into the size of the first graph C1, but preferably the second embodiment of converting the subject's body movement amplitude into the size of the first graph is performed together with the first embodiment.

[0117] For example, in Figure 6 In the case of a curve represented by a single-dotted line, a linear transformation is performed when converting the subject's body movement amplitude into the size of the first graph C1. However, by weighting the parameters of this linear transformation according to the magnitude of its influence on the image, the effect can be changed. Figure 6 The slope of the curve represented by the single-dot dashed line allows the size of the first graph C1, which represents the subject's body movement, to change more sensitively with respect to the body movement.

[0118] [Boundary value setting]

[0119] The boundary values ​​allowed by the MRI device 100 are preferably set based on imaging conditions such as the imaging subject area of ​​the subject 102 based on the MRI device 100, the imaging sequence, and the k-space filling method. The processor 210 obtains the imaging conditions from the MRI device 100 and sets the boundary values ​​corresponding to those imaging conditions.

[0120] <Example 1 of Boundary Value Setting>

[0121] For example, in head DWI (diffusion imaging) or DTI (diffusion tensor imaging) sequences, it is preferable to set the size of the boundary value corresponding to the second pattern C2 to be smaller than that of other imaging sequences.

[0122] If the subject moves between a pair of MPG (Motion Probing Gradient) pulses during a head DWI or DTI sequence, errors occur when calculating the diffusion coefficient. Therefore, it is desirable to minimize movement of the subject during imaging. Thus, by reducing the boundary value (reducing the circle of the second pattern C2 corresponding to the boundary value), it is possible to encourage less movement of the subject's subject. Furthermore, DWI or DTI sequences are often taken after morphological imaging based on other imaging sequences such as T1W or T2W sequences. In this case, reducing the boundary value displayed in other imaging sequences also informs the subject that less movement than was desired during the previous imaging.

[0123] <Example 2 of boundary value setting>

[0124] In high-resolution imaging in orthopedic fields such as knee joint examinations, it is desirable to minimize movement of the subject area being imaged. Therefore, similar to the first example above, by setting the boundary value to be smaller than that of other imaging sequences, it is possible to inform the patient that it is desirable to reduce movement of the subject area being imaged.

[0125] <Example 3 of Boundary Value Setting>

[0126] For example, in MRA (MR angiography) sequences, it is preferable to set the boundary value to be greater than that of other imaging sequences.

[0127] MRA sequences typically involve long imaging times, and compared to morphological imaging, the need to remain stationary on the subject area is less pronounced. Therefore, by increasing the threshold values, some movement is permitted. Furthermore, this allows the patient to understand that the tolerance for movement of the subject area is not stringent.

[0128] Prolonged periods of stillness during video recording can cause psychological stress for the subject. Informing the subject that they can relax during the recording session can help reduce this stress.

[0129] [How the motion display device works]

[0130] Figure 9 This is a flowchart illustrating an embodiment of the operation method of the motion display device according to the present invention. In an examination based on the MRI device 100, a method based on... Figure 4 The processing content and processing order of the processor 210 of the motion display device 200 shown.

[0131] exist Figure 9If an examination based on the MRI device 100 begins, the processor 210 repeatedly executes steps S10 to S70 until the examination ends. Here, the processing of steps S10 to S70 corresponds to the period of one frame of the camera image.

[0132] The processor 210 begins acquiring camera images from at least one of the first camera 220A and the second camera 220B, which function as part of a motion detection sensor (step S10).

[0133] Next, the processor 210 uses optical flow to calculate the amplitude of body movement of the subject's camera-viewed object based on the acquired camera images (step S20). The processor 210 acquires the body movement vector of the camera-viewed object between adjacent frames of the camera images, and uses the integral value (area) of the body movement vector over a predetermined time to detect the amplitude of the subject's body movement. Therefore, in step S20, after a predetermined time has elapsed since the start of acquiring the camera images, the amplitude of the subject's camera-viewed object's body movement is detected (calculated) for each frame.

[0134] Processor 210 converts the detected body motion amplitude into the size of the object (first graphic C1) (step S30). In this case, processor 210 performs the conversion according to preset linear or nonlinear parameters (see reference). Figure 6 , Figure 7 The amplitude of body movement is converted into the size of the first graph C1 (the curve). Furthermore, when performing this conversion, it is preferable to perform a weighted conversion based on imaging conditions such as the location of the subject being imaged, the imaging sequence, and the k-space filling method. This is because the effect of the subject's body movement on the imaging of the MRI device 100 varies depending on the imaging conditions.

[0135] Next, the processor 210 generates a first graphic C1 corresponding to the size of the converted first graphic C1 (step S40). In this example, the shape of the first graphic C1 is a circle, so the size of the converted first graphic C1 corresponds to the diameter or area of ​​the circle.

[0136] The processor 210 projects (displays) the generated first pattern C1 as an image into the scanning aperture 120 via the projector 230 (step S50). In this case, the processor 210 preferably also simultaneously displays a second pattern C2 corresponding to the boundary value of the subject 102's body movement amplitude. Furthermore, the second pattern C2 is a concentric circle with the same center as the first pattern C1 (see reference). Figure 5 ).

[0137] By observing the size of the first graphic C1 contained in the image displayed in the scanning hole 120, the subject can grasp the amplitude of his / her body movements and can adjust (suppress) his / her body movements as needed (step S60).

[0138] Next, the processor 210 determines whether the examination based on the MRI device 100 has ended (step S70). Then, if it is determined that the examination based on the MRI device 100 has not ended (in progress) (in the case of "No"), it transitions to step S10 and repeats the processing of steps S10 to S70. In addition, as described above, since the processing of steps S10 to S70 is performed in each cycle of each frame, the first graphic C1 corresponding to the current body movement amplitude of the examinee is displayed in real time in the image projected into the scanning aperture 120, and the examinee can grasp his body movement amplitude in real time by observing the projected image.

[0139] On the other hand, in step S70, if it is determined that the examination based on the MRI device 100 has ended (in the case of "yes"), the operation based on the motion display device 200 ends. Furthermore, the processor 210 can determine whether the imaging has ended based on communication with the control unit 150 of the MRI device 100.

[0140] According to the operating method of the motion display device of the present invention, the subject 102 can confirm their own body movement range by observing the image such as the first graphic C1 projected into the scanning aperture 120. In particular, the size (diameter, area) of the first graphic C1 changes according to the body movement range of the subject 102, but since the outer shape is circular with a fixed center, the subject 102 can view the first graphic C1, etc., which changes in size without moving their line of sight, thus minimizing eye movement. As a result, it is possible to reduce the movement of the head inducing eye movement and the movement of other parts of the body besides the head.

[0141] <Second Embodiment of Motion Display Device>

[0142] Next, a second embodiment of the motion display device according to the present invention will be described.

[0143] In the examination of the abdomen of the subject based on the MRI device 100, in order to reduce motion artifacts caused by the subject's breathing, respiratory-synchronized imaging or imaging under breath-holding conditions was used.

[0144] In respiratory-synchronous imaging and other methods, Figure 3 The breathing belts 222A and 222B shown were installed on the subject's abdomen, and data were measured only when the abdominal movements were small and stable (mainly exhalation).

[0145] The second embodiment of the motion display device differs from the first embodiment in that, when respiratory-synchronous imaging is performed by the MRI device 100, the display method of the image projected from the projector 230 is changed during and outside of respiratory-synchronous measurement.

[0146] As an example of changing the display method of images in and out of respiratory synchronization measurements, the following methods can be considered.

[0147] (1) Change the overall brightness of the displayed graphics or images. For example, displaying them brighter during data acquisition than during non-data acquisition prompts subject 102 to suppress body movement. By changing the brightness of the display to notify subjects during and outside of respiratory synchronization measurements, it is possible to suppress eye movement by subject 102 compared to notifications using text.

[0148] (2) The brightness is gradually changed from a few seconds before the start of the data acquisition period to the brightness during the data acquisition period (gradual increase). This allows the subject 102 to be notified in advance that the data acquisition has begun.

[0149] (3) Change the color of the displayed graphic. Changing the color also includes displaying the graphic in color during respiratory synchronization measurements but in black and white during non-measurement measurements.

[0150] According to the second embodiment, the subject 102 can be notified during the recording period, and the subject 102 can suppress body movement (breathing movements) while observing the image during the recording period.

[0151] <Third Embodiment of the Motion Display Device>

[0152] From the viewpoint that a warning is issued when the size of the first graphic C1 approaches or exceeds the boundary value corresponding to the subject's body movement amplitude allowed by the MRI device 100 (the case of approaching the threshold) or exceeds the boundary value, the processor 210 of the third embodiment of the body movement display device is different from that of the first embodiment.

[0153] As a threshold used to determine whether the subject's body movement amplitude is close to the boundary value, it can be set to about 0.8 of the boundary value, but it can also be set appropriately.

[0154] Warnings can be issued via one or more of the following: a warning sound generator, a display, a lighting device within the rack of the MRI device 100, and a vibration generator.

[0155] A warning sound generator produces a beeping sound or similar noise to notify the subject that the amplitude of body movement is approaching the boundary value. A display, including projector 230, notifies the subject that the amplitude of body movement is approaching the boundary value by changing the graphic (making the second graphic C2 corresponding to the boundary value flash). Furthermore, an internal lighting device notifies the subject that the amplitude of body movement is approaching the boundary value by illuminating the internal lighting.

[0156] Furthermore, the vibration generator, for example, notifies the subject that their body movement amplitude is approaching a boundary value by vibrating a vibrating body held by the subject. In this case, the warning level can be changed by altering the vibration frequency; the frequency increases as the boundary value approaches, thereby drawing attention.

[0157] Alternatively, the warning sound generator, display, lighting device and vibration generator inside the MRI device 100 rack can be appropriately combined to issue a warning.

[0158] <Fourth Embodiment of the Motion Display Device>

[0159] Figure 10 This is a diagram showing a portion of the image projected by the projector 230, with particular emphasis on the case where the line of sight is fixed.

[0160] The processor 210 of the fourth embodiment of the motion display device is in Figure 5 The center of the first figure C1 shown is marked with a fixed line of sight, labeled M. In this example, the label M is a cross, but it is not limited to this.

[0161] Additionally, although it also shows Figure 5 The first figure C1 shown, but... Figure 10 The first graphic C1 is omitted. Furthermore, even if the first graphic C1 is displayed, it is preferable to composite it onto the first graphic C1 in the form of a mark M with a different color and / or brightness than the first graphic C1, so that the mark M can always be visually identifiable.

[0162] According to the fourth embodiment, when visually recognizing the first graphic C1, the subject 102's gaze can be further fixed, and gaze movement that induces body movement, including head movement, can be prevented.

[0163] [other]

[0164] In this embodiment, the shape of the graphic including the first graphic C1 is set to be circular, but it is not limited to this. It can be set to be a rotationally symmetric graphic with a fixed center, for example, it can be set to be a regular polygon.

[0165] Figure 11 It is a diagram showing the graphic projected by the projector 230, and in particular, a diagram showing the composite graphic of a first graphic H1 that varies according to the amplitude of body movement and a second graphic H2 that corresponds to the magnitude of the boundary value.

[0166] Figure 11 The first figure H1 shown is a regular hexagon, and similarly, the second figure H2 is also a regular hexagon. The centers of these two figures are aligned. Furthermore, the first figure H1 is... Figure 5 The first figure C1 shown corresponds to the figure shown, and the second figure H2 is the figure corresponding to the figure shown.Figure 5 The figure corresponding to the second figure C2 shown has a different shape.

[0167] Figure 1 H1 and Figure 5 The first figure C1 shown corresponds to, Figure 11 The first figure H1 on the left shows state A where the body motion is sufficiently small. Figure 11 The first graph H1 on the right shows the state B of the large volumetric motion (the state of the second graph H2, which is close to the boundary value).

[0168] Furthermore, in this embodiment, the display for displaying the first graphic, etc., is a projector 230 that projects images onto the scanning aperture 120 within the gantry 110 of the MRI apparatus 100, but it is not limited to this. For example, a head-up display, a head-mounted display, a monitor such as a liquid crystal display or an organic FL display within the scanning aperture 120, a monitor outside the scanning aperture 120, and a set of mirrors for observing the monitor, etc., can be considered.

[0169] Furthermore, the image diagnostic device suitable for motion display is not limited to MRI devices; for example, it can also be an X-ray CT device.

[0170] Furthermore, in this embodiment, each process is executed by any computer. And any computer can execute these processes via a processor, a program, or a combination thereof. Any computer can be a general-purpose computer, a purpose-built computer, a workstation, or other hardware components capable of executing programs.

[0171] The processor can be composed of one or more hardware components, and the type of hardware is not limited. For example, the processor can be composed of programmable logic devices such as CPUs (Central Processing Units), MPUs (Micro Processing Units), FPGAs (Field Programmable Gate Arrays), dedicated circuits for performing specific processes such as ASICs (Application Specific Integrated Circuits), GPUs (Graphics Processing Units), or NPUs (Neural Processing Units). Furthermore, the processor has units or means that execute the various processes described in this embodiment. The type of hardware can be a combination of different types of hardware. When multiple hardware components are configured to execute one or more processes of a certain processor, these multiple hardware components can exist in physically separate devices or in the same device. Furthermore, in any embodiment, the steps of each processor-based process are not limited to the steps described above and can be appropriately modified. Additionally, the hardware can be composed of circuits composed of semiconductor elements and other circuit elements.

[0172] Furthermore, this embodiment can also be implemented using hardware, software, firmware, microcode, or a combination thereof. Software, firmware, and microcode consist of programs. Furthermore, a program can be, for example, a group of program modules, each of which can be implemented by a processor configured to perform its respective function. A program can be program code or multiple code segments stored on one or more non-transitory computer-readable media (e.g., storage media or other storage devices). A program can be divided and stored on multiple non-transitory computer-readable media existing in physically separate devices. Program code or code segments can represent any combination of sequences, functions, subroutines, routines, subroutines, modules, software packages, classes or commands, data structures, or program statements. Program code or code segments can be connected to other code segments or hardware circuits by sending and receiving information, data, arguments, parameters, or memory contents.

[0173] Moreover, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

Claims

1. A body movement display device comprising: a processor; a display for displaying images in a manner visually recognizable by the subject during an examination using an image diagnostic device; and a body movement detection sensor for detecting the body movements of the subject, wherein the body movement display device, The processor generates a first, rotationally symmetric pattern with a fixed center. The size of the first pattern varies according to the amplitude of the subject's body movements detected by the body movement detection sensor. The generated first graphic is then displayed on the monitor as the image.

2. The motion display device according to claim 1, wherein, The processor converts the subject's body movement amplitude into the size of the first graphic and generates the first graphic corresponding to the converted size of the first graphic.

3. The motion display device according to claim 2, wherein, The conversion of the subject's body movement amplitude to the size of the first graph is either a linear conversion or a non-linear conversion.

4. The motion display device according to claim 2, wherein, The conversion of the subject's body movement amplitude to the size of the first image is a weighted conversion, and the weight corresponds to the magnitude of the impact of the subject's body movement on the imaging of the image diagnostic device.

5. The motion display device according to claim 4, wherein, The magnitude of the impact of the subject's body movement on the imaging of the image diagnostic device varies by at least one of the subject's imaging target area, the imaging sequence, and the k-space filling method based on the image diagnostic device.

6. The motion display device according to claim 1, wherein, A boundary value is set, which is the boundary value allowed by the image diagnostic device for the range of body movement of the subject, and the relationship between this boundary value and the size of the first image is indicated. The processor displays the second graphic on the display with the center of the first graphic aligned with the center of the second graphic. The second graphic has a size corresponding to the boundary value and a shape similar to the first graphic.

7. The motion display device according to claim 6, wherein, The boundary value is set by at least one of the subject's photographic object location, the photographic sequence, and the k-space filling method based on the image diagnostic device.

8. The motion display device according to claim 6, wherein, The processor displays the first graphic and the second graphic on the display differently in at least one of color, line type, and brightness.

9. The motion display device according to any one of claims 6 to 8, wherein, The processor issues a warning if the size of the first graphic exceeds the threshold and approaches or exceeds the boundary value.

10. The motion display device according to claim 9, wherein, The warning is issued by one or more of the following: a warning sound generator, the display, the lighting device within the frame of the image diagnostic device, and a vibration generator.

11. The motion display device according to any one of claims 1 to 8, wherein, The body movement detection sensor includes: a camera for capturing images of the subject and outputting the subject's image; and an image processing unit for processing the image to detect the subject's body movements. The image processing unit extracts the image of the subject's photographic object region from the image, based on the image diagnostic device. The motion of the extracted camera object region between consecutive frames of the image is obtained as the volumetric motion vector of the camera object region. Furthermore, the amplitude of the subject's body movement is detected based on the body movement vector.

12. The motion display device according to any one of claims 1 to 8, wherein, The first graphic is circular or a regular polygon.

13. An image diagnostic system, comprising: Image diagnostic device; and The motion display device according to any one of claims 1 to 12.

14. The image diagnostic system according to claim 13, wherein, The image diagnostic device includes a magnetic resonance imaging device or an X-ray CT device.

15. A method of operating a body motion display device, the body motion display device comprising: a processor; a display for displaying images in a manner visually recognizable by the subject during an examination based on an image diagnostic device; and a body motion detection sensor for detecting the body motion of the subject, the method of operating the body motion display device comprising the following steps: The processor acquires the subject's body movement amplitude from the body movement detection sensor; The processor generates a first, rotationally symmetric pattern with a fixed center, the size of which varies according to the acquired range of motion of the subject; and The processor displays the generated first graphic as the image on the display.

Images