Body position control system and body position control method

Abstract

A body position control system for controlling an imaging body position of an imaging site of a subject during imaging by a magnetic resonance imaging device, the body position control system comprising: a body position fixing device for adjusting and fixing the imaging body position of the imaging site by deformation; the body position control device is connected with the body position fixing device and controls deformation of the body position fixing device by sending deformation parameters to the body position fixing device; the display device is used for displaying images, the body position control device carries out parameter setting processing, and in the parameter setting processing, the deformation parameters are set and sent to the body position fixing device, so that the body position fixing device adjusts the shooting body position of the shooting part.

Description

Technical Field

[0001] The present invention relates to a body position control system and a body position control method used in imaging of a magnetic resonance imaging device. Background Art

[0002] Magnetic resonance imaging is a non-invasive medical imaging diagnostic device that uses the magnetic resonance phenomenon of hydrogen nuclei placed in a static magnetic field resonating with a high-frequency magnetic field of a specific frequency. Magnetic resonance imaging technology has the characteristics of high resolution, non-invasiveness, and no radiation. It can examine various substantial organs of the human body and is therefore widely used in the diagnosis of clinical diseases. Magnetic resonance imaging devices include a magnetic resonance imaging device that photographs the subject and a magnetic resonance image reconstruction device that reconstructs the image based on the photographed image.

[0003] Magnetic resonance imaging has three imaging modes, namely T1-weighted imaging (T1 Weighted Imaging), T2-weighted imaging (T2 Weighted Imaging) and proton density weighted imaging (Proton Density Weighted Imaging). T1-weighted imaging uses short repetition time (repetition time) and echo time (echo time). The generated T1-weighted image (T1 Weighted Image) can show the difference in T1 relaxation time (T1 relaxation time) between different tissues, and can be used to observe fat and blood, etc. T2-weighted imaging uses long repetition time and echo time. The generated T2-weighted image (T2 Weighted Image) can show the difference in T2 relaxation time (T2 relaxation time) between different tissues, and can be used to observe cerebrospinal fluid and tumors, etc. Proton density weighted imaging uses long repetition time and short echo time. The generated proton density weighted image (Proton Density Weighted Image) can show the difference in regional particle concentration, and can be used in conjunction with T1-weighted images and T2-weighted images.

[0004] In magnetic resonance imaging, sometimes the imaging quality is affected by the imaging position of the subject. For example, in magnetic resonance imaging, when a structure with collagen fibers such as tendons or cartilage is at an angle of about 55° to the main magnetic field, the structure will appear as a high signal on the T1-weighted image and proton density-weighted image with a short repetition time. This phenomenon is called the magic angle effect. The magic angle effect can improve the clarity of the originally low-signal areas in the above-mentioned structure, but it will become impossible to distinguish between the low-signal areas and the high-signal areas. In order to suppress or utilize the magic angle effect, a body position control system and method that can accurately control the angle between the imaging site of the subject (hereinafter referred to as the imaging site) and the main magnetic field is required.

[0005] In the past, in order to fix the imaging part of the subject at a certain angle, it is known to set a support member at the imaging part of the subject to maintain the body position of the subject during the imaging process. However, when the support member is used, if the subject needs to adjust the body position, for example, when performing different scanning sequences, an operator needs to enter the imaging room to adjust the body position of the subject.

[0006] Patent Document 1 discloses a magnetic resonance imaging system including a stand for holding the whole body of a subject, and adjusting the patient's body position by rotating and deforming the stand.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent document 1: US8111067B1 Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, the MRI system of Patent Document 1 needs to change the body position of the whole body of the patient in order to change the angle of the imaging part of the subject, so it is possible that the patient takes a body position that makes the patient uncomfortable. In addition, the MRI system of Reference Document 1 cannot accurately set the imaging body position of the imaging part of the subject, and cannot set the angle between the structure with collagen fibers in the imaging part and the main magnetic field. Therefore, it is possible that repeated imaging may occur because the magic angle effect cannot be reliably generated or suppressed.

[0012] The present invention is made to solve the above-mentioned problems. An object of the present invention is to provide a body position control system and a body position control method that can accurately adjust the imaging body position of an imaging part.

[0013] Means used to solve problems

[0014] A body position control system of an embodiment controls the imaging body position of an imaging part of a subject during imaging performed by a magnetic resonance imaging device, and comprises: a body position fixing device, which adjusts and fixes the imaging body position of the imaging part by deformation; a body position control device, which is connected to the body position fixing device, and controls the deformation of the body position fixing device by sending deformation parameters to the body position fixing device; and a display device, which displays an image, wherein the body position control device performs parameter setting processing, in which the deformation parameters are set and sent to the body position fixing device, so that the body position fixing device adjusts the imaging body position of the imaging part.

[0015] A body position control method of an embodiment controls the imaging body position of an imaging part of a subject during imaging performed by a magnetic resonance imaging device. The body position control method is used for a body position control system, which comprises: a body position fixing device, which adjusts and fixes the imaging body position of the imaging part by deformation; a body position control device, which is connected to the body position fixing device and controls the deformation of the body position fixing device by sending deformation parameters to the body position fixing device; and a display device, which displays an image. The body position control method comprises a parameter setting step, in which the body position control device sets the deformation parameters and sends them to the body position fixing device, so that the body position fixing device adjusts the imaging body position of the imaging part.

[0016] Effects of the Invention

[0017] According to the present invention, it is possible to provide a body position control system and a body position control method capable of accurately adjusting an imaging body position of an imaging part. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a block diagram showing the structure of the body posture control system according to the first embodiment.

[0019] Figure 2 This is a diagram showing the structure of the body position fixing device used in the first embodiment.

[0020] Figure 3 This is a flowchart showing the body posture control method according to the first embodiment.

[0021] Figure 4 This is an explanatory diagram for explaining the installation of the body positioning device.

[0022] Figure 5 This is a schematic diagram showing a first graphical user interface displayed in the body posture control method according to the first embodiment.

[0023] Figure 6It is an explanatory diagram for explaining the relationship between the angle between the direction of the ankle and the direction of the main magnetic field and the opening angle of the body position fixing device.

[0024] Figure 7 This is a diagram showing an example of a second graphical user interface for measuring the angle between the axial direction of the Achilles tendon and the main magnetic field direction.

[0025] Figure 8 This is an explanatory diagram for explaining the rotation of an image.

[0026] Fig. 9 This is a block diagram showing the structure of the body posture control system according to the second embodiment.

[0027] Fig.10 This is a flowchart showing the body posture control method according to the second embodiment.

[0028] Fig.11 This is a diagram showing the structure of a body position fixing device used in the third embodiment.

[0029] Fig.12 This is a flowchart showing the body posture control method according to the third embodiment.

[0030] Fig.13 This is an explanatory diagram for explaining the installation of the body position fixing device and the imaging coil.

[0031] Fig.14 This is a schematic diagram showing a third graphical user interface displayed in the body posture control method according to the third embodiment.

[0032] Fig.15 This is an explanatory diagram of the relationship between the angle between the surface direction of the knee joint and the main magnetic field direction and the rising height of the body position fixing device.

[0033] Fig.16 3 is a diagram showing an example of a fourth graphical user interface for measuring the angle between the axial direction of the ligament and the main magnetic field direction. DETAILED DESCRIPTION

[0034] The body position control system and body position control method of the present invention are described below with reference to the accompanying drawings. The body position control system and body position control method of the present invention are used to control the imaging body position of the imaging part of the subject (patient) during the imaging stage of magnetic resonance imaging.

[0035] (Implementation Method 1)

[0036] In the first embodiment, the body position control system and the body position control method of the present invention are used for magnetic resonance imaging examination of the Achilles tendon.

[0037] Figure 11 is a block diagram showing the structure of the body position control system 1 of Embodiment 1. The body position control system 1 of this embodiment comprises a body position fixing device 10, a body position control device 20 and a display device 30. The body position control device 20 and the display device 30 may be provided independently of the console of the magnetic resonance imaging apparatus or may be integrated into the console.

[0038] The body position fixing device 10 is a mechanical device that adjusts and fixes the imaging position of the imaging part of the subject by deformation. The body position fixing device 10 directly contacts the imaging part of the subject to support the imaging part, and adjusts the imaging position of the imaging part by deformation. The deformation of the body position fixing device 10 includes, for example, up and down movement, left and right movement, telescopic or rotational movement, etc., but is not limited to these. The body position fixing device 10 is fixed to the examination bed on which the subject is placed when in use, and can be removed from the examination bed after use. The body position fixing device 10 has a communication unit 11 and a sensor 12 built in.

[0039] The communication unit 11 is a network adapter including a network interface, which enables the body position fixation device 10 and the body position control device 20 to exchange data via the network N. The network N can be a LAN (Local Area Network), a WAN (Wide Area Network), the Internet, or a dedicated line, etc. The network N can be connected by wire or wirelessly. When using a wired connection, for example, a twisted pair, a coaxial cable, an optical fiber, etc. can be used for connection. When using a wireless connection, for example, Wi-Fi, a cellular mobile network (4G LTE, 5G), etc. can be used for connection.

[0040] The sensor 12 is used to detect the current deformation of the body position fixing device 10, such as displacement, rotation, etc. The information such as the deformation detected by the sensor 12 is sent to the body position control device 20 via the network N by the communication unit 11.

[0041] The body position fixing device 10 includes a plurality of body position fixing devices corresponding to different examination parts. For example, the body position fixing device 10 may include body position fixing devices corresponding to the calf, thigh, knee, forearm, upper arm, waist, etc. In this embodiment, the body position fixing device 10a corresponding to the calf is used.

[0042] Figure 2 This is a diagram showing the structure of a body position fixing device 10a used in the first embodiment.

[0043] like Figure 2 As shown, the body position fixing device 10a includes an upper arm portion 13a, a lower arm portion 14a, and a rotating portion 15a.

[0044] The upper arm 13a is in the shape of a rectangular parallelepiped, in direct contact with the calf of the subject, supporting the calf and fixing the imaging position of the calf. The lower arm 14a is in the shape of a rectangular parallelepiped, placed on the examination bed 2, and fixes the body position fixing device 10a relative to the examination bed 2. In order to prevent the body position fixing device 10a from moving relative to the examination bed 2, for example, the lower surface of the lower arm 14a can be roughened to increase the friction between the lower arm 14a and the examination bed 2. The upper arm 13a and the lower arm 14a are made of non-magnetic materials such as plastic, ceramic or glass. The rotating part 15a rotatably connects the upper arm 13a and the lower arm 14a, and according to the instructions from the body position control device 20, the upper arm 13a is rotated relative to the lower arm 14a and the angle between the upper arm 13a and the lower arm 14a is fixed to a specified angle. The rotating part 15a is a non-magnetic motor without permanent magnets, electromagnetic coils, and iron cores, such as a piezoelectric motor or a pneumatic motor. Since the body position fixing device 10a is made of non-magnetic material, the quality of the captured image will not deteriorate even if the body position fixing device 10a enters the FOV.

[0045] Return to the following Figure 1 Description. The body position control device 20 controls the deformation of the body position fixing device 10. The body position control device 20 is connected to the body position fixing device 10 via a network N, and controls the deformation of the body position fixing device 10 by sending deformation parameters to the body position fixing device 10 so that the imaging part of the subject becomes the desired imaging body position. The body position control device 20 includes an input unit 21, a control unit 22, a display control unit 23, a storage unit 24, and a communication unit 25.

[0046] The input unit 21 receives the operation of the operator. The input unit 21 includes an input interface and an input device. The input interface is, for example, a serial bus interface such as USB, which is used to exchange information with the input device. The input device includes a mouse and keyboard, a trackball, a switch, a button, a joystick, a touch screen, a microphone, etc., which are used to input information.

[0047] The control unit 22 implements the functions described below by executing various programs stored in the storage unit 24. The control unit 22 is composed of hardware such as a CPU (Central Processing Unit), an FPGA (field programmable gate array), an ASIC (application specific integrated circuit), a programmable logic device (for example, a simple programmable logic device (SPLD) or a complex programmable logic device (CPLD)). In addition, the control unit 22 is not limited to being configured as a single circuit, and multiple independent circuits can also be combined to form a hardware processor to implement various functions.

[0048] The display control unit 23 is connected to the display device 30 via a display interface, and causes the display device 30 to display an image. The display control unit 23 is composed of, for example, a GPU (Graphics Processing Unit) or the like. The display interface is, for example, an image output interface such as a Digital Visual Interface (DVI) or a High-Definition Multimedia Interface (HDMI (registered trademark)).

[0049] The storage unit 24 stores various parameters used in the posture control method and programs used by the control unit 22. The storage unit 24 is implemented by, for example, a storage device such as a ROM (Read-Only Memory), a flash memory, a RAM (Random Access Memory), a HDD, a SSD, a register, etc. Flash memory, a HDD, a SSD, etc. are non-volatile storage media. These non-volatile storage media can be implemented by other storage devices connected via a network such as a NAS (Network Attached Storage) or an external storage server device.

[0050] The communication unit 25 is a network adapter including a network interface, and enables the body position control device 20 and the body position fixing device 10 to exchange data via the network N. The structure of the communication unit 25 is the same as that of the communication unit 11, and detailed description thereof is omitted here.

[0051] The display device 30 is controlled by the display control unit 23 of the posture control device 20, and displays images such as a user interface for accepting input operations from the operator. The user interface is, for example, a GUI (Graphical User Interface). The display device 30 is, for example, an LCD (Liquid Crystal Display) or an organic EL (Electroluminescence) display.

[0052] (Magic Angle Effect of Achilles Tendon)

[0053] When performing magnetic resonance imaging on the Achilles tendon, if the angle between the axial direction of the Achilles tendon and the main magnetic field direction is close to 54.74°, the Achilles tendon with collagen fibers will show a high signal compared with other structures in the T1-weighted image or proton density-weighted image with a short echo time. This phenomenon is called the magic angle effect of the Achilles tendon. If the magic angle effect occurs, the resolution of the fiber structure can be optimized, providing clearer fiber structure information, which can be used to show partial rupture of the Achilles tendon, which is of great significance for timely, accurate, and early surgical repair and functional reconstruction.

[0054] In the posture control method of this embodiment, in order to produce the magic angle effect on the Achilles tendon, the imaging posture of the subject's calf is adjusted so that the angle between the axial direction of the subject's Achilles tendon and the main magnetic field direction is approximately 54.74°.

[0055] Figure 3 Flowchart showing the posture control method of Embodiment 1. Figure 3 , the posture control method of implementation mode 1 is explained.

[0056] In step S100 , the operator enters the imaging room and installs the body position fixing device 10 a on the calf of the subject. Figure 4 This is an explanatory diagram for explaining the installation of the body position fixing device 10a. Figure 4 When the Achilles tendon near the ankle is photographed, the subject lies prone on the examination bed 2, the opening angle of the body position fixing device 10a is reduced, and it is installed between the subject's calf to be examined and the examination bed 2. After the processing of step S100 is completed, the processing proceeds to step S200.

[0057] In step S200, the operator determines whether the subject and the body position fixing device 10a are fixed to the examination bed 2, and moves the examination bed 2 into the magnetic resonance imaging apparatus. After the processing of step S200 is completed, the process proceeds to step S300.

[0058] In step S300, the operator sets the parameters of the scanning sequence of the magnetic resonance imaging. The parameters of the scanning sequence include imaging mode, repetition time, echo time, resolution, magnetic field strength, etc. After the processing of step S300 is completed, the process proceeds to step S400.

[0059] In step S400, the body position control device 20 determines whether the set imaging method is T1 weighted imaging with short echo time or proton density weighted imaging based on the parameters in the scanning sequence set by the operator. If the determination is "yes", the process proceeds to step S500, and if the determination is "no", the process proceeds to step S600.

[0060] In step S500, the display device 30 displays a message "The set scanning sequence has a magic angle effect on tendons, cartilages, etc. Please adjust the patient's position." to remind the operator to pay attention to the magic angle effect. In addition, the above information is only an example, and the displayed information is not limited to this. After the processing of step S500 is completed, the process proceeds to the processing of step S600.

[0061] In step S600, the operator sets deformation parameters for controlling the deformation of the body position fixing device 10a, so that the body position fixing device 10a adjusts the imaging body position of the imaging part of the subject.

[0062] Specifically, first, the operator inputs parameters for controlling the deformation of the body position fixing device 10 a on the first graphical user interface displayed on the display device 30 . Figure 5 FIG. 2 is a schematic diagram showing a first graphical user interface G1 displayed in the body posture control method according to the first embodiment. Figure 5 , a first graphical user interface G1 for the operator to input parameters for controlling the deformation of the body position fixation device 10a is displayed on the display device 30. In the first graphical user interface G1, the message "Please enter the opening angle of the body position fixation device" is displayed in the lower area of ​​the screen, and an input box for inputting the opening angle of the body position fixation device 10a is provided in the upper area of ​​the screen. The setting range of the opening angle of the body position fixation device 10a is 0° to 120°. If the operator inputs an angle exceeding the setting range, the operator is reminded to reset it. In addition, for ease of observation, a schematic diagram of the main magnetic field direction B0 and the body position fixation device 10a opened at the set opening angle is displayed near the input box.

[0063] Next, if the user confirms the opening angle, the opening angle is sent to the body position fixing device 10a. After receiving the opening angle set by the operator, the body position fixing device 10a rotates the rotating part 15a to fix the angle of the upper arm part 13a relative to the lower arm part 14a to the set opening angle. In this way, the imaging body position of the subject's lower leg is adjusted.

[0064] Next, the relationship between the angle between the axial direction of the Achilles tendon and the main magnetic field direction B0 and the opening angle of the body position fixing device 10a will be described.

[0065] Figure 6 1 is an explanatory diagram for explaining the relationship between the angle α3 between the direction of the ankle and the main magnetic field direction B0 and the opening angle α1 of the body position fixing device 10a. Figure 6 For a magnetic resonance imaging device, the main magnetic field direction B0 is usually a horizontal direction parallel to the imaging bed 2, so the main magnetic field direction B0 is also parallel to the long side direction of the lower arm portion 14a of the body position fixing device 10a horizontally arranged on the examination bed 2. Furthermore, since the lower leg of the subject is placed on the upper arm portion 13a, the long side direction of the upper arm portion 13a is roughly parallel to the direction of the subject's ankle, and the angle α3 between the direction of the ankle and the main magnetic field direction B0 is roughly equal to the opening angle α1 of the body position fixing device 10a.

[0066] Furthermore, since the direction of the ankle is substantially parallel to the axial direction of the Achilles tendon, the angle between the axial direction of the Achilles tendon and the main magnetic field direction B0 is substantially equal to the opening angle α1 of the position fixing device 10a. In this embodiment, it is desirable to set the angle between the axial direction of the Achilles tendon and the main magnetic field direction B0 to 54.74°, so as to enhance the imaging of the Achilles tendon through the magic angle effect. By setting the opening angle α1 of the position fixing device 10a to 54.74°, the angle between the axial direction of the Achilles tendon and the main magnetic field direction B0 can be made close to 54.74°, thereby causing the magic angle effect.

[0067] Return to the following Figure 3 After the processing of step S600 is completed, the process proceeds to step S700.

[0068] In step S700, the imaging part of the subject, i.e., the ankle, is imaged using the set scanning sequence. Specifically, first obtain the cross-sectional and coronal positioning maps of the ankle. Then, in the positioning maps of the multiple cross-sectional areas obtained, determine the cross-sectional area in which the medial malleolus and lateral malleolus are most clearly depicted, so that the positioning line of the sagittal plane is perpendicular to the line between the medial malleolus and lateral malleolus. Afterwards, adjust the angle of the positioning line on the coronal plane so that the sagittal positioning line is parallel to the direction of the Achilles tendon. Next, image the subject's ankle on the determined sagittal plane. After the processing of step S700 is completed, proceed to the processing of step S800.

[0069] In step S800, the difference between the angle between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74° is measured.

[0070] Specifically, first, a second graphical user interface for measuring the angle between the axial direction of the Achilles tendon and the main magnetic field direction B0 is displayed on the display device 30 . Figure 7 2 is a diagram showing an example of a second graphical user interface G2 for measuring the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0. Figure 7 , a video image of the ankle of the subject obtained in step S700 is displayed in the second graphical user interface G2, and an indicator I that can be moved arbitrarily is displayed overlapping the video image. The indicator I includes an arrow indicating the main magnetic field direction B0, an auxiliary line A1 that forms an angle of 54.74° with the main magnetic field direction B0 in the clockwise direction and intersects with the arrow indicating the main magnetic field direction B0 at the intersection D, and an auxiliary line A2 that forms an angle of 54.74° with the main magnetic field direction B0 in the counterclockwise direction and intersects with the arrow indicating the main magnetic field direction B0 at the intersection D. Figure 7 In FIG. 8 , the position of the Achilles tendon is indicated by a thick solid line, and the axial direction of the Achilles tendon is indicated by an arrow L1.

[0071] Next, the operator moves the indicator I so that the intersection D is located within the Achilles tendon. Then, the operator selects one of the auxiliary lines A1 and A2 according to the direction of the Achilles tendon, and rotates the camera image so that the arrow L1 is consistent with the selected auxiliary line. In addition, the indicator I itself can also be rotated instead of rotating the camera image. Figure 8 is an illustration for explaining the rotation of an image. Figure 8 In FIG. 1 , the operator rotates the image of the ankle so that the arrow L1 of the Achilles tendon is in the same direction as the auxiliary line A1 . At this time, the angle α2 between the arrow L1 and the main magnetic field direction B0 is 54.74°.

[0072] Thereafter, the angle of rotation is calculated and set to be the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74°.

[0073] Return to the following Figure 3 After the processing of step S800 is completed, the process proceeds to step S900.

[0074] In step S900, it is determined whether the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74° is within the threshold range. If it is within the threshold range (determined as "yes"), the process of the posture control method of this embodiment ends. If it is not within the threshold range (determined as "no"), the process proceeds to step S1000. The above threshold range is preferably less than 1°.

[0075] In step S1000, the deformation parameter for controlling the body position fixing device 10a is calculated based on the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74°, so that the body position fixing device 10a adjusts the imaging position of the imaging part of the subject.

[0076] Specifically, when the angle α2 between the current axial direction of the Achilles tendon and the main magnetic field direction B0 is less than 54.74°, the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74° is added to the opening angle α1, and the opening angle α1 after the addition is sent to the body position fixing device 10a. When the angle α2 between the current axial direction of the Achilles tendon and the main magnetic field direction B0 is greater than 54.74°, the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74° is subtracted from the opening angle α1, and the opening angle α1 after the subtraction is sent to the body position fixing device 10a. After receiving the calculated opening angle α1, the body position fixing device 10a rotates the rotating part 15a to fix the upper arm part 13a relative to the lower arm part 14a to the calculated opening angle α1.

[0077] After the processing of step S1000 is completed, the process proceeds to step S700 to re-image the imaging part of the subject.

[0078] According to the above embodiment, since the body position fixing device 10 is provided to adjust and fix the imaging position of the imaging part of the subject, the imaging part can be fixed to the desired imaging position without adjusting the whole body position of the subject, and the subject will not feel uncomfortable. In addition, since the imaging part is supported by the body position fixing device 10 during imaging, artifacts caused by the movement of the imaging part during imaging will not be generated.

[0079] In addition, by using the indicator I, the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74° can be accurately measured, thereby accurately adjusting the imaging position of the imaging part so that the Achilles tendon can reliably produce the magic angle effect. Therefore, repeated imaging due to incorrect generation of the magic angle effect can be avoided, and the imaging time can be shortened.

[0080] (Implementation Method 2)

[0081] Next, a body position control system and a body position control method according to Embodiment 2 are described. In Embodiment 2, the differences from Embodiment 1 are mainly described, and the description of the common points with Embodiment 1 is omitted. In the description of Embodiment 2, the same parts as those in Embodiment 1 are denoted by the same reference numerals.

[0082] In the second embodiment, similarly to the first embodiment, the body position control system and the body position control method of the present invention are used for magnetic resonance imaging examination of the Achilles tendon. Fig. 9 1 is a block diagram showing the configuration of a body position control system according to Embodiment 2. The body position control system 1 a according to Embodiment 2 further includes an optical imaging device 40 , as compared to the body position control system 1 according to Embodiment 1.

[0083] The optical imaging device 40 is mounted on the magnetic resonance imaging device and captures the imaging part of the subject. The optical imaging device 40 is, for example, a non-magnetic camera dedicated to magnetic resonance imaging. The optical imaging device 40 includes a communication unit (not shown) and is connected to the body position control device 20 via the network N.

[0084] Fig.10 2 is a flowchart showing a body posture control method according to Embodiment 2. Compared with Embodiment 1, the body posture control method according to Embodiment 2 includes step S600a instead of step S600. The other steps are the same as those in Embodiment 1.

[0085] In step S600a, the optical camera device 40 photographs the ankle of the subject, and the position control device 20 estimates the angle between the axial direction of the Achilles tendon and the main magnetic field direction B0 based on the optical image of the captured ankle, and sets parameters for controlling the deformation of the position fixing device 10a, so that the position fixing device 10a adjusts the imaging position of the imaging part of the subject.

[0086] Specifically, first, the optical camera device 40 captures an optical image of the subject's ankle and sends it to the body position control device 20. The body position control device 20 performs image processing on the received optical image of the ankle, determines the axial direction of the Achilles tendon in the image, and calculates the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74°. The body position control device 20 preferably performs image processing through a trained neural network model, which can be a feedforward neural network, a convolutional neural network, or a Transformer, etc.

[0087] Afterwards, when the angle α2 between the current axial direction of the Achilles tendon and the main magnetic field direction B0 is less than 54.74°, the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74° is added to the opening angle α1, and the opening angle α1 after the addition is sent to the body position fixing device 10a. When the angle α2 between the current axial direction of the Achilles tendon and the main magnetic field direction B0 is greater than 54.74°, the difference between the angle α2 between the axial direction of the Achilles tendon and the main magnetic field direction B0 and 54.74° is subtracted from the opening angle α1, and the opening angle α1 after the subtraction is sent to the body position fixing device 10a. After receiving the calculated opening angle α1, the body position fixing device 10a rotates the rotating part 15a to fix the upper arm part 13a relative to the lower arm part 14a to the calculated opening angle α1.

[0088] After the process of step S600a is completed, the process proceeds to step S700.

[0089] Through the above implementation, the shooting position of the shooting part can be accurately adjusted before the first shooting, so that the Achilles tendon can reliably produce the magic angle effect and avoid repeated shooting.

[0090] (Implementation method 3)

[0091] Next, a body position control system and a body position control method according to Embodiment 3 are described. In Embodiment 3, the differences from Embodiment 1 are mainly described, and the description of the common points with Embodiment 1 is omitted. In the description of Embodiment 3, the same parts as those in Embodiment 1 are denoted by the same reference numerals.

[0092] In the third embodiment, the body position control system and the body position control method of the present invention are used for magnetic resonance imaging examination of the ligament at the patella.

[0093] (Magic Angle Effect of Patellar Ligament)

[0094] When the patellar ligament is examined by magnetic resonance imaging, the lesioned part of the ligament will be displayed as a high signal. On the other hand, if the angle between the axial direction of the collagen fiber ligament and the main magnetic field direction B0 is close to 54.74°, the entire ligament will be displayed as a high signal due to the magic angle effect when using T1-weighted imaging or proton density-weighted imaging with a short echo time, which can easily confuse doctors and lead to misdiagnosis.

[0095] In the posture control method of this embodiment, in order to suppress the magic angle effect of the patellar ligament, the imaging posture of the subject's knee is adjusted so that the angle between the axial direction of the ligament and the main magnetic field direction B0 is away from 54.74°.

[0096] Fig.11 2 is a diagram showing the structure of a body position fixing device used in Embodiment 3. Fig.11 As shown, the body position fixing device 10b has a base portion 16b and a telescopic portion 17b.

[0097] The base 16b is a table with a trapezoidal cross-section, placed on the examination bed 2, and fixes the body position fixing device 10b relative to the examination bed 2. In order to prevent the body position fixing device 10b from moving relative to the examination bed 2, for example, the lower surface of the base 16b can be roughened to increase the friction between the base 16b and the examination bed 2. The telescopic part 17b is a structure that can be telescoped in the vertical direction, directly contacts the knee of the subject, supports the knee and fixes the knee for imaging. The base 16b and the telescopic part 17b are made of non-magnetic materials such as plastic, ceramic or glass.

[0098] Fig.12 : is a flowchart showing the body posture control method according to Embodiment 3. Compared with Embodiment 1, the body posture control method according to Embodiment 3 includes steps S100b and S600b to S1000b instead of steps S100 and S600 to S1000.

[0099] In step S100b, the operator enters the imaging room and attaches the body position fixing device 10b and the imaging coil C to the knee of the subject. Fig.13 This is an explanatory diagram for explaining the installation of the body position fixing device 10b and the imaging coil C. Fig.13 When the patellar ligament is to be photographed, the subject lies supinely on the examination bed 2, and the operator installs the imaging coil C to the knee joint of the subject, and then contracts the telescopic part 17b of the body position fixing device 10b to the lowest height, and installs the body position fixing device 10b under the knee of the subject. The imaging coil C can be a coil dedicated to the knee joint, or it can be a surface coil. In this embodiment, it is assumed that the imaging coil C is a coil dedicated to the knee joint for description. After the processing of step S100b is completed, the processing proceeds to step S200b.

[0100] In step S600b, the operator sets parameters for controlling the deformation of the body position fixing device 10b, and causes the body position fixing device 10b to adjust the imaging body position of the imaging part of the subject.

[0101] Specifically, first, the operator inputs parameters for controlling the deformation of the body position fixing device 10 b on the graphical user interface displayed on the display device 30 . Fig.14 2 is a schematic diagram showing a third graphical user interface G3 displayed in the body posture control method according to the third embodiment. Fig.14, a third graphical user interface G3 for the operator to input parameters for controlling the deformation of the body position fixing device 10b is displayed on the display device 30. The message "Please input the rising height of the body position fixing device" is displayed in the lower area of ​​the screen. An input box for inputting the rising height of the body position fixing device 10b is provided in the upper area of ​​the screen. The setting range of the rising height of the body position fixing device 10b is 0 cm to 30 cm. If the operator inputs a height exceeding the setting range, the operator is reminded to reset it.

[0102] Next, if the user confirms the height, the height is sent to the body position fixing device 10b. After receiving the height set by the operator, the body position fixing device 10b expands and contracts the telescopic part 17b so that the body position fixing device 10b reaches the height set by the operator. Thus, the imaging position of the subject's knee joint is adjusted.

[0103] Next, the relationship between the angle between the axial direction of the patellar ligament and the main magnetic field direction B0 and the rising height of the body position fixing device 10b will be described.

[0104] The patellar ligament is located in the knee joint, and the axial direction of the patella forms a certain angle with the surface direction of the knee joint. Therefore, by adjusting the angle between the surface direction of the knee joint and the main magnetic field direction B0, the angle between the axial direction of the patella and the main magnetic field direction B0 can be adjusted. Fig.15 4 is an explanatory diagram for explaining the relationship between the angle α4 between the surface direction of the knee joint and the main magnetic field direction B0 and the rising height h of the body position fixing device 10b. Fig.15 (a), by reducing the rising height h of the position fixing device 10b, the angle α4 between the surface direction of the knee joint and the horizontal direction (the main magnetic field direction B0) can be reduced, thereby reducing the angle between the axial direction of the patellar ligament and the main magnetic field direction B0. On the other hand, referring to Fig.15 (b) By increasing the rising height h of the position fixing device 10b, the angle α4 between the surface direction of the knee joint and the horizontal direction (the main magnetic field direction B0) can be increased, thereby increasing the angle between the axial direction of the patellar ligament and the main magnetic field direction B0.

[0105] Return to the following Fig.12 After the processing of step S600b is completed, the process proceeds to the processing of step S700b.

[0106] In step S700b, the imaging part, i.e., the knee joint part of the subject is imaged using the set scanning sequence. Specifically, first obtain the cross section of the knee joint and the positioning map of the coronal plane. Then, in the positioning map of the multiple cross sections obtained, determine the cross section where the medial femoral condyle and the lateral femoral condyle are most clearly depicted, so that the positioning line of the sagittal plane is perpendicular to the line between the posterior edge of the medial femoral condyle and the lateral femoral condyle. Afterwards, adjust the angle of the positioning line on the coronal plane so that the sagittal plane positioning line is perpendicular to the articular surface, and the center is located at the lower edge of the patella, including the medial femoral condyle and the lateral femoral condyle. Then, the knee joint of the subject is imaged on the determined sagittal plane. After the processing of step S700b is completed, proceed to the processing of step S800b.

[0107] In step S800b, the difference between the angle between the patellar ligament axis direction and the main magnetic field direction B0 and 54.74° is measured.

[0108] Specifically, first, a fourth graphical user interface for measuring the angle between the axial direction of the patellar ligament and the main magnetic field direction B0 is displayed on the display device 30 . Fig.16 FIG. 4 is a diagram showing an example of a fourth graphical user interface G4 for measuring the angle between the axial direction of the patellar ligament and the main magnetic field direction B0. Fig.16 In the fourth graphical user interface G4, the camera image of the subject's knee obtained in step S700b is displayed, and an indicator I that can be moved arbitrarily is displayed superimposed on the camera image. The structure of the indicator I has been described in the first embodiment, and repeated description is omitted here. Fig.16 In the figure, the position of the patellar ligament is indicated by a thick solid line. The patellar ligament is in the shape of a broken line and has two axial directions. The two axial directions of the patellar ligament are indicated by arrows L2 and L3 respectively.

[0109] Next, the operator moves the indicator I so that the intersection D is located within the patellar ligament. Then, the operator selects one of the auxiliary lines A1 and A2 according to the two axial directions of the patellar ligament, and rotates the camera image so that the axial directions L2 and L3 are consistent with the selected auxiliary line. In addition, the indicator I itself can also be rotated instead of rotating the camera image.

[0110] Afterwards, the rotation angle is calculated and set to the difference between the angle between the two axial directions of the patellar ligament and the main magnetic field direction B0 and 54.74°.

[0111] After the process of step S800b is completed, the process proceeds to step S900b.

[0112] In step S900b, it is determined whether the difference between the angle between the two axial directions of the ligament of the patella and the main magnetic field direction B0 and 54.74° is within the threshold range. If both are within the threshold range (determined as "yes"), the process of the posture control method of this embodiment ends. If any difference is not within the threshold range (determined as "no"), the process proceeds to step S1000b. The above threshold range is preferably greater than 10° and less than 55°.

[0113] In step S1000b, the parameters for controlling the deformation of the position fixing device 10b are calculated based on the difference between the angle between the two ligament axes of the patella and the main magnetic field direction B0 and 54.74°, and the camera position of the knee is adjusted. The angle between the two ligament axes of the patella and the main magnetic field direction B0 is set to be greater than 10° and less than 55 degrees from 54.74°.

[0114] According to the above embodiment, since the body position fixing device 10 is provided to adjust and fix the imaging position of the imaging part of the subject, the imaging part can be fixed to the desired imaging position without adjusting the whole body position of the subject, and the subject will not feel uncomfortable. In addition, since the imaging part is supported by the body position fixing device 10 during imaging, artifacts caused by the movement of the imaging part during imaging will not be generated.

[0115] In addition, by using the indicator I, the difference between the angle α2 between the axial direction of the ligament and the main magnetic field direction B0 and 54.74° can be accurately measured, so as to accurately adjust the imaging position of the imaging part so that the ligament reliably does not produce the magic angle effect. Therefore, repeated imaging due to the inability to suppress the magic angle effect can be avoided, and the imaging time can be shortened.

[0116] In the above embodiment, the present invention is applied to the control of the imaging position when performing magnetic resonance imaging of the ankle and the knee, but the present invention can also be applied to the control of the imaging position of other parts.

[0117] In the above embodiment, the case where the indicator 1 includes two auxiliary lines is illustrated, but the number of auxiliary lines may be one.

[0118] Several embodiments of the present invention are illustrated above, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other forms, and various omissions, substitutions, changes, etc. can be made without departing from the scope of the main purpose of the invention. These embodiments and their variations are included in the scope or main purpose of the invention, and are included in the invention described in the claims and their equivalent scope. In addition, the aforementioned embodiments can be implemented in combination with each other.

Claims

1. A body position control system for controlling the imaging body position of an imaging part of a subject during imaging by a magnetic resonance imaging apparatus, comprising: A body position fixing device, which adjusts and fixes the imaging body position of the imaging part by deformation; a body position control device, which controls the deformation of the body position fixing device by sending deformation parameters to the body position fixing device; and Display device, displaying an image, The body position control device performs parameter setting processing, in which the deformation parameters are set and sent to the body position fixing device, so that the body position fixing device adjusts the imaging body position of the imaging part.

2. The body position control system according to claim 1, wherein: The body position control device also performs the following processing: Difference measurement processing, measuring the difference between the angle between the axial direction of the structure with collagen fibers in the imaging part and the main magnetic field direction of the magnetic resonance imaging device and 54.74°; as well as The first determination process determines whether the difference is within a threshold range, and if the difference is not within the threshold range, resets the deformation parameter based on the difference.

3. The body position control system according to claim 2, wherein: In the difference measurement process, the body position control device causes the display device to display a graphical user interface, in which the camera image and an indicator of the imaging part are displayed in an overlapping manner, and the indicator includes an arrow indicating the direction of the main magnetic field, an auxiliary line that is 54.74° away from the main magnetic field direction and intersects with the arrow at an intersection, and the difference is measured by moving the intersection into the structure in the graphical user interface and rotating the camera image in such a way that the axial direction of the structure is consistent with the auxiliary line.

4. The body position control system according to claim 1, wherein: The body position control system further comprises an optical camera device for photographing the imaging part of the subject. In the parameter setting process, the deformation parameter is set according to the optical image captured by the optical camera device, so that the body position fixing device adjusts the imaging body position of the imaging part.

5. The body position control system according to claim 4, wherein: In the parameter setting process, the optical image is processed by a neural network model to estimate the angle between the structure and the main magnetic field direction.

6. The body position control system according to claim 2, wherein: The structure is the Achilles tendon.

7. The body position control system according to claim 6, wherein: The threshold range is below 1°.

8. The body position control system according to claim 2, wherein: The structure is a ligament.

9. The body position control system according to claim 8, wherein: The threshold range is greater than 10° and less than 55°.

10. The body position control system according to claim 1, wherein: The body position control device further performs a second determination process to determine whether the imaging mode of the camera is T1-weighted imaging with a short echo time or proton density-weighted imaging. When the imaging mode is T1-weighted imaging with short echo time or proton density-weighted imaging, the display device is made to display information to remind the operator to pay attention to the magic angle effect.

11. The body position control system according to claim 1, wherein: The body position fixing device is made of non-magnetic material.

12. The body position control system according to claim 4, wherein: The imaging device is made of non-magnetic material.

13. A body position control method for controlling the imaging body position of an imaging part of a subject during imaging performed by a magnetic resonance imaging device, the body position control method comprising: The step of adjusting and fixing the imaging body position of the imaging part by deformation of a body position fixing device; The step of sending deformation parameters to the body position fixing device by a body position control device to control the deformation of the body position fixing device; and The step of displaying an image by a display device, In a parameter setting step, the body position control device sets the deformation parameter and sends it to the body position fixing device, so that the body position fixing device adjusts the imaging body position of the imaging part.

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