Magnetic resonance imaging system, non-contact motion monitoring method and storage medium

Abstract

The present application relates to a magnetic resonance imaging system, a non-contact motion monitoring method and a storage medium. The non-contact motion monitoring method includes: obtaining motion information of the surface of a subject within the scanning field of view of the magnetic resonance imaging system, wherein the motion information is obtained based on a non-contact motion monitoring unit; extracting spatial feature information of the surface of the subject and physiological motion information of the subject from the motion information, and determining the posture change information of the subject based on the spatial feature information. Through the present application, the problem that the motion monitoring system in the related art cannot simultaneously monitor the posture change information of the subject and the physiological motion caused by vital signs is solved, and the simultaneous monitoring of the posture change information of the subject and the physiological motion caused by vital signs is achieved.

Description

Technical Field

[0001] The present application relates to the field of medical imaging technology, and in particular to a magnetic resonance imaging system, a non-contact motion monitoring method and a storage medium. Background Art

[0002] In medical imaging systems, due to various intentional or unintentional movements of the subject, artifacts are present on the acquired medical scan images, which seriously affects the imaging quality and brings many unfavorable factors to the diagnosis of the disease. At the same time, in application scenarios such as cardiac and abdominal imaging, the subtle changes caused by the subject's inevitable heartbeat, breathing, etc. will also have a certain impact on the imaging. Therefore, it is very necessary to monitor the subject's various movement information during the medical imaging process.

[0003] For the motion information generated by the subject's posture changes, two high-definition cameras are usually used in related technologies to monitor the human posture, and the scanning parameters are adjusted according to the real-time feedback of relevant information of the human posture. For the motion information generated by the subject's breathing and heartbeat, contact equipment is usually used in related technologies to collect it, such as electrocardiogram (ECG) collection equipment and chest strap electrode detector.

[0004] However, there is currently no motion monitoring system that can simultaneously monitor posture change information generated by posture changes of the subject and physiological motion information generated by vital signs. Summary of the invention

[0005] The embodiments of the present application provide a magnetic resonance imaging system, a non-contact motion monitoring method and a storage medium to at least solve the problem that the motion monitoring system in the related art cannot simultaneously monitor the posture change information and the physiological movements caused by the vital signs of the subject.

[0006] In a first aspect, an embodiment of the present application provides a magnetic resonance imaging system, the magnetic resonance imaging system comprising: a scanning bed, a magnetic resonance scanner, a non-contact motion monitoring unit and a computer device; the magnetic resonance scanner forms a scanning cavity with a scanning field of view; the scanning bed is used to carry the subject and move the subject into the scanning field of view; the magnetic resonance scanner and the scanning bed are respectively connected to the computer device; the computer device is used to control the movement of the scanning bed, control the magnetic resonance scanner to collect magnetic resonance data of the subject, and reconstruct a magnetic resonance image according to the magnetic resonance data; the non-contact motion monitoring unit is used to control the movement of the scanning bed, control the magnetic resonance scanner to collect magnetic resonance data of the subject, and reconstruct a magnetic resonance image according to the magnetic resonance data; The touch motion monitoring unit includes a frequency modulated continuous wave sensor, which is connected to the computer device, wherein the frequency modulated continuous wave sensor is used to transmit a radio frequency sweep signal to the scanning field of view, receive a radio frequency echo signal reflected by the surface of the subject within the scanning field of view, and determine the motion information of the subject's surface based on the radio frequency sweep signal and the radio frequency echo signal; the computer device is also used to extract spatial feature information of the subject's surface and physiological motion information of the subject from the motion information, and determine the posture change information of the subject based on the spatial feature information.

[0007] In some embodiments, there are multiple FMCW sensors, the scanning field of view is covered by the RF sweep signals emitted by the multiple FMCW sensors, and the RF sweep signals emitted by each FMCW sensor at the same time do not interfere with each other.

[0008] In some embodiments, the FMCW sensor includes a transmitting antenna and a receiving antenna, and the transmitting antenna and the receiving antenna are embedded in the magnetic resonance scanner of the magnetic resonance imaging system.

[0009] In some embodiments, the multiple frequency-modulated continuous wave sensors include a first frequency-modulated continuous wave sensor and a second frequency-modulated continuous wave sensor, wherein the transmitting antenna and the receiving antenna of the first frequency-modulated continuous wave sensor are embedded in the magnetic resonance scanner of the magnetic resonance imaging system and are distributed on one side of the scanning field of view along the axial direction; the transmitting antenna and the receiving antenna of the second frequency-modulated continuous wave sensor are embedded in the magnetic resonance scanner of the magnetic resonance imaging system and are distributed on the other side of the scanning field of view along the axial direction.

[0010] In some of the embodiments, the FMCW sensor includes at least one transmitting antenna and a plurality of receiving antennas.

[0011] In some embodiments, the frequency of the RF swept frequency signal emitted by the FMCW sensor is not less than 60 GHz.

[0012] In a second aspect, an embodiment of the present application provides a non-contact motion monitoring method, which is applied to the magnetic resonance imaging system described in the first aspect, comprising: acquiring motion information of the surface of a subject within the scanning field of view of the magnetic resonance imaging system, wherein the motion information is acquired based on the non-contact motion monitoring unit; extracting spatial feature information of the surface of the subject and physiological motion information of the subject from the motion information, and determining posture change information of the subject based on the spatial feature information.

[0013] In some of the embodiments, after extracting the spatial feature information of the subject's surface and the physiological motion information of the subject from the motion information, and determining the posture change information of the subject based on the spatial feature information, the method further includes: generating a gated acquisition signal for controlling the magnetic resonance imaging system to perform data acquisition based on the posture change information and the physiological motion information.

[0014] In some of the embodiments, after extracting the spatial feature information of the subject's surface and the subject's physiological motion information from the motion information, and determining the subject's posture change information based on the spatial feature information, the method further includes: performing artifact correction on the magnetic resonance image based on the posture change information and the physiological motion information during reconstruction of the magnetic resonance image by the magnetic resonance imaging system.

[0015] In some of the embodiments, when the motion information is acquired by a plurality of the frequency modulated continuous wave sensors respectively, acquiring the motion information of the surface of the subject within the scanning field of view of the magnetic resonance imaging system includes: acquiring the motion information acquired by each of the plurality of frequency modulated continuous wave sensors at the same time respectively, and fusing the motion information acquired by each frequency modulated continuous wave sensor at the same time according to the spatial position of the scanning field of view covered by each frequency modulated continuous wave sensor, so as to obtain the motion information of the surface of the subject.

[0016] In some embodiments, the spatial feature information includes contour feature information; extracting the spatial feature information of the subject's surface from the motion information, and determining the subject's posture change information based on the spatial feature information includes: extracting the contour feature information of the subject's surface from the motion information; tracking the motion information of the contour of the subject's surface based on the contour feature information; determining the subject's posture change information based on the motion information of the subject's surface contour.

[0017] In some of the embodiments, extracting the spatial characteristic information of the subject's surface and the physiological movement information of the subject from the motion information, and determining the posture change information of the subject based on the spatial characteristic information includes: extracting the motion information corresponding to the region of interest from the motion information; extracting the spatial characteristic information of the subject's surface and the physiological movement information of the subject from the motion information corresponding to the region of interest, and determining the posture change information of the subject based on the spatial characteristic information.

[0018] In a third aspect, an embodiment of the present application provides a storage medium, in which a computer program is stored, wherein the computer program is configured to execute the non-contact motion monitoring method described in the second aspect when running.

[0019] Compared with the related art, the magnetic resonance imaging system, non-contact motion monitoring method and storage medium provided in the embodiments of the present application obtain motion information of the surface of the subject within the scanning field of view of the magnetic resonance imaging system, wherein the motion information is obtained based on a non-contact motion monitoring unit; extract spatial feature information of the surface of the subject and physiological motion information of the subject from the motion information, and determine the posture change information of the subject based on the spatial feature information, thereby solving the problem that the motion monitoring system in the related art cannot simultaneously monitor the posture change information of the subject and the physiological motion caused by vital signs, and realizes the simultaneous monitoring of the posture change information of the subject and the physiological motion caused by vital signs.

[0020] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0022] Figure 1 is a structural block diagram of a magnetic resonance imaging system according to an embodiment of the present application;

[0023] Figure 2 is a structural block diagram of a digitally controlled oscillator 302 according to a preferred embodiment of the present application;

[0024] Figure 3 is a schematic structural diagram of a magnetic resonance imaging system with a non-contact motion monitoring unit according to an embodiment of the present application;

[0025] Figure 4is a top view of a magnetic resonance imaging system with a non-contact motion monitoring unit according to an embodiment of the present application;

[0026] Figure 5 is a front view of a magnetic resonance imaging system with a non-contact motion monitoring unit according to an embodiment of the present application;

[0027] Figure 6 is a top view of a magnetic resonance imaging system with a non-contact motion monitoring unit according to a preferred embodiment of the present application;

[0028] Figure 7 is a flow chart of a non-contact motion monitoring method according to an embodiment of the present application;

[0029] Figure 8 is a structural block diagram of an electronic device according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0031] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0032] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0033] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0034] In an embodiment of the present application, a magnetic resonance imaging system is provided. Figure 1 is a structural block diagram of a magnetic resonance imaging system according to an embodiment of the present application, such as Figure 1 As shown, the magnetic resonance imaging system includes: a scanning bed 10 , a magnetic resonance scanner 20 , a non-contact motion monitoring unit 30 and a computer device 40 .

[0035] The magnetic resonance scanner 20 is formed with a scanning cavity having a scanning field of view 201. In some embodiments, a body coil 202 and a main magnet 203 are provided in the magnetic resonance scanner 20. The main magnet 203 may be composed of a superconducting coil for generating a main magnetic field. In some embodiments, the main magnet 203 may also be a permanent magnet. The main magnet 203 may be used to generate a main magnetic field strength of 0.2 Tesla, 0.5 Tesla, 1.0 Tesla, 1.5 Tesla, 3.0 Tesla or higher.

[0036] During magnetic resonance imaging, the subject 50 is carried by the scanning bed 10 , and as the bed board of the scanning bed 10 moves, the subject 50 is moved into a scanning field of view 201 where the magnetic field distribution of the main magnetic field is uniform.

[0037] Typically for magnetic resonance imaging systems, such as Figure 1As shown, the z direction of the spatial coordinate system is set to be the same as the axial direction of the magnetic resonance imaging system. The length direction of the subject 50 is usually kept consistent with the z direction for imaging. The horizontal plane of the magnetic resonance imaging system is set to the xz plane, the x direction is perpendicular to the z direction, and the y direction is perpendicular to both the x and z directions.

[0038] In magnetic resonance imaging, in the magnetic resonance scanner 20, the pulse control unit 204 controls the radio frequency pulse generating unit 205 to generate radio frequency pulses. After being amplified by the amplifier, the radio frequency pulses are sent out by the body coil 202 through the switch control unit 206 to perform radio frequency excitation on the subject 50. According to the radio frequency excitation, the subject 50 will generate corresponding radio frequency signals by resonance. When receiving the radio frequency signal generated by the subject 50 according to the excitation, it can be received by the body coil 202. There can be many radio frequency receiving links. After the radio frequency signal is sent to the radio frequency receiving unit 207, it is further sent to the image reconstruction unit 401 of the computer device 40 for image reconstruction to form a magnetic resonance image.

[0039] The magnetic resonance scanner 20 further includes a gradient coil 208, which can be used to spatially encode the radio frequency signal during magnetic resonance imaging. The pulse control unit 204 controls the gradient signal generating unit 209 to generate a gradient signal, which is usually divided into three mutually orthogonal direction signals: x direction, y direction and z direction. The gradient signals in different directions are amplified by the gradient amplifier (210, 211, 212) and then emitted by the gradient coil 208 to generate a gradient magnetic field within the scanning field of view 201.

[0040] The computer device 40 at least includes an image reconstruction unit 401 and a processor 402 , and may further include a display unit 403 , an input / output device 404 , a memory 405 , and a communication port 406 .

[0041] The pulse control unit 204, the image reconstruction unit 401, the processor 402, the display unit 403, the input / output device 404, the memory 405, and the communication port 406 can transmit data through the communication bus 60, thereby realizing the control of the magnetic resonance imaging process.

[0042] The processor 402 may be composed of one or more processors, including a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0043] The display unit 403 may be a display provided to the user for displaying images.

[0044] The input / output device 404 may be a keyboard, a mouse, a control box or other related devices, which supports input / output of corresponding data streams.

[0045] The memory 405 may include a large capacity memory for data or instructions. By way of example and not limitation, the memory 405 may include a hard disk drive (HDD), a floppy disk drive, a solid state drive (SSD), a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these.

[0046] The communication port 406 can realize data communication with other components such as external devices, image acquisition devices, databases, external storage, and image processing workstations.

[0047] Wherein, the communication bus 60 includes hardware, software or both, coupling the components of the magnetic resonance imaging system to each other. The communication bus 60 includes, but is not limited to, at least one of the following: a data bus, an address bus, a control bus, an expansion bus, and a local bus. Where appropriate, the communication bus 60 may include one or more buses. Although the embodiments of the present application describe and illustrate specific buses, the present application considers any suitable bus or interconnection.

[0048] The non-contact motion monitoring unit 30 of this embodiment includes one or more frequency modulated continuous wave sensors. The frequency modulated continuous wave sensor is used to transmit a radio frequency sweep signal to a scanning field of view, receive a radio frequency echo signal reflected from the surface of the subject in the scanned field of view, and determine the motion information of the surface of the subject according to the radio frequency sweep signal and the radio frequency echo signal.

[0049] The computer device 40 of this embodiment is also used to extract spatial feature information of the subject's surface and physiological motion information of the subject from the motion information, and to determine posture change information of the subject according to the spatial feature information.

[0050] Among them, the frequency modulated continuous wave sensor can be but is not limited to a radar sensor operating in a frequency modulated continuous wave mode, and the radar sensor can be composed of analog devices and / or digital chips. For example, in some of the embodiments, the non-contact motion monitoring unit can also include a housing and a circuit board, the circuit board is accommodated in the housing, and one or more frequency modulated continuous wave sensors are mounted on the circuit board. In the above manner, the non-contact motion monitoring unit is integrated into a relatively independent module to facilitate multi-module expansion and installation. The non-contact motion monitoring unit can be embedded in the housing of the magnetic resonance scanner and located on the outside of the superconducting coil. In other embodiments, the non-contact motion monitoring unit can be packaged as a whole, or implemented by a digital circuit, so as to be integrated into a digital chip, and the transmitting antenna and the receiving antenna are peripheral devices of the digital chip. The non-contact motion monitoring unit is integrated and digitized in the above manner, and the volume of the non-contact motion monitoring unit is further reduced.

[0051] By way of example and not limitation, Figure 1 For example, the frequency modulated continuous wave sensor of this embodiment may include a clock generator 301, a digitally controlled oscillator 302, a signal processing unit 303, a coupler 304, a mixer 305, a transmitting antenna 306, a receiving antenna 307 and a digital signal processor 308. The clock generator 301 is connected to the digitally controlled oscillator 302 to generate a reference clock signal. The digitally controlled oscillator 302 is respectively connected to the signal processing unit 303 and the digital signal processor 308 to generate a digital frequency sweep signal of a preset bandwidth according to the reference clock signal and the waveform parameters output by the digital signal processor 308. The signal processing unit 303 is respectively coupled to the transmitting antenna 306 and the mixer 305 through the coupler 304 to convert the digital frequency sweep signal into an analog frequency sweep signal, and modulate the analog frequency sweep signal to radio frequency to obtain a radio frequency sweep signal. The transmitting antenna 306 is used to transmit the radio frequency sweep signal to the scanning field of view. The receiving antenna 307 is connected to the mixer 305 and is used to receive the radio frequency echo signal reflected from the surface of the subject 50 in the scanned field of view 201. The digital signal processor 308 is connected to the mixer 305 and the digital control oscillator 302 respectively and is used to determine the motion information of the surface of the subject according to the radio frequency sweep signal and the radio frequency echo signal.

[0052] The computer device 40 is connected to the digital signal processor 308, and is used to extract the spatial feature information of the subject's surface and the subject's physiological movement information from the motion information output by the digital signal processor 308, and determine the subject's posture change information based on the spatial feature information.

[0053] In some embodiments, the RF sweep signal can be generated by any sweep signal generation technology in the prior art. For example, a direct digital frequency synthesis technology can be used to generate a digital sweep signal, and the signal processing unit performs digital-to-analog conversion and modulates it to radio frequency to obtain a RF sweep signal.

[0054] Take the implementation of direct digital frequency synthesis by digitally controlled oscillator 302 as an example. Figure 2 3 is a block diagram of a digital controlled oscillator 302 according to an embodiment of the present application. Figure 2 As shown, in some embodiments, the digital controlled oscillator 302 includes: a frequency control word register 3021, a phase accumulator 3022, a phase control word register 3023, a phase modulator 3024 and a waveform lookup table 3025, wherein the frequency control word register 3021, the phase accumulator 3022, the phase modulator 3024 and the waveform lookup table 3025 are connected in sequence, the phase control word register 3023 is connected to the phase modulator 3024, and the clock generator 301 is respectively connected to the phase accumulator 3022, the phase modulator 3024 and the waveform lookup table 3025. The phase accumulation increment corresponding to the frequency control word stored in the frequency control word register is used to control the frequency sweep rate of the frequency sweep digital signal; the phase offset stored in the phase control word register changes within a preset phase offset range to control the working frequency point of the digital signal generated by the phase modulator to change within the corresponding frequency band to obtain a frequency sweep digital signal. Wherein, the frequency control word and the phase control word are determined by the waveform parameters output by the digital signal processor 308.

[0055] By using the above-mentioned digital controlled oscillator and direct digital frequency synthesis technology, the phase offset of the reference clock signal is continuously changed by adjusting the phase control word in the phase control word register, and the phase accumulation increment is changed by adjusting the frequency control word in the frequency control word register, and the frequency sweep rate is changed, thereby obtaining a digital frequency sweep signal with a preset bandwidth. The preset bandwidth can be any value between 100MHz and 150MHz. The digital frequency sweep signal generated by the above-mentioned digital controlled oscillator includes a rising portion whose frequency rises linearly in sequence, and a falling portion whose frequency falls linearly in sequence following the rising portion.

[0056] The digital frequency sweep signal is converted into an analog frequency sweep signal by the signal processing unit and modulated to a radio frequency to obtain a radio frequency frequency sweep signal. In some embodiments, the frequency of the radio frequency sweep signal is not less than 60 GHz.

[0057] The frequency modulated continuous wave sensor of this embodiment may include at least one transmitting antenna and multiple receiving antennas. In this embodiment, the frequency modulated continuous wave sensor operates in a frequency modulated continuous wave (FMCW) mode, that is, a radio frequency sweep signal with a linearly changing frequency is continuously transmitted through at least one transmitting antenna, and then multiple receiving antennas are used to receive radio frequency echo signals reflected from various angles of the subject's surface within the scanning field of view, and the distance or speed information of the subject's surface can be determined based on the frequency and / or phase difference between these radio frequency sweep signals and the radio frequency echo signals, thereby obtaining the motion information of the subject's surface.

[0058] In the related art, the motion monitoring unit used in the field of medical imaging is usually a 24GHz sensor. In the related art, a radio frequency sweep signal of one frequency band is usually used to detect the movement of the lungs to obtain respiratory motion information, and a radio frequency sweep signal of another frequency band is used to detect the movement of the heart to obtain heartbeat motion information. There are also related technologies that use the same frequency band to simultaneously detect the movement of the heart and lungs, and then obtain heartbeat motion information and respiratory motion information through spectrum analysis.

[0059] The difference from the related art is that, in this embodiment, the frequency of the RF sweep signal emitted by the frequency modulated continuous wave sensor is not less than 60 GHz, for example, it can be between 60 GHz and 64 GHz, and / or between 64 GHz and 80 GHz. Since the respiratory movement and cardiac movement of the human body will cause micro-motion on the surface of the chest cavity, the physiological motion information of the subject, such as respiratory motion information and cardiac motion information, can be obtained by detecting the surface motion of the subject in this embodiment. Compared with the 24 GHz sensor, the detection accuracy of the motion information of the surface of the subject by using the RF sweep signal of not less than 60 GHz is higher than that of the 24 GHz sensor because the wavelength of the RF sweep signal of not less than 60 GHz is not greater than 5 mm, and it is particularly suitable for the detection of motion information of the micro-motion on the surface of the chest cavity caused by the respiratory movement and cardiac movement of the human body.

[0060] In addition, in an embodiment, the posture change information of the subject is simultaneously obtained by extracting the spatial feature information of the surface of the subject. For example: when the human body breathes evenly, each position on the human chest presents an undulating motion with a certain regularity, and the undulating motion of each position is compared with other positions, and there are slight differences in amplitude, speed, and direction. Therefore, if these slight differences are used as spatial feature information, and the changes of these spatial feature information in space are tracked in the acquired motion information of the subject's surface, the posture change information of the subject can be obtained. It can be seen that the posture change information and physiological motion information of the subject can be obtained at the same time through the embodiments of the present application.

[0061] In addition, compared with the 24 GHz sensor commonly used in the prior art, the frequency modulation continuous wave sensor of this embodiment has a larger frequency interval between the RF frequency sweep signal of not less than 60 GHz and the working frequency of the magnetic resonance imaging system, so the frequency modulation continuous wave sensor has a strong anti-interference ability when used in the magnetic resonance imaging system. In addition, since the wavelength becomes smaller, the antenna size of a single transmitting antenna and a receiving antenna of the frequency modulation continuous wave sensor can be made smaller, and it is easier to be embedded in the magnetic resonance imaging system.

[0062] Figure 3 is a schematic structural diagram of a magnetic resonance imaging system with a non-contact motion monitoring unit according to an embodiment of the present application, such as Figure 3 As shown, the magnetic resonance imaging system includes: a magnetic resonance scanner 20 for collecting scanning data, a scanning cavity with a scanning field of view formed by the magnetic resonance scanner 20, a scanning bed 10 for carrying an examinee and being able to move the examinee into the scanning field of view as the bed plate moves, and a computer device 40 for controlling the scanning bed 10 and the magnetic resonance scanner 20 to collect scanning data and reconstruct a medical scanning image according to the collected scanning data. The magnetic resonance imaging system also includes: a non-contact motion monitoring unit 30. Figure 4 is a top view of a magnetic resonance imaging system with a non-contact motion monitoring unit according to an embodiment of the present application; Figure 5 is a front view of a magnetic resonance imaging system with a non-contact motion monitoring unit according to an embodiment of the present application. Figures 3 to 5 The non-contact motion monitoring unit 30 includes at least a portion of an antenna embedded above the scanning cavity of the magnetic resonance imaging system, for example, embedded on the magnetic resonance scanner 20, and arranged toward the scanning field of view. The non-contact motion monitoring unit 30 is also connected to a computer device 40. The computer device 40 is also used to extract spatial feature information of the surface of the subject from the motion information, and determine the posture change information of the subject according to the spatial feature information; and extract physiological motion information of the subject from the motion information.

[0063] In order to achieve coverage of most or almost the entire scanning field of view, in some embodiments, two or more frequency modulated continuous wave sensors are used to monitor various parts of the scanning field of view. Figure 6 is a top view of a magnetic resonance imaging system with a non-contact motion monitoring unit according to a preferred embodiment of the present application, such as Figure 6As shown, the non-contact motion monitoring unit 30 includes at least two frequency modulated continuous wave sensors, namely a first frequency modulated continuous wave sensor and a second frequency modulated continuous wave sensor. The first frequency modulated continuous wave sensor 3001 includes at least a portion of an antenna embedded above the scanning cavity of the magnetic resonance imaging system; the second frequency modulated continuous wave sensor 3002 includes at least a portion of an antenna embedded above the scanning cavity of the magnetic resonance imaging system, and they are distributed on both sides of the scanning field of view along the axial direction AA. The scanning field of the magnetic resonance imaging system can be covered by the RF sweep signals emitted by the first frequency modulated continuous wave sensor 3001 and the second frequency modulated continuous wave sensor 3002, and the RF sweep signals emitted by each frequency modulated continuous wave sensor at the same time do not interfere with each other.

[0064] Among them, the partial scanning fields of view covered by the first FMCW sensor 3001 and the second FMCW sensor 3002 may not overlap, may partially overlap or completely overlap, which is not limited in the present application. Among them, when the coverage areas of the two FMCW sensors do not overlap, the motion information obtained by the two FMCW sensors at the same time can be obtained respectively, and the motion information obtained by the two FMCW sensors at the same time can be fused according to the spatial position of the scanning fields of view covered by each FMCW sensor to obtain the motion information of the surface of the subject. For example, when the coverage areas of the two FMCW sensors partially overlap, the RF echo signal data of the overlapping areas detected by the two FMCW sensors can be selected and fused to obtain the RF echo signal data of the entire area covered by the RF sweep signal; the RF echo signal data of the overlapping areas can also be weighted and fused to obtain the RF echo signal data of the entire area covered by the RF sweep signal. When the coverage areas of the two FMCW sensors completely overlap, the RF echo signal data detected by one FMCW sensor can be used to verify the RF echo signal data detected by the other FMCW sensor.

[0065] It should be noted that, although two frequency modulated continuous wave sensors are described and illustrated in the above embodiment, the embodiment of the present application is not limited to using two frequency modulated continuous wave sensors for motion monitoring. For example, according to the size of the space for installing the non-contact motion monitoring unit, the scanning field of view of a single frequency modulated continuous wave sensor, the size of the scanning field of view of the magnetic resonance imaging system and the distance from the frequency modulated continuous wave sensor and other factors, one, three or more frequency modulated continuous wave sensors can be selected. When a non-contact motion monitoring unit with three or more frequency modulated continuous wave sensors is used, these frequency modulated continuous wave sensors are evenly embedded above the scanning cavity of the magnetic resonance imaging system and distributed on both sides of the scanning field of view along the axial direction, so as to make full use of the installation position of the scanning cavity and ensure as complete coverage of the scanning field of view as possible.

[0066] In this embodiment, the non-contact motion monitoring unit transmits a radio frequency sweep signal that can cover the scanning field of view of the magnetic resonance imaging system, receives a radio frequency echo signal reflected from the scanning field of view, and then determines the motion information of the surface of the subject based on the radio frequency sweep signal and the radio frequency echo signal reflected from the surface of the subject in the scanning field of view; the computer device obtains the motion information of the surface of the subject in the scanning field of view of the magnetic resonance imaging system, and then extracts the spatial feature information of the surface of the subject from the motion information, and determines the posture change information of the subject based on the spatial feature information; and extracts the physiological motion information of the subject from the motion information. The motion information determined by the non-contact motion monitoring unit can be instantaneous speed information or displacement information relative to a reference position.

[0067] In the above embodiment, the spatial feature information of the surface of the subject is extracted from the motion information, and the posture change information of the subject is determined based on the spatial feature information. For example, when the human body breathes evenly, each position on the thorax of the human body exhibits a regular ups and downs motion, and the ups and downs motion of each position is slightly different in amplitude, speed, and direction compared with other positions. Therefore, if these slight differences are used as spatial feature information, and the changes of these spatial feature information in space are tracked in the acquired motion information of the subject's surface, the posture change information of the subject can be obtained.

[0068] Among them, the significant spatial feature information of the subject is the contour feature information of the subject's surface. For example, under a fixed scanning field of view, the edge of the subject's surface forms a contour, and the non-contact motion monitoring unit can detect motion information at the detection position within the contour, while the detection position outside the contour is the bed board of the scanning bed, which usually has no relative motion with the non-contact motion monitoring unit during the scanning process. Therefore, the motion information of the contour of the subject's surface can be located through the contour feature information, and the posture change information of the subject can be determined based on the motion information of the contour, such as determining whether the subject has left-right translational motion within the scanning field of view.

[0069] In some of the embodiments, extracting spatial feature information of the subject's surface from the motion information, and determining the subject's posture change information based on the spatial feature information includes: extracting contour feature information of the subject's surface from the motion information; tracking the motion information of the contour of the subject's surface based on the contour feature information; and determining the subject's posture change information based on the motion information of the subject's surface contour.

[0070] The following describes the extraction process of posture change information by taking the instantaneous velocity information of 16 detection positions of 4×4 uniformly distributed in spatial positions on the entire surface of the subject within the scanning field of view as an example.

[0071] At time t1, according to the radio frequency echo signal monitored by the non-contact motion monitoring unit, the instantaneous speeds at 16 detection positions are:

[0072]

[0073] At time t2, the instantaneous speeds at these 16 detection positions are obtained again based on the radio frequency echo signal monitored by the non-contact motion monitoring unit:

[0074]

[0075] This means that from time t1 to time t2, the subject changed his posture to the right, resulting in the subject not being detected on the left side of the scanning field of view, and thus the detected instantaneous speed was 0.

[0076] The above examples are merely schematic illustrations of how the subject's posture change information can be obtained by using the motion information of the entire surface, and are not limited to the above methods when actually extracting the posture change information. For example, the motion characteristics of the target at each detection position (such as the range of change of the instantaneous velocity, the magnitude of change of the instantaneous velocity compared to the adjacent detection position, etc.) can also be extracted, and the detection position can be tracked according to the motion characteristics, and the posture change information can be obtained according to the tracking results. For example, the subject can also be spatially imaged according to the motion information, and then the posture change information can be determined according to the displacement of the real-time spatial imaging.

[0077] The above-mentioned non-contact motion monitoring unit can also monitor physiological motion, wherein the physiological motion includes but is not limited to respiratory motion and / or cardiac motion. Since the frequencies of respiratory motion and cardiac motion are greatly different, the respiratory motion information and cardiac motion information in the motion information can be separated by spectrum analysis. For example, the motion information is first filtered to remove interference signals; then the filtered motion information is Fourier transformed and transformed into the frequency domain; then the respiratory motion information and cardiac motion information are separated in the frequency domain according to the frequency interval of the respiratory motion and the frequency interval of the cardiac motion, and then transformed into the time domain to obtain the respiratory motion information and the cardiac motion information.

[0078] It can be seen that the above-mentioned magnetic resonance imaging system can simultaneously monitor the posture change information of the subject and the physiological movement caused by the vital signs. Moreover, after obtaining the posture change information, the posture change information can also be used to correct the physiological movement caused by the vital signs, thereby improving the monitoring effect of the physiological movement.

[0079] This embodiment also provides a non-contact motion monitoring method, which can be applied to the above-mentioned magnetic resonance imaging system.

[0080] Figure 7 is a flow chart of a non-contact motion monitoring method according to an embodiment of the present application, such as Figure 7 As shown, the process includes the following steps:

[0081] Step S701 : acquiring motion information of a surface of a subject within a scanning field of view of a magnetic resonance imaging system, wherein the motion information is acquired based on a non-contact motion monitoring unit.

[0082] Step S702: extracting spatial feature information of the subject's surface and physiological motion information of the subject from the motion information, and determining posture change information of the subject according to the spatial feature information.

[0083] Through the above steps, the problem that the motion monitoring system in the related art cannot simultaneously monitor the posture change information of the subject and the physiological movements caused by vital signs is solved, and the simultaneous monitoring of the posture change information of the subject and the physiological movements caused by vital signs is achieved.

[0084] In some embodiments, the motion information is detected by multiple frequency modulated continuous wave sensors. When acquiring the motion information of the surface of the subject within the scanning field of view of the magnetic resonance imaging system, the motion information acquired by each frequency modulated continuous wave sensor in the multiple frequency modulated continuous wave sensors at the same time can be acquired respectively, and the motion information acquired by each frequency modulated continuous wave sensor at the same time can be fused according to the spatial position of the scanning field of view covered by each frequency modulated continuous wave sensor to obtain the motion information of the surface of the subject. Through the detection of multiple frequency modulated continuous wave sensors and the fusion of motion information, the scanning field of view can be fully covered.

[0085] In some of the embodiments, the spatial feature information includes contour feature information; extracting the spatial feature information of the subject's surface from the motion information, and determining the subject's posture change information based on the spatial feature information includes the following steps: extracting the contour feature information of the subject's surface from the motion information; tracking the motion information of the contour of the subject's surface based on the contour feature information; determining the subject's posture change information based on the motion information of the subject's surface contour.

[0086] Typically, the physiological motion information of the subject can be extracted from the motion information of the subject by selecting the motion information of one of the detection positions, and separating the physiological motion information from the motion information by filtering and spectrum analysis. However, since the motion information of the subject at each position in the scanning field of view is not the same, and each detection position is affected by the posture change information, the selection of the detection position is critical to whether accurate physiological motion information can be extracted; if the detection position is not selected accurately, physiological motion monitoring may fail. In order to solve this problem, in the embodiment of the present application, de-averaging is used to eliminate or reduce the impact of posture changes on physiological motion information, and the physiological motion information is extracted by changing the motion mean of the subject's surface, thereby avoiding the difference in physiological motion response of different detection positions.

[0087] For example, in some embodiments, the mean of motion information corresponding to multiple detection positions of the subject's surface detected by the non-contact motion monitoring unit is determined, and the subject's respiratory motion information is determined based on the change in the mean of the motion information corresponding to the multiple detection positions; the motion information corresponding to the multiple detection positions is de-averaged respectively; and the subject's heartbeat motion information is determined based on the motion information corresponding to the multiple detection positions after de-averaging. In this way, the problem that a single detection position cannot accurately represent physiological motion is avoided.

[0088] The frequency of the respiratory signal is lower than that of the heartbeat signal, and in the motion information of the subject detected by the non-contact motion monitoring unit, the waveforms of the respiratory signal and the heartbeat signal are superimposed on each other. In the related art, the respiratory signal and the heartbeat signal are usually separated by spectrum analysis or filtering. In this embodiment, the motion information of multiple detection positions can be subtracted from the mean of the motion information of multiple detection positions, that is, the mean value is removed to obtain the heartbeat motion information of multiple detection positions, thereby achieving a similar filtering effect. Similar to the respiratory signal, when determining the heartbeat signal of the subject based on the heartbeat motion information of multiple detection positions, the mean method can also be used to avoid the problem that a single detection position cannot accurately describe the respiratory signal, thereby improving the robustness of the system.

[0089] In some embodiments, after the subject's physiological motion information is extracted from the subject's motion information, a gated acquisition signal can be generated according to the physiological motion information, and the gated acquisition signal is used to trigger the magnetic resonance imaging system to scan the subject. In this way, the magnetic resonance imaging system can be triggered to acquire scanning data at an appropriate time to improve the imaging quality.

[0090] In some of the embodiments, after obtaining the motion information of the surface of the subject within the scanning field of view of the magnetic resonance imaging system, the motion information can be sent to a medical image reconstruction device corresponding to the magnetic resonance imaging system, so that the medical image reconstruction device can perform motion artifact correction according to the motion information during the medical scanning image reconstruction process. In the above manner, motion artifacts can be corrected in real time according to the motion information, thereby improving the imaging quality.

[0091] In some of the embodiments, the region of interest of the subject can also be determined based on the scanning information of the subject obtained by the magnetic resonance imaging system. In the above step S702, the spatial feature information of the region of interest on the surface of the subject can be extracted from the motion information, and the posture change information of the subject can be determined based on the spatial feature information; and the physiological motion information of the subject can be extracted from the motion information of the region of interest on the surface of the subject. By extracting the region of interest, the amount of data required for calculation can be reduced and the real-time performance can be improved; and by setting the scanning area of ​​interest of the magnetic resonance imaging system as the region of interest, or setting the area significantly affected by breathing and heartbeat motion as the region of interest, the interference of non-interested regions can be eliminated.

[0092] This embodiment also provides an electronic device, Figure 8 is a structural block diagram of an electronic device according to an embodiment of the present application. Figure 8 As shown, the electronic device may include one or more processors 82 and a memory 84 for storing data. Optionally, the electronic device may also include a transmission device 86 and an input / output device 88 for communication functions. It will be understood by those skilled in the art that Figure 8 The structure shown is only for illustration and does not limit the structure of the above terminal. Figure 8 More or fewer components as shown, or with Figure 8 Different configurations shown.

[0093] The memory 84 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the non-contact motion monitoring method in the embodiment of the present application. The processor 82 executes various functional applications and data processing by running the computer program stored in the memory 84, that is, to implement the above method. The memory 84 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 84 may further include a memory remotely arranged relative to the processor 82, and these remote memories may be connected to the electronic device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0094] The transmission device 86 is used to receive or send data via a network. The specific example of the above network may include a wireless network provided by a communication provider of the electronic device. In one example, the transmission device 86 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 86 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0095] In addition, in combination with the non-contact motion monitoring method in the above embodiments, the present application embodiment can provide a computer-readable storage medium for implementation. The computer-readable storage medium stores a computer program; when the computer program is executed by a processor, any non-contact motion monitoring method in the above embodiments is implemented.

[0096] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A magnetic resonance imaging system, comprising: A scanning bed, a magnetic resonance scanner, a non-contact motion monitoring unit and a computer device; the magnetic resonance scanner is formed with a scanning cavity having a scanning field of view; The scanning bed is used to carry the subject and move the subject into the scanning field of view; The magnetic resonance scanner and the scanning bed are connected to the computer device respectively; the computer device is used to control the movement of the scanning bed, control the magnetic resonance scanner to collect magnetic resonance data of the subject, and reconstruct a magnetic resonance image according to the magnetic resonance data; the non-contact motion monitoring unit includes a frequency modulated continuous wave sensor, the number of the frequency modulated continuous wave sensors is multiple, the coverage areas corresponding to the scanning field of view of two of the frequency modulated continuous wave sensors are at least partially different, the scanning field of view is covered by the radio frequency sweeping signals emitted by the multiple frequency modulated continuous wave sensors, and the frequency modulated continuous wave sensors are connected to the computer device, wherein, The frequency modulated continuous wave sensor is used to transmit a radio frequency sweep signal to the scanning field of view, receive a radio frequency echo signal reflected by the surface of the subject within the scanning field of view, and determine the motion information of the surface of the subject based on the radio frequency sweep signal and the radio frequency echo signal; The computer device is also used to obtain motion information obtained by each frequency modulated continuous wave sensor at the same time, and fuse the motion information obtained by each frequency modulated continuous wave sensor at the same time according to the spatial position of the scanning field of view covered by each frequency modulated continuous wave sensor to obtain motion information of the surface of the subject; extract spatial feature information of the surface of the subject and physiological motion information of the subject from the motion information of the surface of the subject, and determine posture change information of the subject based on the spatial feature information.

2. The magnetic resonance imaging system according to claim 1, characterized in that The RF sweep signals emitted by each FMCW sensor at the same time do not interfere with each other.

3. The magnetic resonance imaging system according to claim 1, characterized in that The frequency modulated continuous wave sensor comprises a transmitting antenna and a receiving antenna, and the transmitting antenna and the receiving antenna are embedded in the magnetic resonance scanner of the magnetic resonance imaging system.

4. The magnetic resonance imaging system according to claim 2, characterized in that: The multiple frequency-modulated continuous wave sensors include a first frequency-modulated continuous wave sensor and a second frequency-modulated continuous wave sensor, wherein the transmitting antenna and the receiving antenna of the first frequency-modulated continuous wave sensor are embedded in the magnetic resonance scanner of the magnetic resonance imaging system and are distributed on one side of the scanning field of view along the axial direction; the transmitting antenna and the receiving antenna of the second frequency-modulated continuous wave sensor are embedded in the magnetic resonance scanner of the magnetic resonance imaging system and are distributed on the other side of the scanning field of view along the axial direction.

5. The magnetic resonance imaging system according to claim 1, characterized in that: The frequency modulated continuous wave sensor includes at least one transmitting antenna and a plurality of receiving antennas.

6. The magnetic resonance imaging system according to claim 1, characterized in that: The frequency of the radio frequency sweep signal emitted by the frequency modulated continuous wave sensor is not less than 60 GHz.

7. A non-contact motion monitoring method, applied to the magnetic resonance imaging system according to any one of claims 1 to 6, characterized in that include: Acquiring motion information of a surface of a subject within a scanning field of view of a magnetic resonance imaging system, wherein the motion information is acquired based on the non-contact motion monitoring unit; The spatial feature information of the subject's surface and the subject's physiological movement information are extracted from the movement information, and the subject's posture change information is determined according to the spatial feature information.

8. The non-contact motion monitoring method according to claim 7, characterized in that: After extracting the spatial feature information of the subject's surface and the physiological motion information of the subject from the motion information, and determining the posture change information of the subject according to the spatial feature information, the method further includes: A gated acquisition signal for controlling the magnetic resonance imaging system to acquire data is generated according to the posture change information and the physiological movement information.

9. The non-contact motion monitoring method according to claim 7, characterized in that: After extracting the spatial feature information of the subject's surface and the physiological motion information of the subject from the motion information, and determining the posture change information of the subject according to the spatial feature information, the method further includes: During the process of reconstructing a magnetic resonance image by the magnetic resonance imaging system, artifact correction is performed on the magnetic resonance image according to the posture change information and the physiological movement information.

10. The non-contact motion monitoring method according to claim 7, characterized in that: In the case where the motion information is acquired by a plurality of the frequency modulated continuous wave sensors respectively, acquiring the motion information of the surface of the subject within the scanning field of view of the magnetic resonance imaging system includes: The motion information acquired by each of the multiple frequency modulated continuous wave sensors at the same time is acquired respectively, and the motion information acquired by each frequency modulated continuous wave sensor at the same time is fused according to the spatial position of the scanning field of view covered by each frequency modulated continuous wave sensor to obtain the motion information of the surface of the subject.

11. The non-contact motion monitoring method according to claim 7, characterized in that: The spatial feature information includes contour feature information; Extracting spatial feature information of the surface of the subject from the motion information, and determining the posture change information of the subject according to the spatial feature information includes: Extracting contour feature information of the surface of the subject from the motion information; Tracking motion information of the contour of the surface of the subject according to the contour feature information; The posture change information of the subject is determined based on the motion information of the contour of the surface of the subject.

12. The non-contact motion monitoring method according to claim 7, characterized in that: Extracting spatial feature information of the subject's surface and physiological motion information of the subject from the motion information, and determining posture change information of the subject according to the spatial feature information includes: extracting motion information corresponding to the region of interest from the motion information; The spatial feature information of the surface of the subject and the physiological movement information of the subject are extracted from the movement information corresponding to the region of interest, and the posture change information of the subject is determined according to the spatial feature information.

13. A storage medium, characterized in that: The storage medium stores a computer program, wherein the computer program is configured to execute the non-contact motion monitoring method according to any one of claims 7 to 12 when running.

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