Motion detection apparatus, method and magnetic resonance imaging system, method

Abstract

The application discloses a motion detection device, a method and a magnetic resonance imaging system and a method, wherein the motion detection device comprises at least one radio frequency coil, a detection module and a control module, the radio frequency coil is connected with the detection module, is used for transmitting a first radio frequency signal, receiving a second radio frequency signal, and sending the second radio frequency signal to the detection module, the second radio frequency signal corresponds to a reflection signal of the first radio frequency signal; the control module is connected with the detection module and the radio frequency coil respectively, is used for controlling opening and closing between the radio frequency coil and the detection module; the detection module is used for receiving the second radio frequency signal sent by the radio frequency coil when the radio frequency coil and the detection module are open, detecting a parameter related to motion of a target human body in the second radio frequency signal, and determining whether the target human body has motion according to the parameter. The embodiment of the application can monitor whether the target human body has relative motion in real time.

Description

Technical Field

[0001] The present invention relates to the field of medical device technology, and in particular to a motion detection device, method, and magnetic resonance imaging system and method. Background Technology

[0002] In clinical scanning, especially MRI scans, there is often a problem where the entire image sequence obtained from the scan becomes unusable due to patient movement.

[0003] Even slight patient movement during a scan can significantly impact the results. Therefore, current technology typically employs additional devices to monitor patient movement during scanning, allowing for timely interruption of the scan or appropriate intervention. However, these additional devices often cause patient discomfort or occupy limited scanning space. Summary of the Invention

[0004] This invention provides a motion detection device, method, and magnetic resonance imaging system and method, which achieve the effect of real-time monitoring of whether there is relative motion in the target human body.

[0005] In a first aspect, embodiments of the present invention provide a motion detection device, the motion detection device comprising at least one radio frequency coil, a detection module, and a control module, wherein...

[0006] The radio frequency coil is connected to the detection module and is used to transmit a first radio frequency signal, receive a second radio frequency signal, and send the second radio frequency signal to the detection module. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal.

[0007] The control module is connected to the detection module and the radio frequency coil respectively, and is used to control the opening and closing of the radio frequency coil and the detection module;

[0008] The detection module is used to receive the second radio frequency signal sent by the radio frequency coil when the connection between the radio frequency coil and the detection module is not open, detect parameters related to the movement of the target human body in the second radio frequency signal, and determine whether the target human body has moved based on the parameters.

[0009] Secondly, embodiments of the present invention also provide a magnetic resonance imaging system, the magnetic resonance imaging system including any of the motion detection devices described in any of the embodiments of the present invention.

[0010] Thirdly, embodiments of the present invention also provide a motion detection method, the motion detection method comprising:

[0011] During magnetic resonance imaging, the target human body is excited by an imaging pulse sequence, which includes multiple imaging pulses.

[0012] The control module detects whether the radio frequency coil is in a preset state. If the radio frequency coil is detected to be in a preset state, the control module controls the connection between the radio frequency coil and the detection module and controls the radio frequency coil to transmit a first radio frequency signal. The preset state is the state of the radio frequency coil during the transmission interval between two adjacent imaging pulses.

[0013] The second radio frequency signal is received using the radio frequency coil and then sent to the detection module. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal.

[0014] The detection module is used to detect parameters in the second radio frequency signal that are related to the motion of the target human body, and the target human body is determined to have moved based on the parameters.

[0015] Fourthly, embodiments of the present invention also provide a magnetic resonance imaging method, the method comprising:

[0016] The target human body is excited by an imaging pulse sequence, the magnetic resonance signal of the target human body is acquired, and the motion of the target human body is detected during the emission interval between two adjacent imaging pulses. The imaging pulse sequence includes multiple imaging pulses.

[0017] If no movement is detected in the target human body, the magnetic resonance signal of the target human body is reconstructed to obtain the magnetic resonance image of the target human body;

[0018] If movement of the target human body is detected, the motion compensation module is used to perform data compensation or scan compensation on the magnetic resonance signal of the target human body in order to obtain the magnetic resonance image of the target human body.

[0019] The step of detecting whether the target human body has moved during the interval between the emission of two adjacent imaging pulses includes:

[0020] The control module detects whether the radio frequency coil is in a preset state. If the radio frequency coil is detected to be in a preset state, the control module controls the connection between the radio frequency coil and the detection module and controls the radio frequency coil to transmit a first radio frequency signal. The preset state is the state of the radio frequency coil during the transmission interval between two adjacent imaging pulses.

[0021] The second radio frequency signal is received using the radio frequency coil and then sent to the detection module. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal.

[0022] The detection module is used to detect parameters in the second radio frequency signal that are related to the motion of the target human body, and the target human body is determined to have moved based on the parameters.

[0023] This invention, through the inclusion of at least one radio frequency coil, a detection module, and a control module in a motion detection device, utilizes the detection module to transmit a first radio frequency signal and send it to the radio frequency coil. The radio frequency coil receives the first radio frequency signal, generates a second radio frequency signal based on the first radio frequency signal, and sends the second radio frequency signal to the detection module. The control module sends a parameter detection signal to the detection module, which receives the parameter detection signal, detects parameters related to the motion of the target human body in the second radio frequency signal, and determines whether the target human body is moving based on the parameters. This achieves the effect of real-time monitoring of whether the target human body is undergoing relative motion. Attached Figure Description

[0024] Figure 1a This is a schematic diagram of the structure of a motion detection device according to Embodiment 1 of the present invention;

[0025] Figure 1b This is a schematic diagram of another motion detection device in Embodiment 1 of the present invention;

[0026] Figure 2 This is a schematic diagram of the structure of a magnetic resonance imaging system according to Embodiment 2 of the present invention;

[0027] Figure 3a This is a flowchart of a motion detection method according to Embodiment 3 of the present invention;

[0028] Figure 3b This is a flowchart of a magnetic resonance imaging method according to Embodiment 3 of the present invention. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0030] Example 1

[0031] Figure 1a This is a schematic diagram of the structure of a motion detection device provided in Embodiment 1 of the present invention. Figure 1b This is a schematic diagram of another motion detection device provided in Embodiment 1 of the present invention, as shown below. Figure 1a or Figure 1b As shown, the motion detection device includes: an radio frequency coil 110, a detection module 120, and a control module 130, wherein:

[0032] The radio frequency coil 110 is connected to the detection module 120. After the target human body is fixed in position, it can transmit a first radio frequency signal, receive a second radio frequency signal, and send the second radio frequency signal to the detection module 120. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal.

[0033] In this embodiment, the radio frequency coil 110 is preferably positioned at a preset distance from the target location of the target human body. Specifically, if it is to detect whether the head of the target human body is moving, it is preferable to position the radio frequency coil 110 at a preset distance from the head of the target human body; if it is to detect the abdomen of the target human body, it is preferable to position the radio frequency coil 110 at a preset distance from the abdomen of the target human body. The number of radio frequency coils 110 can be single (e.g., ...). Figure 1a (as shown), or multiple (such as) Figure 1b (As shown).

[0034] The radio frequency (RF) coil 110 may include both an RF transmitting coil and an RF receiving coil, and can be connected to the control module 130. The control module 130 can control the RF coil 110 to receive magnetic resonance signals generated by the human body during imaging sequence pulse excitation, and to transmit a first RF signal or receive a second RF signal during the intervals between imaging sequence pulses. In this embodiment, the control module 130 may be a spectrometer, including a sequence generator (waveform generator), an RF power amplifier, etc. More specifically, the sequence generator can generate an imaging sequence and a motion detection sequence, with the motion detection sequence distributed during the imaging sequence. In one embodiment, the imaging sequence signal generated by the sequence generator is amplified by the RF power amplifier to generate an imaging drive signal, which is sent to the RF transmitting coil of the RF coil 110 to generate imaging pulses that can excite the nuclear spin of water molecules in the human body. In another embodiment, when the RF coil 110 neither transmits imaging pulses nor receives magnetic resonance imaging signals, the motion detection sequence signal generated by the sequence generator is amplified by the RF power amplifier to generate a detection drive signal, which is sent to the RF coil 110 to cause the RF coil 110 to transmit a first RF signal. The radio frequency coil 110 receives the second radio frequency signal, and the specific process is as follows:

[0035] After the radio frequency coil 110 transmits the first radio frequency signal, it can send the first radio frequency signal to the target human body. After the transmitted first radio frequency signal reaches the target human body, part of it can be absorbed by the target human body, and the other part can be reflected back to the radio frequency coil 110. The radio frequency signal received by the radio frequency coil 110 is the second radio frequency signal. Once the target human body moves relative to the previous position (or the initial position), the amount of the first radio frequency signal absorbed by it will be different from the amount of absorption corresponding to the previous position (or the initial position), resulting in the second radio frequency signal received by the detection module 120 being different from the second radio frequency signal corresponding to the previous position (or the initial position). Based on this, it can be determined whether the target human body has moved by whether the two adjacent second radio frequency signals received by the detection module 120 (or the current second radio frequency signal and the initial second radio frequency signal) are the same, or whether the ratio of the two adjacent second radio frequency signals to the first signal (or the ratio of the current second radio frequency signal to the current first signal and the ratio of the initial second radio frequency signal to the initial first signal) is the same.

[0036] The control module 130 is connected to both the detection module 120 and the RF coil 110, and is used to control the switching on and off between the RF coil 110 and the detection module 120. Preferably, the control module 130 can send a switching signal to the detection module 120 or to the RF coil 110. The switching signal includes an on signal and an off signal, which are used to control the switching on and off between the RF coil 110 and the detection module 120, respectively. Alternatively, the control module 130 can also be connected to both the detection module 120 and the RF coil 110 (not shown in the figure), and can directly control the switching on and off between the RF coil 110 and the detection module 120 through its own on / off state.

[0037] The detection module 120 is connected to the control module 130 and is used to receive the second radio frequency signal sent by the radio frequency coil 110 when the connection between the radio frequency coil 110 and the detection module 120 is not open. After receiving the second radio frequency signal, the detection module 120 detects parameters related to the movement of the target human body in the second radio frequency signal or parameters related to the movement of the target human body in the ratio of the second radio frequency signal to the first signal, and determines whether the target human body has moved based on the parameters. Generally, if the currently measured parameters change (this change can be relative to the initial parameters or relative to the previous parameters), it can be determined that the target human body has moved.

[0038] It should be noted that when using multiple radio frequency coils 110 for motion detection, any change in the parameters of any one of the radio frequency coils 110 can be considered as movement of the target human body within the detection range of that radio frequency coil 110. Using multiple radio frequency coils 110 for motion detection improves the sensitivity and accuracy of motion detection.

[0039] This embodiment sets up at least one radio frequency coil, a detection module, and a control module in the motion detection device. The control module controls the switching on and off between the radio frequency coil and the detection module. When the radio frequency coil and the detection module are not connected, the radio frequency coil emits a first radio frequency signal, receives a second radio frequency signal, and sends the second radio frequency signal to the detection module. The detection module detects the parameters related to the motion of the target human body in the second radio frequency signal and determines whether the target human body has moved based on the parameters, thus achieving the effect of real-time monitoring of whether the target human body has relative motion.

[0040] Based on the above embodiments, the parameters may further include scattering parameters S and / or impedance parameters Z or other parameters. The scattering parameter S may include radio frequency characteristic parameters S11, S12, S21, and S22. S11 may represent the input reflection coefficient of a single radio frequency coil a, which is directly related to the coil's load. S12 may represent the transmission coefficient from radio frequency coil a to radio frequency coil b in the two radio frequency coils. S21 may represent the transmission coefficient from radio frequency coil b to radio frequency coil a in the two radio frequency coils. S22 may represent the input reflection coefficient of a single radio frequency coil b. The impedance parameter Z may include radio frequency characteristic parameters Z11, Z12, Z21, and Z22. When the number of radio frequency coils 110 is n=1, it is preferable to use radio frequency characteristic parameters S11 and / or Z11 to determine whether the target human body is moving; when the number of radio frequency coils 110 is n>1, it is preferable to use at least one of radio frequency characteristic parameters Sij and Zij (i=1,2…n; j=1,2…n, n is an integer greater than 1) to determine whether the target human body is moving.

[0041] For example, a detailed explanation of motion detection using radio frequency coil 110 as a single coil and taking radio frequency characteristic parameter S11 in scattering parameter S as an example:

[0042] After the target human body is fixed in position, at time t1, the detection module 120 uses the single radio frequency coil 110 to measure S11 as S. (11-t1) _=A t1 _+i*_B t1 (where A) t1 B is the real part of S11. t1 (This refers to the imaginary part of S11). S11 is acquired in real time. At time t2, the detection module 120 uses this single RF coil 110 to measure S11, which is S... (11-t2) _=A t2 _+i*_B t2 (where A) t2 B is the real part of S11. t2 (where A is the imaginary part of S11), if At1 =A t2 B t1 =B t2 If so, it can be determined that the target human body did not move at time t2. If A t1 ≠A t2 and / or B t1 ≠B t2 Therefore, it can be determined that the target human body moved at time t2. It should be noted that, in order to distinguish the real and imaginary parts of the parameter signal, the detection module 120 of this invention is configured as a network analyzer. This network analyzer may include a synchronous detector. The real part of the parameter signal is related to the amplitude of the target human body's motion, and the imaginary part of the parameter signal is related to the phase (phase angle) of the target human body's motion. In this embodiment, the real part of the parameter signal can be obtained by multiplying it with a carrier signal having the same phase angle as the parameter signal; the imaginary part of the parameter signal can be obtained by multiplying it with a carrier signal having a phase angle 90 degrees different from the parameter signal.

[0043] In addition to detecting relative motion of the target human body, the motion detection device provided in this embodiment can also detect the periodic motion of the target human body, such as respiratory motion. Preferably, periodic changes can be detected by recording the changes in scattering parameter S and / or impedance parameter Z in real time, and the period corresponding to this change is the period of the patient's motion (e.g., respiratory cycle).

[0044] For example, by real-time monitoring of the change in radio frequency characteristic parameter S11, at time ti (i = 1, 2, 3...), the detection module 120 uses the single radio frequency coil 110 to measure S11 as S... (11-ti) _=A ti _+i*_B ti If A exists _tm =A tn B _tm ≠B _tn Then, one period of the periodic motion can be determined by T = |tm - tn|, and this period corresponds to the smallest T among all the possible values ​​of T.

[0045] Example 2

[0046] Figure 2 This is a schematic diagram of the structure of a magnetic resonance imaging system provided in Embodiment 2 of the present invention, as shown below. Figure 2 As shown, the magnetic resonance imaging system 2 includes the motion detection device 20 in the above embodiments, wherein the motion detection device 20 may include: a radio frequency coil 210 ( Figure 2Only a single radio frequency coil is shown in the diagram; however, multiple radio frequency coils can also be used. A detection module 220 and a control module 230 are also included. The detection module 220 can send its detection results to the control module 230, which can then respond accordingly. Furthermore, the magnetic resonance imaging system 2 may also include a motion compensation module 240.

[0047] The motion detection device 20 is disposed inside the magnetic resonance imaging system 2, and the radio frequency coil 210 is preferably a built-in radio frequency coil of the magnetic resonance imaging system 2. The detection module 220 can be a built-in module of the magnetic resonance imaging system 2 or it can be added separately. The radio frequency coil 210 may include at least one of the following: head coil, body coil, spine coil, knee joint coil, ankle joint coil, dual lower limb array coil, head and neck coil, soft surface coil, and special coils for breast, rectum, and uterine cavity, as well as volume transmit coil (VTC).

[0048] For example, taking the radio frequency coil 210 as a commonly used loop coil in the magnetic resonance imaging system 2, with a single coil, and using the radio frequency characteristic parameter S11 in the scattering parameter S as an example for motion detection:

[0049] The equivalent load of the RF coil 210 can be expressed by the following formula:

[0050] R = σω 2 ∫ V1 / 2 |Ar p | 2 dυ p

[0051] Where R is the magnetic vector potential Ar in the space inside the human body. V The integral of the (current imaging area) is the equivalent load of the RF coil 210, where ω is the operating frequency and σ is the conductivity of the human body. If the human body (current imaging area) moves, the integration space will change, thus causing a change in the equivalent load R. At this time, the detection module 220 can measure S11 corresponding to the RF coil 210. In this embodiment, S11 is the result of the S-parameter measurement by the network analyzer. Taking a single-channel coil as an example (or a multi-channel coil but with little coupling between the channels), the expression for S11 is:

[0052]

[0053] Where Z0 is the characteristic impedance of the system, typically 50 Ohms. total The equivalent load R of RF coil 210 and the impedance Z of RF coil 210 itself are given. CoilThe impedance after impedance transformation by the matching network. That is:

[0054] Z total =h(R+Z) Coil )

[0055] Where h is the characteristic transformation parameter of the matching network, and different matching networks have different characteristic transformation parameters.

[0056] Whether the target human body has moved can be determined based on whether S11 changes. Specifically, if a change in S11 is detected, it can be determined that the target human body has moved; if S11 remains unchanged, it can be determined that the target human body has not moved.

[0057] During a magnetic resonance imaging (MRI) scan, movement of the target human body can lead to motion artifacts in the images acquired based on the MRI signals. These artifacts can affect subsequent data reconstruction results, and in severe cases, may render the entire scanned image sequence unusable. Therefore, to minimize the impact of motion artifacts, a motion compensation module 240 is preferably included in the MRI system 2. The motion compensation module 240 is connected to the control module 230 and, under the control of the control module, compensates for the image data acquired based on the MRI signals according to the parameters obtained by the motion detection device 20 after receiving parameters from the detection module 220. The MRI signals are generated by the radio frequency coil 210 by sensing the electromagnetic energy released by the target human body.

[0058] The motion compensation module 240 may include a data compensation unit and / or a scan compensation unit, wherein,

[0059] The data compensation unit is used to perform data compensation on the image data corresponding to the current magnetic resonance signal based on the parameter change when the parameter change is within a first preset range; and / or

[0060] The scan compensation unit is used to rescan and acquire the image data corresponding to the current magnetic resonance signal when the parameter change is within a second preset range.

[0061] In this embodiment, the maximum value within the first preset range is equal to the minimum value within the second preset range. When the parameter change is within the first preset range, it can be considered that the motion artifacts caused by the movement of the target human body are sufficient to affect the results of subsequent data reconstruction. At this time, the acquired image data can be compensated using a data compensation algorithm based on the parameter change to offset the impact of motion artifacts. Alternatively, a scan compensation unit can be used to rescan to obtain the image data corresponding to the current magnetic resonance signal. When the parameter change is within the second preset range, it can be considered that the motion artifacts caused by the movement of the target human body are likely to render the entire image sequence unusable. At this time, a scan compensation unit can be used to rescan to obtain the image data corresponding to the current magnetic resonance signal. Alternatively, a data compensation unit can be used to compensate the acquired image data using a data compensation algorithm to reduce the impact of motion artifacts.

[0062] This embodiment incorporates a motion detection device and a motion compensation module within the magnetic resonance imaging (MRI) system. After the motion detection device detects movement in the target human body, the motion compensation module compensates for the image data acquired based on the MRI signals. By monitoring the relative motion of the target human body in real time, it can promptly identify and compensate for image data in the MRI image data that requires compensation. This results in more accurate MRI images, improves the usability of the MRI images, and avoids the problem of having to rescan the entire MRI image sequence due to the unavailability of a single set of data.

[0063] Based on the above embodiments, the magnetic resonance imaging system 2 may further include at least one low-noise preamplifier, wherein the at least one low-noise preamplifier is connected to at least one radio frequency coil 210 (i.e., one low-noise preamplifier corresponds to one radio frequency coil 210). The low-noise preamplifier is used to receive and amplify the magnetic resonance signal emitted by the radio frequency coil 210.

[0064] Furthermore, to reduce the impact of the MRI process of the magnetic resonance imaging system 2 on the detection results of the motion detection device, it is preferable to use the control module 230 to detect the current state of the radio frequency coil 210 to determine the detection timing of the motion detection device 20. Preferably, when the control module 230 detects that the radio frequency coil 210 is not in the stage of transmitting radio frequency pulse signals and not in the stage of receiving MRI signals, it controls the detection parameters of the detection module 220.

[0065] In addition, Figure 2In addition to the location of the control module 230 described herein, the control module 230 may preferably also be connected to the radio frequency coil 210 and the detection module 220 respectively, that is, the control module 230 is disposed between the radio frequency coil 210 and the detection module 220. When the control module 230 detects that the radio frequency coil 210 is not in the stage of transmitting radio frequency pulse signals and not in the stage of receiving nuclear magnetic resonance signals, the control module 230 is in the conducting state, used to transmit radio frequency signals between the radio frequency coil 210 and the detection module 220. When the control module 230 detects that the radio frequency coil 210 is in the stage of transmitting radio frequency pulse signals and / or in the stage of receiving nuclear magnetic resonance signals, the control module 230 is in the disconnected state.

[0066] Example 3

[0067] Figure 3a This is a flowchart of the motion detection method provided in Embodiment 3 of the present invention. This method can be executed by the magnetic resonance imaging system described in the above embodiments, such as... Figure 3a As shown, the motion detection method in this embodiment specifically includes:

[0068] S310. When performing magnetic resonance imaging, the target human body is excited by an imaging pulse sequence.

[0069] The imaging pulse sequence includes multiple imaging pulses.

[0070] S311. The control module detects whether the radio frequency coil is in a preset state. If the radio frequency coil is detected to be in a preset state, the control module controls the connection between the radio frequency coil and the detection module and controls the radio frequency coil to transmit the first radio frequency signal. The preset state is the state of the radio frequency coil during the transmission interval between two adjacent imaging pulses.

[0071] The interval between two adjacent imaging pulses is the time between the completion of the current imaging pulse and the start of the next imaging pulse.

[0072] S312. Receive the second radio frequency signal using a radio frequency coil and send the second radio frequency signal to the detection module. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal.

[0073] S313. Use the detection module to detect parameters related to the movement of the target human body in the second radio frequency signal, and determine whether the target human body has moved based on the parameters.

[0074] The motion detection method provided in this invention involves exciting a target human body with an imaging pulse sequence during magnetic resonance imaging (MRI). A control module detects whether the state of the radio frequency (RF) coil is in the state between the transmission intervals of two adjacent imaging pulses. If the RF coil is detected to be in this state, the control module controls the RF coil to connect with the detection module and controls the RF coil to transmit a first RF signal while simultaneously receiving a second RF signal. The second RF signal is then sent to the detection module, which detects the motion-related parameters of the target human body in the second RF signal and determines whether the target human body has moved based on these parameters. This achieves the effect of real-time monitoring of whether the target human body has relative motion.

[0075] Based on the above embodiments, the motion detection method may further include:

[0076] The first parameter corresponding to the first time period and the second parameter corresponding to the second time period are determined respectively. The first time period is the time period when the current RF coil and the detection module are turned on; the second time period is the time period when the RF coil and the detection module were turned on last time.

[0077] If the first parameter and the second parameter contain the same real part and / or imaginary part, then it is determined that the target human body has not moved;

[0078] If the real and imaginary parts of the first parameter and the real and imaginary parts of the second parameter are both different, then it is determined that the target human body is moving.

[0079] Figure 3b This is a flowchart of a magnetic resonance imaging method provided in Embodiment 3 of the present invention. This method can be executed by the magnetic resonance imaging systems described in the above embodiments, such as... Figure 3b As shown, the magnetic resonance imaging method in this embodiment specifically includes:

[0080] S320. Excite the target human body using an imaging pulse sequence, acquire the magnetic resonance signal of the target human body, and detect whether the target human body moves during the emission interval between two adjacent imaging pulses. The imaging pulse sequence includes multiple imaging pulses.

[0081] S321. If no movement is detected in the target human body, the magnetic resonance signal of the target human body is reconstructed to obtain the magnetic resonance image of the target human body.

[0082] S322. If movement of the target human body is detected, the motion compensation module is used to perform data compensation or scan compensation on the magnetic resonance signal of the target human body to obtain the magnetic resonance image of the target human body.

[0083] Based on the above embodiments, further, detecting whether the target human body moves during the interval between the emission of two adjacent imaging pulses includes:

[0084] The control module detects whether the radio frequency coil is in a preset state. If the radio frequency coil is detected to be in a preset state, the control module controls the connection between the radio frequency coil and the detection module and controls the radio frequency coil to transmit the first radio frequency signal. The preset state is the state of the radio frequency coil during the transmission interval between two adjacent imaging pulses.

[0085] The second radio frequency signal is received by the radio frequency coil and sent to the detection module. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal.

[0086] The detection module detects parameters related to the motion of the target human body in the second radio frequency signal, and determines whether the target human body has moved based on the parameters.

[0087] The magnetic resonance imaging method of this invention can detect the motion state of the target human body during magnetic resonance imaging. Based on the motion state, it can determine which of the acquired magnetic resonance signals are affected by motion and which are not affected by motion. It has stronger real-time performance, and the reconstructed image can effectively reduce motion artifacts.

[0088] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A motion detection device, characterized in that, It includes at least one radio frequency coil, a detection module, and a control module, wherein, The radio frequency coil is connected to the detection module and is used to transmit a first radio frequency signal, receive a second radio frequency signal, and send the second radio frequency signal to the detection module. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal. The control module is connected to both the detection module and the radio frequency coil, and is used to control the switching on and off of the radio frequency coil and the detection module, including: The control module detects whether the radio frequency coil is in a preset state. If the radio frequency coil is detected to be in a preset state, the control module controls the connection between the radio frequency coil and the detection module to be turned on, and controls the radio frequency coil to transmit a first radio frequency signal. The preset state is the state of the radio frequency coil during the transmission interval between two adjacent imaging pulses. The detection module is used to receive the second radio frequency signal sent by the radio frequency coil when the connection between the radio frequency coil and the detection module is not open, detect parameters related to the movement of the target human body in the second radio frequency signal, and determine whether the target human body has moved based on the parameters. Among them, motion-related parameters include scattering parameter S and impedance parameter Z. If the scattering parameter S and / or the impedance parameter Z change, it indicates that the target human body has moved. When the detection module determines that the target human body is moving, the control module is further configured to control the motion compensation module to perform data compensation and / or scan compensation on the image data acquired based on the magnetic resonance signal based on the parameters.

2. A magnetic resonance imaging system, characterized in that, Includes the motion detection device as described in claim 1.

3. The system according to claim 2, characterized in that, Also includes: A motion compensation module, connected to the control module, is used to perform data compensation and / or scan compensation on image data acquired based on magnetic resonance signals according to the parameters, wherein the magnetic resonance signal is generated by the radio frequency coil by sensing the electromagnetic energy released by the target human body.

4. The system according to claim 3, characterized in that, The motion compensation module includes a data compensation unit and / or a scan compensation unit, wherein, The data compensation unit is configured to, when the parameter change is within a first preset range, perform data compensation on the current magnetic resonance signal according to the parameter change, so as to obtain image data corresponding to the current magnetic resonance signal; and / or The scanning compensation unit is used to rescan and acquire the image data corresponding to the current magnetic resonance signal when the parameter change is within a second preset range.

5. The system according to claim 2, characterized in that, The control module is specifically used for: When it is detected that the radio frequency coil is not in the stage of transmitting radio frequency pulse signals and not in the stage of receiving nuclear magnetic resonance signals, the detection module is controlled to detect the parameters.

6. The system according to any one of claims 2-5, characterized in that, The radio frequency coil includes at least one of a head coil, a body coil, a spine coil, a knee joint coil, an ankle joint coil, a VTC coil, and a dual lower limb array coil.

7. A motion detection method, characterized in that, include: During magnetic resonance imaging, the target human body is excited by an imaging pulse sequence, which includes multiple imaging pulses. The control module detects whether the radio frequency coil is in a preset state. If the radio frequency coil is detected to be in a preset state, the control module controls the connection between the radio frequency coil and the detection module and controls the radio frequency coil to transmit a first radio frequency signal. The preset state is the state of the radio frequency coil during the transmission interval between two adjacent imaging pulses. The second radio frequency signal is received using the radio frequency coil and then sent to the detection module. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal. The detection module is used to detect parameters in the second radio frequency signal that are related to the motion of the target human body, and the target human body is determined to have moved based on the parameters. Among them, motion-related parameters include scattering parameter S and impedance parameter Z. If the scattering parameter S and / or the impedance parameter Z change, it indicates that the target human body has moved. When the detection module determines that the target human body is moving, the control module controls the motion compensation module to perform data compensation and / or scan compensation on the image data acquired based on the magnetic resonance signal based on the parameters.

8. The method according to claim 7, characterized in that, Determining whether the target human body has moved based on the parameters includes: The first parameter corresponding to the first time period and the second parameter corresponding to the second time period are determined respectively, wherein the first time period is the time period when the radio frequency coil and the detection module are currently connected; and the second time period is the time period when the radio frequency coil and the detection module were connected last time. If the first parameter and the second parameter contain the same real part and / or imaginary part, then it is determined that the target human body has not moved; If the real and imaginary parts of the first parameter and the real and imaginary parts of the second parameter are both different, then it is determined that the target human body is moving.

9. A magnetic resonance imaging method, characterized in that, include: The target human body is excited by an imaging pulse sequence, the magnetic resonance signal of the target human body is acquired, and the motion of the target human body is detected during the emission interval between two adjacent imaging pulses. The imaging pulse sequence includes multiple imaging pulses. If no movement is detected in the target human body, the magnetic resonance signal of the target human body is reconstructed to obtain the magnetic resonance image of the target human body; If movement of the target human body is detected, the motion compensation module is used to perform data compensation or scan compensation on the magnetic resonance signal of the target human body in order to obtain the magnetic resonance image of the target human body. The step of detecting whether the target human body has moved during the interval between the emission of two adjacent imaging pulses includes: The control module detects whether the radio frequency coil is in a preset state. If the radio frequency coil is detected to be in a preset state, the control module controls the connection between the radio frequency coil and the detection module and controls the radio frequency coil to transmit a first radio frequency signal. The preset state is the state of the radio frequency coil during the transmission interval between two adjacent imaging pulses. The second radio frequency signal is received using the radio frequency coil and then sent to the detection module. The second radio frequency signal corresponds to the reflected signal of the first radio frequency signal. The detection module is used to detect parameters in the second radio frequency signal that are related to the motion of the target human body, and the target human body is determined to have moved based on the parameters. Among them, motion-related parameters include scattering parameter S and impedance parameter Z. If the scattering parameter S and / or the impedance parameter Z change, it indicates that the target human body has moved.

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