Respiratory and motion monitoring method for MRI system, MRI system and method, storage medium

Abstract

The present application provides a method for respiratory and motion monitoring of an MRI system, an MRI system and method, and a storage medium. The MRI system includes a scanner, a controller, and a signal processor. The scanner includes a radio frequency transmit link and a radio frequency transmit coil, and detects an object positioned relative to the radio frequency transmit coil. The controller is configured to control the scanner to perform a scan sequence on the detected object to acquire image data. The scan sequence includes a radio frequency excitation, a signal acquisition, and an idle phase. During the radio frequency excitation phase, the radio frequency transmit link transmits a first radio frequency pulse to the radio frequency transmit coil. The signal processor is configured to acquire, in real time, a scattering parameter of the radio frequency transmit coil, wherein, during the radio frequency excitation phase, the signal processor acquires, in real time, a first radio frequency power signal detected on a line between the radio frequency transmit link and the radio frequency transmit coil, and acquires the scattering parameter based on the signal; and acquires at least one of respiratory information and motion information of the detected object based on the scattering parameter.

Description

Technical Field

[0001] This invention relates to medical imaging technology, and more specifically to a method for monitoring respiration and motion in a magnetic resonance imaging system, the magnetic resonance imaging system, and a non-transitory computer-readable storage medium. Background Technology

[0002] In some clinical applications of magnetic resonance imaging (MRI), to reduce respiratory artifacts, it is necessary to have the subject hold their breath during the scan, or to predict the subject's respiratory curve before the scan using certain techniques. This allows the scanning process to be performed during a smoother phase of the predicted respiratory curve, resulting in images with fewer artifacts. The former method places higher demands on the subject and increases the difficulty of the scan, while the latter increases the scan time, and the accuracy of the prediction needs improvement. Summary of the Invention

[0003] One embodiment of the present invention provides a method for respiratory and motion monitoring in a magnetic resonance imaging (MRI) system. The MRI system includes a scanner and a controller. The controller controls the scanner to perform a scanning sequence on a target object to acquire image data of the target object. The scanner includes a radio frequency (RF) transmission link and an RF transmission coil. The target object is positioned relative to the RF transmission coil. The scanning sequence includes an RF excitation phase, a signal acquisition phase, and an idle phase between the RF excitation phase and the signal acquisition phase. The method includes:

[0004] During the execution of the scanning sequence, scattering parameters are acquired in real time, including, during the radio frequency excitation phase, acquiring a first radio frequency power signal detected on the line between the radio frequency transmission link and the radio frequency transmission coil in real time, and acquiring scattering parameters based on the first radio frequency power signal; and,

[0005] At least one of the respiratory information and motion information of the detected object is obtained based on the real-time acquired scattering parameters.

[0006] On the other hand, real-time acquisition of scattering parameters also includes:

[0007] During the idle phase, the radio frequency transmission link is controlled to transmit a second radio frequency pulse to the radio frequency transmission coil;

[0008] When transmitting the second radio frequency pulse, the second radio frequency power signal detected on the line between the radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and...

[0009] Scattering parameters are obtained based on the second radio frequency power signal.

[0010] On the other hand, the frequencies of the second radio frequency pulse and the first radio frequency pulse are both the operating frequencies of the magnetic resonance imaging system. The first radio frequency pulse has a first power that can excite the object being detected, while the second radio frequency pulse has a second power that cannot excite the object being detected.

[0011] On the other hand, the magnetic resonance imaging system also includes a first additional radio frequency transmission link, and the step of acquiring scattering parameters in real time further includes:

[0012] During the idle phase, the first additional radio frequency transmission link is controlled to transmit a third radio frequency pulse to the radio frequency transmission coil;

[0013] When transmitting the third radio frequency pulse, the third radio frequency power signal detected on the line between the first additional radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and,

[0014] Scattering parameters are obtained based on the third radio frequency power signal.

[0015] On the other hand, the frequency range of the third radio frequency pulse deviates from the operating frequency range of the magnetic resonance imaging system.

[0016] On the other hand, the power of the third radio frequency pulse is in the milliwatt or watt range.

[0017] On the other hand, the magnetic resonance imaging system also includes a second additional radio frequency transmission link, and the real-time acquisition of scattering parameters also includes:

[0018] During the signal acquisition phase, the second additional radio frequency transmission link is controlled to transmit a fourth radio frequency pulse to the radio frequency transmission coil;

[0019] When transmitting the fourth radio frequency pulse, the fourth radio frequency power signal detected on the line between the second additional radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and,

[0020] Scattering parameters are obtained based on the fourth radio frequency power signal.

[0021] On the other hand, the frequency range of the fourth radio frequency pulse deviates from the operating frequency range of the magnetic resonance imaging system.

[0022] On the other hand, the respiratory information of the detected object is obtained from the scattering parameters acquired in real time based on the first filter, and the motion information of the detected object is obtained from the scattering parameters acquired in real time based on the second filter.

[0023] On the other hand, embodiments of the present invention also provide a magnetic resonance imaging method, including the respiratory and motion monitoring method of any of the above aspects, and further including: processing the image data of the detection object based on at least one of the respiratory information and motion information of the detection object.

[0024] On the other hand, embodiments of the present invention also provide a computer-readable storage medium comprising a stored computer program, wherein the method of any of the above aspects is executed when the computer program is run.

[0025] On the other hand, embodiments of the present invention also provide a magnetic resonance imaging system, comprising:

[0026] The scanner includes an RF transmission link and an RF transmission coil, wherein the object to be detected is positioned relative to the RF transmission coil.

[0027] A controller is configured to control the scanner to perform a scanning sequence on a detection object to acquire image data of the detection object. The scanning sequence includes a radio frequency (RF) excitation phase, a signal acquisition phase, and an idle phase between the RF excitation phase and the signal acquisition phase. During the RF excitation phase, the RF transmission link transmits a first RF pulse to the RF transmission coil.

[0028] Signal processors are used for:

[0029] During the execution of the scanning sequence, scattering parameters are acquired in real time, including: during the radio frequency excitation phase, acquiring a first radio frequency power signal detected on the line between the radio frequency transmission link and the radio frequency transmission coil in real time, and acquiring scattering parameters based on the first radio frequency power signal;

[0030] At least one of the respiratory information and motion information of the detected object is obtained based on the real-time acquired scattering parameters.

[0031] On the other hand, the controller is also configured to: during the idle phase, control the radio frequency transmission link to transmit a second radio frequency pulse to the radio frequency transmission coil;

[0032] The signal processor is also used for:

[0033] When transmitting the second radio frequency pulse, the second radio frequency power signal detected on the line between the radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and...

[0034] Scattering parameters are obtained based on the second radio frequency power signal.

[0035] On the other hand, the frequencies of the second radio frequency pulse and the first radio frequency pulse are both the operating frequencies of the magnetic resonance imaging system. The first radio frequency pulse has a first power that can excite the object being detected, while the second radio frequency pulse has a second power that cannot excite the object being detected.

[0036] On the other hand, the system also includes a first additional radio frequency transmission link, and the controller is further configured to: during the idle phase, control the first additional radio frequency transmission link to transmit a third radio frequency pulse to the radio frequency transmission coil;

[0037] The signal processor is also used for:

[0038] When transmitting the third radio frequency pulse, the third radio frequency power signal detected on the line between the first additional radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and,

[0039] Scattering parameters are obtained based on the third radio frequency power signal.

[0040] On the other hand, the frequency range of the third radio frequency pulse deviates from the operating frequency range of the magnetic resonance imaging system.

[0041] On the other hand, the power of the third radio frequency pulse is in the milliwatt or watt range.

[0042] On the other hand, the system also includes a second additional radio frequency transmission link, and the controller is further configured to: control the second additional radio frequency transmission link to transmit a fourth radio frequency pulse to the radio frequency transmission coil during the signal acquisition phase;

[0043] The signal processor is also used for:

[0044] When transmitting the fourth radio frequency pulse, the fourth radio frequency power signal detected on the line between the second additional radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and,

[0045] Scattering parameters are obtained based on the fourth radio frequency power signal.

[0046] On the other hand, the frequency range of the fourth radio frequency pulse deviates from the operating frequency range of the magnetic resonance imaging system.

[0047] On the other hand, the signal processor is used to extract the respiratory information of the detected object from the scattering parameters acquired in real time based on the first filter, and the signal processor is used to extract the motion information of the detected object from the scattering parameters acquired in real time based on the second filter.

[0048] On the other hand, the system also includes an image data processor for processing image data of the detected object based on at least one of the object's breathing information and motion information. Other features and aspects will become clear from the following detailed description, accompanying drawings, and claims. Attached Figure Description

[0049] The invention can be better understood by describing exemplary embodiments of the invention in conjunction with the accompanying drawings, in which:

[0050] Figure 1 A schematic diagram of an MRI system according to some embodiments of the present invention is shown;

[0051] Figure 2 A schematic diagram of an MRI system according to other embodiments of the present invention is shown;

[0052] Figure 3 A schematic diagram of an MRI system according to other embodiments of the present invention is shown;

[0053] Figure 4 The following are some embodiments of the present invention, showing scattering parameters obtained when a first radio frequency pulse or a second radio frequency pulse is emitted;

[0054] Figure 5 It shows the basis Figure 4 Respiratory information obtained from scattering parameters;

[0055] Figure 6 It shows the basis Figure 4 Motion information obtained from scattering parameters;

[0056] Figure 7 The following are some embodiments of the present invention, showing scattering parameters obtained when a third or fourth radio frequency pulse is emitted;

[0057] Figure 8 It shows the basis Figure 7 Respiratory information obtained from scattering parameters;

[0058] Figure 9 It shows the basis Figure 7 Motion information obtained from scattering parameters;

[0059] Figure 10 Flowcharts of breathing and motion monitoring methods for magnetic resonance imaging systems according to some embodiments of the present invention are shown;

[0060] Figure 11 A flowchart of a magnetic resonance imaging method according to some embodiments of the present invention is shown. Detailed Implementation

[0061] The following describes specific embodiments of the present invention. It should be noted that, in order to provide a concise description, this specification cannot exhaustively describe all features of the actual embodiments. It should be understood that, in the actual implementation of any embodiment, just as in any engineering or design project, various specific decisions are often made to achieve the developer's specific goals and to meet system-related or business-related constraints, and this can change from one embodiment to another. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, some design, manufacturing, or production modifications based on the technical content disclosed herein are merely conventional technical means and should not be construed as insufficient content of this disclosure.

[0062] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in the patent application description and claims of this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the element or object preceding "comprising" or "including" encompasses the element or object listed following "comprising" or "including" and its equivalents, and do not exclude other elements or objects. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0063] Figure 1 A schematic diagram of an MRI system 10 according to some embodiments of the present invention is shown. Figure 1 As shown, the MRI system 10 includes a scanner 100 and a controller 200.

[0064] The scanner 100 can be used to acquire data of the object 16 to be inspected. The controller 200 is coupled to the scanner 100 to control the operation of the scanner 100, for example, to control the scanner 100 to perform a scanning sequence on the object 16 to acquire image data of the object 16.

[0065] Specifically, the controller 200 can send sequence control signals to relevant components of the scanner 100 (including the radio frequency generator and / or gradient coil driver described below) via a sequence generator (not shown in the figure) to cause the scanner 100 to execute a preset scanning sequence.

[0066] Performing a magnetic resonance imaging (MRI) scan on the object 16 may include a localization scan (three-panel scan) and a formal scan. During the localization and formal scans, one or more scan sequences may be executed. In the localization scan, at least one coronal, sagittal, and transverse localization image of the object may be acquired, and the scanning parameters for the formal scan, such as the scanning range, are determined based on this localization image. Before performing one or more scan sequences for the localization or formal scans, a pre-scan may be performed automatically or manually. During the pre-scan, frequency adjustment may be performed to determine the Larmor frequency of the proton resonance for this scan based on MRI signal feedback at different frequencies, and radio frequency emission intensity adjustment may be performed to determine the radio frequency emission power for this scan based on MRI signal feedback at different radio frequency emission intensities.

[0067] Those skilled in the art will understand that the aforementioned "scanning sequence" refers to a combination of pulses with specific power, amplitude, width, direction, and timing applied during magnetic resonance imaging (MRI) scanning (different clinical applications may include different pulse combinations). These pulses typically include, for example, radio frequency pulses and gradient pulses. The radio frequency pulse may include, for example, radio frequency emission pulses used to excite protons in the human body to resonate. The gradient pulse may include, for example, slice selection gradient pulses, phase-encoded gradient pulses, frequency-encoded gradient pulses, etc. Typically, multiple scanning sequences can be pre-set in the MRI system to allow selection of sequences adapted to clinical testing needs, which may include, for example, imaging sites, imaging functions, and imaging effects.

[0068] Scanner 100 typically includes a ring-shaped superconducting magnet defined within a housing, which is mounted within a ring-shaped vacuum container and forms a cylindrical space.

[0069] In some embodiments, the scanner 100 may include a radio frequency transmitting coil 120, which may include a body coil disposed along the inner ring of a toroidal superconducting magnet.

[0070] In some embodiments, the scanner 100 includes a gradient coil assembly 130 disposed between the inner surface of the main magnet assembly 110 and the outer surface of the radio frequency transmitting coil 120.

[0071] Those skilled in the art will understand that the scanner 100 may also include a housing (not shown), and the main magnet assembly 110, the radio frequency transmitting coil 120, the gradient coil assembly 130, and other components may be disposed in the housing.

[0072] The object to be detected 16 is positioned relative to the radio frequency transmitting coil 120. Specifically, the inner ring and the outer shell of the radio frequency transmitting coil 120 define a scanning cavity for accommodating the object to be detected 16.

[0073] In some embodiments, the scanner 100 includes a bed 150 for carrying the object to be detected 16 and for moving in and out of the scanning cavity in response to the control of the controller 200 along the Z direction (typically the direction of the object to be detected extending from head to feet when positioned in the scanning cavity). For example, in one embodiment, the imaging volume of the object to be detected 16 can be positioned in a central region of the scanning cavity where the magnetic field strength is relatively uniform, so as to facilitate scanning and imaging of the imaging volume of the object to be detected 16.

[0074] In some embodiments, the main magnet assembly 110 can generate a main magnetic field along the Z direction, such as a main magnetic field B0. The MRI system 10 uses the generated main magnetic field B0 to transmit a magnetostatic pulse signal to the object 16 placed in the imaging space, thereby ordering the precession of protons within the object 16 and generating a longitudinal magnetization vector.

[0075] In some embodiments, the scanner 100 includes an RF transmission link 160, which can be used to transmit RF power signals (or RF pulses) to the RF transmission coil 120.

[0076] In some embodiments, the radio frequency (RF) transmit link includes an RF signal generator 161, an RF power amplifier 162, a beam splitter 163, and a transmit / receive (T / R) switch 164. The transmit / receive (T / R) switch 164 is connected to the RF transmit coil 120 to switch the RF transmit coil 120 to either an RF power transmit mode or a receive mode in response to a control signal from the controller 200.

[0077] The radio frequency signal generator 161 is used to generate radio frequency pulses in response to the sequence control signals of the controller 200. The radio frequency pulses may include radio frequency excitation pulses. In the radio frequency transmission mode, the radio frequency excitation pulses are amplified by the radio frequency power amplifier 162 (e.g., through the beam splitter 163 and the T / R switch 164) and applied to the radio frequency transmission coil 120, so that the radio frequency transmission coil 120 emits a radio frequency magnetic field B1 orthogonal to the main magnetic field B0 to the detection object 16 to excite the atomic nuclei in the detection object 16, and the longitudinal magnetization vector is transformed into a transverse magnetization vector.

[0078] The beam splitter 163 is used to split the radio frequency signal output by the radio frequency power amplifier 162 into two orthogonal signals (with a phase difference of 90 degrees). One signal is transmitted to the radio frequency transmitting coil 120 via the first line (I line), and the other signal is transmitted to the radio frequency transmitting coil 120 via the second line (Q line).

[0079] After the radio frequency excitation pulse ends, the transverse magnetization vector of the detection object 16 gradually recovers to zero, generating a free induction decay signal, which is the magnetic resonance signal that can be acquired.

[0080] In some embodiments, the scanner 100 includes a gradient coil driver 170, which provides a suitable power signal to the gradient coil assembly 130 in response to a sequence control signal issued by the controller 200, so that the gradient coil assembly 130 forms a magnetic field gradient in the imaging space to provide three-dimensional position information for the magnetic resonance signal.

[0081] Specifically, the gradient coil assembly 130 may include gradient coils in three directions, each generating a gradient magnetic field tilted to one of three mutually perpendicular spatial axes (e.g., the X, Y, and Z axes), and generating gradient fields in each of the slice selection direction, phase encoding direction, and frequency encoding direction according to the imaging conditions. Specifically, the gradient coil assembly 130 applies a gradient field in the slice selection direction of the detection object 16 to select slices to be excited by radio frequency. The gradient coil assembly 130 also applies a gradient field in the phase encoding direction of the detection object 16 to perform phase encoding of the magnetic resonance signal of the excited slice. The gradient coil assembly 130 then applies a gradient field in the frequency encoding direction of the detection object 16 to perform frequency encoding of the magnetic resonance signal of the excited slice.

[0082] Magnetic resonance signals with location information can be received by an RF receiving coil. For example, controller 200 can control transmit / receive (T / R) switch 164 to switch RF transmitting coil 120 to receive mode and control RF transmitting coil 120 to receive magnetic resonance signals by a specific coil channel in its receive mode.

[0083] The scanner 100 may also include a surface receiving coil 180, which is typically positioned close to the scanning area (region of interest) of the object 16 (e.g., covering or laying on the body surface of the object 16). The surface receiving coil 180 may also be used to receive magnetic resonance signals from the object 16. For example, the controller 200 may select the coil channel of the surface receiving coil 180 to receive magnetic resonance signals.

[0084] In some embodiments, the scanner 100 may further include a data acquisition unit 190 for acquiring magnetic resonance signals received by the surface receiving coil 180 or the radio frequency transmitting coil 120 in receiving mode. The data acquisition unit 190 may include, for example, a radio frequency preamplifier (not shown), a phase detector (not shown), and an analog-to-digital converter (not shown), wherein the radio frequency preamplifier amplifies the magnetic resonance signals received by the surface receiving coil 180 or the radio frequency transmitting coil 120, the phase detector performs phase detection on the amplified magnetic resonance signals, and the analog-to-digital converter converts the phase-detected magnetic resonance signals from analog signals to digital signals.

[0085] In some embodiments, the data acquisition unit 190 is further configured to respond to a control signal from the controller 200 to store the digitized magnetic resonance signal (or echo) in the K-space. The K-space is the space filled with the original magnetic resonance signal data containing spatial positioning encoding information.

[0086] In some embodiments, the MRI system 10 further includes an image data processor 300, through which the raw data can be processed to obtain the desired medical magnetic resonance images. This processing may include, for example, signal preprocessing, image reconstruction, and post-processing.

[0087] For example, the image data processor 300 may include an image reconstruction unit for performing an inverse Fourier transform on data stored in the K-space to reconstruct a three-dimensional image or a two-dimensional slice image of the imaging volume of the detected object 16.

[0088] In some embodiments, the MRI system 10 may further include a display unit 400, which can be used to display the operation interface and various data, images or parameters generated during data acquisition and processing.

[0089] In some embodiments, the MRI system 10 includes an operation console 500, which may include user input devices such as a keyboard and mouse. The controller 200 can communicate with the scanner 100, image data processor 300, display unit 400, etc., in response to control commands generated by the user based on the operation console 500 or an operation panel / buttons disposed on the main magnet housing. The control commands may include, for example, scanning protocols and parameters selected manually or automatically; the scanning protocol may include the aforementioned scanning sequence.

[0090] In embodiments of the present invention, a signal processor 700 may also be included, which can set parameters or acquire necessary information based on feedback / detection signals, such as acquiring scattering parameters in real time and acquiring at least one of the object's breathing information and motion information in real time based on the scattering parameters.

[0091] In some embodiments, the signal processor 700 may be integrated with the controller 200 or (e.g., as a module) as part of the controller 200. The controller 200, image data processor 300, and signal processor 700 may each include a computer processor and a storage medium, on which a program for predetermined data processing to be executed by the computer processor is recorded. For example, the storage medium may store programs for performing scanning, signal preprocessing, image reconstruction, image postprocessing, etc., and may also store programs for implementing the respiratory and motion monitoring methods and magnetic resonance imaging methods of the embodiments of the present invention. The aforementioned storage medium may include, for example, a ROM, floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, or non-volatile memory card.

[0092] Embodiments of the present invention may also provide a non-transitory computer-readable storage medium comprising a stored instruction set and / or computer program, wherein, when the instruction set and / or computer program is executed, the respiratory and motion monitoring method or magnetic resonance imaging method of the embodiments of the present invention is performed. This method will be described in detail below.

[0093] As used herein, the term "computer" can include any processor-based or microprocessor-based system, including systems that use microcontrollers, reduced instruction set computers (RISC), application-specific integrated circuits (ASICs), logic circuits, and any other circuitry or processors capable of performing the functions described herein. The examples above are merely illustrative and are not intended to limit the definition and / or meaning of the term "computer" in any way.

[0094] Instructions in the instruction set can be combined into a single instruction for execution, and any instruction can be split into multiple instructions for execution. Furthermore, the execution order is not limited to that described above.

[0095] The instruction set may include various commands that instruct a computer or processor, acting as a processor, to perform specific operations, such as methods and processes according to various embodiments. The instruction set may take the form of a software program, which may be part of one or more tangible, non-transitory computer-readable media. The software may take various forms, such as system software or application software. Furthermore, the software may take the form of a collection of independent programs or modules, a program module within a larger program, or part of a program module. The software may also include modular programming in the form of object-oriented programming. Input data processing by the processor may be in response to operator commands, previous processing results, or requests made by another processor.

[0096] Controller 200, image data processor 300, and signal processor 700 can be configured and / or arranged for use in different ways. For example, in some implementations, a single unit may be used; in others, multiple (control or processing) units are configured to work together (e.g., based on a distributed processing configuration) or individually, each unit configured to handle specific aspects and / or functions, and / or process data for generating models specific to a particular MRI system. In some implementations, controller 200, image data processor 300, and signal processor 700 may be local (e.g., within the same facility and / or the same local network as one or more systems); in others, controller 200, image data processor 300, and signal processor 700 may be remote and therefore accessible only via a remote connection (e.g., via the Internet or other available remote access technologies). In a particular implementation, controller 200, image data processor 300, and signal processor 700 may be configured in a cloud-like manner and may be accessed and / or used in a manner substantially similar to accessing and using other cloud-based systems.

[0097] The MRI system 10 described above is only an example. In other embodiments, the MRI system 10 can have various variations, as long as it can acquire image data from the object being detected.

[0098] In embodiments of the present invention, the scanning sequence may include a radio frequency excitation stage and a signal acquisition stage. The radio frequency excitation stage may include: transmitting a first radio frequency pulse to a radio frequency transmitting coil via a radio frequency transmitting link. The first radio frequency pulse may be a radio frequency excitation pulse, which has a first frequency and a first power capable of exciting the target object. For example, the first frequency is the operating frequency of the MRI system, and the first power is a kilowatt-level radio frequency power.

[0099] The signal acquisition phase may include: receiving a magnetic resonance signal through a selected coil channel in a surface receiving coil array, or switching the radio frequency transmitting coil to a receiving mode and receiving the magnetic resonance signal through a selected coil channel therein. In some embodiments, a frequency-coded gradient pulse is applied during the signal acquisition phase. An idle phase is also included between the radio frequency excitation phase and the signal acquisition phase, which may be used to apply a sequence of pulses with other functions, such as radio frequency refocusing pulses, phase-coded gradient pulses, inversion recovery pulses, etc., which will not be listed here.

[0100] In some clinical applications (such as abdominal and chest examinations), to reduce image artifacts caused by respiration, it is necessary to have the subject hold their breath during the scanning sequence, or to use navigation techniques, i.e., predicting the subject's respiratory motion curve through low-resolution imaging and performing the scanning sequence during the smoother phase of the predicted respiratory curve to obtain the required high-resolution image. In embodiments of the present invention, the motion and respiratory information of the subject can be acquired in real time during the execution of the scanning sequence, so that the acquired raw image data corresponds to the motion and respiratory information. This allows for the selection of more ideal raw data (e.g., data obtained when the subject has no motion and / or respiration is stable) for image reconstruction during reconstruction.

[0101] When a first radio frequency (RF) pulse is transmitted to the RF transmitting coil via the RF transmitting link, a first RF power signal, including a forward signal and a reverse signal, can be detected on the line between the RF transmitting link and the RF transmitting coil. For example, the front end of the RF transmitting link (e.g., on the transmission line closer to the RF transmitting coil) has a forward signal transmitted to the RF transmitting coil 120 and a reverse signal reflected from the RF transmitting coil 120. Based on this reverse signal and forward signal, the scattering parameters (S-parameters) of the RF transmitting coil can be obtained. This invention assumes and verifies that when the detection object 16 undergoes periodic (or physiological) movement (e.g., breathing) or non-periodic (or active) movement (e.g., movement of the body or body parts), the aforementioned S-parameters will correspondingly change periodically or non-periodicly, and this change can reflect the respiratory and motion characteristics of the detection object. By acquiring these S-parameters in real time, at least one of the respiratory and motion information of the detection object can be obtained.

[0102] In an embodiment of the present invention, the signal processor 700 can be used to acquire scattering parameters in real time when executing a scanning sequence, including: acquiring a first radio frequency power signal detected on the line between the radio frequency transmission link 160 and the radio frequency transmission coil 120 in real time during the radio frequency excitation stage, and acquiring scattering parameters based on the first radio frequency power signal.

[0103] To avoid resource redundancy, the first radio frequency power signal can be the radio frequency excitation signal (i.e., the first radio frequency pulse) itself.

[0104] Specifically, the first radio frequency power signal may include a first forward power signal and a first reverse power signal, wherein the first forward power signal represents the power signal detected on the line transmitted from the radio frequency transmission link to the radio frequency transmission coil, and the first reverse power signal represents the power signal detected on the line reflected back from the radio frequency transmission coil to the radio frequency transmission link.

[0105] To more accurately detect the scattering parameters of the RF transmitting coil, the first RF power signal can be detected as close as possible to the RF transmitting coil in the RF transmitting link. For example, the first RF power signal can be detected at the front end of the line between the transmit / receive (T / R) switch 164 and the RF transmitting coil 120 (the end closer to the RF transmitting coil 120).

[0106] Those skilled in the art will understand that the aforementioned first radio frequency power signal can be acquired by a detection device 600 disposed at the detection location. In some embodiments, detection devices 600 can be disposed on the I-line and Q-line respectively, and the data obtained by the detection devices 600 on the I-line and Q-line can be fused to obtain scattering information, or the first radio frequency power signal can be detected using only the detection devices 600 on the I-line or Q-line. The detection device 600 responds to the control signal of the signal processor 700 to detect and feedback the first power signal. In one embodiment, the detection device includes a directional coupler.

[0107] Specifically, the detection device response signal processor 700 can obtain scattering parameters based on the ratio of the first reverse power signal to the first forward power signal, for example, obtain the scattering parameters of the radio frequency transmitting coil.

[0108] Furthermore, the signal processor 700 is also used to acquire at least one of the respiratory information and motion information of the detected object based on the real-time acquired scattering parameters.

[0109] For example, the signal processor 700 can acquire the curve of the scattering parameters changing over time in real time and apply an appropriate filter to filter the acquired scattering parameters in order to extract the breathing information and / or motion information of the detected object. This filter can be a low-pass filter.

[0110] In one embodiment, the signal processor 700 obtains the required breathing information and motion by setting the frequency selection of the filter. For example, a first filter is applied to filter the scattering parameters to obtain breathing information, and a second filter is applied to filter the scattering parameters to obtain motion information.

[0111] During the radio frequency excitation phase of the scanning sequence, since the radio frequency transmission link needs to transmit radio frequency excitation signals to the radio frequency transmission coil to excite the atomic nuclei of the tissue being detected to resonate, the scattering parameters can be obtained by real-time monitoring of the forward and reverse signals of the signal, without the need to set up an additional radio frequency signal transmission source, thus saving hardware costs.

[0112] Typically, the time required to perform a single repetition (TR) of a scan sequence is very short. Therefore, obtaining motion and respiratory information of the subject during the radiofrequency excitation phase is sufficient to help obtain fewer motion or respiratory artifacts. However, to meet special or higher requirements, at least one of the subject's motion and respiratory information can be monitored in real time over more time periods.

[0113] In conventional scanning methods, after the radio frequency excitation phase ends, the radio frequency transmission link no longer transmits radio frequency signals. In the embodiments of the present invention, in order to further acquire breathing and motion information during the idle phase and improve the accuracy and continuity of the information, after the radio frequency excitation ends, the controller 200 controls the radio frequency transmission link to continue transmitting a second radio frequency pulse to the radio frequency coil. Furthermore, when transmitting the second radio frequency pulse, the signal processor 700 is also used to acquire the second radio frequency power signal detected on the line between the radio frequency transmission link and the radio frequency transmission coil in real time, and to acquire scattering parameters based on the second power signal.

[0114] The second radio frequency power signal can be detected at the same detection location or using the same detection device.

[0115] Similar to the first radio frequency power signal, the second radio frequency power signal may include a second forward power signal and a second reverse power signal. The signal processor 700 can obtain scattering parameters based on the ratio of the second reverse power signal to the second forward power signal.

[0116] In the embodiments described above, since the radio frequency transmission link is idle during the idle phase, it can be used to transmit a second radio frequency pulse to generate a second radio frequency power signal that can be detected. In order to avoid exciting the detection object 16 during the idle phase, the second radio frequency pulse has a second power that cannot excite the detection object. At the same time, in order to reduce energy consumption, the second power can be at the watt or milliwatt level.

[0117] Figure 2 A schematic diagram of another embodiment of an MRI system 20 is shown, which is similar to the MRI system 10 described above, but may differ in that the MRI system 20 includes a first additional radio frequency transmission link 210. This first additional radio frequency transmission link 210 includes a radio frequency source additionally configured independently of the radio frequency transmission link 160.

[0118] During the idle phase of the MRI system 20 performing the scan sequence, the controller 200 controls the first additional radio frequency transmission link 210 to transmit a third radio frequency pulse to the radio frequency transmission coil 120.

[0119] When the third radio frequency pulse is transmitted, the signal processor 700 also acquires the third radio frequency power signal detected on the line between the first additional radio frequency transmission link 210 and the radio frequency transmission coil 120 in real time, and acquires the scattering parameters based on the third radio frequency power signal.

[0120] Specifically, an additional detection device can be set at the front end of the line between the first additional RF transmission link 210 and the RF transmission coil 120 (the end closer to the RF transmission coil 120) to detect the third RF power signal.

[0121] The third radio frequency power signal may include a third forward power signal transmitted from the first additional radio frequency transmission link 210 to the radio frequency transmission coil 120 and a third reverse power signal transmitted from the radio frequency transmission coil 120 back to the first additional radio frequency transmission link 210. The signal processor 700 may obtain scattering parameters based on the ratio of the third reverse power signal to the third forward power signal.

[0122] Similarly, to avoid exciting the detection target 16 during idle phases, the third radio frequency pulse has a third power that cannot excite the detection target. Furthermore, to reduce energy consumption, this third power can be in the watt or milliwatt range. Therefore, the first additional radio frequency transmission link can include a radio frequency source that only transmits low-power signals, which is also beneficial for saving hardware space and cost.

[0123] Because an additional radio frequency source is used, the frequency of the third radio frequency pulse can differ from the operating frequency of the MRI system 20, and its frequency range can deviate from the operating frequency range of the MRI system (greater or less than the operating frequency). Specifically, the frequency of the third radio frequency pulse can be set to a value that is insufficient to excite the detection object 16.

[0124] Figure 3 A schematic diagram of an MRI system 30 according to other embodiments of the present invention is shown. This MRI system 30 is similar to the MRI system 10 described above, but the difference may include that the MRI system 30 includes a second additional radio frequency transmission link 310. The second additional radio frequency transmission link 310 includes a radio frequency source that is additionally provided independently of the radio frequency transmission link 160 (e.g., it may also be the first additional radio frequency transmission link 210).

[0125] During the signal acquisition phase of the MRI system 30 when performing a scan sequence, the controller 200 controls the second additional radio frequency transmission link 310 to transmit a fourth radio frequency pulse to the radio frequency transmission coil 120.

[0126] When the fourth radio frequency pulse is transmitted, the signal processor 700 also acquires the fourth radio frequency power signal detected on the line between the second additional radio frequency transmission link 310 and the radio frequency transmission coil 120 in real time, and acquires the scattering parameters based on the fourth radio frequency power signal.

[0127] Specifically, an additional detection device can be set at the front end of the line between the second additional RF transmission link 310 and the RF transmission coil 120 (the end closer to the RF transmission coil 120) to detect the fourth RF power signal.

[0128] The fourth radio frequency power signal may include a fourth forward power signal transmitted from the second additional radio frequency transmission link 310 to the radio frequency transmission coil 120 and a fourth reverse power signal reflected back from the radio frequency transmission coil 120 to the second additional radio frequency transmission link 310. The signal processor 700 may obtain scattering parameters based on the ratio of the fourth reverse power signal to the fourth forward power signal.

[0129] To avoid exciting the detection target 16 during the signal acquisition phase, the fourth radio frequency pulse has a fourth power (which can be the same as the third power) that cannot excite the detection target. Furthermore, to reduce power consumption, this fourth power can be in the watt or milliwatt range. Therefore, the second additional radio frequency transmission link 310 can include a radio frequency source that only transmits low-power signals, which is beneficial for saving hardware space and cost.

[0130] Because an additional radio frequency source is used, the frequency of the fourth radio frequency pulse can differ from the operating frequency of the MRI system 30, and its frequency range can deviate from the operating frequency range of the MRI system 30 (greater or less than the operating frequency). Specifically, the frequency of the fourth radio frequency pulse can be set to a value that cannot excite the detection object 16.

[0131] In an embodiment of the present invention, the signal processor 700 is used to acquire a radio frequency power signal (including one or more of the first to fourth radio frequency power signals) detected during the peak of the transmitted radio frequency pulse (e.g., one or more of the first to fourth radio frequency transmitted pulses described above), and to obtain the scattering parameters of the radio frequency transmitting coil 120 based on the radio frequency power signal acquired during the peak period.

[0132] The aforementioned peak period can be a continuous time period with pulse peaks, such as within 50 microseconds when the pulse value is high (including the peak).

[0133] In other implementations, during the signal acquisition phase of the MRI system 30 performing the scanning sequence, an additional radio frequency transmission link may not be required. Instead, when the radio frequency transmission coil in the receiving mode receives the magnetic resonance signal, the fifth reverse power signal emitted from the human body to the radio frequency transmission coil is detected at the receiving end of the radio frequency transmission coil. The signal processor 700 can obtain scattering parameters based on the ratio of the fifth reverse power signal to the first forward power signal, and obtain at least one of the respiratory information and motion information of the detection object 16 based on the scattering parameters.

[0134] Alternatively, during the signal acquisition phase of the MRI system 30 performing the scanning sequence, when the surface coil 180 receives the magnetic resonance signal, a sixth reverse power signal emitted from the human body to the surface receiving coil 180 can be detected at the receiving end of the surface receiving coil 180. The signal processor 700 can obtain scattering parameters based on the ratio of the sixth reverse power signal to the first forward power signal, and obtain at least one of the respiratory information and motion information of the detection object 16 based on the scattering parameters.

[0135] Figure 4 One embodiment is shown, in which scattering parameters are acquired when a first radio frequency pulse or a second radio frequency pulse (at the operating frequency of the MRI system) is emitted, including scattering parameters acquired during the steady breathing and motion phases of the subject being tested. Figure 5 It shows the basis Figure 4 The respiratory information obtained from the scattering parameters Figure 6 It shows the basis Figure 4 Motion information is obtained from the scattering parameters. Figure 7 One embodiment is shown, showing scattering parameters acquired when a third or fourth radio frequency pulse (at a frequency deviating from the operating frequency) is emitted, including scattering parameters acquired during steady breathing and movement phases. Figure 8 It shows the basis Figure 7 The respiratory information obtained from the scattering parameters Figure 9 It shows the basis Figure 7 Motion information is obtained from the scattering parameters.

[0136] As described above, the image data processor 300 is used to perform preprocessing, image reconstruction, and post-processing on the acquired magnetic resonance signals. In embodiments of the present invention, the image data processor is used to process image data of the detected object based on at least one of the respiratory information and motion information of the detected object. For example, from Figure 5 , Figure 6 , Figure 8 , Figure 9 It can be determined which time periods the subject is breathing steadily, which time periods are breathing erratically, which time periods are not moving, and which time periods are moving. Based on this determined information, when the image data processor 300 processes the acquired magnetic resonance signals, it can choose to retain appropriate raw data (e.g., image data generated during periods of steady breathing and no movement) and discard abnormal raw data (e.g., image data generated during periods of erratic breathing or movement).

[0137] The reconstructed images obtained based on the preserved original data have fewer breathing and motion artifacts. Furthermore, it eliminates the need to spend more time predicting the respiratory information of the subject before scanning, and also eliminates the need to require the subject to hold their breath at specific times during scanning, saving scanning time and reducing scanning difficulty.

[0138] Experimental verification shows that the respiratory and motion information obtained based on the embodiments of the present invention are consistent with the actual breathing and motion of the detected subjects. Specifically, when the detected subjects inhaled, exhaled, held their breath, and moved during the experiment, the respiratory and motion curves generated based on the scattering information were consistent with the actual results. When detected subjects with different characteristics (including body size, gender, age, etc.) performed deep breathing and free breathing respectively during the experiment, the respiratory and motion curves generated based on the scattering information were consistent with the actual results. When the respiratory information of the subject was monitored simultaneously based on the Bluetooth sensor and the respiratory information was obtained based on the scattering information, the consistency between the two was high. Activating the surface receiving coil covering the abdomen or chest of the detected subject 16 to obtain respiratory and motion information showed good consistency with the respiratory and motion information obtained without using the surface receiving coil, indicating that using the surface receiving coil does not affect the accuracy of the respiratory and motion information.

[0139] Figure 10 A flowchart 1000 illustrating a method for monitoring respiration and motion in a magnetic resonance imaging (MRI) system according to some embodiments of the present invention is shown. The MRI system may include the MRI systems 10, 20, or 30 described in the above embodiments. For example, the MRI system includes a scanner and a controller, the controller controlling the scanner to perform a scanning sequence on a target object to obtain image data of the target object. The scanner includes a radio frequency (RF) transmission link and an RF transmission coil, the target object being positioned relative to the RF transmission coil, and the scanning sequence including an RF excitation phase, a signal acquisition phase, and an idle phase between the RF excitation phase and the signal acquisition phase. Figure 10 As shown, the method 1000 includes steps 1010 and 1020.

[0140] In step 1010, during the execution of the above scanning sequence, scattering parameters are acquired in real time, including, during the radio frequency excitation stage, acquiring a first radio frequency power signal detected on the line between the radio frequency transmission link and the radio frequency transmission coil in real time, and acquiring scattering parameters based on the first radio frequency power signal.

[0141] In step 1020, at least one of the respiratory information and motion information of the detected object is obtained based on the real-time acquired scattering parameters.

[0142] In some embodiments, step 1010 further includes:

[0143] During this idle phase, the control radio frequency transmission link transmits a second radio frequency pulse to the radio frequency transmission coil;

[0144] When transmitting the second radio frequency pulse, the second radio frequency power signal detected on the line between the radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and,

[0145] Scattering parameters are obtained based on the second radio frequency power signal.

[0146] In some embodiments, the frequencies of the second radio frequency pulse and the first radio frequency pulse are both the operating frequencies of the magnetic resonance imaging system, the first radio frequency pulse has a first power capable of exciting the object being detected, and the second radio frequency pulse has a second power unable to excite the object being detected.

[0147] In some embodiments, the magnetic resonance imaging system further includes a first additional radio frequency transmission link, and step 1010 further includes:

[0148] During this idle phase, the first additional RF transmission link is controlled to transmit a third RF pulse to the RF transmission coil;

[0149] When transmitting the third radio frequency pulse, the third radio frequency power signal detected on the line between the first additional radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and,

[0150] Scattering parameters are obtained based on the third radio frequency power signal.

[0151] In some embodiments, the frequency range of the third radio frequency pulse deviates from the operating frequency range of the magnetic resonance imaging system.

[0152] In some embodiments, the power of the third radio frequency pulse is in the milliwatt or watt range.

[0153] In some embodiments, the magnetic resonance imaging system further includes a second additional radio frequency transmission link, and step 1010 further includes:

[0154] During the signal acquisition phase, the second additional radio frequency transmission link is controlled to transmit a fourth radio frequency pulse to the radio frequency transmission coil;

[0155] When transmitting the fourth radio frequency pulse, the fourth radio frequency power signal detected on the line between the second additional radio frequency transmission link and the radio frequency transmission coil is acquired in real time; and,

[0156] Scattering parameters are obtained based on the fourth radio frequency power signal.

[0157] In some embodiments, the frequency range of the fourth radio frequency pulse deviates from the operating frequency range of the magnetic resonance imaging system.

[0158] In some embodiments, step 1020 obtains the respiratory information of the detected object from the real-time scattering parameters based on the first filter, and obtains the motion information of the detected object from the real-time scattering parameters based on the second filter.

[0159] Figure 11 A flowchart 1100 of a magnetic resonance imaging method according to some embodiments of the present invention is shown, which includes the respiratory and motion monitoring method of any of the above embodiments. The magnetic resonance imaging method 1100 further includes step 1110: processing the image data of the detection object based on at least one of the acquired respiratory information and motion information of the detection object.

[0160] Some exemplary embodiments have been described above; however, it should be understood that various modifications can be made. For example, suitable results may be achieved if the described techniques are performed in a different order and / or if components in the described system, architecture, device, or circuit are combined in a different manner and / or replaced or supplemented by other components or their equivalents. Accordingly, other embodiments also fall within the scope of the claims.

Claims

1. A method for respiratory and motion monitoring for a magnetic resonance imaging system, the magnetic resonance imaging system comprising a scanner and a controller, the controller configured to control the scanner to perform a scan sequence on a subject to acquire image data of the subject, the scanner comprising a radio frequency transmit chain and a radio frequency transmit coil, the subject positioned relative to the radio frequency transmit coil, the scan sequence comprising a radio frequency excitation phase, a signal acquisition phase, and an idle phase between the radio frequency excitation phase and the signal acquisition phase; the method comprising: acquiring, in real time, a scattering parameter while performing the scan sequence, wherein comprising, transmitting a first radio frequency pulse to the radio frequency transmit coil during the radio frequency excitation phase, acquiring, in real time, a first radio frequency power signal detected on a line between the radio frequency transmit chain and the radio frequency transmit coil, and acquiring a scattering parameter based on the first radio frequency power signal; and, acquiring, in real time, at least one of respiratory information and motion information of the subject based on the scattering parameter acquired in real time, wherein, during the idle phase, the radio frequency transmit chain is controlled to transmit a second radio frequency pulse to the radio frequency transmit coil; and acquiring, in real time, a second radio frequency power signal detected on a line between the radio frequency transmit chain and the radio frequency transmit coil while transmitting the second radio frequency pulse; and, acquiring a scattering parameter based on the second radio frequency power signal, wherein the second radio frequency pulse has a second power that is incapable of exciting the subject, wherein the magnetic resonance imaging system further comprises a first additional radio frequency transmit chain, and the step of acquiring, in real time, the scattering parameter further comprises: controlling the first additional radio frequency transmit chain to transmit a third radio frequency pulse to the radio frequency transmit coil during the idle phase; acquiring, in real time, a third radio frequency power signal detected on a line between the first additional radio frequency transmit chain and the radio frequency transmit coil while transmitting the third radio frequency pulse; acquiring a scattering parameter based on the third radio frequency power signal, and wherein the third radio frequency pulse has a frequency range that deviates from a range of an operating frequency of the magnetic resonance imaging system.

2. The respiratory and motion monitoring method of claim 1, wherein, The second radio frequency pulse and the first radio frequency pulse both have a frequency of the operating frequency of the magnetic resonance imaging system, and the first radio frequency pulse has a first power that is capable of exciting the subject.

3. The respiratory and motion monitoring method of claim 1, wherein, The third radio frequency pulse has a power of milliwatt level or watt level.

4. The respiratory and motion monitoring method of claim 1, wherein, The magnetic resonance imaging system further comprises a second additional radio frequency transmit chain, and acquiring, in real time, the scattering parameter further comprises: controlling the second additional radio frequency transmit chain to transmit a fourth radio frequency pulse to the radio frequency transmit coil during the signal acquisition phase; acquiring, in real time, a fourth radio frequency power signal detected on a line between the second additional radio frequency transmit chain and the radio frequency transmit coil while transmitting the fourth radio frequency pulse; and, acquiring a scattering parameter based on the fourth radio frequency power signal.

5. The respiratory and motion monitoring method of claim 4, wherein, The fourth radio frequency pulse has a frequency range that deviates from a range of an operating frequency of the magnetic resonance imaging system.

6. The respiratory and motion monitoring method of claim 1, wherein, The respiratory information of the detection object is acquired based on the first filter from the real-time acquired scatter parameters, and the motion information of the detection object is acquired based on the second filter from the real-time acquired scatter parameters.

7. A magnetic resonance imaging method comprising the respiration and motion monitoring method of any one of claims 1 to 6, further comprising: The image data of the detection object is processed based on at least one of the respiratory information and the motion information of the detection object.

8. A computer readable storage medium comprising a stored computer program, wherein, The method of any one of claims 1-7 is performed when the computer program is run.

9. A magnetic resonance imaging system, comprising: a scanner comprising a radio frequency transmit chain and a radio frequency transmit coil, a detection object being positioned relative to the radio frequency transmit coil, the a controller configured to control the scanner to perform a scan sequence on a detection object to acquire image data of the detection object, the scan sequence comprising a radio frequency excitation phase, a signal acquisition phase, and an idle phase between the radio frequency excitation phase and the signal acquisition phase, wherein, in the radio frequency excitation phase, the radio frequency transmit chain transmits a first radio frequency pulse to the radio frequency transmit coil; and a signal processor configured to: acquire, in real time, a scatter parameter while performing the scan sequence, wherein this comprises transmitting a first radio frequency pulse to the radio frequency transmit coil in the radio frequency excitation phase, acquiring, in real time, a first radio frequency power signal detected on a line between the radio frequency transmit chain and the radio frequency transmit coil, and acquiring a scatter parameter based on the first radio frequency power signal; acquire, in real time, at least one of respiratory information and motion information of the detection object based on the scatter parameter, wherein the controller is further configured to control the radio frequency transmit chain to transmit a second radio frequency pulse to the radio frequency transmit coil in the idle phase; the signal processor is further configured to: acquire, in real time, a second radio frequency power signal detected on a line between the radio frequency transmit chain and the radio frequency transmit coil while transmitting the second radio frequency pulse; and acquire a scatter parameter based on the second radio frequency power signal, wherein the second radio frequency pulse has a second power that is incapable of exciting the detection object, the magnetic resonance imaging system further comprises a first additional radio frequency transmit chain, and the controller is further configured to control the first additional radio frequency transmit chain to transmit a third radio frequency pulse to the radio frequency transmit coil in the idle phase; the signal processor is further configured to: acquire, in real time, a third radio frequency power signal detected on a line between the first additional radio frequency transmit chain and the radio frequency transmit coil while transmitting the third radio frequency pulse; and acquire a scatter parameter based on the third radio frequency power signal, wherein the third radio frequency pulse has a frequency range that deviates from a range of an operating frequency of the magnetic resonance imaging system.

10. The magnetic resonance imaging system of claim 9, wherein, The second radio frequency pulse and the first radio frequency pulse both have the operating frequency of the magnetic resonance imaging system, and the first radio frequency pulse has a first power that is capable of exciting the detection object.

11. The magnetic resonance imaging system of claim 9, wherein, The third radio frequency pulse has a power that is in the order of milliwatts or watts.

12. The magnetic resonance imaging system of claim 9, further comprising a second additional radio frequency transmit chain, and the controller is further configured to: control the second additional radio frequency transmit chain to transmit a fourth radio frequency pulse to the radio frequency transmit coil during the signal acquisition phase; the signal processor is further configured to: acquire, in real time, a fourth radio frequency power signal detected on a line between the second additional radio frequency transmit chain and the radio frequency transmit coil when the fourth radio frequency pulse is transmitted; and acquire a scatter parameter based on the fourth radio frequency power signal.

13. The magnetic resonance imaging system of claim 12, wherein, a frequency range of the fourth radio frequency pulse deviates from a range of an operating frequency of the magnetic resonance imaging system.

14. The magnetic resonance imaging system of claim 9, wherein, the signal processor is configured to extract, based on a first filter, breathing information of the detected object from the scatter parameter acquired in real time, and the signal processor is configured to extract, based on a second filter, motion information of the detected object from the scatter parameter acquired in real time.

15. The magnetic resonance imaging system of claim 9, further comprising an image data processor configured to process image data of the detected object based on at least one of breathing information and motion information of the detected object.

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