Multi-modal parameter determination method, apparatus, magnetic resonance device, and storage medium

Abstract

The application relates to a multi-modal parameter determination method and device, a magnetic resonance equipment and a storage medium. A target magnetic resonance image is obtained by applying an imaging sequence to an imaging region, the target magnetic resonance image comprising a plurality of amplitude maps and a plurality of phase maps. Based on the phase maps, displacement parameters and temperature parameters of the imaging region are obtained. Based on the amplitude maps, hemodynamic parameters of the imaging region are obtained. In the application, the spatiotemporal encoding technique, MR-ARFI and the blood oxygenation level dependent functional magnetic resonance imaging technique BOLD are combined. An interleaved acquisition mode is adopted to complete the acquisition of multiple modal parameters in one imaging sequence. The fusion of the multiple modal parameters can realize multi-dimensional information complementation, break through the limitation of a single modal parameter, realize accurate positioning, real-time monitoring and comprehensive evaluation in a complex physiological environment, and improve the accuracy of the evaluation of the treatment effect after the neural regulation.

Description

Technical Field

[0001] This application relates to the field of medical technology, and in particular to a method, apparatus, magnetic resonance imaging device, and storage medium for determining multimodal parameters. Background Technology

[0002] Functional neurological disorders are clinically challenging diseases affecting the nervous system, characterized by high prevalence and recurrence rates. There is a very close relationship between neuromodulation and functional neurological disorders. With the continuous development of neuromodulation technology, methods such as electricity, light, and ultrasound are being used to inhibit or regulate the nervous system, thereby improving patients' neurological function and achieving guided therapy; for example, in the treatment of functional neurological disorders such as epilepsy, Parkinson's disease, and anxiety disorders.

[0003] In actual clinical applications, how to accurately locate the diseased area or affected brain functional area in order to evaluate the therapeutic effect after neuromodulation based on displacement parameters is a technical problem that urgently needs to be solved in this field.

[0004] Currently, the main technique used is magnetic resonance acoustic radiation force imaging (MR-ARFI) to scan tissues to determine displacement parameters, and then to evaluate the therapeutic effect after neuromodulation based on these displacement parameters.

[0005] However, the above-mentioned method of using displacement parameters to assess the therapeutic effect after neuromodulation has the problem of incomplete assessment. Summary of the Invention

[0006] Therefore, it is necessary to provide a method, apparatus, magnetic resonance device, and storage medium for determining multimodal parameters that can acquire multiple modal parameters and improve the accuracy of evaluation, in order to address the above-mentioned technical problems.

[0007] Firstly, this application provides a method for determining multimodal parameters, including:

[0008] An imaging sequence is applied to the imaging region to obtain a target magnetic resonance image; the imaging sequence includes a focused ultrasound pulse, a spatial coding excitation unit, and an acquisition unit; the spatial coding excitation unit is positioned before the focused ultrasound pulse and the acquisition unit, and the spatial coding gradient pulse in the spatial coding excitation unit and the acquisition gradient pulse in the acquisition unit satisfy a preset relationship so that the spatial coding gradient pulse applied to the imaging region covers the imaging region; the target magnetic resonance image includes multiple amplitude maps and multiple sets of phase maps;

[0009] Based on the phase maps, the displacement and temperature parameters of the imaging region are obtained;

[0010] Based on the amplitude maps, the hemodynamic parameters of the imaging region are obtained; the multimodal parameters include the displacement parameters, temperature parameters, and hemodynamic parameters.

[0011] In one embodiment, the imaging sequence further includes a convergence pulse unit and a first motion-coded gradient pulse; the spatial coding excitation unit, the first motion-coded gradient pulse, the focused ultrasound pulse, the convergence pulse unit, the acquisition unit, the spatial coding excitation unit, the convergence pulse unit, the acquisition unit, the spatial coding excitation unit, and the acquisition unit are applied sequentially; the spatial coding excitation unit further includes a sweep excitation pulse; the convergence pulse unit includes a convergence pulse and a slice-selective gradient pulse, and the acquisition unit further includes a readout gradient pulse.

[0012] In one embodiment, the imaging sequence further includes a second motion-coded gradient pulse, which is applied sequentially between the spatial coding excitation unit and the convergence pulse unit, along with the focused ultrasound pulse; the polarity of the second motion-coded gradient pulse is opposite to that of the first motion-coded gradient pulse.

[0013] In one embodiment, the first motion-coded gradient pulse includes a first sub-motion-coded gradient pulse, a second sub-motion-coded gradient pulse, and a third sub-motion-coded gradient pulse, wherein the first sub-motion-coded gradient pulse and the second sub-motion-coded gradient pulse have the same polarity, and the first sub-motion-coded gradient pulse and the third sub-motion-coded gradient pulse have opposite polarities.

[0014] In one embodiment, the first magnitude of the zeroth gradient moment of the first sub-motion-coded gradient pulse is equal to the second magnitude of the zeroth gradient moment of the second sub-motion-coded gradient pulse, and the third magnitude of the zeroth gradient moment of the third sub-motion-coded gradient pulse is equal to the sum of the first magnitude and the second magnitude.

[0015] In one embodiment, the preset relationship is that the first product result corresponding to the acquired gradient pulse is equal to the second product result corresponding to the spatially encoded gradient pulse; the first product result is the product of the amplitude of the acquired gradient pulse and the duration of the acquired gradient pulse, and the second product result is the product of the amplitude of the spatially encoded gradient pulse and the duration of the spatially encoded gradient pulse.

[0016] Secondly, this application also provides a multimodal parameter determination device, comprising:

[0017] An application module is used to apply an imaging sequence to an imaging region to obtain a target magnetic resonance image. The imaging sequence includes a focused ultrasound pulse, a spatially encoded excitation unit, and an acquisition unit. The spatially encoded excitation unit is positioned before the focused ultrasound pulse and the acquisition unit. The spatially encoded gradient pulse in the spatially encoded excitation unit and the acquisition gradient pulse in the acquisition unit satisfy a preset relationship so that the spatially encoded gradient pulse applied to the imaging region covers the imaging region. The target magnetic resonance image includes multiple amplitude maps and multiple sets of phase maps.

[0018] The first acquisition module is used to acquire displacement parameters and temperature parameters of the imaging region based on each of the phase maps;

[0019] The second acquisition module is used to acquire hemodynamic parameters of the imaging region based on each amplitude map; the multimodal parameters include the displacement parameters, temperature parameters, and hemodynamic parameters. In a third aspect, this application also provides a magnetic resonance imaging device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method steps provided in the first aspect.

[0020] Fourthly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method steps provided in the first aspect.

[0021] Fifthly, this application also provides a computer program product, including a computer program that, when executed by a processor, implements the method steps provided in the first aspect.

[0022] The aforementioned multimodal parameter determination method, apparatus, magnetic resonance equipment, and storage medium obtain a target magnetic resonance image by applying an imaging sequence to the imaging region. Based on each phase map, displacement and temperature parameters of the imaging region are acquired, and based on each amplitude map, hemodynamic parameters of the imaging region are acquired. The imaging sequence includes focused ultrasound pulses, a spatial coding excitation unit, and an acquisition unit. The spatial coding excitation unit is positioned before the focused ultrasound pulses and the acquisition unit. The spatial coding gradient pulses in the spatial coding excitation unit and the acquisition gradient pulses in the acquisition unit satisfy a preset relationship so that the spatial coding gradient pulses applied to the imaging region cover the imaging region. The multimodal parameters include displacement, temperature, and hemodynamic parameters, and the target magnetic resonance image includes multiple amplitude maps and multiple sets of phase maps. In this embodiment, spatiotemporal coding technology and MR-ARFI and blood oxygen level dependent functional magnetic resonance imaging (BOLD) are combined. An interleaved acquisition mode is adopted to complete the acquisition of multiple modal parameters in one imaging sequence. The fusion of multiple modal parameters can achieve multidimensional information complementarity, break through the limitation of single modal parameters, and achieve precise positioning, real-time monitoring and comprehensive evaluation in complex physiological environments, thereby improving the accuracy of the evaluation of the treatment effect after neuromodulation. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments of this application or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is an application environment diagram of a multimodal parameter determination method in one embodiment;

[0025] Figure 2 This is a flowchart illustrating a method for determining multimodal parameters in one embodiment;

[0026] Figure 3 This is a schematic diagram of an imaging sequence in one embodiment;

[0027] Figure 4 This is a structural block diagram of a multimodal parameter determination device in one embodiment. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0029] The multimodal parameter determination method provided in this application can be applied to, for example... Figure 1 The application environment shown includes a magnetic resonance imaging (MRI) device, which comprises a computer device 11 and a scanning device 12, wherein the computer device 11 communicates with the scanning device 12. A data storage system can store the data that the computer device 11 needs to process. The data storage system can be integrated onto the computer device 11 or placed on a cloud or other network server. The computer device can be a terminal, and its internal structure diagram can be as shown... Figure 1 As shown, the computer device includes a processor, memory, input / output interface, communication interface, display unit, and input device. The processor, memory, and input / output interface are connected via a system bus, and the communication interface, display unit, and input device are also connected to the system bus via the input / output interface. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The input / output interface is used for exchanging information between the processor and external devices. The communication interface is used for wired or wireless communication with external terminals; wireless communication can be achieved through Wi-Fi, mobile cellular networks, Near Field Communication (NFC), or other technologies. When executed by the processor, the computer program implements a multimodal parameter determination method. The display unit is used to form a visually visible image and can be a display screen, projection device, or virtual reality imaging device. The display screen can be an LCD screen or an e-ink screen. The input device of the computer device can be a touch layer covering the display screen, or buttons, trackballs, or touchpads set on the casing of the computer device, or external keyboards, touchpads, or mice, etc.

[0030] Those skilled in the art will understand that Figure 1 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the magnetic resonance device to which the present application is applied. A specific magnetic resonance device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0031] In one exemplary embodiment, such as Figure 2 As shown, a method for determining multimodal parameters is provided, which can be applied to... Figure 1 The following explanation uses a magnetic resonance imaging (MRI) device as an example, including steps S201 to S203. Wherein:

[0032] S201, an imaging sequence is applied to the imaging region to obtain a target magnetic resonance image; the imaging sequence includes a focused ultrasound pulse, a spatial coding excitation unit, and an acquisition unit; the spatial coding excitation unit is positioned before the focused ultrasound pulse and the acquisition unit, and the spatial coding gradient pulse in the spatial coding excitation unit and the acquisition gradient pulse in the acquisition unit satisfy a preset relationship so that the spatial coding gradient pulse applied to the imaging region covers the imaging region; the target magnetic resonance image includes multiple amplitude maps and multiple sets of phase maps.

[0033] Among them, the spatially encoded gradient pulse in the spatially encoded excitation unit and the acquired gradient pulse in the acquisition unit satisfy a preset relationship. The preset relationship can be that the first product result corresponding to the acquired gradient pulse is equal to the second product result corresponding to the spatially encoded gradient pulse. The first product result is the product of the amplitude of the acquired gradient pulse and the duration of the acquired gradient pulse, and the second product result is the product of the amplitude of the spatially encoded gradient pulse and the duration of the spatially encoded gradient pulse.

[0034] The preset relationship can also be that the difference between the first product result corresponding to the acquired gradient pulse and the second product result corresponding to the spatially encoded gradient pulse is less than a preset threshold, so that the spatially encoded gradient pulse applied to the imaging area covers the imaging area.

[0035] In this embodiment, the imaging sequence includes multiple basic units, each of which includes a focused ultrasound pulse, a spatial coding excitation unit, and an acquisition unit. By applying the focused ultrasound pulse, the spatial coding excitation unit, and the acquisition unit to the imaging region through multiple basic units, multiple amplitude maps and multiple sets of phase maps can be obtained.

[0036] Taking a basic unit as an example, a spatially encoded excitation unit, a first motion-coded gradient pulse, a focused ultrasound pulse, a convergence pulse unit, and an acquisition unit are sequentially applied to the imaging region to generate a first magnetic resonance signal, and a first phase map is obtained based on the first magnetic resonance signal. The spatially encoded excitation unit, convergence pulse unit, and acquisition unit are then applied to the imaging region to generate a second magnetic resonance signal, and a second phase map is obtained based on the second magnetic resonance signal. Finally, the spatially encoded excitation unit and acquisition unit are applied to the imaging region to generate a third magnetic resonance signal, and an amplitude map is obtained based on the third magnetic resonance signal. Optionally, the spatially encoded excitation unit includes a swept-frequency excitation pulse and a spatially encoded gradient pulse, the convergence pulse unit includes a convergence pulse and a slice-selective gradient pulse, and the acquisition unit includes a readout gradient pulse and an acquisition gradient pulse.

[0037] In one possible implementation, a crushing gradient pulse can also be applied to the imaging region while applying a refocusing pulse unit to the imaging region.

[0038] An image reconstruction algorithm is used to reconstruct the first phase map of the first magnetic resonance signal, the second phase map of the second magnetic resonance signal, and the amplitude map of the third magnetic resonance signal. Image reconstruction methods include, but are not limited to, inverse Fourier transform and super-resolution reconstruction.

[0039] The spatially encoded excitation unit and the acquisition unit can be used as blood oxygen level dependent functional magnetic resonance imaging (BOLD-fMRI). In the embodiments of this application, the BOLD-fMRI obtained by combining the spatially encoded excitation unit and the acquisition unit is different from the BOLD-fMRI obtained by combining the traditional radio frequency pulse and the slice-selective gradient pulse. The BOLD-fMRI of the embodiments of this application can reduce the scan time and is not easily affected by metal components such as external ultrasound transducers, thus having higher robustness to magnetic field inhomogeneity, magnetic susceptibility distortion and chemical shift artifacts.

[0040] Optionally, the order of the acquisition module for blood oxygenation level-dependent functional magnetic resonance imaging (fMRI) and the two acquisition modules for spatiotemporal coded imaging (SCEMI) and MR-ARFI is not restricted; that is, amplitude images can be acquired first, followed by the first and second phase images. Specifically, the order of application of the imaging sequence is as follows: spatially coded excitation unit, acquisition unit, spatially coded excitation unit, first motion-coded gradient pulse, focused ultrasound pulse, convergence pulse unit, acquisition unit, spatially coded excitation unit, convergence pulse unit, and acquisition unit.

[0041] Among them, the spatial coding excitation unit, the convergence pulse unit, and the acquisition unit can be used as spatiotemporal coding imaging technology, and the first motion coding gradient pulse and the focused ultrasound pulse can be used as MR-ARFI. That is, this application combines spatiotemporal coding imaging technology and MR-ARFI for imaging.

[0042] Optionally, the timing of the high-intensity focused ultrasound pulses is controlled by a sequence triggering module in the computer device.

[0043] Optionally, the amplitude and shape of the spatially encoded gradient pulse Ge can be defined according to the specific application.

[0044] S202, based on each phase map, obtains the displacement and temperature parameters of the imaging region.

[0045] In this embodiment, the same slice is acquired twice. The polarity of the first motion-coded gradient pulse acquired in the first acquisition is opposite to that of the second motion-coded gradient pulse acquired in the second acquisition, or no second motion-coded gradient pulse is applied in the second acquisition, thereby obtaining a set of phase maps, namely the first phase map and the second phase map. Each second phase map is subtracted from the corresponding first phase map, etc., to obtain the displacement parameters and temperature parameters of the imaging area caused by the high-intensity focused ultrasound pulse.

[0046] Theoretically, after subtracting the first and second phase maps, the phase in the non-focal region should be equal to 0. However, considering that the phase of the two phase maps in the non-focal region may not be 0 due to magnetic field inhomogeneity, phase correction can be performed. For example, two additional sets of phase maps without focused ultrasound can be acquired, and the corresponding first and second phase maps can be phase corrected respectively.

[0047] Furthermore, by obtaining tissue displacement through displacement parameters, precise positioning of the imaging area can be achieved. Moreover, the phase changes captured based on motion coding can also be used for simultaneous temperature imaging. Combined with temperature parameters, the temperature of the focused area can be monitored in real time to prevent tissue damage caused by overtreatment due to temperature rise.

[0048] S203, based on each amplitude map, obtains the hemodynamic parameters of the imaging area; the multimodal parameters include displacement parameters, temperature parameters and hemodynamic parameters.

[0049] In this embodiment of the application, after obtaining each amplitude map through the imaging sequence, the mean value of the pixels in the focal area corresponding to each amplitude map is obtained. Based on each mean value, a response function for hemodynamics can be obtained, which is the hemodynamic parameter. The hemodynamic parameter is combined to monitor the blood flow changes in the imaging area. The hemodynamic parameter can be used to assess whether the expected functional changes or metabolic changes occur in the neuromodulated brain region.

[0050] Furthermore, by combining focused ultrasound pulses, spatial coding excitation units, and acquisition units, real-time linkage of displacement parameters, temperature parameters, and hemodynamic parameters is achieved, constructing an integrated neuromodulation platform of "positioning-regulation-evaluation and verification." This not only improves the accuracy and real-time nature of treatment but also provides auxiliary decision-making basis for individualized treatment.

[0051] In the aforementioned multimodal parameter determination method, an imaging sequence is applied to the imaging region to obtain a target magnetic resonance image. Based on each phase map, displacement and temperature parameters of the imaging region are acquired, and based on each amplitude map, hemodynamic parameters of the imaging region are acquired. The imaging sequence includes focused ultrasound pulses, a spatial coding excitation unit, and an acquisition unit. The spatial coding excitation unit is positioned before the focused ultrasound pulses and the acquisition unit. The spatial coding gradient pulses in the spatial coding excitation unit and the acquisition gradient pulses in the acquisition unit satisfy a preset relationship, so that the spatial coding gradient pulses applied to the imaging region cover the imaging region. The multimodal parameters include displacement, temperature, and hemodynamic parameters, and the target magnetic resonance image includes multiple amplitude maps and multiple sets of phase maps. In this embodiment, spatiotemporal coding technology and MR-ARFI and oxygen level-dependent functional magnetic resonance imaging (BOLD) technology are combined. An interleaved acquisition mode is adopted to complete the acquisition of multiple modal parameters in one imaging sequence. The fusion of multiple modal parameters can achieve multidimensional information complementarity, overcome the limitations of single modal parameters, and achieve precise positioning, real-time monitoring, and comprehensive evaluation in complex physiological environments, thereby improving the accuracy of the evaluation of the treatment effect after neuromodulation.

[0052] In one embodiment, the imaging sequence further includes a refocusing pulse unit and a first motion-coded gradient pulse; a spatial coding excitation unit, a first motion-coded gradient pulse, a focused ultrasound pulse, a refocusing pulse unit, an acquisition unit, a spatial coding excitation unit, a refocusing pulse unit, an acquisition unit, a spatial coding excitation unit, and an acquisition unit are applied sequentially; the spatial coding excitation unit further includes a sweep excitation pulse; the refocusing pulse unit includes a refocusing pulse and a slice-selective gradient pulse, and the acquisition unit further includes a readout gradient pulse.

[0053] In the embodiments of this application, such as Figure 3 As shown, Figure 3 This is a schematic diagram of an imaging sequence in one embodiment. A sweep excitation pulse (90° Chirp) with a flip angle of 90° and a spatial coding gradient pulse Ge are simultaneously applied to the imaging region. Hydrogen protons in the human body spin along the spatial coding direction under the influence of the spatial coding gradient pulse Ge. The duration of the spatial coding gradient pulse is T. Ge At the end of the frequency sweep excitation pulse, the accumulated spin phase of the hydrogen protons is a quadratic function of different positions in the matrix spatial coding direction, exhibiting a quadratic parabolic shape. A spin-based spatial coding gradient pulse is used on the spatial coding axis instead of the traditional phase coding gradient pulse, increasing the bandwidth in the spatial coding direction through quadratic phase technology.

[0054] After applying the spatial coding excitation unit, the first motion encoding gradient (MEG) pulse and the focused ultrasound pulse in the imaging sequence are applied to the imaging region. The focused ultrasound pulse causes tissue displacement in the imaging region. The first motion encoding gradient pulse MEG1 is used to encode the tiny displacement (micrometer level) caused by the focused ultrasound pulse in the tissue of the imaging region, so as to accurately locate the focus of the focused ultrasound pulse neuromodulation.

[0055] After applying the spatially encoded excitation unit, the first motion-coded gradient pulse, and the focused ultrasound pulse, a refocusing pulse and a slice-selective gradient pulse (Gss) from the imaging sequence are applied to the imaging region. The refocusing pulse is used to refocus the dephased hydrogen protons, causing them to re-converge in phase. The slice-selective gradient pulse (Gss) is used to select specific slices for imaging. By applying a linearly varying magnetic field in a certain direction, the frequency of hydrogen protons in the body changes linearly along that direction, thereby achieving precise selection of specific slices. TE1 is the echo time in the first image acquisition sequence.

[0056] After applying the refocusing pulse unit, an acquisition gradient pulse (Gacq) is applied to the tissue along the spatial encoding axis, and a readout gradient pulse (Gro) is applied along the readout axis. The acquisition gradient pulse (Gacq) is mainly used for spatial localization of the signal before imaging, ensuring that the received signal accurately corresponds to a specific location within the imaging region. The readout gradient pulse (Gro) is used to read the acquired signal from the imaging region and convert it into an electrical signal. The readout gradient pulse (Gro) works in conjunction with the acquisition gradient pulse (Gacq) to complete the imaging process. After applying the acquisition gradient pulse (Gacq), hydrogen protons within the imaging region generate signals of different frequencies. The function of the readout gradient pulse (Gro) is to separate these signals of different frequencies, arrange them in a certain order, and then convert them into electrical signals through a receiving coil. In this way, a set of first magnetic resonance signals representing the tissue structure information within the imaging region can be obtained.

[0057] Based on the above method, a spatially encoded excitation unit, a convergence pulse unit, and an acquisition unit are sequentially applied to the imaging region to obtain a second magnetic resonance signal, and a second phase map is obtained based on the second magnetic resonance signal. Alternatively, a spatially encoded excitation unit, a second motion-coded gradient pulse, a focused ultrasound pulse, a convergence pulse unit, and an acquisition unit are sequentially applied to the imaging region to obtain a second magnetic resonance signal, and a second phase map is obtained based on the second magnetic resonance signal. The target logic axis applied by the second motion-coded gradient pulse is the same as that applied by the first motion-coded gradient pulse, but the polarity of the second motion-coded gradient pulse is opposite to that of the first motion-coded gradient pulse.

[0058] A sweep excitation pulse and a spatially encoded gradient pulse Ge are applied to the imaging region. After applying the spatially encoded excitation unit, an acquisition gradient pulse Gacq and a readout gradient pulse Gro are applied to the imaging region to generate a third magnetic resonance signal, and an amplitude map based on the third magnetic resonance signal is obtained.

[0059] Optionally, the focused ultrasound pulse can be emitted simultaneously with the first motion-coded gradient pulse MEG1, and the starting point of the focused ultrasound pulse can be spaced apart from the starting point of the first motion-coded gradient pulse MEG1 by a preset time interval Tdelay, which is less than the duration of the first motion-coded gradient pulse.

[0060] The target logical axis applied by the first motion-coded gradient pulse (MEG1) can be any one of the readout axis (RO), spatial coding axis (SP), or slice selection axis (SS). The target logical axis applied by the first motion-coded gradient pulse (MEG1) can be determined based on the propagation direction of the focused ultrasound pulse and / or a preset displacement measurement direction. For example, if the propagation direction of the focused ultrasound pulse is the readout axis, then the target logical axis applied by the first motion-coded gradient pulse (MEG1) is the readout axis; or, if the preset displacement measurement direction is the spatial coding axis, then the target logical axis applied by the first motion-coded gradient pulse (MEG1) is the spatial coding axis.

[0061] Optionally, the type of radio frequency pulse can be a hard pulse, a soft pulse, an adiabatic pulse, etc., that is, the type of sweep excitation pulse and the subsequent refocusing pulse can be a hard pulse, a soft pulse, an adiabatic pulse, etc. The flip angle of the sweep excitation pulse can be 90° or other angles, and the amplitude of the sweep excitation pulse is not limited.

[0062] Optionally, the amplitude and time of the first motion-coded gradient pulse MEG1, the amplitude and time of the retraction pulse, and the flip angle can be defined according to the actual application. The first motion-coded gradient pulse MEG1 can be a bipolar repetitive displacement-coded gradient pulse, a unipolar motion-coded gradient pulse, an inverse bipolar motion-coded gradient pulse, or other displacement-coded gradient pulses that may be used, which also improves the signal-to-noise ratio of the first phase map to a certain extent.

[0063] Optionally, the readout gradient pulse Gro can be acquired using non-Cartesian acquisition (based on spiral readout or radial readout) or Cartesian acquisition. It can also be acquired using methods including but not limited to Echo Planar Imaging (EPI), Gradient Recalled Echo (GRE), and Spin Echo (SE).

[0064] Optionally, the frequency, duration, and Tdelay time of the focused ultrasound pulses can vary depending on the subject site and treatment purpose. The focused ultrasound pulses are controlled by the sequence triggering module and can be applied to any axis, i.e., the target logical axis to which the first motion-coded gradient pulse is applied. By changing the target logical axis to which the first motion-coded gradient pulse is applied, three first phase maps can be obtained, thereby obtaining a three-dimensional displacement distribution map based on the corresponding second phase map.

[0065] In this embodiment, a spatial coding excitation unit, a first motion coding gradient pulse, a focused ultrasound pulse, a convergence pulse unit, an acquisition unit, a spatial coding excitation unit, a convergence pulse unit, an acquisition unit, a spatial coding excitation unit, and an acquisition unit are applied sequentially. The spatial coding excitation unit further includes a sweep frequency excitation pulse; the convergence pulse unit includes a convergence pulse and a slice-selective gradient pulse; and the acquisition unit further includes a readout gradient pulse. This embodiment combines spatiotemporal coding technology with MR-ARFI and blood oxygen level-dependent functional magnetic resonance imaging technology, employing an interleaved acquisition mode to accelerate scanning speed, achieve rapid image acquisition in a shorter time, and reduce heat deposition caused by focused ultrasound pulses. Furthermore, it is less susceptible to the influence of external devices containing metal components, exhibiting high robustness to magnetic field homogeneity, magnetic susceptibility distortion, and chemical shift artifacts in neuromodulation applications, reducing image distortion, improving the signal-to-noise ratio of the image, and laying an important foundation for precise localization of nervous system modulation and subsequent modulatory treatment.

[0066] In one embodiment, the imaging sequence further includes a second motion-coded gradient pulse, which and the focused ultrasound pulse are applied sequentially between the spatial coding excitation unit and the convergence pulse unit; the polarity of the second motion-coded gradient pulse is opposite to that of the first motion-coded gradient pulse.

[0067] The first motion-coded gradient pulse and the second motion-coded gradient pulse are applied to the same target logic axis, which includes any one of the layer selection axis, spatial coding axis and readout axis; the target logic axis is determined based on the propagation direction of the focused ultrasound pulse and / or the preset displacement measurement direction.

[0068] In this embodiment, a second motion-coded gradient pulse may be applied simultaneously with the applied focused ultrasound pulse, or the starting time of the applied focused ultrasound pulse may be later than the starting time of the applied second motion-coded gradient pulse.

[0069] In this embodiment, the polarity of the second motion-coded gradient pulse is opposite to that of the first motion-coded gradient pulse, which eliminates phase artifacts caused by field inhomogeneity and improves the sensitivity of displacement, thereby improving the signal-to-noise ratio of the first phase map and the second phase map.

[0070] In one embodiment, the first motion-coded gradient pulse includes a first sub-motion-coded gradient pulse, a second sub-motion-coded gradient pulse, and a third sub-motion-coded gradient pulse. The first and second sub-motion-coded gradient pulses have the same polarity, while the first and third sub-motion-coded gradient pulses have opposite polarities.

[0071] In this embodiment, the first motion-coded gradient pulse includes a three-lobed motion-coded gradient pulse consisting of a first sub-motion-coded gradient pulse, a second sub-motion-coded gradient pulse, and a third sub-motion-coded gradient pulse. The first and second sub-motion-coded gradient pulses have the same polarity, while the first and third sub-motion-coded gradient pulses have opposite polarities. Since the first and second motion-coded gradient pulses have opposite polarities, the second motion-coded gradient pulse includes a fourth and a fifth sub-motion-coded gradient pulse with opposite polarities to the first sub-motion-coded gradient pulse, and a sixth sub-motion-coded gradient pulse with opposite polarities to the third sub-motion-coded gradient pulse.

[0072] In this embodiment, the first motion-coded gradient pulse includes a first sub-motion-coded gradient pulse, a second sub-motion-coded gradient pulse, and a third sub-motion-coded gradient pulse. The three-lobed motion-coded gradient pulse has low sensitivity to displacement caused by unrecovered tissue and high robustness to background phases such as residual motion, which is beneficial for measuring instantaneous phase displacement and related parameters of magnetic resonance elastography.

[0073] In one embodiment, the first magnitude of the zeroth gradient moment of the first sub-motion-coded gradient pulse is equal to the second magnitude of the zeroth gradient moment of the second sub-motion-coded gradient pulse, and the third magnitude of the zeroth gradient moment of the third sub-motion-coded gradient pulse is equal to the sum of the first and second magnitudes.

[0074] In the embodiments of this application, as described above Figure 3 As shown, assume that the first modulus of the zeroth-order gradient moment of the first sub-motion-coded gradient pulse is A1, the second modulus of the zeroth-order gradient moment of the second sub-motion-coded gradient pulse is A2, and the third modulus of the zeroth-order gradient moment of the third sub-motion-coded gradient pulse is A3. By setting A1 = A2 and A3 = A1 + A2, and combining the conditions that the polarities of the first and second sub-motion-coded gradient pulses are the same and the polarities of the first and third sub-motion-coded gradient pulses are opposite, the total zeroth-order gradient is made equal to zero, thereby eliminating the phase shift of stationary tissues, improving image quality, reducing motion artifacts, and increasing the signal-to-noise ratio of the image.

[0075] In one embodiment, the preset relationship is that the first product result corresponding to the acquired gradient pulse is equal to the second product result corresponding to the spatially encoded gradient pulse; the first product result is the product of the amplitude of the acquired gradient pulse and the duration of the acquired gradient pulse, and the second product result is the product of the amplitude of the spatially encoded gradient pulse and the duration of the spatially encoded gradient pulse.

[0076] In this embodiment of the application, the first product result is the amplitude A of the acquired gradient pulse. Gacq and the duration T of the acquired gradient pulse Gacq The product result is the amplitude A of the spatially encoded gradient pulse. Ge The duration T of the spatially encoded gradient pulse Ge The product result, i.e., the pre-defined relation is |T Ge ×A Ge =T Gacq ×A Gacq This allows spatial coding to cover the entire imaging area.

[0077] In one embodiment, the imaging sequence further includes crushed gradient pulses and damaged gradient pulses.

[0078] In the embodiments of this application, as described above Figure 3 As shown, the crushing gradient pulse includes a first crushing gradient pulse crush1 and a second crushing gradient pulse crush2. The first crushing gradient pulse crush1 and the second crushing gradient pulse crush2 are applied before and after the recoil pulse. The first crushing gradient pulse crush1 and the second crushing gradient pulse crush2 are used to suppress interference signals, that is, to suppress unwanted coherent spin signals.

[0079] After applying the acquisition unit to the imaging area, a damaged gradient pulse S can be added to the readout axis, spatial coding axis, and layer selection axis to eliminate residual phase in the lateral plane, so as to facilitate the next image acquisition.

[0080] Optionally, only the crushing gradient pulse or the destroying gradient pulse can be applied, or both can be applied simultaneously.

[0081] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0082] Based on the same inventive concept, this application also provides a multimodal parameter determination apparatus for implementing the multimodal parameter determination method described above. The solution provided by this apparatus is similar to the implementation scheme described in the above method; therefore, the specific limitations in one or more embodiments of the multimodal parameter determination apparatus provided below can be found in the limitations of the multimodal parameter determination method described above, and will not be repeated here.

[0083] In one exemplary embodiment, such as Figure 4 As shown, a multimodal parameter determination device is provided, comprising: an application module 51, a first acquisition module 52, and a second acquisition module 53, wherein:

[0084] The application module 51 is used to apply an imaging sequence to the imaging region to obtain a target magnetic resonance image. The imaging sequence includes a focused ultrasound pulse, a spatial coding excitation unit, and an acquisition unit. The spatial coding excitation unit is positioned before the focused ultrasound pulse and the acquisition unit. The spatial coding gradient pulse in the spatial coding excitation unit and the acquisition gradient pulse in the acquisition unit satisfy a preset relationship so that the spatial coding gradient pulse applied to the imaging region covers the imaging region. The target magnetic resonance image includes multiple amplitude maps and multiple sets of phase maps.

[0085] The first acquisition module 52 is used to acquire displacement parameters and temperature parameters of the imaging area based on each phase map;

[0086] The second acquisition module 53 is used to acquire hemodynamic parameters of the imaging region based on each amplitude map; the multimodal parameters include displacement parameters, temperature parameters and hemodynamic parameters.

[0087] In one embodiment, the imaging sequence further includes a refocusing pulse unit and a first motion-coded gradient pulse; a spatial coding excitation unit, a first motion-coded gradient pulse, a focused ultrasound pulse, a refocusing pulse unit, an acquisition unit, a spatial coding excitation unit, a refocusing pulse unit, an acquisition unit, a spatial coding excitation unit, and an acquisition unit are applied sequentially; the spatial coding excitation unit further includes a sweep excitation pulse; the refocusing pulse unit includes a refocusing pulse and a slice-selective gradient pulse, and the acquisition unit further includes a readout gradient pulse.

[0088] In one embodiment, the imaging sequence further includes a second motion-coded gradient pulse, which and the focused ultrasound pulse are applied sequentially between the spatial coding excitation unit and the convergence pulse unit; the polarity of the second motion-coded gradient pulse is opposite to that of the first motion-coded gradient pulse.

[0089] In one embodiment, the first motion-coded gradient pulse includes a first sub-motion-coded gradient pulse, a second sub-motion-coded gradient pulse, and a third sub-motion-coded gradient pulse. The first and second sub-motion-coded gradient pulses have the same polarity, while the first and third sub-motion-coded gradient pulses have opposite polarities.

[0090] In one embodiment, the first magnitude of the zeroth gradient moment of the first sub-motion-coded gradient pulse is equal to the second magnitude of the zeroth gradient moment of the second sub-motion-coded gradient pulse, and the third magnitude of the zeroth gradient moment of the third sub-motion-coded gradient pulse is equal to the sum of the first and second magnitudes.

[0091] In one embodiment, the preset relationship is that the first product result corresponding to the acquired gradient pulse is equal to the second product result corresponding to the spatially encoded gradient pulse; the first product result is the product of the amplitude of the acquired gradient pulse and the duration of the acquired gradient pulse, and the second product result is the product of the amplitude of the spatially encoded gradient pulse and the duration of the spatially encoded gradient pulse.

[0092] Each module in the aforementioned multimodal parameter determination device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of the magnetic resonance imaging (MRI) device in hardware form or independent of it, or they can be stored in the memory of the MRI device in software form, so that the processor can call and execute the operations corresponding to each module.

[0093] In one exemplary embodiment, a magnetic resonance device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the method steps provided in any of the above embodiments.

[0094] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method steps provided in any of the above embodiments.

[0095] In one embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the method steps provided in any of the above embodiments.

[0096] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0097] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM). The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, artificial intelligence (AI) processors, etc., and are not limited to these.

[0098] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0099] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for determining multimodal parameters, characterized in that, The method includes: An imaging sequence is applied to an imaging region to obtain a target magnetic resonance image. The imaging sequence includes a focused ultrasound pulse, a spatially encoded excitation unit, a convergence pulse unit, a first motion-coded gradient pulse, and an acquisition unit. The spatially encoded excitation unit is positioned before the focused ultrasound pulse and the acquisition unit. The spatially encoded gradient pulse in the spatially encoded excitation unit and the acquisition gradient pulse in the acquisition unit satisfy a preset relationship, such that the spatially encoded gradient pulse applied to the imaging region covers the imaging region. The target magnetic resonance image includes multiple amplitude maps and multiple phase maps. The preset relationship is that the first product result corresponding to the acquisition gradient pulse is equal to the second product result corresponding to the spatially encoded gradient pulse. The first product result is the product of the amplitude and duration of the acquisition gradient pulse, and the second product result is the product of the amplitude and duration of the spatially encoded gradient pulse. The phase maps include a first phase map and a second phase map. Based on the phase maps, the displacement and temperature parameters of the imaging region are obtained; Based on the amplitude maps, the hemodynamic parameters of the imaging region are obtained; the multimodal parameters include the displacement parameters, temperature parameters, and hemodynamic parameters. The step of applying an imaging sequence to the imaging region to obtain a target magnetic resonance image includes: sequentially applying a spatially encoded excitation unit, a first motion-coded gradient pulse, a focused ultrasound pulse, a convergence pulse unit, and an acquisition unit to the imaging region to obtain a first phase map; applying the spatially encoded excitation unit, the convergence pulse unit, and the acquisition unit to the imaging region to obtain a second phase map; and applying the spatially encoded excitation unit and the acquisition unit to the imaging region to obtain an amplitude map.

2. The method according to claim 1, characterized in that, The spatial coding excitation unit further includes a sweep frequency excitation pulse; the refocusing pulse unit includes a refocusing pulse and a layer selection gradient pulse; and the acquisition unit further includes a readout gradient pulse.

3. The method according to claim 2, characterized in that, The imaging sequence further includes a second motion-coded gradient pulse, which and the focused ultrasound pulse are applied sequentially between the spatial coding excitation unit and the convergence pulse unit. The polarity of the second motion-coded gradient pulse is opposite to that of the first motion-coded gradient pulse.

4. The method according to claim 3, characterized in that, The first motion-coded gradient pulse includes a first sub-motion-coded gradient pulse, a second sub-motion-coded gradient pulse, and a third sub-motion-coded gradient pulse. The first sub-motion-coded gradient pulse and the second sub-motion-coded gradient pulse have the same polarity, and the first sub-motion-coded gradient pulse and the third sub-motion-coded gradient pulse have opposite polarities.

5. The method according to claim 4, characterized in that, The first magnitude of the zeroth gradient moment of the first sub-motion-coded gradient pulse is equal to the second magnitude of the zeroth gradient moment of the second sub-motion-coded gradient pulse, and the third magnitude of the zeroth gradient moment of the third sub-motion-coded gradient pulse is equal to the sum of the first magnitude and the second magnitude.

6. A multimodal parameter determination device, characterized in that, The device includes: An application module is used to apply an imaging sequence to an imaging region to obtain a target magnetic resonance image. The imaging sequence includes a focused ultrasound pulse, a spatially encoded excitation unit, a convergence pulse unit, a first motion-coded gradient pulse, and an acquisition unit. The spatially encoded excitation unit is positioned before the focused ultrasound pulse and the acquisition unit. The spatially encoded gradient pulse in the spatially encoded excitation unit and the acquisition gradient pulse in the acquisition unit satisfy a preset relationship so that the spatially encoded gradient pulse applied to the imaging region covers the imaging region. The target magnetic resonance image includes multiple amplitude maps and multiple phase maps. The preset relationship is that the first product result corresponding to the acquisition gradient pulse is equal to the second product result corresponding to the spatially encoded gradient pulse. The first product result is the product of the amplitude and duration of the acquisition gradient pulse, and the second product result is the product of the amplitude and duration of the spatially encoded gradient pulse. The phase maps include a first phase map and a second phase map. The first acquisition module is used to acquire the displacement parameters and temperature parameters of the imaging region based on each of the phase maps; The second acquisition module is used to acquire hemodynamic parameters of the imaging region based on each amplitude map; the multimodal parameters include the displacement parameters, temperature parameters and hemodynamic parameters; The application module is specifically used to sequentially apply a spatial coding excitation unit, a first motion coding gradient pulse, a focused ultrasound pulse, a refocusing pulse unit, and an acquisition unit to the imaging region to obtain a first phase map; apply the spatial coding excitation unit, the refocusing pulse unit, and the acquisition unit to the imaging region to obtain a second phase map; and apply the spatial coding excitation unit and the acquisition unit to the imaging region to obtain an amplitude map.

7. A magnetic resonance imaging (MRI) device, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

9. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

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