Magnetic resonance imaging method, device, equipment and storage medium

Abstract

The present application provides a magnetic resonance imaging method, which includes: at a first moment, applying a non-layer-selective adiabatic pulse to a scanning area, and waiting for the scanning area to perform inversion recovery for a preset time period; wherein the scanning area includes fluid tissue, and the preset time period is 600ms-1000ms; at a second moment when the preset time period ends, using an imaging radio frequency pulse to excite the scanning area after inversion recovery to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed; and performing image reconstruction according to the magnetic resonance signal to obtain a magnetic resonance image. By applying a non-layer-selective adiabatic pulse and performing magnetic resonance imaging at an appropriate time of inversion recovery, the fluid signal in the imaging area is not recovered before the start of the scan, presenting a low signal, effectively suppressing the fluid signal, reducing fluid motion artifacts, and improving the stability and reliability of imaging.

Description

Technical Field

[0001] The present application relates to the technical field of magnetic resonance imaging, and in particular to a magnetic resonance imaging method, apparatus, device and storage medium. Background Art

[0002] The principle of Magnetic Resonance Imaging (MRI) is as follows: when an external magnetic field is applied, radio frequency (RF) pulses of a specific frequency are used to excite protons in the tissue being measured. The protons absorb a certain amount of energy and resonate. When the RF pulse is stopped, the excited protons gradually release the absorbed energy in the form of scanning signals. The scanning signals are collected and processed using image reconstruction technology to obtain a scanning image of the tissue being measured.

[0003] At present, 2D-T1 weighted MRI of the upper abdomen requires that the signals of long relaxation components such as blood and bile are very small, and the signals of short relaxation components such as liver parenchyma are highlighted. Since respiratory movement and changes in vascular flow velocity will produce large artifacts, MRI of existing methods will be affected by the blood inflow enhancement effect, and image weighting is unreliable and of low quality. Summary of the invention

[0004] In view of this, the purpose of the embodiments of the present application is to provide a magnetic resonance imaging method, apparatus, device and storage medium, by applying a non-selective adiabatic pulse to a region containing fluid tissue, waiting for an inversion recovery time of 600ms-1000ms, and then performing magnetic resonance imaging after the inversion recovery. Since the fluid tissue has a relatively long longitudinal relaxation time, it is not fully recovered within the inversion recovery time period, so that the fluid tissue signal in the magnetic resonance signal is suppressed, thereby solving the above-mentioned technical problem of "magnetic resonance imaging will be affected by the blood inflow enhancement effect, image weighting is unreliable, and the quality is not high".

[0005] In a first aspect, an embodiment of the present application provides a magnetic resonance imaging method, the method comprising: at a first moment, applying a non-layer-selective adiabatic pulse to a scanning area, and waiting for the scanning area to perform inversion recovery for a preset time period; wherein the scanning area includes fluid tissue, and the preset time period is 600ms-1000ms; at a second moment when the preset time period ends, using an imaging radio frequency pulse to excite the scanning area after inversion recovery to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed; and performing image reconstruction based on the magnetic resonance signal to obtain a magnetic resonance image.

[0006] In the above implementation process, magnetic resonance imaging is performed after applying non-layer-selective adiabatic pulse inversion recovery for a period of time, so that the fluid signals in the imaging area are all low signals before the scanning begins, and then there will be no signals of long relaxation components in the imaging area during the scanning process, which effectively suppresses the fluid signals, reduces fluid motion artifacts, and improves the stability and reliability of imaging; at the same time, the adiabatic pulse can also suppress the influence of the radio frequency field uniformity on the saturation effect.

[0007] Optionally, the first moment is the moment when the peak of the respiratory waveform decreases to 10%.

[0008] In the above implementation process, by combining respiratory gating and utilizing the waiting time of inversion recovery, the delay time required for respiratory gating in conventional methods is completed, the inversion recovery process is started at the starting point of the falling edge of the respiratory waveform, and the function of magnetic resonance imaging at the end of the falling edge of the respiratory waveform is realized, thereby minimizing motion artifacts to the greatest extent.

[0009] Optionally, the preset time period is 700ms.

[0010] In the above implementation process, by eliminating the fluid tissue signal motion artifact, the respiratory motion artifact can also be eliminated in combination with respiratory gating, thereby avoiding the influence of the respiratory pattern on the image, improving the reliability of the image, and improving the adaptability to different respiratory patterns.

[0011] Optionally, at a second moment after the preset time period ends, an imaging radio frequency pulse is used to excite the scanning area after inversion recovery to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed, comprising: at a second moment after the preset time period ends, an imaging radio frequency pulse with a TR period is used to excite the scanning area after inversion recovery; and a gradient field is applied and spatial encoding is performed to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed.

[0012] In the above implementation process, by completing the emission of imaging radio frequency pulses and data acquisition within the shortest possible TR time, the accuracy of weighting is ensured and motion artifacts are reduced.

[0013] Optionally, applying the gradient field and performing spatial encoding to obtain the magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed includes: jointly applying a layer selection gradient and a phase encoding gradient; and acquiring the magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed during the duration of the read gradient.

[0014] In the above implementation process, by completing the emission of imaging radio frequency pulses and the cyclic data acquisition of each layer phase encoding within the shortest possible TR time, the accuracy of weighting is guaranteed and the motion artifact is reduced.

[0015] Optionally, at the second moment after the preset time period ends, after the scanning area after inversion recovery is excited by an imaging radio frequency pulse with a TR period, the method further includes: shortening the scanning time by using a parallel accelerated magnetic resonance imaging method; wherein the parallel accelerated magnetic resonance imaging method includes: partial K-space acquisition, GRAPPA acceleration, SENSE acceleration, and compressed sensing acceleration. One or more.

[0016] In the above implementation process, by combining a variety of acceleration means, the fastest imaging speed can be ensured, the smallest motion artifacts can be ensured in the scanning time, and the stability and reliability of the final weighted imaging can be improved.

[0017] Optionally, the fluid tissue comprises one or more long relaxing components; the long relaxing components comprise bile, blood, cerebrospinal fluid.

[0018] In the above implementation process, by applying an adiabatic pulse and waiting for a suitable inversion recovery time to perform magnetic resonance imaging, the fluid signal with a long relaxation component can be suppressed, thereby achieving an imaging effect of eliminating fluid artifacts.

[0019] In a second aspect, an embodiment of the present application provides a magnetic resonance imaging device, comprising: an inversion recovery module, for applying a non-layer-selective adiabatic pulse to a scanning area at a first moment, and waiting for the scanning area to perform inversion recovery for a preset time period; wherein the scanning area includes fluid tissue, and the preset time period is 600ms-1000ms; an excitation sampling module, for using an imaging radio frequency pulse to excite the scanning area after inversion recovery at a second moment after the preset time period ends, so as to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed; and an imaging module, for performing image reconstruction according to the magnetic resonance signal to obtain a magnetic resonance image.

[0020] In a third aspect, an embodiment of the present application further provides an electronic device, comprising: a processor and a memory, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the machine-readable instructions are executed by the processor to perform the steps of the above method.

[0021] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are executed.

[0022] In order to make the above-mentioned objects, features and advantages of the present application more obvious and understandable, embodiments are given below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A flowchart of a magnetic resonance imaging method provided in an embodiment of the present application;

[0025] Figure 2 A schematic diagram of a magnetic resonance imaging method provided in an embodiment of the present application;

[0026] Figure 3 A schematic diagram of the functional modules of a magnetic resonance imaging device provided in an embodiment of the present application; and

[0027] Figure 4 A block diagram of an electronic device of a magnetic resonance imaging device provided in an embodiment of the present application.

[0028] Icon: 210 - inversion recovery module; 220 - excitation sampling module; 230 - imaging module; 300 - electronic device; 311 - memory; 312 - storage controller; 313 - processor; 314 - peripheral interface; 315 - input and output unit; 316 - display unit. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0030] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. The terms "comprises", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the statement "comprising one..." do not exclude the presence of other identical elements in the process, method, article or equipment including the elements. The terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0031] The inventor of the present application has noticed that the multiplanar gradient review (MPGR) method uses the largest possible RF transmission bandwidth and receiving bandwidth to achieve the shortest possible TR (repetition time), and the continuous short TR repetition acquisition time with different phase encodings to achieve fast K-space acquisition. When the total acquisition time is reduced from about half a minute of the conventional sequence to less than 1 second, the artifacts caused by respiratory motion can be avoided. The weighting of the existing method is affected by the blood inflow enhancement effect, the image weighting is unreliable, and it is not combined with respiratory gating. The adaptability to different respiratory modes is poor, the acceleration method is relatively simple, and the acceleration multiple is not increased as much as possible according to the characteristics of the imaging system.

[0032] Based on the above research, the embodiment of the present application provides a magnetic resonance imaging method, which includes: at a first moment, applying a non-selective adiabatic pulse to the scanning area, and waiting for the scanning area to perform inversion recovery for a preset time period; wherein the scanning area includes fluid tissue, and the preset time period is 600ms-1000ms; at a second moment after the preset time period ends, using an imaging radio frequency pulse to excite the scanning area after inversion recovery to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed; and performing image reconstruction based on the magnetic resonance signal to obtain a magnetic resonance image. By applying a non-selective adiabatic pulse inversion recovery for a period of time and then performing magnetic resonance imaging, the fluid signals in the imaging area before the scanning begins are all low signals, and there will be no fluid with signals in the imaging area during the scanning process, which effectively suppresses the fluid signal, reduces fluid motion artifacts, and improves the stability and reliability of imaging.

[0033] See also Figure 1 , Figure 1 A flowchart of a magnetic resonance imaging method provided in an embodiment of the present application is as follows. Figure 1The method may include: step 100, step 120, and step 140.

[0034] Step 100: at a first moment, applying a non-layer-selective adiabatic pulse to a scanning region, and waiting for the scanning region to perform inversion recovery for a preset time period; wherein the scanning region includes fluid tissue, and the preset time period is 600ms-1000ms;

[0035] Step 120: At a second moment after the preset time period ends, an imaging radio frequency pulse is used to excite the scanning area after inversion recovery to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed;

[0036] Step 140: Perform image reconstruction according to the magnetic resonance signal to obtain a magnetic resonance image.

[0037] For step 100:

[0038] Exemplarily, the first moment may be any moment of the magnetic resonance examination, and the test object may be a healthy subject, a patient, or an animal. The scanning area may be any part or tissue of the test object, such as the heart, blood vessels, abdomen, or other organs or tissues. Each scanning area may be a three-dimensional block / three-dimensional volume, and the three-dimensional block may include multiple two-dimensional slices, and the flowing tissue may be a variety of flowing components such as bile, blood, and cerebrospinal fluid.

[0039] Adiabatic pulse can change the nuclear magnetic signal of human body components from normal +1 to -1, that is, to achieve inversion, and then the process of recovery from -1 to +1 is called inversion recovery. After the adiabatic pulse is emitted, each component recovers to normal along the exponential curve. The characteristic time of the exponential curve is the longitudinal relaxation time. The relaxation time of different components is different, and the recovery speed is different. Since the longitudinal relaxation time of long relaxation components such as bile, blood, and cerebrospinal fluid is basically around 1000ms, after the adiabatic pulse is emitted, wait for ln2*1s (about 700ms) before starting the normal sequence scan. Due to the empirical value of human body testing, the fluctuation will not exceed 100ms, so wait for at least 600ms. The signal generated by the long relaxation component is close to 0 and is black on the image. It is easy to know that after the adiabatic pulse is emitted, the signal generated by the long relaxation component is still close to 0 after waiting for about 1000ms at most. As for the short relaxation component, since the longitudinal relaxation time is very short, after about 600ms-1000ms, the signal has completely recovered to the normal state and is bright on the image.

[0040] The frequency of the non-selective adiabatic pulse is always equal to the resonance frequency of the system, which is a constant proportional to the main magnetic field strength of the magnetic resonance system. The non-selective layer is selected to better suppress the blood signal, which is a key step in T1-weighted imaging. Both the selected and non-selective inversion recovery can form T1 weighting. The selected adiabatic pulse can only suppress part of the fluid signal in the imaging scanning area, and the non-selective inversion recovery can obtain the entire image in which all fluid signals in the imaging scanning area are suppressed after only one inversion recovery.

[0041] For steps 120 and 140:

[0042] Exemplarily, the second moment is the moment after the first moment, when the inversion recovery process reaches the end of the preset time period. The magnetic resonance imaging device is used to send an excitation signal to the object to be detected, and the sent excitation signal is a scanning imaging sequence composed of imaging radio frequency pulses. The scanning imaging sequence can be a high-speed, dense short TR repeated acquisition sequence, where TR is the repetition time of the radio frequency pulse, that is, it can be the time interval between two consecutive radio frequency pulses.

[0043] The magnetic resonance signal can be obtained by sampling the magnetic resonance data of the detection object using a magnetic resonance imaging device, obtaining the magnetic resonance data of the gradient echo signal of the sent excitation signal, and obtaining the imaging data in which the fluid signal of the detection object is suppressed and eliminated. Specifically, the coded data corresponding to the magnetic resonance signal can be filled into the K space by conventional reconstruction means, and the K space is reconstructed to obtain the magnetic resonance image of the scanning area of ​​the detection object.

[0044] like Figure 2 As shown in the figure, since the relaxation time of the fluid tissue signal is about 1000ms, the blood signal just recovers to the vertical 0 point and will not be stimulated to generate a signal again. Figure 1 The normalized component changes are shown by the dashed lines, while the short relaxation component signal is Figure 2 In the case of solid arcs, the short relaxation component signals are all high signals, and inversion recovery is equivalent to weighting. Figure 2 This is accomplished by repeatedly collecting data with TR as the cycle as described in the previous section.

[0045] By applying non-layer-selective adiabatic pulse inversion recovery for a period of time and then performing magnetic resonance imaging, the fluid signals in the imaging area are all low signals before the scanning begins, and then there will be no signals of long relaxation components in the imaging area during the scanning process, which effectively suppresses the fluid signals, reduces fluid motion artifacts, and improves the stability and reliability of imaging; at the same time, the adiabatic pulse can also suppress the influence of the radio frequency field uniformity on the saturation effect.

[0046] In one embodiment, the first moment is the moment when the peak value of the respiratory waveform decreases to 10%.

[0047] For example, if the image is collected during the period of body contour fluctuation (during the rising and falling edges of the peak), the motion artifact of the image will be large, and by monitoring the respiratory waveform through respiratory gating, it is possible to select the end of the falling edge of the peak (such as Figure 2 The double arrows in the figure show the stable area) for scanning, so that the motion artifact will be very small. Through respiratory gating to monitor the respiratory waveform, a long air bag is placed on the abdomen of the person and tied to the abdomen with a strap. The pressure sensor monitors the pressure changes of the air bag. The pressure waveform is the change of the abdominal contour waveform during breathing.

[0048] On the basis of obtaining the respiratory waveform, it is necessary to accurately determine the end of the falling edge of the respiratory waveform. While obtaining the respiratory waveform signal at a certain moment, it is constantly compared with the previous signal. When the signal is significantly reduced, that is, the first moment when the relative peak value is reduced by more than 10%, the non-selective adiabatic pulse is applied, and the respiratory waveform will enter the end of the falling edge. At this time, the emission of the imaging radio frequency pulse and the scanning of the magnetic resonance signal are started. The signal will be completed at the most stable stage of breathing. Finally, after image reconstruction, a magnetic resonance image with respiratory motion artifacts eliminated is obtained.

[0049] By combining respiratory gating and utilizing the waiting time of inversion recovery, the delay time required for respiratory gating in conventional methods is achieved, and the inversion recovery process is started at the starting point of the falling edge of the respiratory waveform. The function of magnetic resonance imaging at the end of the falling edge of the respiratory waveform is achieved. Completing the scan at the end of the respiratory waveform can minimize motion artifacts.

[0050] In one embodiment, the preset time period is 700 ms.

[0051] For example, during breathing, the best imaging time period is usually the end of exhalation. From the moment when the respiratory waveform drops significantly, it can be judged that the exhalation period has begun, but it is generally impossible to accurately judge whether the end of exhalation has been reached. According to the average person's breathing speed, it takes about 700ms from the beginning of exhalation to the end of exhalation.

[0052] When the peak of the respiratory waveform signal is significantly reduced, that is, the first moment when the relative peak value is reduced by more than 10%, the non-selective adiabatic pulse is applied. Under normal breathing speed, it will take about 700ms from the time when the relative peak value is reduced by 10% to reach the end of exhalation. At this stage, imaging radio frequency pulses are applied for magnetic resonance imaging. The 700ms is the waiting time in respiratory gating imaging, which is also the delay time. This time is used to complete inversion recovery, thereby eliminating fluid tissue signal motion artifacts and combining respiratory gating to eliminate respiratory motion artifacts, avoiding the influence of respiratory pattern on the image, improving the reliability of the image, and improving the adaptability to different respiratory patterns.

[0053] In one embodiment, step 120 may specifically include: step 121 and step 122 .

[0054] Step 121: at a second moment after the preset time period ends, using an imaging radio frequency pulse with a TR period to excite the scanned area after inversion recovery; and

[0055] Step 122: Apply a gradient field and perform spatial encoding to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed.

[0056] For example, in order to suppress the fluid signal of the long relaxation component during the inversion recovery process, that is, to complete the scan when the signal of the long relaxation component has not yet fully recovered, it is necessary to complete the subsequent imaging RF pulse emission, phase encoding and data acquisition process in the shortest possible time to ensure the accuracy of weighting and reduce motion artifacts. In order to shorten the total scanning time as much as possible, it is necessary to shorten the repetition period TR of the imaging RF pulse as much as possible. The emission bandwidth of the imaging RF pulse is inversely proportional to the time P1 occupied by the emission pulse, and the acquisition bandwidth is inversely proportional to the time Tacq occupied by one data acquisition. In order to shorten TR, it is necessary to shorten P1 and Tacq, and the RF transmission bandwidth and receiving bandwidth are as large as possible.

[0057] The direction of the layer selection gradient is perpendicular to the scanning layer. The scanning layer can be in any direction according to the doctor's needs. Under a specific layer selection gradient, the frequency of the radio frequency emission is proportional to the distance of the selected layer from the center of the system (positive or negative), and the intensity of the layer selection gradient is inversely proportional to the layer thickness and proportional to the emission bandwidth. During the imaging process with TR as the cycle, imaging radio frequency pulses are continuously emitted, and gradient fields are applied at the same time, and the magnetic resonance data corresponding to their echo signals are collected for image reconstruction. Specifically, the magnetic resonance signal can be phase-encoded using the gradient field in the front-to-back direction (i.e., the y direction), layer selection (or layer selection) encoding can be performed using the gradient field in the left-right direction (i.e., the x direction), and frequency encoding / frequency readout encoding can be performed using the gradient field in the up-down direction (i.e., the z direction). By completing the emission of imaging radio frequency pulses and data acquisition in the shortest possible TR time, the accuracy of weighting is guaranteed and motion artifacts are reduced.

[0058] In one embodiment, step 122 may specifically include: step 122a and step 122b.

[0059] Step 122a: applying a slice selection gradient and a phase encoding gradient together; and

[0060] Step 122b: During the duration of the read gradient, acquire magnetic resonance signals in which the signals of the fluid tissue in the scanning region are suppressed.

[0061] For example, according to the requirements of acceleration or partial k-space acquisition, a gradient strength that can achieve a specific phase encoding amount is selected. The phase encoding gradient is along the phase direction, so that the detection object has different phases along the phase direction. The phase encoding gradient is changed by sending different values ​​each time, see Figure 2 Trapezoid with shadow in the middle.

[0062] The number of selected layers determines how many images will be scanned in the end, and the number of layers determines how many times the scan is cyclically scanned. Therefore, the number of scanning layers and range can be further predetermined on the operating interface of the magnetic resonance imaging equipment system, and then other specific parameters in the scan can be determined, and a specific acceleration method and resolution can be selected to determine the number of phase encodings required for imaging. During the imaging process with TR as the cycle, the emission of imaging RF pulses, acquisition, layer selection gradients, and reading gradients are repeated continuously, and their frequency, timing, waveform, and start and end time points are also repeated periodically, and the phase encoding gradient must be changed each time to obtain the phase encoding required for imaging. After all the data corresponding to a set of phase encodings required for imaging are acquired, the final image can be obtained from the acquired signals through the image reconstruction process required for magnetic resonance imaging.

[0063] By completing the emission of imaging radio frequency pulses and the cyclic data acquisition of phase encoding for each layer within the shortest possible TR time, the accuracy of weighting is guaranteed and motion artifacts are reduced.

[0064] In one embodiment, step 120 may specifically include: step 130 and step 131.

[0065] Step 130: shortening the scanning time by using a parallel accelerated magnetic resonance imaging method;

[0066] Step 131: wherein the parallel accelerated magnetic resonance imaging method includes: one or more of partial K-space acquisition, GRAPPA acceleration, SENSE acceleration, and compressed sensing acceleration.

[0067] For example, in addition to shortening the TR period, a variety of acceleration techniques can be combined to shorten the total scanning time to reduce motion artifacts and improve weighted accuracy. The accelerated magnetic resonance imaging method is mainly to collect a part of the phase encoding data in a set of complete phase encoding required for imaging, and use the reconstruction method unique to the corresponding acceleration method to obtain a complete image, so that the time required for image scanning can be shortened again when the TR cannot be shortened any further.

[0068] Combining multiple parallel acceleration measures to shorten the scanning time, including but not limited to: (1) Partial K-space acquisition: only perform phase encoding of the first part (about 60%) or the second part (about 60%); (2) GRAPPA acceleration: continuous acquisition of phase encoding in the middle; phase encoding on both sides is acquired every one or two times; (3) SENSE acceleration: phase encoding is acquired every one or two times; (4) Compressed sensing acceleration: continuous acquisition of phase encoding in the middle and random acquisition of phase encoding on both sides. By combining multiple acceleration methods, the fastest imaging speed can be ensured, the smallest motion artifacts can be ensured in the scanning time, and the stability and reliability of the final weighted imaging can be improved.

[0069] In one embodiment, the fluid tissue comprises one or more long relaxing components; long relaxing components include bile, blood, cerebrospinal fluid.

[0070] Exemplarily, for the original signal under the same inversion time TI, different tissue components have different corresponding longitudinal relaxation times T1. After the adiabatic pulse is emitted, each component recovers to the normal state along the exponential curve. The characteristic time of the exponential curve is the longitudinal relaxation time. The relaxation time of different components is different, and the recovery speed is different. Fluid tissue can contain a variety of fluid components such as bile, blood, cerebrospinal fluid, etc. Their longitudinal relaxation time is basically about 1s, that is, they can only recover to a normal state after 1000ms. Therefore, after applying the adiabatic pulse and waiting for 600ms-1000ms, the long relaxation component has not yet recovered, and the generated signal is close to 0, and the brightness presented on the image is black. By applying an adiabatic pulse and waiting for the appropriate inversion recovery time for magnetic resonance imaging, the fluid signal with the long relaxation component can be suppressed, thereby achieving the imaging effect of eliminating fluid artifacts.

[0071] See also Figure 3 , Figure 3 An embodiment of the present application provides a magnetic resonance imaging device, which may include: an inversion recovery module 210 , an excitation sampling module 220 , and an imaging module 230 .

[0072] The inversion recovery module 210 is used to apply a non-layer-selective adiabatic pulse to the scanning area at a first moment, and wait for the scanning area to perform inversion recovery for a preset time period; wherein the scanning area includes fluid tissue, and the preset time period is 600ms-1000ms;

[0073] The excitation sampling module 220 is used to use an imaging radio frequency pulse to excite the scanning area after inversion recovery at a second moment after the preset time period ends, so as to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed;

[0074] The imaging module 230 is used to perform image reconstruction according to the magnetic resonance signal to obtain a magnetic resonance image.

[0075] Optionally, the first moment is the moment when the peak of the respiratory waveform decreases to 10%.

[0076] Optionally, the preset time period is 700ms.

[0077] Optionally, the excitation sampling module 220 may be used to:

[0078] At a second moment when the preset time period ends, an imaging radio frequency pulse with a TR period is used to excite the scanning area after inversion recovery; and

[0079] A gradient field is applied and spatial encoding is performed to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed.

[0080] Optionally, the excitation sampling module 220 may be used to:

[0081] applying a slice selection gradient and a phase encoding gradient together; and

[0082] During the duration of the readout gradient, magnetic resonance signals in which the signals of the fluid tissue in the scanning region are suppressed are acquired.

[0083] Optionally, the excitation sampling module 220 may be used to:

[0084] Use parallel accelerated MRI to shorten scanning time;

[0085] The parallel accelerated magnetic resonance imaging method includes one or more of partial K-space acquisition, GRAPPA acceleration, SENSE acceleration, and compressed sensing acceleration.

[0086] Optionally, the fluid tissue comprises one or more long relaxing components; the long relaxing components comprise bile, blood, cerebrospinal fluid.

[0087] See also Figure 4 , Figure 4 31 is a block diagram of an electronic device. The electronic device 300 may include a memory 311, a storage controller 312, a processor 313, a peripheral interface 314, an input and output unit 315, and a display unit 316. A person skilled in the art may understand that Figure 4 The structure shown is only for illustration and does not limit the structure of the electronic device 300. For example, the electronic device 300 may also include Figure 4 More or fewer components as shown, or with Figure 4 Different configurations are shown.

[0088] The above-mentioned memory 311, storage controller 312, processor 313, peripheral interface 314, input / output unit 315, and display unit 316 are electrically connected to each other directly or indirectly to achieve data transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses or signal lines. The above-mentioned processor 313 is used to execute the executable module stored in the memory.

[0089] The memory 311 may be, but is not limited to, a random access memory (RAM), a read only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), etc. The memory 311 is used to store programs, and the processor 313 executes the program after receiving the execution instruction. The method executed by the electronic device 300 defined by the process disclosed in any embodiment of the present application can be applied to the processor 313, or implemented by the processor 313.

[0090] The processor 313 may be an integrated circuit chip with signal processing capability. The processor 313 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The methods, steps and logic block diagrams disclosed in the embodiments of the present application may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0091] The above-mentioned peripheral interface 314 couples various input / output devices to the processor 313 and the memory 311. In some embodiments, the peripheral interface 314, the processor 313 and the memory controller 312 can be implemented in a single chip. In some other examples, they can be implemented by separate chips.

[0092] The input and output unit 315 is used to provide input data to the user. The input and output unit 315 can be, but is not limited to, a mouse and a keyboard.

[0093] The display unit 316 provides an interactive interface (e.g., a user operation interface) between the electronic device 300 and the user for the user to refer to. In this embodiment, the display unit 316 may be a liquid crystal display or a touch display. The liquid crystal display or the touch display may display the process of the processor executing the program.

[0094] The electronic device 300 in this embodiment can be used to execute each step in each method provided in the embodiments of the present application.

[0095] In addition, an embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps in the above method embodiment are executed.

[0096] The computer program product of the above method provided in the embodiment of the present application includes a computer-readable storage medium storing program code, and the instructions included in the program code can be used to execute the steps in the above method embodiment. For details, please refer to the above method embodiment, which will not be repeated here.

[0097] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some communication interfaces, devices or units, which can be electrical, mechanical or other forms. The functional modules in the embodiments of the present application can be integrated together to form an independent part, or each module can exist separately, or two or more modules can be integrated to form an independent part.

[0098] It should be noted that if the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can essentially be embodied in the form of a software product, or the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM) random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0099] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0100] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A magnetic resonance imaging method, characterized in that: The method comprises: At the first moment, a non-selective adiabatic pulse is applied to the scanning area, and the scanning area is waited for inversion recovery for a preset time period; wherein the scanning area includes fluid tissue, the preset time period is 600ms-1000ms; the first moment is the moment when the peak of the respiratory waveform decreases to 10%; At a second moment when the preset time period ends, using an imaging radio frequency pulse to excite the scanning area after inversion recovery to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed; and Image reconstruction is performed according to the magnetic resonance signal to obtain a magnetic resonance image.

2. The method according to claim 1, characterized in that in, The preset time period is 700ms.

3. The method according to claim 1, characterized in that At the second moment when the preset time period ends, the imaging radio frequency pulse is used to excite the scanning area after inversion recovery to obtain the magnetic resonance signal of the fluid tissue in the scanning area where the signal is suppressed, including: At a second moment when the preset time period ends, an imaging radio frequency pulse with a TR period is used to excite the scanning area after inversion recovery; and A gradient field is applied and spatial encoding is performed to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed.

4. The method according to claim 3, characterized in that The step of applying a gradient field and performing spatial encoding to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed comprises: applying a slice selection gradient and a phase encoding gradient together; and During the duration of the readout gradient, magnetic resonance signals in which the signals of the fluid tissue in the scanning region are suppressed are acquired.

5. The method according to claim 3, characterized in that: At the second moment after the preset time period ends, after the imaging radio frequency pulse with TR as a period is used to excite the scanning area after inversion recovery, the method further includes: Use parallel accelerated MRI to shorten scanning time; The parallel accelerated magnetic resonance imaging method includes one or more of partial K-space acquisition, GRAPPA acceleration, SENSE acceleration, and compressed sensing acceleration.

6. The method according to any one of claims 1 to 5, characterized in that: in, The fluid tissue includes one or more long relaxing components; the long relaxing components include bile, blood, and cerebrospinal fluid.

7. A magnetic resonance imaging device, characterized in that: The device comprises: An inversion recovery module is used to apply a non-selective adiabatic pulse to a scanning area at a first moment, and wait for the scanning area to perform inversion recovery for a preset time period; wherein the scanning area includes fluid tissue, the preset time period is 600ms-1000ms; and the first moment is the moment when the peak of the respiratory waveform decreases to 10%; an excitation sampling module, configured to use an imaging radio frequency pulse to excite the scanning area after inversion recovery at a second moment after the preset time period ends, so as to obtain a magnetic resonance signal in which the signal of the fluid tissue in the scanning area is suppressed; The imaging module is used to perform image reconstruction according to the magnetic resonance signal to obtain a magnetic resonance image.

8. An electronic device, characterized in that: include: A processor and a memory, wherein the memory stores machine-readable instructions executable by the processor, and when the electronic device is running, the machine-readable instructions are executed by the processor to perform the steps of any method according to claim 1 to 6.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of any one of the methods described in claims 1 to 6 are executed.

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