CN112858975A

CN112858975A - Noise control method for magnetic resonance examination and scan sequence determination method

Info

Publication number: CN112858975A
Application number: CN201911176210.5A
Authority: CN
Inventors: 王超洪; 李国斌
Original assignee: Shanghai United Imaging Healthcare Co Ltd
Current assignee: Shanghai United Imaging Healthcare Co Ltd
Priority date: 2019-11-26
Filing date: 2019-11-26
Publication date: 2021-05-28
Anticipated expiration: 2039-11-26
Also published as: CN112858975B

Abstract

The embodiment of the invention discloses a noise control method and a scanning sequence determination method for magnetic resonance examination, wherein the method comprises the following steps: acquiring a mute parameter, and determining a mute gradient waveform corresponding to the mute parameter; and scanning a target scanning part based on the mute gradient waveform. The technical scheme of the embodiment of the invention solves the technical problem of high noise when a user performs magnetic resonance scanning in the prior art, and realizes the technical effect of balancing the scanning noise and the scanning time in the magnetic resonance scanning process.

Description

Noise control method for magnetic resonance examination and scan sequence determination method

Technical Field

The embodiment of the invention relates to the technical field of medical treatment, in particular to a noise control method and a scanning sequence determination method for magnetic resonance examination.

Background

Magnetic resonance imaging is an imaging sequence method. Magnetic resonance imaging is a relatively new technique compared to CT scanning, which can provide emerging soft tissue contrast. A typical magnetic resonance imaging system comprises the following components: a magnet, a gradient coil, a radio frequency transmitting coil, a radio frequency receiving coil, and a signal processing and image reconstruction unit. The hydrogen nuclear spin in human body can be equivalent to a small magnetic needle. In the strong magnetic field provided by the magnet, the hydrogen nuclei are converted from a disordered thermal equilibrium state to a partially cis state and a partially trans state to the main magnetic field direction. The difference between the two forms the net magnetization vector. The hydrogen nuclei precess around the main magnetic field with precession frequency proportional to magnetic field strength. The gradient units generate magnetic fields whose intensity varies with spatial position for spatial encoding of the signals. The radio frequency transmit coil flips the hydrogen nuclei from the direction of the main magnetic field into the transverse plane and precesses around the main magnetic field. A current signal is induced in the radio frequency receive coil. The image of the imaged tissue is obtained by a signal processing and image reconstruction unit.

That is, the lorentz forces acting on the gradient coils are very large and at the same time constantly changing, and the nmr system generates strong noise. When the noise is too loud, the auditor hearing is affected, and on the other hand, the loud noise also causes a problem of poor user experience.

Disclosure of Invention

The invention provides a noise control method and a scanning sequence determination method for magnetic resonance examination, which aim to realize the technical effect that the noise degree, namely the mute degree, is set before nuclear magnetic resonance, and the technical effect that the mute degree and the scanning time are balanced from the arrival.

In a first aspect, an embodiment of the present invention provides a noise control method for magnetic resonance examination, including:

acquiring a mute parameter associated with a scanning sequence, and determining a mute gradient waveform corresponding to the mute parameter;

scanning a target scanning part based on the mute gradient waveform;

wherein, the mute parameter comprises an expected volume or an expected scanning time.

In a second aspect, an embodiment of the present invention further provides a noise control apparatus for magnetic resonance examination, the apparatus including:

a silence gradient waveform determining module, configured to acquire a silence parameter associated with a scan sequence, and determine a silence gradient waveform corresponding to the silence parameter;

the scanning module is used for scanning a target scanning part based on the mute gradient waveform;

In a third aspect, an embodiment of the present invention further provides a scan sequence determination method for a magnetic resonance examination, including:

selecting a scanning sequence for carrying out magnetic resonance examination on a detection object; the scan sequence includes gradient pulse parameters;

setting a volume threshold or a scanning time threshold for performing magnetic resonance examination on the detection object based on the scanning sequence;

acquiring expected volume or expected scanning time according to the parameters corresponding to the scanning sequence;

when the expected volume exceeds the volume threshold, adjusting gradient pulse parameters of the scanning sequence; or, when the expected scan time exceeds the scan time threshold, adjusting gradient pulse parameters of the scan sequence;

the expected volume corresponding to the adjusted scanning sequence is within the volume threshold range and the corresponding expected scanning time is within the scanning time threshold range.

In a fourth aspect, an embodiment of the present invention further provides a scan sequence determining apparatus for magnetic resonance examination, the apparatus including:

the scanning sequence selection module is used for selecting a scanning sequence for carrying out magnetic resonance examination on the detected object; the scan sequence includes gradient pulse parameters;

a threshold setting module, configured to set a volume threshold or a scanning time threshold for performing a magnetic resonance examination on the detection object based on the scanning sequence;

the expected time or volume determining module is used for acquiring expected volume or expected scanning time according to the parameters corresponding to the scanning sequence;

a parameter adjusting module, configured to adjust a gradient pulse parameter of the scan sequence when the expected volume exceeds the volume threshold; or, when the expected scan time exceeds the scan time threshold, adjusting gradient pulse parameters of the scan sequence;

and the scanning sequence determining module is used for adjusting the expected volume corresponding to the scanning sequence to be within the volume threshold range and the corresponding expected scanning time to be within the scanning time threshold range.

According to the technical scheme of the embodiment of the invention, the mute parameter is obtained, the mute gradient waveform corresponding to the mute parameter is determined, and the target scanning part is scanned based on the mute gradient waveform, so that the technical problems of high noise and poor user experience in the nuclear magnetic resonance process in the prior art are solved, and the technical effect of balancing the scanning time and the scanning noise of the magnetic resonance system according to the preset mute parameter is realized.

Drawings

In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, a brief description is given below of the drawings used in describing the embodiments. It should be clear that the described figures are only views of some of the embodiments of the invention to be described, not all, and that for a person skilled in the art, other figures can be derived from these figures without inventive effort.

Fig. 1 is a flowchart illustrating a noise control method for magnetic resonance examination according to an embodiment of the present invention;

fig. 2 is a flowchart illustrating a scan sequence determining method for magnetic resonance examination according to a second embodiment of the present invention;

fig. 3 is a flowchart illustrating a noise control method for magnetic resonance examination according to a third embodiment of the present invention;

fig. 4 is a schematic diagram of adjusting a mute parameter on a display interface according to a third embodiment of the present invention;

fig. 5 is a schematic diagram of a silence gradient waveform transformation according to a third embodiment of the present invention;

fig. 6 is a schematic diagram of a silence gradient waveform transformation according to a third embodiment of the present invention;

fig. 7 is a schematic diagram of a silence gradient waveform transformation according to a third embodiment of the present invention;

fig. 8 is a schematic diagram of a silence gradient waveform transformation according to a third embodiment of the present invention;

fig. 9 is a schematic diagram of a silence gradient waveform transformation according to a third embodiment of the present invention;

FIG. 10 is a schematic diagram of an interface display according to an embodiment of the present invention;

fig. 11 is a schematic structural diagram of a noise control apparatus for magnetic resonance examination according to a fourth embodiment of the present invention;

fig. 12 is a schematic structural diagram of a server according to a fifth embodiment of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Example one

Fig. 1 is a flowchart illustrating a noise control method for magnetic resonance examination according to an embodiment of the present invention, which is applicable to adjusting a scan time and a scan noise balance of a magnetic resonance system, and the method can be performed by a noise control apparatus for magnetic resonance examination, which can be implemented in software and/or hardware.

As shown in fig. 1, the method of this embodiment includes:

s110, acquiring a mute parameter associated with the scanning sequence, and determining a mute gradient waveform corresponding to the mute parameter.

It should be noted that the magnetic resonance system selectively excites the hydrogen protons in the space by controlling the gradient system in time sequence, and when the space is encoded, the image can be reconstructed and obtained only after the radio frequency receiving coil receives enough signals. In the process of MR imaging, a gradient system is switched and transformed in a magnet containing a strong magnetic field for space encoding, and the gradient system can generate strong noise. Currently, reducing the acoustic noise of magnetic resonance systems can be achieved by improving the way in which gradients are used in the sequence.

The muting parameter can be understood as a scanning time of the magnetic resonance system or a noise level of the magnetic resonance system during operation. Noise may be expressed in decibels (dB). The mute gradient waveform comprises the application timing of the gradient, the gradient amplitude and the gradient climbing rate, and can be understood as that when current is applied to a gradient coil in a magnetic resonance system, the current value is converted from zero to a target value, and the waveform corresponding to the conversion of the current value is converted from the target value to zero to be used as the mute gradient waveform.

Specifically, if the user displays the interface muting parameter, the server corresponding to the magnetic resonance system may calculate a muting gradient waveform corresponding to the muting parameter, and based on the muting gradient waveform, may determine the scanning time corresponding to the muting parameter.

Determining a mute gradient waveform corresponding to the mute parameter according to the mute parameter, comprising: and acquiring a mute parameter, and determining a mute gradient waveform corresponding to the mute parameter according to a preset scanning sequence.

Wherein the scanning sequence can be understood as: the scanning sequence required when the magnetic resonance scanning is carried out on the part to be scanned. Because the target current values required by the gradient coils are different when the scanning sequences are different, namely the amplitude of the current is uncertain, and correspondingly, the noise generated by the gradient coils is different. In order to accurately realize the technical effect of balancing noise and scanning time, after the mute parameter is set and the scanning sequence corresponding to the part to be scanned is obtained, the mute parameter and the scanning sequence can be integrated to determine the mute gradient waveform.

Specifically, a scanning sequence corresponding to a portion to be scanned is obtained, and a set mute parameter, i.e., a noise decibel of scanning, is obtained, so that mute gradient waveforms corresponding to different scanning portions can be calculated.

Of course, obtaining the mute parameter and determining the mute gradient waveform corresponding to the mute parameter includes: and acquiring a mute parameter, and searching a pre-established mapping relation table to determine a mute gradient waveform corresponding to the mute parameter.

The mapping relationship table established in advance may be: after determining the scanning sequence corresponding to the part to be scanned, setting a mute parameter, namely a mute degree (noise decibel), determining a mute gradient waveform corresponding to different mute parameters according to the scanning sequence by a server corresponding to the magnetic resonance scanning system, and respectively storing the obtained scanning sequence, the mute parameter and the corresponding mute gradient waveform into a pre-established mapping relation table. After the scan sequence corresponding to the target user and the mute parameter are determined, the mute gradient waveform corresponding to the scan sequence can be directly called from the mapping relation table. Certainly, in order to reduce the cost, after the magnetic resonance scanning is performed, the scanning part, the scanning sequence, the mute parameter and the corresponding mute gradient waveform corresponding to the patient may be stored in the mapping relation table established in advance so as to be called next time.

Specifically, when the scan sequence is determined, different mute levels may be set according to the requirements of the user, and a mute gradient waveform corresponding to the different mute levels is determined, and when the mute gradient waveform is determined, the scan time corresponding to the user may be determined and stored in the mapping relationship table of the database. After determining the target scanning sequence and the target muting parameter corresponding to the target user, it may first search whether a mapping table of the database stores the target scanning sequence and the muting gradient waveform corresponding to the target muting parameter, and if so, call the muting gradient waveform from the database for use.

It should be noted that, determining the mute gradient waveform corresponding to the mute parameter may be: after the silence parameters and the scan sequence are acquired, a calculation formula may be invoked to determine a silence gradient waveform.

Note that, when determining a mute gradient waveform corresponding to a mute level, a scan time corresponding to the mute level can be obtained.

Generally, the acoustic noise output of a magnetic resonance system can be modeled approximately as a linear time-invariant system, and the acoustic vibration characteristics of the system can be obtained by measuring the frequency response functions of the gradient coils, i.e., acoustic transfer functions h (x), h (y), h (z), in advance. When the magnetic resonance system is in operation, gradient waveforms applied to each gradient coil by gradient pulse parameters included in the scanning sequence are respectively g (x), g (y), g (z), and the predicted acoustic noise can be approximated as: p ═ h (x) × g (x) + h (y) × g (y) + h (z) × g (z).

Wherein P represents the desired volume; h (X) represents the system response function of the X-axis gradient coil; h (Y) represents the system response function of the Y-axis gradient coil; h (Z) represents the system response function of the Z-axis gradient coil, which represents the convolution operation.

Based on the above formula, the noise corresponding to different scanning sequences can be determined, and then the silence gradient waveform corresponding to the predicted noise can be determined according to the predicted noise.

And S120, scanning the target scanning part based on the mute gradient waveform.

Specifically, after the user triggers the mute level, the server of the magnetic resonance system may determine a mute gradient waveform corresponding to the mute level, and determine a gradient using mode based on the mute gradient waveform to scan the target portion, thereby significantly reducing the acoustic noise of the magnetic resonance system, and achieving a technical effect of balancing the scanning time with the noise.

It should be noted that once the mute program is selected on the operation interface and the confirmation button is clicked, the re-determination of the mute program cannot be changed during the scanning of the magnetic resonance system.

On the basis of the above technical solution, after obtaining the scanning time, before scanning the target scanning region based on the mute gradient waveform, the method further includes: and when the scanning time exceeds a preset time threshold, adjusting the mute parameter.

It should be noted that, in this embodiment, a preset scanning time may also be predetermined, and optionally, five minutes. After the mute parameter, i.e. the noise decibel, is set, the mute gradient waveform can be determined according to the set noise decibel, and then the scanning time corresponding to the mute parameter is determined. If the scanning time is longer than the preset scanning time by five minutes, the scanning time can be fed back to the display interface, optionally, the calculated scanning time is displayed on the display interface, optionally, 6 minutes, and the worker can readjust the mute parameter according to the time displayed on the display interface, namely the feedback time, optionally, the mute degree is increased, namely the noise is increased a little. After readjusting the muting parameters, the system may determine a muting gradient waveform based on the adjusted muting parameters. If the obtained scanning time is within the preset scanning time range according to the adjusted mute parameter, scanning can be performed according to the adjusted mute gradient waveform.

It should be noted that, in order to reach the target gradient in a short time, the gradient climbs slowly as the scanning time is longer, and the corresponding noise is smaller; conversely, the shorter the scanning time, the faster the gradient climbs, and the higher the corresponding noise.

According to the technical scheme of the embodiment of the invention, the technical problems of high noise and poor user experience in the nuclear magnetic resonance process in the prior art are solved by acquiring the mute parameter, determining the mute gradient waveform corresponding to the mute parameter and scanning the target scanning part based on the mute gradient waveform, and the technical effects of adjusting the scanning time of the magnetic resonance system to be balanced with the scanning noise by setting different mute parameters are improved.

Example two

Fig. 2 is a scan sequence determination method for magnetic resonance examination according to a second embodiment of the present invention, which is applied to flexibly balance scan time and acoustic noise. The method comprises the following steps:

s210, selecting a scanning sequence for carrying out magnetic resonance examination on the detected object.

The detection target may be a scanned region. The scan sequence may be a scan sequence corresponding to a scan site. Gradient pulse parameters are included in the scan sequence. The scanning sequence of the embodiment of the invention comprises a radio frequency pulse, a slice selection gradient field, a phase encoding gradient field, a frequency encoding gradient field and an MR signal.

Specifically, a magnetic resonance scan sequence corresponding to a scan object is acquired according to the detection object, and the setting of various parameters related to the radio frequency pulse, the gradient field, the signal acquisition time and the like and the arrangement of the parameters in the time sequence are called a scan sequence. Illustratively, the parameters of the rf pulse include rf bandwidth, rf amplitude, application time, and duration; the parameters of the gradient pulses include the gradient field application direction, the gradient field strength, when to apply and the duration. The kind of the scan sequence may be a Free Induction Decay (FID) type sequence, a Spin Echo (SE) type sequence, a gradient echo type sequence, or a hybrid sequence of gradient echo and spin echo. In some embodiments, the test object is a heart, and the scan sequence may be a gradient echo cine imaging sequence, a gradient echo cardiac marker cine imaging sequence, or a balanced steady state precession sequence, among others. In some embodiments, the object of examination is a brain, and the scan sequence may be a 2D SE T1WI, a 2D FSE (fast spin echo) T2WI, a Diffusion Weighted Imaging (DWI) sequence, a Susceptibility Weighted Imaging (SWI) sequence, or the like.

S220, setting a volume threshold or a scanning time threshold for carrying out magnetic resonance examination on the detection object based on the scanning sequence.

Wherein, the volume threshold may be a preset scanning volume threshold. The scan time threshold may be a preset scan time threshold. The volume threshold and the scan time threshold are both set based on the scan sequence.

Specifically, a volume threshold or a scan time threshold for performing a magnetic resonance examination on the test object may be set based on the scan sequence.

It should be noted that the scanning volume and the scanning time are in an inverse proportional relationship, and the lower the scanning volume, the longer the corresponding scanning time, and correspondingly, the higher the scanning volume, the shorter the corresponding scanning time.

And S230, acquiring expected volume or expected scanning time according to the parameters corresponding to the scanning sequence.

Specifically, the staff member may drag the progress bar to determine the scanning time, and may adjust an expected volume corresponding to the detection object or an expected scanning time based on the feedback of the user.

S240, when the expected volume exceeds a volume threshold, adjusting gradient pulse parameters of the scanning sequence; alternatively, the gradient pulse parameters of the scan sequence are adjusted when the expected scan time exceeds a scan time threshold.

Specifically, after the user determines the expected volume or the expected scanning time threshold, it may be determined whether the expected volume is within a volume threshold range or whether the expected scanning time is within a scanning time threshold range, and if so, the current pulse gradient parameter is used as the current pulse gradient parameter; if not, adjusting the pulse parameters of the scanning sequence.

It should be noted that the expected volume corresponding to the adjusted scanning sequence is within the volume threshold.

In this embodiment, adjusting the pulse gradient parameters comprises at least one of the following adjustment strategies. Optionally, adjusting the gradient pulse parameters of the scan sequence includes one or more of the following adjustment strategies; adjusting gradient pulse amplitude parameters; adjusting gradient pulse inclination rate; the profile of the gradient pulse waveform is adjusted.

The gradient pulse amplitude can be understood as field intensity, the field intensity of the gradient field has higher requirements on ultrafast sequences such as plane echo imaging and the like and water molecule diffusion weighted imaging, the high gradient field can shorten a back-dialing gap to accelerate signal acquisition, and the signal to noise ratio is favorably improved, so that the gradient pulse amplitude can be ensured to be unchanged when pulse parameters are adjusted under the condition. When adjusting gradient pulse parameters, the profile of the gradient pulse waveform can also be adjusted, such as a set of gradients with dynamically changing amplitudes, such as phase encoding gradients, and a set of curve gradients with the same area can be used for reducing acoustic noise. If a plurality of adjacent gradients with opposite amplitudes are adopted, if the adjacent gradients cannot be simply combined into one gradient, the acoustic noise can be reduced by using curve gradients with the same number and opposite amplitudes, but the total area is kept the same or the integral of the total area and the area over time is kept the same at the same time according to different practical requirements.

Specifically, when the gradient pulse parameters need to be adjusted, the pulse amplitude, the pulse slope, and/or the profile of the gradient pulse waveform can be determined and adjusted according to actual requirements.

Optionally, at least two adjustment strategies are respectively adopted as a group of adjustment strategies, and gradient pulse parameters of the scanning sequence are adjusted based on each group of adjustment strategies; respectively calculating the expected volume or the expected scanning time corresponding to the scanning sequence after being adjusted based on each group of adjustment strategies; determining a group of adjustment strategies corresponding to the minimum expected volume or expected scanning time as a target adjustment strategy, and taking the scanning sequence corresponding to the target adjustment strategy as a target scanning sequence.

By the method, a user can set the mute level or the scanning time through the interface, the scanning sequence estimates the optimization degree of the gradient waveform according to the set mute level or the scanning time, and then the gradient waveform of the whole scanning sequence is accurately calculated to obtain the corresponding scanning time length or the mute level; if the user is not satisfied with the scan time, the setting can be reset by readjusting the mute level, and finally, the balance between the mute level and the acceptable scan time is achieved.

On the basis of the technical scheme, after the gradient pulse parameters corresponding to the detection object are determined, the detection object can be scanned based on the determined target scanning sequence, and whether the currently determined target scanning sequence meets the quality requirement of the reconstructed image is further determined.

Optionally, scanning the detection object based on the target scanning sequence, and acquiring a magnetic resonance signal; reconstructing the magnetic resonance signal to acquire a detection image; evaluating the quality of the inspection image; and when the quality of the detection image does not meet the quality threshold value, readjusting the gradient pulse parameters of the scanning sequence.

The quality of the detected image may be that the machine or the user can evaluate the image quality including the signal-to-noise ratio, the image resolution or the image contrast, etc.

Specifically, the detection object is scanned based on the determined target scanning sequence, and magnetic resonance signals are acquired so as to determine and detect an image based on the magnetic resonance signals. When the quality of the detected image does not meet the preset image quality requirement, it indicates that the determined gradient pulse parameter does not meet the preset requirement, and S210 to S240 need to be repeatedly executed to determine the gradient pulse parameter, i.e., the target scanning sequence.

For example, when it is determined that the current image quality does not meet the diagnostic requirements, the adjustment strategy for the scan sequence may be altered, for example: adjusting the scanning sequence in the previous period by adjusting the gradient pulse amplitude parameter, wherein if the corresponding image signal-to-noise ratio does not meet the set threshold, the adjusting strategy of the scanning sequence is adjusted to adjust the profile of the gradient pulse waveform; as another example, if the adjustment strategy of the scanning sequence of the previous period is gradient pulse gradient, and it is monitored that the corresponding peripheral nerve stimulation value exceeds the regulatory threshold, the adjustment strategy of the scanning sequence is adjusted to a hybrid strategy (a hybrid of multiple adjustment strategies).

In one embodiment, the adjustment of the scan sequence may comprise a plurality of times, and each adjusted scan sequence performs the acquisition of a plurality of sets of magnetic resonance signals. The multiple sets of magnetic resonance signals can be weighted to obtain target signals. Alternatively, the weight of each set of magnetic resonance signals may be determined by:

magnetic resonance signals closer to the mass threshold are given a higher weight coefficient, and magnetic resonance signals further from the mass threshold are given a higher weight coefficient. In one embodiment, the volume threshold or the scan time threshold may be adjusted when the adjustment strategy of the scan sequence is changed and the reconstructed image does not meet the requirement yet. For example, the volume threshold or the scan time threshold is increased over multiple adjustments.

According to the technical scheme of the embodiment of the invention, the gradient pulse parameters are adjusted through at least one adjusting strategy, so that the technical problem of poor user experience caused by the fact that gradient scanning noise and scanning time cannot be well balanced in the prior art is solved, and the technical effect of adjusting the balance between the scanning time and the scanning noise is realized.

EXAMPLE III

As a preferred embodiment of the foregoing embodiment, fig. 3 is a flowchart illustrating a noise control method for magnetic resonance examination according to a third embodiment of the present invention. As shown in fig. 3, the method includes:

s310, setting the mute degree of the gradient.

Wherein, setting the mute level of the gradient can be understood as: the decibel of noise that the patient can accept when performing a magnetic resonance scan of the target site. Of course, the scanning time corresponding to the mute program can also be displayed on the display interface. The target user may determine whether the mute level selected by the staff member and the scan time corresponding to the mute level are within the acceptable range, optionally, the scan noise is 20dB (decibel), and the scan time corresponding to the mute level is 4:00 minutes.

Specifically, when the magnetic resonance scanning is performed on the patient, the staff can select the mute level of the magnetic resonance system on the control interface, and the magnetic resonance scanning system can determine the scanning time corresponding to the mute level according to the set mute level, namely the noise decibel.

Illustratively, referring to fig. 4, when a magnetic resonance scan is performed on a target region, the schematic diagram shown in fig. 4 may pop up on the display interface. The operator may control the drag bar to determine the degree of silence. When the noise is minimum, the corresponding scanning time is longest, and can be four and a half minutes; when the noise is the largest, the corresponding scanning time is the shortest, and can be two and a half minutes.

When the scan sequence type is determined, the scanning time is shorter as the noise is larger, and the scanning time is longer as the noise is smaller.

And S320, estimating the gradient waveform optimization degree in the sequence.

Wherein the degree of optimization of the gradient waveforms in the sequence is estimated, i.e. adjusting the gradient pulse parameters, optionally adjusting the gradient pulse amplitude parameters, adjusting the slope of the gradient pulses, and/or adjusting the profile of the gradient pulse waveforms.

It should be noted that when the gradient is used more slowly, the noise of the magnetic resonance system is smaller, and in principle, the use of the gradient includes at least three cases. One is that the gradient amplitude (i.e. the target current amplitude of the gradient coil) is required to be constant, wherein the amplitude can be understood as the field strength. The reason for ensuring that the amplitude is unchanged is that ultrafast sequences such as single-shot relaxation enhanced rapid acquisition (SS-RARE), fast gradient echo (Turbo-GRE), planar echo and the like and water molecule diffusion weighted imaging have higher requirements on the field intensity of a gradient field, the echo gap can be selected by the high gradient field to accelerate the signal acquisition speed, so that the signal-to-noise ratio is favorably improved, and the acoustic noise can be reduced by adjusting the gradient climbing and/or descending slope at the moment, as shown in fig. 5. 5(a) in FIG. 5 represents a gradient waveform without changing the ramp and/or ramp down slope, and 5(b) represents that the ramp up and/or ramp down frequency of the gradient waveform can be adjusted to achieve a reduction in acoustic noise.

Another situation is that when scanning a part to be scanned, the area between the adjusted gradient waveform and the unadjusted gradient waveform is required to be unchanged, that is: before and after the adjustment, the zeroth order moment of the gradient remains unchanged, see fig. 6. Fig. 6(a) shows the gradient waveforms before the gradient waveforms are not changed, and fig. 6(b), 6(c), and 6(d) show the gradient waveforms after the rising and/or falling slopes are changed, respectively. 6(b) indicates that the reduction of the acoustic noise is achieved by reducing the gradient amplitude, 6(c) indicates that the gradient is unchanged in magnitude, the rising and/or falling slope of the gradient is changed to reduce the acoustic noise, and 6(d) reduces the acoustic noise by slowing down the gradient change rate. The gradient waveform areas of 6(a), 6(b), 6(c), and 6(d) are constant. A third way of reducing noise may be to use the above in combination, see fig. 7. Wherein 7(a) represents an unchanged gradient waveform, and 7(b) represents that the requirement for gradient area is unchanged, acoustic noise can be reduced by simultaneously reducing gradient amplitude and gradient rising and/or falling slope; 7(c) shows that when the gradient area requirement is constant, the acoustic noise can be reduced by simultaneously reducing the amplitude, the gradient climbing/descending slope and the gradient change rate. Adjusting gradient pulse parameters can also be adjusting the profile of a gradient pulse waveform, a group of gradients with dynamically changed amplitudes, such as phase encoding gradients, and a group of gradients with the same area and curves can be used for reducing acoustic noise, as shown in fig. 8, and a group of gradients with changed amplitudes, such as mute processing of phase encoding gradients; there may also be several adjacent gradients of opposite amplitudes, and if not simply combined into one gradient, the same number of curved gradients of opposite amplitudes may be used to reduce noise, with the total area remaining the same or both the total area and the integral of the area over time remaining the same, depending on the requirements, see fig. 9, a pair of gradients of opposite amplitudes, such as the muting of a flow compensation gradient.

After the mute level is determined by the operator, the system can determine which of the above manners is adopted to determine the optimized gradient waveform corresponding to the mute level according to the received mute level. Optionally, whether the gradient of the mute gradient waveform changes, whether the area of the gradient waveform city encloses changes, whether the included angle between the waist of the gradient waveform and the horizontal plane changes, and the like.

And S330, recalculating the gradient waveform of the sequence.

After the optimization degree of the gradient waveform is determined, the gradient waveform can be accurately calculated.

After the staff drags the sliding bar to move to the target position, namely after the noise decibel is determined, the mute gradient waveform corresponding to the noise decibel can be calculated. Of course, after the mute level is determined, gradient waveforms which are the same as the scanning sequence and the mute level can be obtained from a mapping relation table in a database according to the mute level; if the mapping table does not store the corresponding silence gradient waveform, the silence gradient waveform corresponding to the silence gradient waveform can be calculated.

And S340, calculating the scanning time of the sequence.

After determining the degree of silence, and after a scan sequence, the silence gradient waveform corresponding thereto may be determined. When the silence gradient waveform is determined, the scan time corresponding to the degree of silence can be determined. The staff member can determine whether the target user receives the mute level and the scanning time.

When the target user receives the mute level and the corresponding scanning time, the mute parameter completion button can be clicked, so that the magnetic resonance system scans the part to be scanned of the target user according to the preset mute parameter, namely the gradient waveform determined according to the mute parameter. Of course, if the target user believes the scan time is too long or too noisy, the mute level may be reset until the adjusted mute level and scan time are acceptable to the target user.

And S350, completing mute parameter setting and starting scanning.

When the target user accepts the mute parameter set by the staff, the confirmation button can be clicked. After the mute parameter setting is completed, a button for starting scanning can be triggered to scan the target part.

According to the technical scheme of the embodiment of the invention, the mute parameter is obtained, the mute gradient waveform corresponding to the mute parameter is determined, and the target scanning part is scanned based on the mute gradient waveform, so that the technical problems of high noise and poor user experience in the nuclear magnetic resonance process in the prior art are solved, the scanning time of a magnetic resonance system is adjusted to be balanced with the scanning noise according to the preset mute parameter, and the technical effect of user experience is improved.

In another embodiment, the noise control method for magnetic resonance examination further sets a scan time first, which comprises the steps of:

firstly, after selecting a scanning sequence for carrying out magnetic resonance examination on a detection object, a user can set the accepted scanning time through an interface; then, the magnetic resonance system estimates the optimization degree of the gradient waveform of the scanning sequence according to the set scanning time; and finally, calculating a noise value corresponding to the gradient waveform optimized by the scanning sequence. It should be noted that if the user is not satisfied with the noise levels corresponding to the various optimized gradient waveforms, the noise levels can be reset by adjusting the scan time, and finally, the balance between the mute level and the acceptable scan time is achieved.

On the basis of the above technical solutions, it should be further noted that the server for adjusting the pulse parameters is further connected to a display device, i.e., a display. As shown in fig. 10: it includes: an inspection interface area and a scan monitor area. The scanning of the monitoring area of the present embodiment may include: an SAR (specific absorption rate of RF energy) monitoring bar for monitoring the absorption of RF energy by the object to be examined; an electrocardio monitoring area (wave lines in the figure) for displaying the motion cycle of the heart of the patient; a patient comfort adjustment area, wherein a volume and scanning time adjustment bar as shown in figure 3 can be arranged; the sickbed adjusting area is used for realizing that the patient moves to the center of the scanning area and moves into or out of the scanning cavity; when the operator triggers a control on the display, the interface identified as fig. 1 can be switched to the interface identified as fig. 2, and the image browsing, patient management, patient registration, printing, post-processing, and the like can be performed. Meanwhile, the monitoring of relevant scanning conditions can be carried out through scanning the monitoring area. It should be noted that the scan monitoring area may be hidden when no scan is currently available, or when a larger interface is required for the above-described work (image review, patient management, patient registration, printing, post-processing).

Example four

Fig. 11 is a schematic structural diagram of a noise control apparatus for magnetic resonance examination according to a fourth embodiment of the present invention, where the apparatus includes: a silence gradient waveform determination module 1110 and a scan module 1120.

The silence gradient waveform determining module 1110 is configured to obtain a silence parameter, and determine a silence gradient waveform corresponding to the silence parameter; a scanning module 1120, configured to scan a target scanning portion based on the silence gradient waveform.

On the basis of the above technical solution, the silence gradient waveform determining module is further configured to:

based on a scan sequence relative to the target scan location, a muting parameter corresponding to the scan sequence is determined.

On the basis of the above technical solutions, the silence gradient waveform determining module is further configured to:

and searching a pre-established mapping relation table according to the acquired mute parameters to determine the mute gradient waveform corresponding to the mute parameters.

and calculating a mute gradient waveform corresponding to the mute parameter according to the pre-selected mute parameter.

On the basis of the above technical solution, the apparatus further includes a scan time determining module, where before the silence gradient waveform determining module is configured to acquire a silence parameter and determine a silence gradient waveform corresponding to the silence parameter, the scan time determining module is further configured to:

and obtaining the scanning time corresponding to the target scanning part according to the mute gradient waveform.

On the basis of the above technical solutions, the apparatus further includes a scanning time determining module, further configured to:

when the scanning time exceeds a preset time threshold, adjusting the mute parameter;

correspondingly, determining a mute gradient waveform corresponding to the mute parameter according to the pre-selected mute parameter comprises:

and determining a mute gradient waveform corresponding to the adjusted mute parameter according to the adjusted mute parameter.

The magnetic resonance noise control device provided by the embodiment of the invention can execute the magnetic resonance noise control method provided by any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the execution method.

It should be noted that, the units and modules included in the apparatus are merely divided according to functional logic, but are not limited to the above division as long as the corresponding functions can be implemented; in addition, specific names of the functional units are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the embodiment of the invention.

EXAMPLE five

Fig. 12 is a schematic structural diagram of a server according to a fourth embodiment of the present invention. FIG. 12 illustrates a block diagram of an exemplary server 1200 suitable for use in implementing embodiments of the present invention. The server 1200 shown in fig. 12 is only an example, and should not bring any limitation to the function and the scope of use of the embodiments of the present invention.

As shown in fig. 12, the server 1200 is in the form of a general purpose computing device. Components of server 1200 may include, but are not limited to: one or more processors or processing units 1201, a system memory 1202, and a bus 1203 that couples the various system components (including the system memory 1202 and the processing unit 1201).

Bus 1203 represents one or more of several types of bus structures, including a memory bus or memory controller, a peripheral bus, an accelerated graphics port, a processor, or a local bus using any of a variety of bus architectures. By way of example, such architectures include, but are not limited to, Industry Standard Architecture (ISA) bus, micro-channel architecture (MAC) bus, enhanced ISA bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus.

The server 1200 typically includes a variety of computer system readable media. Such media can be any available media that is accessible by server 1200 and includes both volatile and nonvolatile media, removable and non-removable media.

The system memory 1202 may include computer system readable media in the form of volatile memory, such as Random Access Memory (RAM)1204 and/or cache memory 1205. The server 1200 may further include other removable/non-removable, volatile/nonvolatile computer system storage media. By way of example only, the storage system 1206 may be used to read from and write to non-removable, nonvolatile magnetic media (not shown in FIG. 12, and commonly referred to as a "hard drive"). Although not shown in FIG. 12, a magnetic disk drive for reading from and writing to a removable, nonvolatile magnetic disk (e.g., a "floppy disk") and an optical disk drive for reading from or writing to a removable, nonvolatile optical disk (e.g., a CD-ROM, DVD-ROM, or other optical media) may be provided. In these cases, each drive may be connected to the bus 1203 by one or more data media interfaces. Memory 1202 may include at least one program product having a set (e.g., at least one) of program modules that are configured to carry out the functions of embodiments of the present invention.

A program/utility 1208, having a set (at least one) of program modules 1207, which may be stored, for example, in memory 1202, such program modules 1207 include, but are not limited to, an operating system, one or more application programs, other program modules, and program data, each of which examples or some combination thereof may comprise an implementation of a network environment. Program modules 1207 generally perform the functions and/or methodologies of the described embodiments of the invention.

The server 1200 may also communicate with one or more external servers 1209 (e.g., keyboard, pointing device, display 1210, etc.), with one or more devices that enable a user to interact with the server 1200, and/or with any devices (e.g., network card, modem, etc.) that enable the server 1200 to communicate with one or more other computing devices. Such communication may occur via an input/output (I/O) interface 1211. Also, the server 1200 may communicate with one or more networks (e.g., a Local Area Network (LAN), a Wide Area Network (WAN) and/or a public network such as the Internet) via a network adapter 1212. As shown, the network adapter 1212 communicates with the other modules of the server 1200 via a bus 1203. It should be appreciated that although not shown in FIG. 12, other hardware and/or software modules may be used in conjunction with the server 1200, including but not limited to: microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data backup storage systems, among others.

The processing unit 1201 executes various functional applications and data processing, such as implementing a noise control method and a scan sequence determination method for magnetic resonance examination provided by an embodiment of the present invention, by executing a program stored in the system memory 1202.

EXAMPLE six

An embodiment of the present invention also provides a storage medium containing computer-executable instructions which, when executed by a computer processor, are used to perform a noise control method for magnetic resonance examination and a scan sequence determination method.

The method comprises the following steps:

acquiring a mute parameter, and determining a mute gradient waveform corresponding to the mute parameter;

and scanning a target scanning part based on the mute gradient waveform.

Computer storage media for embodiments of the invention may employ any combination of one or more computer-readable media. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated data signal may take many forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may also be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for embodiments of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C + + or the like and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a Local Area Network (LAN) or a Wide Area Network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet service provider).

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A noise control method for magnetic resonance examination, comprising:

scanning a target scanning part based on the mute gradient waveform;

2. The method of claim 1, wherein the obtaining the mute parameter and determining the mute gradient waveform corresponding to the mute parameter comprises:

and calculating a mute gradient waveform corresponding to the mute parameter based on a calculation formula of the mute gradient waveform according to the pre-acquired mute parameter.

3. The method of claim 1, wherein after obtaining the mute parameter and determining the mute gradient waveform corresponding to the mute parameter, further comprising:

4. The method of claim 3, wherein after obtaining the scan time, prior to scanning a target scan site based on the silence gradient waveform, further comprising:

5. The method of claim 1, wherein the muting parameter comprises decibels of noise when the magnetic resonance system is in operation.

6. A scan sequence determination method for magnetic resonance examination, comprising:

selecting a scanning sequence for carrying out magnetic resonance examination on a detection object; wherein the scan sequence includes gradient pulse parameters;

and the expected volume corresponding to the adjusted scanning sequence is within the volume threshold range and the corresponding expected scanning time is within the scanning time threshold range.

7. The method of claim 6, wherein adjusting gradient pulse parameters of the scan sequence comprises one or more of the following adjustment strategies:

adjusting gradient pulse amplitude parameters;

adjusting gradient pulse inclination rate;

the profile of the gradient pulse waveform is adjusted.

8. The method of claim 7, wherein the adjusting gradient pulse parameters of the scan sequence comprises:

respectively adopting at least two adjusting strategies as a group of adjusting strategies, and adjusting gradient pulse parameters of the scanning sequence based on each group of adjusting strategies;

respectively calculating the expected volume or the expected scanning time corresponding to the scanning sequence after being adjusted based on each group of adjustment strategies;

determining a group of adjustment strategies corresponding to the minimum expected volume or expected scanning time as a target adjustment strategy, and taking the scanning sequence corresponding to the target adjustment strategy as a target scanning sequence.

9. The method of claim 8, further comprising:

scanning the detection object based on the target scanning sequence to acquire a magnetic resonance signal;

reconstructing the magnetic resonance signal to acquire a detection image corresponding to the detection object;

and when the quality of the detection image does not accord with the quality threshold, readjusting the gradient pulse parameters of the scanning sequence until the quality of the detection image accords with the quality threshold.

10. The method of claim 9, further comprising, after the readjusting gradient pulse parameters of the scan sequence when the quality of the detected image does not meet a quality threshold:

adjusting the volume threshold or scan time threshold.