CN105629187B - The method and system of field uniformity are received for optimizing magnetic resonance radio frequency coil - Google Patents
The method and system of field uniformity are received for optimizing magnetic resonance radio frequency coil Download PDFInfo
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
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- G01R33/20—Arrangements or instruments for measuring magnetic variables involving magnetic resonance
- G01R33/44—Arrangements or instruments for measuring magnetic variables involving magnetic resonance using nuclear magnetic resonance [NMR]
- G01R33/48—NMR imaging systems
- G01R33/54—Signal processing systems, e.g. using pulse sequences ; Generation or control of pulse sequences; Operator console
- G01R33/56—Image enhancement or correction, e.g. subtraction or averaging techniques, e.g. improvement of signal-to-noise ratio and resolution
- G01R33/565—Correction of image distortions, e.g. due to magnetic field inhomogeneities
- G01R33/5659—Correction of image distortions, e.g. due to magnetic field inhomogeneities caused by a distortion of the RF magnetic field, e.g. spatial inhomogeneities of the RF magnetic field
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Abstract
The invention discloses a kind of method and system that field uniformity is received for optimizing magnetic resonance radio frequency coil, the amplitude control parameter and phase controlling parameter in each channel of radio-frequency coil are optimized, and according to the amplitude control parameter after optimization and the composograph after the optimization of the phase controlling gain of parameter after optimization, and according to the composograph after optimization, the susceptibility of local receiving coil is corrected.The present invention carries out amplitude control and phase controlling by the signal to each channel of radio-frequency coil respectively, amplitude control parameter and phase controlling parameter to each channel optimize, optimization receives being uniformly distributed for susceptibility, achieve the purpose that optimize B1-, and the present invention optimized using B1- after reference picture local receiving coil susceptibility is corrected, so as to effectively promote the uniformity of final clinical diagnosis image.
Description
Technical field
The present invention relates to magnetic resonance imaging system, more particularly, to optimization magnetic resonance radio frequency coil receives field uniformity
Method and system.
Background technique
In recent years, with the fast development of high-field magnetic resonance system, B1 optimization problems obtain all the more extensive weight
Depending on and research.B1 field uniformity is a critical technical problem in high field super magnetic resonance system, directly influences figure
The uniformity of picture.B1 can be divided into the field of B1+ and two kinds of B1- different polarization modes again.Wherein, B1+ is positive hand circular polarization field, main
Being uniformly distributed for signal excitation energy is affected, B1- is opposite hand circular polarization field, mainly affects coil and receives the equal of susceptibility
Both even distribution produces large effect to the uniformity of image.About the research of B1+ and B1-, reference can be made to document
(Non-uniformity correction of human brain imaging at high field by RF field
Mapping of B1+and B1-, Journal of Magnetic Resonance 212 (2011) 426-430).
Currently, for B1 calibrations there are mainly two types of bearing calibration:
(1) it is concentrated mainly on the uniformity optimization and excitation area control to launching site B1+, for B1- in clinical application
Optimization also rarely have document report.The specific method of B1+ optimization is the transmitted in parallel individually controlled by multichannel amplitude-phase
B1 spatial distributions are adjusted in system.
But in this method, the receives link and transmitting link of volume dispatch coil are separation, and this method can not be controlled
The compositive relation of multi-channel coil B1- processed, therefore, the heterogeneity of B1- still can reflect in image.Line is received and dispatched for volume
The channel of circle merges mode, although existing SOS merging can guarantee that each pixel reaches theoretically strongest signal width
Degree, but do not account for the optimization of B1- uniformity.
(2) based on the uniformity correcting method of coil sensitivities.The drawn game of acquired volume dispatch coil is distinguished in the bearing calibration
The image of portion's receiving coil, and the relative sensitivity of the local receiving coil of calculating is distributed on the basis of the image of volume dispatch coil
Figure, so that image non-uniform caused by being distributed to coil sensitivities compensates.This method can preferably retain original graph
The contrast and details of picture are shown, therefore are obtained to compare and be widely applied.
But this method can not correct the received field B1- heterogeneity of volume dispatch coil itself, therefore in high field systems
It is middle that there are certain limitations.
Summary of the invention
The invention proposes a kind of methods for the optimization of volume dispatch coil B1- field uniformity, receive line in conjunction with part
The susceptibility alignment technique of circle can provide new approach to improve the uniformity of clinical image.
The method for receiving field uniformity for optimizing magnetic resonance radio frequency coil, comprising the following steps:
S1, the K space data for obtaining several channels of radio-frequency coil carry out Fourier transformation to the K space data and obtain
Obtain several plural number figures of image area；It include the amplitude and phase information of image in the plural number figure；
S2, amplitude control parameter initial value, the phase controlling initial parameter value that several channels are respectively set, according to
Amplitude control parameter initial value, phase controlling initial parameter value and several plural number figures in several channels calculate
Obtain composograph；
S3, amplitude control parameter and the progress of phase controlling parameter according to the composograph, to several channels
Optimization is calculated excellent according to amplitude control parameter, phase controlling parameter and several described plural figures after the optimization
Composograph after change；
S4, according to the composograph after optimization, the susceptibility of local receiving coil is corrected.
Alternatively, the radio-frequency coil in S1 is volume dispatch coil or surface coil array.
Selectively, the number in the channel is -2~32.
Further, according to the amplitude control parameter initial value in several channels, phase controlling ginseng described in S2
Number initial value and several described plural figures are calculated composograph and include:
The amplitude control parameter initial value, phase controlling initial parameter value and the plural number figure are substituted into composograph meter
Formula is calculated, composograph is obtained；The composograph calculation formula is as follows:
Wherein, Img_Opt is composograph, and i is the corresponding number in each channel, ImgiFor the image corresponding to the channel i
The plural number figure in domain, aiFor the amplitude control parameter in the channel i, biFor the phase controlling parameter in the channel i, j is imaginary unit,For
Using natural constant e the bottom of as, with jbiFor the exponential function of index.
Further, described in S3 according to the composograph, amplitude control parameter to several channels and
It includes: to assess the uniformity of the composograph that phase controlling parameter, which optimizes, if according to assessment result to described
The amplitude control parameter and phase controlling parameter in dry a channel optimize.
Further, the uniformity of composograph is assessed by following formula in S3:
Wherein, Uniformity is the uniformity of Img_Opt, and c is scheduled constant, number of the λ between preset 0-1.
Further, the amplitude control parameter described in S3 according to assessment result to several channels and phase control
Parameter processed, which optimizes, includes:
The amplitude control parameter in several channels and the optimization solution of phase controlling parameter are obtained according to the following formula:
Further, it solves
Method be LMS algorithm, simulated annealing or genetic algorithm.
Alternatively, described in S3 according to the composograph, amplitude control parameter to several channels and
It includes: signal acquisition mould in the magnetic resonance signal of the radio-frequency coil for acquiring each channel that phase controlling parameter, which optimizes,
Block with for collected magnetic resonance signal carry out signal processing to obtain the signal processing of the plural figure of corresponding image area
Between module, series connection is used for the RF module of amplitude of accommodation control parameter and phase controlling parameter, is obtained by adjusting the RF module
Amplitude control parameter and phase controlling parameter after taking optimization, assess the uniformity of the composograph, according to assessment
As a result the amplitude control parameter and phase controlling parameter in each channel are optimized by adjusting the RF module.
Further, the RF module for amplitude of accommodation control parameter and phase controlling parameter be adjustable attenuator and
Adjustable phase shifter.
Further, according to the composograph after optimization described in S4, school is carried out to the susceptibility of local receiving coil
Just include:
S401, the image for obtaining local receiving coil, according to the image of composograph and local receiving coil after optimization
Obtain the sensitivity distribution figure of local receiving coil；
S402, susceptibility is carried out to the image that local receiving coil acquires according to the sensitivity distribution figure of local receiving coil
Correction.
Further, S401 includes: the sensitivity distribution figure for obtaining local receiving coil according to the following formula:
SensMap=ImageFilter (Img_LocalCoil/Img_Opt1)
Wherein, SensMap is the sensitivity distribution figure of local receiving coil, and Img_LocalCoil is to use and step S1
Identical sweep parameter, the image of the part receiving coil acquisition, ImageFilter (x) is image filtering function, Img_
Opt1 is the composograph after optimization；
S402 includes: to carry out susceptibility correction to the image of local receiving coil acquisition according to the following formula:
Img_AfterNormlize=Img_BeforeNormlize/SensMap
Wherein, Img_AfterNormlize is the image of the local receiving coil after correction, Img_BeforeNormlize
For the image of local receiving coil acquisition.
Correspondingly, the system that the present invention also provides a kind of to receive field uniformity for optimizing magnetic resonance radio frequency coil, packet
It includes:
Plural number figure obtains module, for obtaining the K space data in several channels of radio-frequency coil, to the K space data
Carry out several plural number figures that Fourier transformation obtains image area；It include the amplitude and phase information of image in the plural number figure；
Image synthesis module, for amplitude control parameter initial value, the phase controlling in several channels to be respectively set
Initial parameter value, according to the amplitude control parameter initial value in several channels, phase controlling initial parameter value and described
Composograph is calculated in several plural figures；
Optimization module, for the amplitude control parameter and phase control according to the composograph, to several channels
Parameter processed optimizes, and is schemed according to amplitude control parameter, phase controlling parameter and several described plural numbers after the optimization
Composograph after optimization is calculated；
Correction module, for being corrected to the susceptibility of local receiving coil according to the composograph after optimization.
The invention has the following beneficial effects:
(1) present invention merges mode to the channel of radio-frequency coil and improves, and overcomes in the merging method of the prior art
The defect not optimized to B1- uniformity, the channel for changing radio-frequency coil merge mode, merge change by conventional SOS
Merge for the vector with amplitude-phase control parameter, amplitude control and phase are carried out by the signal to each channel of radio-frequency coil respectively
Position control, amplitude control parameter and phase controlling parameter to each channel optimize, and optimization receives uniform point of susceptibility
Cloth achievees the purpose that optimize B1-.
(2) present invention is corrected local receiving coil susceptibility using the radio-frequency coil image after B1- optimization, thus
The uniformity of final clinical diagnosis image can effectively be promoted.
(3) present invention can improve influence of the volume dispatch coil B1- heterogeneity to image, be to existing
Supplement and expansion of the RFShimming technology in receiving end.
(4) the present invention provides the optimization methods based on software realization passes through software without increasing additional hardware component
Algorithm is adjusted and optimizes automatically, and save the cost is easy to use, high degree of automation.
(5) the present invention also provides be based on hard-wired optimization method, it is only necessary in circuit connect adjustable attenuator and
The RF module such as adjustable phase shifter has expanded the implementation of invention.
Detailed description of the invention
It in order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology and advantage, below will be to implementation
Example or attached drawing needed to be used in the description of the prior art are briefly described, it should be apparent that, the accompanying drawings in the following description is only
It is only some embodiments of the present invention, for those of ordinary skill in the art, without creative efforts,
It can also be obtained according to these attached drawings other attached drawings.
Fig. 1 is the flow chart that method of the invention is realized；
Fig. 2 is the work flow diagram for the method that the embodiment of the present invention one provides；
Fig. 3 is the hardware block diagram of method provided by Embodiment 2 of the present invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, those of ordinary skill in the art without making creative work it is obtained it is all its
His embodiment, shall fall within the protection scope of the present invention.
Embodiment one:
Since B1- and B1+ are vector field, emit/receive volume coil for multichannel, B1- and B1+ are all satisfied vector
The field B1 of compositive relation, i.e., each channel forms final system B1 by vector superposed.The present inventor proposes one
Kind of the method for receiving field uniformity for optimizing magnetic resonance radio frequency coil, by the B1- in each channel by amplitude-phase control with
It is vector superposed to achieve the purpose that adjust spatial distribution and uniformity optimization.
Referring to Figure 1, Fig. 2, method of the invention realize that process is as follows:
S1, the K space data for obtaining several channels of radio-frequency coil carry out Fourier transformation to the K space data and obtain
Obtain several plural number figures of image area；It include the amplitude and phase information of image in the plural number figure；
Radio-frequency coil of the invention can be volume dispatch coil, be also possible to other forms multi-channel RF coil such as surface
Array coil etc..The present embodiment is illustrated by taking volume dispatch coil as an example.
Image scanning is carried out by volume dispatch coil, obtains magnetic resonance signal.The collected signal of volume dispatch coil
Including multiple channels, the number in channel can be 2~32 etc., and the processing mode of multi channel signals is similar.
The present embodiment is described in detail by taking binary channels as an example.
Binary channels first passage is denoted as CH1, and second channel is denoted as CH2.
Specifically, Fourier transformation is carried out to the K space data of CH1 and CH2 respectively, obtains the image area of CH1 and CH2
Plural number figure, by the plural seal of the image area of CH1 be Img1, the plural seal of the image area of CH2 is Img2, wherein it is described multiple
Number figure Img1And Img2It include the amplitude and phase information of image.
S2, amplitude control parameter initial value, the phase controlling initial parameter value that several channels are respectively set, according to
Amplitude control parameter initial value, phase controlling initial parameter value and several plural number figures in several channels calculate
Obtain composograph；
Wherein, according to the amplitude control parameter initial value, phase controlling initial parameter value and institute in several channels
It states several plural figures composograph is calculated and include:
The amplitude control parameter initial value, phase controlling initial parameter value and the plural number figure are substituted into composograph meter
Formula is calculated, composograph is obtained；The composograph calculation formula is as follows:
Wherein, Img_Opt is composograph, and i is the corresponding number in each channel, ImgiFor the image corresponding to the channel i
The plural number figure in domain, aiFor the amplitude control parameter in the channel i, biFor the phase controlling parameter in the channel i, j is imaginary unit,For
Using natural constant e the bottom of as, with jbiFor the exponential function of index.In the present embodiment, i 1,2.
The amplitude control parameter and phase controlling parameter setting initial value in each channel can be preset arbitrary value.
The initial value of the amplitude control parameter of CH1 is a1, phase controlling parameter is b1；The amplitude control parameter of CH2 it is initial
Value is a2, phase controlling parameter is b2.The then composograph of CH1 and CH2 are as follows:
The formula that conventional SOS merges is as follows:
The merging method can guarantee that each pixel reaches theoretically strongest signal amplitude, but not account for B1-
The optimization of uniformity.Method of the invention by and phase controlling parameter adjusting, the optimization of B1- uniformity may be implemented.
S3, amplitude control parameter and the progress of phase controlling parameter according to the composograph, to several channels
Optimization is calculated excellent according to amplitude control parameter, phase controlling parameter and several described plural figures after the optimization
Composograph after change.
Amplitude control parameter and phase controlling parameter to each channel are optimized and can be realized by software, can also
To be realized by hardware, the present embodiment is described in detail is joined by amplitude control parameter and phase controlling of the software to each channel
The method that number optimizes.
When Optimal Parameters, the uniformity of composograph is assessed first, according to assessment result obtain it is described several
Amplitude control parameter and phase controlling parameter after CHANNEL OPTIMIZATION.The assessment of composograph Img_Opt uniformity can be passed through
Manual type can also carry out quantum chemical method by certain statistical indicator or objective function；For example, can be according to (3) formula institute
State uniformity calculating and evaluation that objective function carries out image entirety, wherein λ ∑i(ai-1)2For penalty term, λ value can be 0~1
Between be rule of thumb adjusted:
Wherein, Uniformity is the uniformity of image.
After the evaluation function that image conformity has been determined, parameter optimization target be can be expressed as:
(4) formula is typical multivariable Global Optimal Problem, has many ripe algorithms to can be used for solving, such as LMS, simulation
Annealing, genetic algorithm etc..(4) formula of solution obtains amplitude control parameter and phase in several described channels after each CHANNEL OPTIMIZATION
The optimization solution of position control parameter, optimization solution corresponding for binary channels is [a1_opt,b1_opt,a2_opt,b2_opt]。
According to ai,biOptimization solution, the composograph after calculation optimization:
Optimization is solved into [a1_opt,b1_opt,a2_opt,b2_opt] (1) formula is substituted into, the Img_Opt1, i=after optimization is calculated
1,2。
Composograph for binary channels dispatch coil, after optimization are as follows:
S4, according to the composograph after optimization, the susceptibility of local receiving coil is corrected.
Correction includes two steps:
S401, the image for obtaining local receiving coil, according to the composograph Img_Opt1 and part reception line after optimization
The image of circle obtains the sensitivity distribution figure of local receiving coil；
The image Img_LocalCoil that local receiving coil is acquired according to sweep parameter identical with step S1, is removed in point
On the basis of carry out image filtering appropriate the sensitivity distribution figure of local receiving coil can be obtained.Part is obtained according to the following formula
The sensitivity distribution figure of receiving coil:
SensMap=ImageFilter (Img_LocalCoil/Img_Opt1) (5)
Wherein, SensMap is the sensitivity distribution figure of local receiving coil, and Img_LocalCoil is to use and step S1
Identical sweep parameter, the image of the part receiving coil acquisition, ImageFilter (x) is image filtering function, Img_
Opt1 is the composograph after optimization；Under normal circumstances, the Img_Opt in above formula and Img_LocalCoil is low resolution
Image.
S402, susceptibility is carried out to the image that local receiving coil acquires according to the sensitivity distribution figure of local receiving coil
Correction.
According to the SensMap that (5) formula is calculated, can other images collected to local receiving coil according to the following formula
Carry out susceptibility correction:
Img_AfterNormlize=Img_BeforeNormlize/SensMap (6)
Wherein, Img_AfterNormlize is the image of the local receiving coil after correction, Img_BeforeNormlize
For the image of local receiving coil acquisition.
The channel for carrying out volume dispatch coil according to the method for the present invention merges, and not can guarantee signal amplitude theoretically most
Greatly, signal noise ratio (snr) of image may also decrease.But in high field systems, the partial loss of signal amplitude and signal-to-noise ratio is can to connect
It receives, serious influence will not be brought on subsequent processing.In addition, for the Img_Opt for being used to carry out susceptibility correction, one
As in the case of its spatial resolution it is very low, signal strength is sufficiently large, therefore the processing result of final algorithm is to signal amplitude and letter
It makes an uproar than not very sensitive.
Embodiment two:
The present embodiment emphasis illustrate by hardware mode to the amplitude control parameter in each channel and phase controlling parameter into
The method of row optimization, rest part are the same as example 1, repeat no more.The hardware structure diagram of the present embodiment is as shown in Figure 3.
The method that hardware mode optimizes the amplitude control parameter and phase controlling parameter in each channel are as follows: be used for
Acquire the signal acquisition module of the magnetic resonance signal of the radio-frequency coil in each channel with for collected magnetic resonance signal into
Row signal processing is to obtain between the signal processing module of plural figure of corresponding image area, and series connection is for amplitude of accommodation control ginseng
Several and phase controlling parameter RF module.The amplitude of accommodation control parameter and the RF module of phase controlling parameter of being used for is adjustable
Attenuator and adjustable phase shifter.
It is illustrated by taking twin-channel volume dispatch coil as an example, certainly, radio-frequency coil of the invention is also possible to other
Form multi-channel RF coil such as surface coil array etc..The present embodiment is illustrated by taking volume dispatch coil as an example.Volume transmitting-receiving
The collected signal of coil includes multiple channels, and the number in channel can be 2~32 etc., the processing mode of multi channel signals with
Binary channels is similar.
Volume dispatch coil is connect with the analog-to-digital conversion of CH1, CH2 and digital processing module respectively, CH1 analog-to-digital conversion and number
The connection of word processing module is gone forward side by side line number word processing, CH2 analog-to-digital conversion and digital processing mould for carrying out analog-to-digital conversion to CH1 signal
Block connection is gone forward side by side line number word processing for carrying out analog-to-digital conversion to CH2 signal, Digital Signal Processing herein include generate CH1 or
The corresponding space the K initial data in the channel CH2.
The analog-to-digital conversion and digital processing module of CH1 analog-to-digital conversion and digital processing module and CH2 with image reconstruction and
The connection of channel merging module, image reconstruction and channel merging module are used to generate the plural number figure in each channel image domain, and merge figure
Picture.
Local receiving coil successively with local receiving coil analog-to-digital conversion and digital signal processing module and image reconstruction and
The connection of channel merging module.Wherein, local receiving coil includes N number of receiving unit.
In order to each channel amplitude control parameter and phase controlling parameter optimize, volume dispatch coil and CH1 mould
Adjustable attenuator and adjustable phase shifter are in series between number conversion and digital processing module, volume dispatch coil and CH2 modulus turn
Change and digital processing module between be also in series with adjustable attenuator and adjustable phase shifter.Adjustable attenuator is for optimizing amplitude control
Parameter, adjustable phase shifter is for optimizing phase controlling parameter.
In order to improve the signal strength of coil transmitting-receiving, volume dispatch coil and CH1 analog-to-digital conversion and digital processing module it
Between be also connected with CH1 front end signal amplification module, also connect between volume dispatch coil and CH2 analog-to-digital conversion and digital processing module
It is connected to CH2 front end signal amplification module；Local receiving coil and local receiving coil analog-to-digital conversion and digital signal processing module
Between be connected with local receiving coil front-end low noise amplification module.
The above is a preferred embodiment of the present invention, it is noted that for those skilled in the art
For, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications are also considered as
Protection scope of the present invention.
Claims (9)
1. the method for receiving field uniformity for optimizing magnetic resonance radio frequency coil, which comprises the following steps:
S1, the K space data for obtaining several channels of radio-frequency coil carry out Fourier transformation to the K space data and are schemed
Several plural number figures of image field；It include the amplitude and phase information of image in the plural number figure；
S2, amplitude control parameter initial value, the phase controlling initial parameter value that several channels are respectively set, according to described
Amplitude control parameter initial value, phase controlling initial parameter value and several plural figures in several channels are calculated
Composograph；
S3, according to the composograph, amplitude control parameter and phase controlling parameter to several channels optimize,
After optimization is calculated according to amplitude control parameter, phase controlling parameter and several described plural figures after the optimization
Composograph；
S4, according to the composograph after optimization, the susceptibility of local receiving coil is corrected.
2. the method according to claim 1 for receiving field uniformity for optimizing magnetic resonance radio frequency coil, feature exist
According to amplitude control parameter initial value, phase controlling initial parameter value and the institute in several channels described in S2
It states several plural figures composograph is calculated and include:
The amplitude control parameter initial value, phase controlling initial parameter value and the plural number figure are substituted into composograph and calculate public affairs
Formula obtains composograph；The composograph calculation formula is as follows:
Img_Opt is composograph in the formula, and i is the corresponding number in each channel, ImgiFor the image corresponding to the channel i
The plural number figure in domain, aiFor the amplitude control parameter in the channel i, biFor the phase controlling parameter in the channel i, j is imaginary unit,For
Using natural constant e the bottom of as, with jbiFor the exponential function of index；A during acquisition composograph in this stepiUsing amplitude control
Initial parameter value processed, biUsing phase controlling initial parameter value.
3. the method according to claim 2 for receiving field uniformity for optimizing magnetic resonance radio frequency coil, feature exist
In, according to the composograph described in S3, amplitude control parameter and phase controlling parameter to several channels into
Row optimization includes: to assess the uniformity of the composograph, according to assessment result to the amplitude in several channels
Control parameter and phase controlling parameter optimize.
4. the method according to claim 3 for receiving field uniformity for optimizing magnetic resonance radio frequency coil, which is characterized in that
The uniformity of composograph is assessed by following formula in S3:
Wherein, Uniformity is Img_Opt's
Uniformity, c are scheduled constant, number of the λ between preset 0-1.
5. the method according to claim 4 for receiving field uniformity for optimizing magnetic resonance radio frequency coil, which is characterized in that
Packet is optimized according to amplitude control parameter and phase controlling parameter of the assessment result to several channels described in S3
It includes:
The amplitude control parameter in several channels and the optimization solution of phase controlling parameter are obtained according to the following formula:
6. the method according to claim 1 for receiving field uniformity for optimizing magnetic resonance radio frequency coil, feature exist
In, according to the composograph described in S3, amplitude control parameter and phase controlling parameter to several channels into
Row optimization include: the magnetic resonance signal of the radio-frequency coil for acquiring several channels signal acquisition module be used for
To collected magnetic resonance signal progress signal processing to obtain between the signal processing module of plural figure of corresponding image area,
Series connection is used for the RF module of amplitude of accommodation control parameter and phase controlling parameter, comments the uniformity of the composograph
Estimate, it is excellent to amplitude control parameter and phase controlling the parameter progress in each channel by adjusting the RF module according to assessment result
Change.
7. the method according to claim 1 for receiving field uniformity for optimizing magnetic resonance radio frequency coil, which is characterized in that
According to the composograph after optimization described in S4, the susceptibility of local receiving coil is corrected includes:
S401, the image for obtaining local receiving coil, according to after optimization composograph and local receiving coil image acquisition office
The sensitivity distribution figure of portion's receiving coil；
S402, susceptibility school is carried out to the image that local receiving coil acquires according to the sensitivity distribution figure of local receiving coil
Just.
8. the method according to claim 7 for receiving field uniformity for optimizing magnetic resonance radio frequency coil, which is characterized in that
S401 includes: the sensitivity distribution figure for obtaining local receiving coil according to the following formula:
SensMap=ImageFilter (Img_LocalCoil/Img_Opt1)
Wherein, SensMap is the sensitivity distribution figure of local receiving coil, and Img_LocalCoil is to obtain K using with step S1
The image for the local receiving coil acquisition that identical sweep parameter used in spatial data process obtains, ImageFilter (x)
For image filtering function, Img_Opt1 is the composograph after optimization；
S402 includes: to carry out susceptibility correction to the image of local receiving coil acquisition according to the following formula:
Img_AfterNormlize=Img_BeforeNormlize/SensMap
Wherein, Img_AfterNormlize is the image of the local receiving coil after correction, and Img_BeforeNormlize is office
The image of portion's receiving coil acquisition.
9. a kind of system for receiving field uniformity for optimizing magnetic resonance radio frequency coil, which is characterized in that including
Plural number figure obtains module, for obtaining the K space data in several channels of radio-frequency coil, carries out to the K space data
Fourier transformation obtains several plural number figures of image area；It include the amplitude and phase information of image in the plural number figure；
Image synthesis module, for amplitude control parameter initial value, the phase controlling parameter in several channels to be respectively set
Initial value, according to the amplitude control parameter initial value in several channels, phase controlling initial parameter value and described several
Composograph is calculated in a plural number figure；
Optimization module, for the amplitude control parameter and phase controlling ginseng according to the composograph, to several channels
Number optimizes, and is calculated according to amplitude control parameter, phase controlling parameter and several described plural number figures after the optimization
Composograph after being optimized；
Correction module, for being corrected to the susceptibility of local receiving coil according to the composograph after optimization.
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| CN102498411A (en) * | 2009-09-17 | 2012-06-13 | 皇家飞利浦电子股份有限公司 | Concurrent optimization of rf power and rf field uniformity in mri |
| CN102612657A (en) * | 2009-09-17 | 2012-07-25 | 皇家飞利浦电子股份有限公司 | Image intensity correction for magnetic resonance imaging |
| CN102749600A (en) * | 2012-05-30 | 2012-10-24 | 苏州安科医疗系统有限公司 | Synthetic method of magnetic resonance multi-channel image |
| CN103720475A (en) * | 2012-10-10 | 2014-04-16 | 三星电子株式会社 | Medical image imaging method and medical diagnostic apparatus using the same |
| CN104749538A (en) * | 2015-04-30 | 2015-07-01 | 郑州轻工业学院 | Phase processing method for parallel magnetic resonance imaging |
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| CN102498411A (en) * | 2009-09-17 | 2012-06-13 | 皇家飞利浦电子股份有限公司 | Concurrent optimization of rf power and rf field uniformity in mri |
| CN102612657A (en) * | 2009-09-17 | 2012-07-25 | 皇家飞利浦电子股份有限公司 | Image intensity correction for magnetic resonance imaging |
| CN102749600A (en) * | 2012-05-30 | 2012-10-24 | 苏州安科医疗系统有限公司 | Synthetic method of magnetic resonance multi-channel image |
| CN103720475A (en) * | 2012-10-10 | 2014-04-16 | 三星电子株式会社 | Medical image imaging method and medical diagnostic apparatus using the same |
| CN104749538A (en) * | 2015-04-30 | 2015-07-01 | 郑州轻工业学院 | Phase processing method for parallel magnetic resonance imaging |
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