CN106249183A - A kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration - Google Patents

Abstract

The present invention relates to a kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration, including the CSSR step excited for hyperpolarization the dissolved xenon, collect magnetic resonance spectrogram, and for the DWI step that hyperpolarization gaseous xenon excites, collect nuclear magnetic resonance image.When being more than the repetition time of DWI step, within this default swap time, run DWI step default swap time in CSSR step；The data that CSSR step obtains are filled in the first data space, the data that DWI step obtains are filled in the second data space；Data in first data space are carried out one-dimensional fast fourier transform and obtains magnetic resonance spectrogram, obtain nuclear magnetic resonance image to carrying out fast two-dimensional fourier transformation after the data permutation in the second data space successively.The present invention can speed up and synchronous acquisition obtains " gas diffusion " and " QI and blood exchange " function information of pulmonary's hyperpolarized xenon.

Description

A kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration

Technical field

The present invention relates to mr imaging technique field, especially relate to a kind of hyperpolarization xenon based on spectrum picture integration Magnetic resonance method.It is applicable to the pulmonary's nuclear magnetic resonance as contrast agent of the hyperpolarization xenon.

Background technology

Along with increase, the aggravation of air pollution (such as haze etc.) of number of smokers, the situation of pulmonary disease goes from bad to worse.Breast (X-ray), computed tomography (Computer Tomography, CT) etc. are the most conventional pulmonary disease clinic shadows thoroughly As diagnostic techniques, but, they have certain radioactivity.Comparatively speaking, nuclear magnetic resonance (Magnetic Resonance Imaging, MRI) technology do not has radioactivity, but, pulmonary is " blind area " of routine MRI.Use hyperpolarization xenon (Xe- 129) it is a kind of new technique as contrast agent, it is possible to realize the MRI of lung mechanics.And, hyperpolarization xenon can be dissolved in lung Tissue and blood (see Fig. 1).Carry out lung functions MRI, it is possible to obtain the function information that pulmonary is important.

At present, the main method utilizing hyperpolarization xenon MRI detection lung functions information has two.One is for super Change gaseous xenon excite Diffusion-Weighted MR Imaging (Diffusion Weighted Imaging, DWI) method (Ouriadov et al., Lung morphometry using hyperpolarized Xe-129apparent diffusion coefficient anisotropy in chronic obstructive pulmonary disease,Magnetic Resonance In Medicine, 2013,70 (6): p.1699-1706.DOI:10.1002/mrm.24595), detection hyperpolarization xenon is in pulmonary Diffusion information, simulates oxygen diffusion in lung, in conjunction with corresponding lung model (the Weibel model as in article), Jin Erneng The estimation lung functions parameter such as alveolar, bronchiolar average-size.Another is the change excited for hyperpolarization the dissolved xenon Displacement study saturation recovery (Chemical Shift Saturation Recovery, CSSR) method (Stewart, Neil J etc. People, Experimental validation of the hyperpolarized Xe-129chemical shift saturation recovery technique in healthy volunteers and subjects with interstitial lung disease,Magnetic Resonance In Medicine,2015,74(1):p.196- 207.DOI:10.1002/mrm.25400), detection hyperpolarization xenon enters from alveolar and becomes hyperpolarization dissolving tissue or blood The process of state xenon, simulation oxygen transports " QI and blood exchange " process blood, in conjunction with corresponding lung model (such as literary composition from alveolar MOXE model in chapter), and then the lung functions parameters such as lung spacer thickness, average QI and blood swap time can be estimated.

In above-mentioned two method, the detection of DWI method is pulmonary's " gas diffusion " function, can obtain alveolar, ramuscule gas The lung functions parameters such as the average-size of pipe；The detection of CSSR method is pulmonary's " QI and blood exchange " function, can obtain lung interval The lung functions parameters such as thickness, average QI and blood swap time.The early stage detection of pulmonary disease typically requires with reference to comprehensive pulmonary Functional parameter, if it is possible to detect " gas diffusion " and " QI and blood exchange " two functions of pulmonary simultaneously, will be to pulmonary's disease Sick early stage detection provides help.But, DWI method collection is lung image, and CSSR method collection is pulmonary's spectrogram, by In current existing hyperpolarization xenon magnetic resonance method, image and spectrogram need to be divided among in 2 samplings completing, therefore, as Fruit to obtain " gas diffusion " and " QI and blood exchange " two functions of patient pulmonary simultaneously, has following several schemes at present:

Scheme one, first running CSSR method in same single-breath hold, after waiting CSSR method end of run, rerun DWI Method；

Scheme two, in same single-breath hold, first run DWI method, after waiting DWI method end of run, CSSR side of reruning Method；

Scheme three, in different holding one's breath, it is separately operable CSSR method and DWI method.

In the first scheme, owing to during operation CSSR method, the signal of hyperpolarization xenon has relaxation loss, because of When this will cause running DWI method, signal is too low.In first scheme, due to hyperpolarization xenon during operation DWI method Signal be excited loss, when causing running CSSR method, signal is too low.Additionally, the most above-mentioned the first or the second side Case, runs 2 methods continuously and all can cause single breath-hold time lengthening, cause the discomfort of patient.In the third scheme, Bing Renxu Suck the hyperpolarization xenon of 2 multiple doses, 2 gas of screen, add time and the material cost collecting hyperpolarization xenon, cause disease People diagnoses the raising of cost and the reduction of diagnosis efficiency.

Accordingly, it would be desirable to a kind of magnetic resonance method that can realize CSSR method and the synchronous operation of DWI method.

In order to solve the problem in above-mentioned background technology, the present invention proposes a kind of hyperpolarization xenon based on spectrum picture integration Magnetic resonance method, in order to collect nuclear magnetic resonance image and spectrogram simultaneously so that CSSR method and DWI method in unitary sampling Can run simultaneously, thus " the gas diffusion " of synchronization gain pulmonary and " QI and blood exchange " function information.The inventive method can allow Patient only sucks a hyperpolarization xenon, only needs unitary sampling just can be detected simultaneously by " the gas diffusion " of pulmonary and " QI and blood is handed over Change " function, and total sampling time is shorter, shortens the breath holding time needed for patient, ensures again when two modules are run all Have higher magnetic resonance signal.

Summary of the invention

Present invention aims to the deficiency that prior art exists, it is provided that a kind of hyperpolarization based on spectrum picture integration Xenon magnetic resonance method.

The object of the invention is realized by following technical proposals:

A kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration, comprises the following steps:

Step 1, initialize total number of repetition m of CSSR step, initialize the τ default swap time of CSSR step₁～τ_m, Preset τ swap time₁～τ_mBetween magnitude relationship be τ₁<τ₂<…<τ_m；

Step 2, initialize DWI step always excite number of times Z, initialize the repetition time TR of DWI step；

Step 3, determine at τ default swap time according to following formula_kInterior can run DWI step can number of run f_k

$f_k=\&lsqb;\frac{{\mathrm{\&tau;}}_k}{TR}\&rsqb;,k\&Element;(1,2,\mathrm{...},m)$

Wherein, square brackets [] expression takes less than the maximum positive integer of numerical value in square brackets；

Step 4, determine at τ default swap time according to following formula_kThe actual motion frequency n of interior operation DWI step_k

$\begin{array}{c}{n}_k=f_k\&times;\{Z\&GreaterEqual;{\&Sigma;}_{i=1}^k{f}_k\}+(Z-{\&Sigma;}_{i=1}^{k-1}{f}_k)\&times;\{{\&Sigma;}_{i=1}^k{f}_k>Z\}\&times;\{f_k>{\&Sigma;}_{i=1}^k{f}_k-Z\},\\ k\&Element;(1,2,\mathrm{...},m)\end{array}$

In above formula, brace { } represents if the expression formula in brace is true, takes 1；If the expression formula in brace It not true, take 0；

Step 5, determine the rear number of run h running DWI step after the m time CSSR step is run according to following formula

$h=(Z-\underset{k=1}{\overset{m}{\&Sigma;}}{f}_k)\&times;\{Z\&GreaterEqual;\underset{k=1}{\overset{m}{\&Sigma;}}{f}_k\},k\&Element;(1,2,\mathrm{...},m)$

In above formula, brace { } represents if the expression formula in brace is true, takes 1；If the expression formula in brace It not true, take 0；

Step 6, determine the actual exchange time T of CSSR step according to following formula_k

T_k=τ_k-TR×n_k, k ∈ (1,2 ..., m)

Step 7, experimenter suck hyperpolarization Xe-129 gas and hold one's breath；

Set k as 1；

Step 8, the saturation process run in kth time CSSR step；

Step 9, according to step 4 determine at τ default swap time_kThe actual motion frequency n of interior operation DWI step_k, fortune Row n_kThe picture sampling step of secondary DWI step, it is thus achieved that echo-signal Echo, and echo-signal Echo is stored in the second data space, At n_kIn the picture sampling step of secondary DWI step, phase encoding gradient P1 and Diffusion Marker gradient DW1 all start to increase successively from 0；

Step 10, the actual exchange time T of the kth time CSSR step determined according to step 6_k, at actual exchange time T_kIn Run the exchange step in CSSR step,

Exchange step in CSSR step is specific as follows: do not carry out any operation；

Step 11, the spectrum sampling step run in kth time CSSR step, it is thus achieved that free induction decay signal (FID) is also deposited Enter in the first data space；

If step 12 k is more than or equal to m, then enter step 13；If k returns step 8 after adding 1 less than m, k；

Step 13, the rear number of run running DWI step after the m time CSSR step is run determined according to step 5 H, runs the picture sampling step of h DWI step, it is thus achieved that echo-signal Echo, and it is empty that echo-signal Echo is stored in the second data Between, in the picture sampling step of h DWI step, phase encoding gradient P1 and Diffusion Marker gradient DW1 all start to increase successively from 0 Greatly；

Step 14, the free induction decay signal (FID) being stored in step 11 collection in the first data space do one-dimensional Fast fourier transform (1Dimensional Fast Fourier Transform, 1D FFT) obtains m magnetic resonance spectrogram；

Step 15, echo-signal Echo being stored in the second data space to step 9, step 13 collection do two dimension quickly Fourier transform (2Dimensional Fast Fourier Transform, 2D FFT) obtains corresponding nuclear magnetic resonance image.

In step 8 as above, the saturation process in CSSR step is specific as follows: first MR imaging apparatus launches One the dissolved xenon selective excitation pulse α₁, the dissolved xenon selective excitation pulse α₁Excitation center frequency alignment hyperpolarization The resonant frequency of the dissolved xenon, the dissolved xenon selective excitation pulse α₁The angle that excites be 90 °, and then nuclear magnetic resonance sets Standby applying one damage gradient G 1 on the direction being perpendicular to main field direction.

The picture sampling step of the DWI step in step 9 as above and step 13 is specific as follows, MR imaging apparatus First launching a gaseous xenon selective excitation pulse α 3, the excitation center frequency alignment of gaseous xenon selective excitation pulse α 3 surpasses The resonant frequency of polarized gaseous xenon, the angle that excites of gaseous xenon selective excitation pulse α 3 is θ °, and applies to select layer ladder simultaneously Degree S1, thus select an imaging aspect；MR imaging apparatus is then reverse direction initialization one forward of applying and one Paired Diffusion Marker gradient DW1 be diffused labelling；MR imaging apparatus then applies on phase encoding gradient direction One phase encoding gradient P1 also applies dephasing gradient R1 on readout gradient direction；Then execute on readout gradient direction Adding a readout gradient R2, and correspondingly carry out as sampling E2 obtains echo-signal Echo, echo-signal Echo is stored in the second number According to space；Last in slice selective gradient direction, phase encoding gradient direction, readout gradient direction respectively apply a damage gradient G 2.

Angle, θ ° is excited to be not more than 10 ° as above.

Spectrum sampling step in CSSR step as above is specific as follows: MR imaging apparatus transmitting one is non-selection Property excitation pulse α₂, non-selective excitation pulse α₂The resonant frequency of excitation center frequency alignment hyperpolarization the dissolved xenon, non-choosing Selecting property excitation pulse α₂Hyperpolarization the dissolved xenon is excited and hyperpolarization gaseous xenon all excites, correspondingly carry out spectrum sampling E1, it is thus achieved that comprise the free induction decay signal (FID) of hyperpolarization the dissolved xenon and hyperpolarization gaseous xenon, by free induction decay Signal (FID) is stored in the first data space.

The present invention has the advantages that relative to prior art:

1, use spectrum as the mode of integration, unitary sampling collect the spectrogram of CSSR and the image of DWI simultaneously, It is thus possible to obtain " gas diffusion " and " QI and blood exchange " function information of pulmonary simultaneously.

2, the mode that the present invention runs in using the swap time that DWI step is embedded CSSR step, can shorten and always adopt The sample time,

3, in the present invention, DWI data can be by synchronous acquisition with CSSR data, and therefore CSSR and DWI step can when running Obtain higher magnetic resonance signal.

Accompanying drawing explanation

Fig. 1 is the hyperpolarization xenon magnetic resonance signal scattergram in live body pulmonary；

Fig. 2 is the time sequencing figure of a kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration of the present invention；

Fig. 3-1 is a kind of spectrogram signal obtained as the hyperpolarization xenon magnetic resonance method of integration based on spectrum of the present invention Figure；

Fig. 3-2 is a kind of image signal obtained as the hyperpolarization xenon magnetic resonance method of integration based on spectrum of the present invention Figure.

Detailed description of the invention

Describe illustrative, the non-limiting example of the present invention with reference to the accompanying drawings in detail, a kind of based on spectrum to the present invention As the technical scheme of the hyperpolarization xenon magnetic resonance method of integration is described in further detail, in order to fully understand this Bright.

Embodiment 1:

The present invention as the mode of integration, completes CSSR method and the fortune of DWI method based on spectrum in unitary sampling simultaneously OK.The step of the present invention is:

Step 1, total number of repetition m of initialization CSSR step (chemical shift saturation recovery step), initialize CSSR step Suddenly the τ default swap time of (chemical shift saturation recovery step)₁～τ_m, preset τ swap time₁～τ_mBetween magnitude relationship It is τ₁<τ₂<…<τ_m；

Step 2, initialize DWI step (Diffusion-Weighted MR Imaging step) always excite number of times Z, initialize (the diffusion of DWI step Weighted imaging step) repetition time TR；

Step 3, determine at τ default swap time according to following formula_kThe interior DWI step (Diffusion-Weighted MR Imaging step) can run Can number of run f_k

$f_k=\&lsqb;\frac{{\mathrm{\&tau;}}_k}{TR}\&rsqb;,k\&Element;(1,2,\mathrm{...},m)$

Wherein, square brackets [] expression takes less than the maximum positive integer of numerical value in square brackets；

Step 4, determine at τ default swap time according to following formula_kThe reality of interior operation DWI step (Diffusion-Weighted MR Imaging step) Border number of run n_k

$\begin{array}{c}{n}_k=f_k\&times;\{Z\&GreaterEqual;{\&Sigma;}_{i=1}^k{f}_k\}+(Z-{\&Sigma;}_{i=1}^{k-1}{f}_k)\&times;\{{\&Sigma;}_{i=1}^k{f}_k>Z\}\&times;\{f_k>{\&Sigma;}_{i=1}^k{f}_k-Z\},\\ k\&Element;(1,2,\mathrm{...},m)\end{array}$

In above formula, brace { } represents if the expression formula in brace is true, takes 1；If the expression formula in brace It not true, take 0；Z be DWI step (Diffusion-Weighted MR Imaging step) always excite number of times；

Step 5, determine according to following formula and run after the m time CSSR step (chemical shift saturation recovery step) is run The rear number of run h of DWI step (Diffusion-Weighted MR Imaging step)

$h=(Z-{\mathrm{\&Sigma;}}_{k=1}^m{f}_k)\&times;\{Z\&GreaterEqual;{\mathrm{\&Sigma;}}_{k=1}^m{f}_k\},k\&Element;(1,2,\mathrm{...},m)$

In above formula, brace { } represents if the expression formula in brace is true, takes 1；If the expression formula in brace It not true, take 0；

Step 6, determine the actual exchange time T of CSSR step (chemical shift saturation recovery step) according to following formula_k

T_k=τ_k-TR×n_k, k ∈ (1,2 ..., m)

Step 7, experimenter suck hyperpolarization Xe-129 gas and hold one's breath.

Experimenter can be patient, it is also possible to be the animal of scientific research；Air-breathing and the process of holding one's breath can be actively to suck also Hold, it is also possible to be passively to be sucked by respirator and hold.

Set k as 1.

Step 8, the saturation process run in kth time CSSR step (chemical shift saturation recovery step):

Saturation process in CSSR step (chemical shift saturation recovery step) is specific as follows: MR imaging apparatus is first Launch a dissolved xenon selective excitation pulse α₁, in the present embodiment, the dissolved xenon selective excitation pulse α₁Select Gaussian Shape, the dissolved xenon selective excitation pulse α₁Resonant frequency (this reality of excitation center frequency alignment hyperpolarization the dissolved xenon Execute in example as 204ppm, as shown in Figure 1), the dissolved xenon selective excitation pulse α₁The angle that excites be 90 °.The dissolved xenon selects Selecting property excitation pulse α₁Only hyperpolarization the dissolved xenon is excited, hyperpolarization gaseous xenon is not excited.Thus hyperpolarization the dissolved xenon Signal be all turned to be perpendicular in the plane in main field direction.And then MR imaging apparatus is being perpendicular to main field A damage gradient G 1 is applied on the direction in direction；After the signal of hyperpolarization the dissolved xenon is all damaged by damage gradient G 1, this Time there is no any hyperpolarization the dissolved xenon signal.

Step 9, according to step 4 determine at τ default swap time_kInterior operation DWI step (Diffusion-Weighted MR Imaging step) Actual motion frequency n_k, run n_kThe picture sampling step of secondary DWI step (Diffusion-Weighted MR Imaging step), at n_kSecondary DWI step In the picture sampling step of (Diffusion-Weighted MR Imaging step), phase encoding gradient P1 and Diffusion Marker gradient DW1 all start successively from 0 Increase:

The picture sampling step of DWI step (Diffusion-Weighted MR Imaging step) specific as follows (wherein, Diffusion Marker gradient DW1 and Phase encoding gradient P1 is variable.Walking as sampling of the corresponding DWI step (Diffusion-Weighted MR Imaging step) reruned each time Suddenly, phase encoding gradient P1 and Diffusion Marker gradient DW1 start to increase successively from 0): first MR imaging apparatus launches one Gaseous xenon selective excitation pulse α₃, in the present embodiment, gaseous xenon selective excitation pulse α₃Select Gaussian in shape, gaseous xenon Selective excitation pulse α₃Excitation center frequency alignment hyperpolarization gaseous xenon resonant frequency (the present embodiment is 0ppm, as Shown in Fig. 1), gaseous xenon selective excitation pulse α₃Excite angle be θ ° the low-angle of no more than 10 ° (θ ° be), gaseous xenon is selected Selecting property excitation pulse α₁Only hyperpolarization gaseous xenon is excited, hyperpolarization the dissolved xenon is not excited.And apply to select layer ladder simultaneously Degree S1, thus select an imaging aspect；MR imaging apparatus (is then phase code side in the present embodiment at direction initialization To) apply a forward and reverse paired Diffusion Marker gradient DW1 (i.e. gradient in dashed rectangle in Fig. 2), it is used for It is diffused labelling；MR imaging apparatus then on phase encoding gradient direction apply a phase encoding gradient P1 and Dephasing gradient R1 is applied on readout gradient direction；Then on readout gradient direction, apply a readout gradient R2, and phase Should carry out as sampling E2 obtains echo-signal Echo on ground, echo-signal Echo is stored in the second data space；Last at slice selective gradient Direction, phase encoding gradient direction, readout gradient direction respectively apply a damage gradient G 2, will be perpendicular to the gas in main field direction State xenon signal is damaged.

Step 10, the kth time CSSR step (chemical shift saturation recovery step) determined according to step 6 actual exchange time Between T_k, at actual exchange time T_kExchange step in interior operation CSSR step (chemical shift saturation recovery step):

Exchange step in CSSR step (chemical shift saturation recovery step) is specific as follows: do not carry out any operation.

Step 11, the spectrum sampling step run in kth time CSSR step (chemical shift saturation recovery step):

Spectrum sampling step in CSSR step (chemical shift saturation recovery step) is specific as follows: MR imaging apparatus is sent out Penetrate a non-selective excitation pulse α₂, non-selective excitation pulse α₂Excitation center frequency alignment hyperpolarization the dissolved xenon Resonant frequency (is 204ppm, as shown in Figure 1), non-selective excitation pulse α in the present embodiment₂The angle that excites be 90 °, non-choosing Selecting property excitation pulse α₂Hyperpolarization the dissolved xenon is excited and hyperpolarization gaseous xenon all excites, correspondingly carry out spectrum sampling E1, just can obtain the free induction decay signal (FID) comprising hyperpolarization the dissolved xenon and hyperpolarization gaseous xenon, and these are freely felt Deamplification (FID) is answered to be stored in the first data space.

If step 12 k is more than or equal to m, then enter step 13；If k returns step 8 after adding 1 less than m, k；

Step 13, the fortune after the m time CSSR step (chemical shift saturation recovery step) is run determined according to step 5 The rear number of run h of row DWI step (Diffusion-Weighted MR Imaging step), runs the picture of h DWI step (Diffusion-Weighted MR Imaging step) Sampling step, in the picture sampling step of h DWI step (Diffusion-Weighted MR Imaging step), phase encoding gradient P1 and diffusion mark Note gradient DW1 all starts to increase successively from 0:

Concrete, the picture sampling step of DWI step (Diffusion-Weighted MR Imaging step) herein and the DWI step in step 9 The picture sampling step of (Diffusion-Weighted MR Imaging step) is consistent.The picture sampling step of DWI step (Diffusion-Weighted MR Imaging step) is concrete (wherein, Diffusion Marker gradient DW1 and phase encoding gradient P1 are variable as follows.The corresponding DWI step reruned each time The picture sampling step of (Diffusion-Weighted MR Imaging step), phase encoding gradient P1 and Diffusion Marker gradient DW1 start to increase successively from 0 Greatly): first MR imaging apparatus launches a gaseous xenon selective excitation pulse α₃, in the present embodiment, gaseous xenon selectivity Excitation pulse α₃Select Gaussian in shape, gaseous xenon selective excitation pulse α₃Excitation center frequency alignment hyperpolarization gaseous xenon Resonant frequency (the present embodiment is 0ppm, as shown in Figure 1), gaseous xenon selective excitation pulse α₃The angle that excites be θ ° The low-angle of no more than 10 ° (θ ° be), gaseous xenon selective excitation pulse α₁Only hyperpolarization gaseous xenon is excited, molten to hyperpolarization Solve state xenon not excite.And apply slice selective gradient S1 simultaneously, thus select an imaging aspect；MR imaging apparatus then exists Direction initialization (for phase-encoding direction in the present embodiment) applies a forward and reverse paired Diffusion Marker gradient DW1 (i.e. gradient in dashed rectangle in Fig. 2), is used for being diffused labelling；MR imaging apparatus is then in phase encoding gradient side Upwards apply a phase encoding gradient P1 and on readout gradient direction, apply dephasing gradient R1；Then at readout gradient Applying a readout gradient R2 on direction, and correspondingly carry out as sampling E2 obtains echo-signal Echo, echo-signal Echo is deposited Enter the second data space；Last in slice selective gradient direction, phase encoding gradient direction, readout gradient direction respectively apply a damage Gradient G 2, the gaseous xenon signal that will be perpendicular to main field direction is damaged.After this step end of run, it is not necessary to experimenter's screen Gas, thus experimenter can be with eupnea.

Step 14, the free induction decay signal (FID) being stored in step 11 collection in the first data space do one-dimensional Fast fourier transform (1Dimensional Fast Fourier Transform, 1D FFT) obtains m magnetic resonance spectrogram；

Step 15, echo-signal Echo being stored in the second data space to step 9, step 13 collection do two dimension quickly Fourier transform (2Dimensional Fast Fourier Transform, 2D FFT) obtains corresponding nuclear magnetic resonance image.

The nuclear magnetic resonance image that the magnetic resonance spectrogram obtained according to step 14 and step 15 obtain, respectively in connection with corresponding model meter Calculate corresponding " QI and blood exchange " and the function information of " gas diffusion ".

In embodiment shown in accompanying drawing 2, RF, G_s、G_p、G_r, Acq represent radio-frequency pulse, slice selective gradient, phase code respectively Gradient, readout gradient and sample event.

Embodiment 2:

Below to some setting values in embodiment 1 to concrete values, thus to the inventive method and 3 in background technology Individual scheme compares.In the present embodiment:

The m=27 set in step 1,

[τ₁,……,τ_m]=[0,10,20,30,40,50,60,70,80,90,100,110,120,130,140,150, 160,170,180,190,200,300,400,500,600,700,900]ms；

The Z=192, TR=30ms set in step 2；

Then corresponding step 3

[f₁,……,f_m]=[0,0,0,1,1,1,2,2,2,3,3,3,4,4,4,5,5,5,6,6,6,10,13,16,20, 23,30]；

Corresponding step 4

[n₁,……,n_m]=[0,0,0,1,1,1,2,2,2,3,3,3,4,4,4,5,5,5,6,6,6,10,13,16,20, 23,30]；

The h=17 of corresponding step 5；

In corresponding step 6

[T₁,……,T_m]=[0,10,20,0,10,20,0,10,20,0,10,20,0,10,20,0,10,20,0,10, 20,0,10,20,0,10,0]ms；

The present embodiment sets the time running saturation process and spectrum 1 needs of sampling step in CSSR method as Ty= 30ms。

Other are same as in Example 1.

If thus scheme one, scheme two or the scheme three in employing background technology, needs of total sampling time If but used the scheme in the present invention, total sampling time would needAnd by In the present invention, CSSR method and DWI method have shifted to an earlier date, thus two methods can have high signal.It is right to set in DWI The angle, θ ° that excites of gaseous xenon is 5 °；Hyperpolarization xenon is 15 seconds at the longitudinal relaxation time of pulmonary, then the inventive method and the back of the body The numerical value that 3 schemes in scape technology compare is shown in Table 1.Visible, during the inventive method can be held one's breath at 1 time, with the shortest Time synchronized collects CSSR signal and DWI signal, and CSSR signal and DWI signal can keep high signal simultaneously.

Table 1 uses the effectiveness comparison that the different schemes in background technology and the present invention program obtain

The foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all essences in the present invention Within god and principle, any modification, equivalent substitution and improvement etc. made, should be included within the scope of the present invention.

Claims (5)

1. a hyperpolarization xenon magnetic resonance method based on spectrum picture integration, it is characterised in that comprise the following steps:

Step 1, initialize total number of repetition m of CSSR step, initialize the τ default swap time of CSSR step₁～τ_m, preset Swap time τ₁～τ_mBetween magnitude relationship be τ₁<τ₂<…<τ_m；

Step 2, initialize DWI step always excite number of times Z, initialize the repetition time TR of DWI step；

Step 3, determine at τ default swap time according to following formula_kInterior can run DWI step can number of run f_k

$f_k=\&lsqb;\frac{{\mathrm{\&tau;}}_k}{TR}\&rsqb;,k\&Element;(1,2,...,m)$

Wherein, square brackets [] expression takes less than the maximum positive integer of numerical value in square brackets；

Step 4, determine at τ default swap time according to following formula_kThe actual motion frequency n of interior operation DWI step_k

$\begin{array}{c}{n}_k=f_k\&times;\{Z\&GreaterEqual;{\mathrm{\&Sigma;}}_{i=1}^k{f}_k\}+(Z-{\&Sigma;}_{i=1}^{k-1}{f}_k)\&times;\{{\mathrm{\&Sigma;}}_{i=1}^k{f}_k>Z\}\&times;\{f_k>{\mathrm{\&Sigma;}}_{i=1}^k{f}_k-Z\},\\ k\&Element;(1,2,\mathrm{...},m)\end{array}$

In above formula, brace { } represents if the expression formula in brace is true, takes 1；If the expression formula in brace is not Very, 0 is taken；

Step 5, determine the rear number of run h running DWI step after the m time CSSR step is run according to following formula

$h=(Z-\underset{k=1}{\overset{m}{\&Sigma;}}{f}_k)\&times;\{Z\&GreaterEqual;\underset{k=1}{\overset{m}{\&Sigma;}}{f}_k\},k\&Element;(1,2,...,m)$

In above formula, brace { } represents if the expression formula in brace is true, takes 1；If the expression formula in brace is not Very, 0 is taken；

Step 6, determine the actual exchange time T of CSSR step according to following formula_k

T_k=τ_k-TR×n_k, k ∈ (1,2 ..., m)

Step 7, experimenter suck hyperpolarization Xe-129 gas and hold one's breath；

Set k as 1；

Step 8, the saturation process run in kth time CSSR step；

Step 9, according to step 4 determine at τ default swap time_kThe actual motion frequency n of interior operation DWI step_k, run n_k The picture sampling step of secondary DWI step, it is thus achieved that echo-signal Echo, and echo-signal Echo is stored in the second data space, at n_k In the picture sampling step of secondary DWI step, phase encoding gradient P1 and Diffusion Marker gradient DW1 all start to increase successively from 0；

Step 10, the actual exchange time T of the kth time CSSR step determined according to step 6_k, at actual exchange time T_kInterior operation Exchange step in CSSR step,

Exchange step in CSSR step is specific as follows: do not carry out any operation；

Step 11, the spectrum sampling step run in kth time CSSR step, it is thus achieved that free induction decay signal (FID) is also stored in the In one data space；

If step 12 k is more than or equal to m, then enter step 13；If k returns step 8 after adding 1 less than m, k；

Step 13, the rear number of run h running DWI step after the m time CSSR step is run determined according to step 5, fortune The picture sampling step of h DWI step of row, it is thus achieved that echo-signal Echo, and echo-signal Echo is stored in the second data space, In the picture sampling step of h DWI step, phase encoding gradient P1 and Diffusion Marker gradient DW1 all start to increase successively from 0；

Step 14, the free induction decay signal (FID) that step 11 collection is stored in the first data space do one-dimensional quickly Fourier transform (1Dimensional Fast Fourier Transform, 1D FFT) obtains m magnetic resonance spectrogram；

Step 15, echo-signal Echo being stored in the second data space to step 9, step 13 collection do two dimension quickly Fourier Leaf transformation (2Dimensional Fast Fourier Transform, 2D FFT) obtains corresponding nuclear magnetic resonance image.

A kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration, it is characterised in that institute In the step 8 stated, the saturation process in CSSR step is specific as follows: first MR imaging apparatus launches a dissolved xenon choosing Selecting property excitation pulse α₁, the dissolved xenon selective excitation pulse α₁The resonance of excitation center frequency alignment hyperpolarization the dissolved xenon Frequency, the dissolved xenon selective excitation pulse α₁The angle that excites be 90 °, and then MR imaging apparatus is being perpendicular to main magnetic A damage gradient G 1 is applied on the direction of field direction.

A kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration, it is characterised in that institute The picture sampling step of the DWI step in the step 9 stated and step 13 is specific as follows, and first MR imaging apparatus launches a gas State xenon selective excitation pulse α 3, being total to of the excitation center frequency alignment hyperpolarization gaseous xenon of gaseous xenon selective excitation pulse α 3 Vibration frequency, the angle that excites of gaseous xenon selective excitation pulse α 3 is θ °, and applies slice selective gradient S1 simultaneously, thus selects one Individual imaging aspect；MR imaging apparatus then applies a forward and a reverse paired Diffusion Marker ladder at direction initialization Degree DW1 is diffused labelling；MR imaging apparatus then applies a phase encoding gradient on phase encoding gradient direction P1 also applies dephasing gradient R1 on readout gradient direction；Then on readout gradient direction, apply a readout gradient R2, and correspondingly carry out as sampling E2 obtains echo-signal Echo, echo-signal Echo is stored in the second data space；Finally in choosing Layer gradient direction, phase encoding gradient direction, readout gradient direction respectively apply a damage gradient G 2.

A kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration, it is characterised in that institute The angle, θ ° that excites stated is not more than 10 °.

A kind of hyperpolarization xenon magnetic resonance method based on spectrum picture integration, it is characterised in that institute Spectrum sampling step in the CSSR step stated is specific as follows: MR imaging apparatus launches a non-selective excitation pulse α₂, Non-selective excitation pulse α₂The resonant frequency of excitation center frequency alignment hyperpolarization the dissolved xenon, non-selective excitation pulse α₂Hyperpolarization the dissolved xenon is excited and hyperpolarization gaseous xenon all excites, correspondingly carry out spectrum sampling E1, it is thus achieved that comprise super Polarization the dissolved xenon and the free induction decay signal (FID) of hyperpolarization gaseous xenon, be stored in free induction decay signal (FID) First data space.