摘要:
A computer-implemented method for learning a tight frame includes acquiring undersampled k-space data over a time period using an interleaved process. An average of the undersampled k-space data is determined and a reference image is generated based on the average of the undersampled k-space data. Next, a tight frame operator is determined based on the reference image. Then, a reconstructed image data is generated from the undersampled k-space data via a sparse reconstruction which utilizes the tight frame operator.
摘要:
A computer-implemented method for learning a tight frame includes acquiring undersampled k-space data over a time period using an interleaved process. An average of the undersampled k-space data is determined and a reference image is generated based on the average of the undersampled k-space data. Next, a tight frame operator is determined based on the reference image. Then, a reconstructed image data is generated from the undersampled k-space data via a sparse reconstruction which utilizes the tight frame operator.
摘要:
A computer-implemented method for reconstruction of a magnetic resonance image includes acquiring a first incomplete k-space data set comprising a plurality of first k-space lines spaced according to an acceleration factor and one or more calibration lines. A parallel imaging reconstruction technique is applied to the first incomplete k-space data to determine a plurality of second k-space lines not included in the first incomplete k-space data set, thereby yielding a second incomplete k-space data set. Then, the parallel imaging reconstruction technique is applied to the second incomplete k-space data to determine a plurality of third k-space lines not included in the second incomplete k-space data, thereby yielding a complete k-space data set.
摘要:
A computer-implemented method for reconstruction of a magnetic resonance image includes acquiring a first incomplete k-space data set comprising a plurality of first k-space lines spaced according to an acceleration factor and one or more calibration lines. A parallel imaging reconstruction technique is applied to the first incomplete k-space data to determine a plurality of second k-space lines not included in the first incomplete k-space data set, thereby yielding a second incomplete k-space data set. Then, the parallel imaging reconstruction technique is applied to the second incomplete k-space data to determine a plurality of third k-space lines not included in the second incomplete k-space data, thereby yielding a complete k-space data set.
摘要:
A method for estimating a coil sensitivity map for a magnetic resonance (MR) image includes providing (61) a matrix A of sliding blocks of a 2D image of coil calibration data, calculating (62) a left singular matrix V∥ from a singular value decomposition of A corresponding to τ leading singular values, calculating (63) P=V∥V∥H, calculating (64) a matrix S that is an inverse Fourier transform of a zero-padded matrix P, and solving (65) MHcr=(Sr)Hcr for cr, where cr is a vector of coil sensitivity maps for all coils at spatial location r, and M ( ( 1 1 … 1 0 0 … 0 … … … 0 0 … 0 ) ( 0 0 … 0 1 1 … 1 … … … 0 0 … 0 ) … ( 0 0 … 0 0 0 … 0 … … … 1 1 … 1 ) ) .
摘要:
A method of image reconstruction for a magnetic resonance imaging (MRI) system having a plurality of coils includes obtaining k-space scan data captured by the MRI system, the k-space scan data being representative of an undersampled region over time, determining a respective coil sensitivity profile for the region for each coil of the plurality of coils, and iteratively reconstructing dynamic images for the region from the k-space scan data via an optimization of a minimization problem. The minimization problem is based on the determined coil sensitivity profiles and redundant Haar wavelet transforms of the dynamic images.
摘要:
A method for estimating a coil sensitivity map for a magnetic resonance (MR) image includes providing a matrix A of sliding blocks of a 3D image of coil calibration data, calculating a left singular matrix V∥ from a singular value decomposition of A corresponding to τ leading singular values, calculating P=V∥V∥H, calculating a matrix S that is an inverse Fourier transform of a zero-padded matrix P, and solving MHcr=(Sr)Hcr for cr, where cr is a vector of coil sensitivity maps for all coils at spatial location r, and M = ( ( 1 1 … 1 0 0 … 0 … … … 0 0 … 0 ) ( 0 0 … 0 1 1 … 1 … … … 0 0 … 0 ) … ( 0 0 … 0 0 0 … 0 … … … 1 1 … 1 ) ) .
摘要:
A method for reconstructing parallel magnetic resonance images includes providing a set of acquired k-space MR image data y, and finding a target MR image x that minimizes ½∥Fv−y∥22+λ∥z∥1 where v=Sx and z=Wx where S is a diagonal matrix containing sensitivity maps of coil elements in an MR receiver array, F is an FFT matrix, W is a redundant Haar wavelet matrix, and λ≧0 is a regularization parameter, by updating x k + 1 = ( μ 1 I + μ 3 S H S ) - 1 [ μ 1 W H ( z k - b z k ) + μ 3 S H ( v k - b v k ) ] , z k + 1 = soft ( Wx k + 1 + b z k , 1 μ 1 ) where soft ( x , T ) = { x + T if x ≤ - T , 0 if x ≤ T , x - T if x ≥ T , and v k + 1 = ( F H F + μ 3 I ) - 1 [ F H y + μ 3 ( Sx k + 1 + b v k ) ] , where k is an iteration counter, μ1 and μ3 are parameters of an augmented Lagrangian function, and bz and bv are dual variables of the augmented Lagrangian.
摘要翻译:重建并行磁共振图像的方法包括提供一组获取的k空间MR图像数据y,并找到最小化½|Fv-y‖22+λ‖z‖1的目标MR图像x,其中v = Sx和z = Wx其中S是包含MR接收机阵列中的线圈元件的灵敏度映射的对角矩阵,F是FFT矩阵,W是冗余Haar小波矩阵,并且λ≥0是正则化参数,通过更新xk + 1 =( μ1 I +μ3 SH S) - 1[μ1 WH(zk-bzk)+μ3 SH(vk-bvk)],zk + 1 =软(Wx k + 1 + bzk,1μ1),其中软(x,T)= {x + T,如果üx≤-T,0如果üx≤T,x-T,如果üx≥T ,υ,υνvk + 1 =(FH F +μ3 I)-1 [FH y +μ3(Sx k + 1 + bvk)],其中k是迭代计数器,μ1和 μ3是增强拉格朗日函数的参数,bz和bv是增强拉格朗日的双变量。
摘要:
A method for reconstructing parallel magnetic resonance images includes providing a set of acquired k-space MR image data y, and finding a target MR image x that minimizes ½∥Fv−y∥22+λ∥z∥1 where v=Sx and z=Wx where S is a diagonal matrix containing sensitivity maps of coil elements in an MR receiver array, F is an FFT matrix, W is a redundant Haar wavelet matrix, and λ≧0 is a regularization parameter, by updating x k + 1 = ( μ 1 I + μ 3 S H S ) - 1 [ μ 1 W H ( z k - b z k ) + μ 3 S H ( v k - b v k ) ] , z k + 1 = soft ( Wx k + 1 b z k , 1 μ 1 ) where soft ( x , T ) = { x + T if x ≤ - T , 0 if x ≤ T , x - T if x ≥ T , and v k + 1 = ( F H F + μ 3 I ) - 1 [ F H y + μ 3 ( Sx k + 1 + b v k ) ] , where k is an iteration counter, μ1 and μ3 are parameters of an augmented Lagrangian function, and bz and bv are dual variables of the augmented Lagrangian.
摘要翻译:重建并行磁共振图像的方法包括提供一组获取的k空间MR图像数据y,并找到最小化½|Fv-y‖22+λ‖z‖1的目标MR图像x,其中v = Sx和z = Wx其中S是包含MR接收器阵列中的线圈元件的灵敏度映射的对角矩阵,F是FFT矩阵,W是冗余Haar小波矩阵,并且λ> = 0是正则化参数,通过更新xk + 1 = (μ1 I +μ3 SH SH) - 1(zk-bzk)+ mu 3 SH(vk-bvk)],zk + 1 =软(Wx k + 1,bzk,1 mu 1)其中软(x,T)= {x + T如果x x = = T,如果x<= T,x - 其中k是迭代,其中k是迭代,其中k是迭代,其中k是迭代,其中k是迭代 计数器,mu1和mu3是增强的拉格朗日函数的参数,bz和bv是增强的拉格朗日的双重变量 ianㄧ。
摘要:
A method for image reconstruction includes receiving under-sampled k-space data, determining a data fidelity term of a first image of the under-sampled k-space data in view of a second image of the under-sampled k-space data, wherein a time component separated the first image and the second image, determining a spatial penalization on redundant Haar wavelet coefficients of the first image in view of the second image, and optimizing the first image according the data fidelity term and the spatial penalization, wherein the spatial penalization selectively penalizes temporal coefficients and an optimized image of the first image is output.