Multiscale reconstruction for MR fingerprinting.
Multiscale reconstruction for MR fingerprinting.
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DOI：
10.1002/mrm.25776
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发表时间：
2016-06
影响因子：
3.3
通讯作者：
Griswold MA
中科院分区：
文献类型：
--
作者：
Pierre EY;Ma D;Chen Y;Badve C;Griswold MA
减少通过磁共振指纹获取可靠参数图所需的采集时间。通过以低图像分辨率重建 MRF 图像系列来初始化迭代去噪算法。对于后续迭代，该方法对最佳匹配的字典模板强制执行像素级保真度，然后以稍高的空间分辨率对所获取的数据强制保真度。收敛后，通过最终图像系列的模板匹配获得具有所需空间分辨率的参数图。使用高度欠采样、可变密度螺旋轨迹对体模和体内数据对所提出的方法进行了评估，并与原始 MRF 方法进行了比较。还评估了额外稀疏约束的好处。如果可用，则使用黄金标准参数图来量化每种方法的性能。与原始 MRF 工作中的 1000 个采集时间点相比，所提出的方法只需 300 个采集时间点即可收敛到精确的参数图。在体内对 256×256 矩阵实现了大脑中 T1、T2、质子密度 (PD) 和 B0 场变化的同步量化，总采集时间为 10.2 秒，采集时间减少了 3 倍。所提出的迭代多尺度重建可靠地提高了 MRF 采集速度和精度。
To reduce acquisition time needed to obtain reliable parametric maps with Magnetic Resonance Fingerprinting. An iterative-denoising algorithm is initialized by reconstructing the MRF image series at low image resolution. For subsequent iterations, the method enforces pixel-wise fidelity to the best-matching dictionary template then enforces fidelity to the acquired data at slightly higher spatial resolution. After convergence, parametric maps with desirable spatial resolution are obtained through template matching of the final image series. The proposed method was evaluated on phantom and in-vivo data using the highly-undersampled, variable-density spiral trajectory and compared with the original MRF method. The benefits of additional sparsity constraints were also evaluated. When available, gold standard parameter maps were used to quantify the performance of each method. The proposed approach allowed convergence to accurate parametric maps with as few as 300 time points of acquisition, as compared to 1000 in the original MRF work. Simultaneous quantification of T1, T2, proton density (PD) and B0 field variations in the brain was achieved in vivo for a 256×256 matrix for a total acquisition time of 10.2s, representing a 3-fold reduction in acquisition time. The proposed iterative multiscale reconstruction reliably increases MRF acquisition speed and accuracy.