Objective

To accelerate tissue sodium concentration (TSC) quantification of skeletal muscle using ²³Na MRI and 3D dictionary-learning compressed sensing (3D-DLCS).

Materials and methods

Simulations and in vivo ²³Na MRI examinations of calf muscle were performed with a nominal spatial resolution of \(\Delta x = \left( {3.0 \times 3.0 \times 15.0} \right){\text{ mm}}^{3}\). Fully sampled and three undersampled ²³Na MRI data sets (undersampling factors (USF) = 3, 4.4, 6.7) were evaluated. Ten healthy subjects were examined on a 3 Tesla MRI system. Results of the simulation study and the in vivo measurements were compared to the ground truth (GT) and the fully sampled fast Fourier transform (NUFFT) reconstruction, respectively.

Results

Reconstruction results of simulated data with optimized 3D-DLCS yielded a lower deviation (< 4%) from the GT than results of the NUFFT reconstruction (> 5%) and a lower standard deviation (SD). For in vivo measurements, a TSC of \(17 \pm 2.7 {\text{ mMol/l}}\) was observed. The mean deviation from the reference is lower for the undersampled 3D-DLCS reconstructions (3.4%) than for NUFFT reconstructions (4.6%). SD is reduced using 3D-DLCS. Compared to a fully sampled NUFFT reconstruction, acquisition time could be reduced by a factor of 4.4 while maintaining similar quantitative accuracy.

Discussion

The optimized 3D-DLCS reconstruction enables accelerated TSC measurements with high quantification accuracy.

中文翻译：

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骨骼肌组织中组织钠浓度的加速定量：字典学习压缩感知的定量能力。

目的

使用²³ Na MRI和3D字典学习压缩感测（3D-DLCS）加快骨骼肌的组织钠浓度（TSC）定量。

材料和方法

小腿肌肉的模拟和体内²³ Na MRI检查以标称空间分辨率为\（\ Delta x = \ left（{3.0 \ times 3.0 \ times 15.0} \ right）{\ text {mm}} ^ {3 } \）。评估了充分采样和三个欠采样的²³ Na MRI数据集（欠采样因子（USF）= 3、4.4、6.7）。在3 Tesla MRI系统上检查了十名健康受试者。仿真研究和体内测量的结果分别与地面真实（GT）和完全采样的快速傅立叶变换（NUFFT）重建进行了比较。

结果

具有优化3D-DLCS的模拟数据的重建结果与GT相比，与NUFFT重建（> 5％）的结果相比，产生了更低的偏差（<4％）和更低的标准偏差（SD）。对于体内测量，观察到TSC为\（17 \ pm 2.7 {\ text {mMol / l}} \）。欠采样的3D-DLCS重建相对于参考的平均偏差（3.4％）比NUFFT重建较低（4.6％）。使用3D-DLCS可以减少SD。与完全采样的NUFFT重建相比，采集时间可以减少4.4倍，同时保持相似的定量精度。

讨论区

优化的3D-DLCS重建可实现高量化精度的加速TSC测量。