In silicoevaluation and optimisation of magnetic resonance elastography of the liver.
In silicoevaluation and optimisation of magnetic resonance elastography of the liver.
复制标题
肝脏磁共振弹性成像的计算机评估和优化。
DOI：
10.1088/1361-6560/ac3263
复制
发表时间：
2021
影响因子：
3.5
通讯作者：
McGrath DM
中科院分区：
文献类型：
--
作者：
McGrath DM
磁共振弹性成像（MRE）被广泛采用作为肝纤维化的生物标志物。然而，在体内MRE的准确性是很难评估的。方法有限元模型（FEM）模拟被用来评估肝脏MRE的准确性和通知方法优化。在包括肝脏的人体躯干的3D FEM中模拟MRE数据，并与自旋回波回波平面成像MRE采集进行比较。将模拟的MRE结果与复剪切模量的真实值幅度（RIG * RIG）进行比较，以改变：（1）真实肝脏RIG * RIG;（2）模拟成像分辨率;（3）添加噪声;（4）数据平滑。运动和应变为基础的信号噪声（SNR）的度量进行了评估的模拟数据作为一种手段，以选择更高质量的体素准备收购MRE的摘要统计的MRE的MRE * 的主要resultsThe模拟MRE的准确性为一个给定的地面真相MRE * 被发现是成像分辨率，运动SNR和平滑的函数。在典型的成像分辨率下，发现由于MRE波场的欠采样，与运动相关的噪声相结合，重建的模拟的HRG * HRG可能包含在肝纤维化阶段之间的差异的尺度上的误差，例如，对于地面实况HRG * HRG = 1 kPa，54%的误差。最佳的成像分辨率被确定为给定的地面真值MRE * 和运动SNR levels.SignificanceThis研究提供了重要的知识，肝脏磁共振成像的准确性和优化。例如，对于运动SNR ≤ 5，为了区分2和3 kPa的肝EGG * s（即早期肝纤维化），预测最佳各向同性体素尺寸为4-6 mm。
ObjectiveMagnetic resonance elastography (MRE) is widely adopted as a biomarker of liver fibrosis. However, in vivo MRE accuracy is difficult to assess.ApproachFinite element model (FEM) simulation was employed to evaluate liver MRE accuracy and inform methodological optimisation. MRE data was simulated in a 3D FEM of the human torso including the liver, and compared with spin-echo echo-planar imaging MRE acquisitions. The simulated MRE results were compared with the ground truth magnitude of the complex shear modulus (∣ G*∣) for varying:(1) ground truth liver∣ G*∣;(2) simulated imaging resolution;(3) added noise;(4) data smoothing. Motion and strain-based signal-to-noise (SNR) metrics were evaluated on the simulated data as a means to select higher-quality voxels for preparation of acquired MRE summary statistics of∣ G*∣.Main resultsThe simulated MRE accuracy for a given ground truth∣ G*∣ was found to be a function of imaging resolution, motion-SNR and smoothing. At typical imaging resolutions, it was found that due to under-sampling of the MRE wave-field, combined with motion-related noise, the reconstructed simulated∣ G*∣ could contain errors on the scale of the difference between liver fibrosis stages, eg 54% error for ground truth∣ G*∣= 1 kPa. Optimum imaging resolutions were identified for given ground truth∣ G*∣ and motion-SNR levels.SignificanceThis study provides important knowledge on the accuracy and optimisation of liver MRE. For example, for motion-SNR≤ 5, to distinguish between liver∣ G*∣ of 2 and 3 kPa (ie early-stage liver fibrosis) it was predicted that the optimum isotropic voxel size is 4–6 mm.