Assessing liver fibrosis distribution through liver elasticity estimates obtained using a biomechanical model of respiratory motion with magnetic resonance elastography
Assessing liver fibrosis distribution through liver elasticity estimates obtained using a biomechanical model of respiratory motion with magnetic resonance elastography
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DOI：
10.1088/1361-6560/ac7d35
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发表时间：
2022-06
影响因子：
3.5
通讯作者：
K. Fujimoto;T. Shiinoki;Y. Yuasa;Y. Kawazoe;M. Yamane;T. Sera;Hidekazu Tanaka
中科院分区：
文献类型：
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作者：
K. Fujimoto;T. Shiinoki;Y. Yuasa;Y. Kawazoe;M. Yamane;T. Sera;Hidekazu Tanaka
目标。本研究的目的是利用有限元方法和T1加权磁共振图像捕获的呼吸诱发运动生成三维肝脏弹性图，并评价其是否可以作为一种可与磁共振弹性成像(MRE)相媲美的成像生物标志物来评估肝纤维化的分布和严重程度。接近。我们招募了14名患者，他们接受了MRI和MRE。在浅吸气和屏气时采集T1加权MR图像，利用可变形图像配准计算两幅图像之间的位移矢量场。利用有限元方法和DVF方法建立有限元-E图。首先，验证和优化了三种泊松比设置(0.45、0.49和0.499995)，以最小化有限元-E-MAP和MRE之间的肝脏弹性差异。然后，将使用有限元-E-MAP估计的整体和区域肝脏弹性值与使用皮尔逊相关系数的MRE获得的值进行比较。使用Spearman等级相关和卡方直方图比较体素水平弹性分布。主要结果。最佳泊松比为0.49。用FE-E-MAP估计的全肝弹性与用MRE测得的全肝弹性有很强的相关性(r=0.96)。在区域肝脏弹性方面，右叶的相关性为0.84，左叶的相关性为0.82。Spearman分析显示，有限元-E-MAP与MRE之间的体素水平弹性分布具有中等相关性(0.61±0.10)。两个直方图之间的小卡方距离(0.11±0.07)显示出良好的一致性。意义重大。FEM-E-MAP代表了一种潜在的成像生物标记物，可以仅使用普通MR扫描仪获得的T1加权图像来可视化肝纤维化的分布，而不需要任何额外的检查或特殊的弹性成像设备。然而，需要进行更多的研究，包括与活检结果的比较，以验证该方法临床应用的可靠性。
Objective. This study aimed to produce a three-dimensional liver elasticity map using the finite element method (FEM) and respiration-induced motion captured by T1-weighted magnetic resonance images (FEM-E-map) and to evaluate whether FEM-E-maps can be an imaging biomarker comparable to magnetic resonance elastography (MRE) for assessing the distribution and severity of liver fibrosis. Approach. We enrolled 14 patients who underwent MRI and MRE. T1-weighted MR images were acquired during shallow inspiration and expiration breath-holding, and the displacement vector field (DVF) between two images was calculated using deformable image registration. FEM-E-maps were constructed using FEM and DVF. First, three Poisson’s ratio settings (0.45, 0.49, and 0.499995) were validated and optimized to minimize the difference in liver elasticity between the FEM-E-map and MRE. Then, the whole and regional liver elasticity values estimated using FEM-E-maps were compared with those obtained from MRE using Pearson’s correlation coefficients. Spearman rank correlations and chi-square histograms were used to compare the voxel-level elasticity distribution. Main results. The optimal Poisson’s ratio was 0.49. Whole liver elasticity estimated using FEM-E-maps was strongly correlated with that measured using MRE (r = 0.96). For regional liver elasticity, the correlation was 0.84 for the right lobe and 0.82 for the left lobe. Spearman analysis revealed a moderate correlation for the voxel-level elasticity distribution between FEM-E-maps and MRE (0.61 ± 0.10). The small chi-square distances between the two histograms (0.11 ± 0.07) indicated good agreement. Significance. FEM-E-maps represent a potential imaging biomarker for visualizing the distribution of liver fibrosis using only T1-weighted images obtained with a common MR scanner, without any additional examination or special elastography equipment. However, additional studies including comparisons with biopsy findings are required to verify the reliability of this method for clinical application.