Catania Roberta, Lopes Vendrami Camila, Bolster Bradley D, Niemzcura Richard, Borhani Amir A, Miller Frank H
Department of Radiology, Northwestern University Feinberg School of Medicine, 676 N. Saint Clair Street, Suite 800, Chicago, IL, 60611, USA.
Siemens Medical Solutions USA, Inc, Salt Lake City, UT, USA.
Abdom Radiol (NY). 2022 Mar;47(3):998-1008. doi: 10.1007/s00261-021-03355-7. Epub 2022 Jan 4.
To evaluate performance of 3D magnetic resonance elastography (MRE) using spin-echo echo-planar imaging (seEPI) for assessment of hepatic stiffness compared with 2D gradient-recalled echo (GRE) and 2D seEPI sequences.
Fifty-seven liver MRE examinations including 2D GRE, 2D seEPI, and 3D seEPI sequences were retrospectively evaluated. Elastograms were analyzed by 2 radiologists and polygonal regions of interests (ROIs) were drawn in 2 different fashions: "curated" ROI (avoiding liver edge, major vessels, and areas of wave interferences) and "non-curated" ROI (including largest cross section of liver, to assess the contribution of artifacts). Liver stiffness measurement (LSM) was calculated as the arithmetic mean of individual stiffness values for each technique. For 3D MRE, LSMs were also calculated based on 4 slices ("abbreviated LSM"). Intra-patient variations in LSMs and different methods of ROI placement were assessed by univariate tests. A p-value of < 0.05 was set as a statistically significant difference.
Mean surface areas of the ROIs were 50,723 mm, 12,669 mm, 5814 mm, and 10,642 mm for 3D MRE, abbreviated 3D MRE, 2D GRE, and 2D seEPI, respectively. 3D LSMs based on curated and non-curated ROIs showed no clinically significant difference, with a mean difference less than 0.1 kPa. Abbreviated 3D LSMs had excellent correlation with 3D LSMs based on all slices (r = 0.9; p < 0.001) and were not significantly different (p = 0.927).
3D MRE allows more reproducible measurements due to its lower susceptibility to artifacts and provides larger areas of parenchyma, enabling a more comprehensive evaluation of the liver.
与二维梯度回波（GRE）和二维自旋回波回波平面成像（seEPI）序列相比，评估使用自旋回波回波平面成像（seEPI）的三维磁共振弹性成像（MRE）在评估肝脏硬度方面的性能。
回顾性评估了57例肝脏MRE检查，包括二维GRE、二维seEPI和三维seEPI序列。弹性图由2名放射科医生分析，并以2种不同方式绘制多边形感兴趣区域（ROI）：“精心挑选的”ROI（避开肝脏边缘、主要血管和波干扰区域）和“未精心挑选的”ROI（包括肝脏最大横截面，以评估伪影的影响）。肝脏硬度测量（LSM）计算为每种技术的各个硬度值的算术平均值。对于三维MRE，LSM也基于4个切片进行计算（“简化LSM”）。通过单变量测试评估患者内LSM的变化以及ROI放置的不同方法。将p值<0.05设定为具有统计学显著差异。
三维MRE、简化三维MRE、二维GRE和二维seEPI的ROI平均表面积分别为50723平方毫米、12669平方毫米、5814平方毫米和10642平方毫米。基于精心挑选和未精心挑选ROI的三维LSM在临床上无显著差异，平均差异小于0.1kPa。简化三维LSM与基于所有切片的三维LSM具有极好的相关性（r = 0.9；p < 0.001），且无显著差异（p = 0.927）。
三维MRE因其对伪影的敏感性较低，能够进行更可重复的测量，并提供更大的实质区域，从而能够对肝脏进行更全面的评估。
