BackgroundLiver iron overload is the most common cause of magnetic resonance elastography (MRE) failure.PurposeTo determine a threshold of R2*, a surrogate of liver iron concentration (LIC), which predicts the failure of liver MRE for either 2D gradient-recalled echo (GRE) or spin-echo echo-planar imaging (SE-EPI) MRE sequence at 3 T.Material and MethodsThis single-center retrospective study included 247 patients who underwent GRE MRE, SE-EPI MRE sequences for fibrosis evaluation and 2D multi-echo GRE sequence for R2* quantification using MRQuantif software. The ability of R2* to predict the failed MRE related to liver iron accumulation was estimated by the area under the receiver operating characteristic curve (AUC).ResultsAfter excluding 26 exams for technical failure, we evaluated 221 patients (52 women; mean age = 56 ± 13) with R2* values in the range of 37-1665 s^-1. The iron-related failure rates of GRE MRE and SE-EPI MRE were 62.9% (139/221) and 10.0% (22/221), respectively. The best cutoff of R2* to predict failure exam due to liver iron deposition with GRE MRE was 101 s^-1 with a sensitivity of 79.1% and specificity of 97.6% (AUC = 0.97; 95% confidence interval [CI] = 0.95-0.99). This cutoff for SE-EPI MRE was 289 s^-1 with a sensitivity of 82.8% and specificity of 99.5% (AUC = 0.89; 95% CI = 0.78-1).ConclusionLiver R2* is a good predictor of MRE examination failure related to iron deposition for MRE at 3 T.

Keywords: Liver; iron; magnetic resonance elastography.

背景：肝脏铁负荷过量是磁共振弹性成像（MRE）失败最常见的原因。
Purpose：确定R2*的阈值，R2*是肝脏铁浓度（LIC）的一个替代指标，该阈值可以预测在3T下使用二维梯度回波（GRE）或自旋回波-平面回波成像（SE-EPI）MRE序列时肝MRE失败的可能性。
Material and Methods：这项单中心回顾性研究包括了247名患者，他们接受了GRE MRE、SE-EPI MRE序列用于评估纤维化，并使用MRQuantif软件进行了二维多回波GRE序列进行R2*量化。通过受试者操作特性曲线下的面积（AUC）来估计R2*预测由于肝脏铁沉积导致的MRE失败的能力。
Results：排除了26项技术性失败的检查后，我们评估了221名患者（其中52名为女性；平均年龄= 56±13岁），其R2*值范围为37-1665 s^-1。与肝脏铁沉积相关的GRE MRE和SE-EPI MRE失败率分别为62.9%（139/221）和10.0%（22/221）。对于使用GRE MRE预测由于肝铁沉积导致的检查失败，R2*的最佳阈值为101 s^-1，其灵敏度为79.1%，特异性为97.6%（AUC = 0.97；95%置信区间[CI] = 0.95-0.99）。对于SE-EPI MRE，该阈值为289 s^-1，其灵敏度为82.8%，特异性为99.5%（AUC = 0.89；95% CI = 0.78-1）。
Conclusion：肝脏R2*是预测3T下由于铁沉积导致的MRE检查失败的良好指标。

关键词：肝脏；铁；磁共振弹性成像。