From the Department of Radiology, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave, Cincinnati, OH 45229.
Radiology. 2017 Mar;282(3):761-770. doi: 10.1148/radiol.2016160589. Epub 2016 Oct 10.
Purpose To compare two-dimensional (2D) gradient-recalled echo (GRE) and 2D spin-echo (SE) echo-planar imaging (EPI) magnetic resonance (MR) elastography for measurement of hepatic stiffness in pediatric and young adult patients suspected of having liver disease. Materials and Methods In this institutional review board-approved, HIPAA-compliant study, 58 patients underwent both 2D GRE and 2D SE-EPI MR elastography at 1.5 T during separate breath holds. Liver stiffness (mean of means; in kilopascals) was measured by five blinded reviewers. Pooled mean liver stiffness and region-of-interest (ROI) size were compared by using paired t tests. Intraclass correlation coefficients (ICCs) were used to assess agreement between techniques. Respiratory motion artifacts were compared across sequences by using the Fisher exact test. Results Mean patient age was 14.7 years ± 5.2 (standard deviation; age range, 0.7-20.5 years), and 55.2% (32 of 58) of patients were male. Mean liver stiffness was 2.92 kPa ± 1.29 measured at GRE MR elastography and 2.76 kPa ± 1.39 at SE-EPI MR elastography (n = 290; P = .15). Mean ROI sizes were 8495 mm ± 4482 for 2D GRE MR elastography and 15 176 mm ± 7609 for 2D SE-EPI MR elastography (n = 290; P < .001). Agreement was excellent for measured stiffness between five reviewers for both 2D GRE (ICC, 0.97; 95% confidence interval: 0.95, 0.98) and 2D SE-EPI (ICC, 0.98; 95% confidence interval: 0.96, 0.99). Mean ICC (n = 5) for agreement between 2D GRE and 2D SE-EPI MR elastography was 0.93 (range, 0.91-0.95). Moderate or severe breathing artifacts were observed on 27.5% (16 of 58) of 2D GRE images versus 0% 2D SE-EPI images (P < .001). Conclusion There is excellent agreement on measured hepatic stiffness between 2D GRE and 2D SE-EPI MR elastography across multiple reviewers. SE-EPI MR elastography allowed for stiffness measurement across larger areas of the liver and can be performed in a single breath hold. RSNA, 2016.
目的 比较二维（2D）梯度回波（GRE）和 2D 自旋回波（SE）回波平面成像（EPI）磁共振弹性成像（MR 弹性成像）在测量疑似患有肝病的儿科和年轻成年患者肝硬度中的作用。
材料与方法 在这项获得机构审查委员会批准并符合 HIPAA 规定的研究中，在 1.5 T 下，58 例患者分别在两次屏气时接受 2D GRE 和 2D SE-EPI MR 弹性成像检查。由 5 位盲法评估者测量肝脏硬度（平均值；千帕）。采用配对 t 检验比较两组的平均肝硬度和感兴趣区（ROI）大小。采用组内相关系数（ICC）评估两种技术之间的一致性。采用 Fisher 确切检验比较两组序列的呼吸运动伪影。
结果 患者平均年龄为 14.7 岁±5.2（标准差；年龄范围，0.7-20.5 岁），55.2%（32/58）为男性。2D GRE MR 弹性成像测量的平均肝脏硬度为 2.92 kPa±1.29，2D SE-EPI MR 弹性成像为 2.76 kPa±1.39（n=290；P=.15）。2D GRE MR 弹性成像的平均 ROI 大小为 8495 mm±4482，2D SE-EPI MR 弹性成像为 15176 mm±7609（n=290；P<.001）。2D GRE（ICC，0.97；95%置信区间：0.95，0.98）和 2D SE-EPI（ICC，0.98；95%置信区间：0.96，0.99）两种方法的 5 位评估者对测量硬度的一致性均为极好。2D GRE 和 2D SE-EPI MR 弹性成像的平均 ICC（n=5）为 0.93（范围，0.91-0.95）。2D GRE 图像上观察到 27.5%（58 例中的 16 例）中度或重度呼吸运动伪影，而 2D SE-EPI 图像上未见伪影（P<.001）。
结论 在多位评估者中，2D GRE 和 2D SE-EPI MR 弹性成像在测量肝硬度方面具有极好的一致性。SE-EPI MR 弹性成像可在肝脏较大区域进行弹性测量，且可在单次屏气时完成。
放射学学会，2016 年。
