Department of Radiology, Wisconsin Institutes of Medical Research, University of Wisconsin, Room 2478, 1111 Highland Avenue, Madison, WI, 53705, USA.
Department of Radiology and Neuroradiology, University Greifswald, Greifswald, Germany.
Abdom Radiol (NY). 2021 Sep;46(9):4200-4209. doi: 10.1007/s00261-021-03099-4. Epub 2021 May 12.
To evaluate the reproducibility of liver R2* measurements between a 2D cardiac ECG-gated and a 3D breath-hold liver CSE-MRI acquisition for liver iron quantification.
A total of 54 1.5 T MRI exams from 51 subjects (18 women, 36 men, age 35.2 ± 21.8) were included. These included two sub-studies with 23 clinical MRI exams from 19 patients identified retrospectively, 24 participants with known or suspected iron overload, and 7 healthy volunteers acquired prospectively. The 2D cardiac and the 3D liver R2* maps were acquired in the same exam. Either acquisitions were reconstructed using a complex R2* algorithm that accounts for the presence of fat and residual phase errors due to eddy currents. Data were analyzed using colocalized ROIs in the liver.
Linear regression analysis demonstrated high Pearson's correlation and Lin's concordance coefficient for the overall study and both sub-studies. Bland-Altman analysis also showed good agreement, except for a slight increase of the mean R2* value above ~ 400 s. The Kolmogorow-Smirnow test revealed a non-normal distribution for (R2* 3D-R2* 2D) values from 0 to 600 s in contrast to the 0-200 s and 0-400 s subpopulations. Linear regression analysis showed no relevant differences other than the intercept, likely due to only 7 measurements above 400 s.
The results demonstrate that R2*-measurements in the liver are feasible using 2D cardiac R2* maps compared to 3D liver R2* maps as the reference. Liver R2* may be underestimated for R2* > 400 s using the 2D cardiac R2* mapping method.
评估二维心脏 ECG 门控和三维屏气肝脏 CSE-MRI 采集用于肝脏铁定量的肝脏 R2*测量的重现性。
共纳入 51 例受试者（18 例女性，36 例男性，年龄 35.2±21.8 岁）的 54 例 1.5T MRI 检查。这些检查包括两项子研究，共 23 例临床 MRI 检查来自 19 例回顾性识别的患者，24 例已知或疑似铁过载参与者，以及 7 例健康志愿者前瞻性采集。在同一次检查中获得了二维心脏和三维肝脏 R2图谱。使用复杂的 R2算法重建两种采集，该算法考虑了脂肪的存在和由于涡流引起的残余相位误差。使用肝脏中的共定位 ROI 进行数据分析。
线性回归分析表明，总体研究和两项子研究均显示出高 Pearson 相关系数和 Lin 一致性系数。Bland-Altman 分析也显示出良好的一致性，除了在~400s 以上的平均 R2值略有增加。Kolmogorow-Smirnow 检验显示，在 0 到 600s 的（R23D-R2*2D）值与 0 到 200s 和 0 到 400s 亚群的分布呈非正态分布。线性回归分析除了截距外，没有发现其他相关差异，可能是由于只有 7 次测量值大于 400s。
结果表明，与使用 3D 肝脏 R2图谱作为参考相比，二维心脏 R2图谱可用于肝脏 R2测量。对于 R2>400s，使用二维心脏 R2映射方法可能会低估肝脏 R2。
