Department of Radiology, University of Washington, 1705 NE Pacific St., Box 357233, Seattle, WA, 98195, USA.
Department of Statistics, University of Washington, Seattle, WA, USA.
Abdom Radiol (NY). 2023 Jul;48(7):2302-2310. doi: 10.1007/s00261-023-03902-4. Epub 2023 Apr 13.
To investigate the intra-examination agreement between multi-echo gradient echo (MEGE) and confounder-corrected chemical shift-encoded (CSE) sequences for liver T2*/R2* estimations in a wide range of T2*/R2* and proton density fat fraction (PDFF) values. Exploratorily, to search for the T2*/R2* value where the agreement line breaks and examine differences between regions of low and high agreement.
Consecutive patients at risk for liver iron overload who underwent MEGE and CSE sequences within the same exam at 1.5 T were retrospectively selected. Regions of interest were drawn in the right and one in the left liver lobes on post-processed images for R2*(sec) and PDFF (%) estimation. Agreement between MEGE-R2* and CSE-R2* was evaluated using intra-class correlation coefficient (ICC) and Bland-Altman analysis. 95% confidence intervals (CI) were computed. Segment-and-regression analysis was performed to find the point where the agreement between sequences is interrupted. Regions of low and high agreement were examined using tree-based partitioning analyses.
49 patients were included. Mean MEGE-R2* was 94.2 s (range: 31.0-737.1) and mean CSE-R2* 87.7 (29.7-748.1). Mean CSE-PDFF was 9.12% (0.1-43.3). Agreement was strong for R2* estimations (ICC: 0.992,95%CI 0.987,0.996), but the relation was nonlinear and possibly heteroskedastic. Lower agreement occurred when MEGE-R2* > 235 s, with MEGE-R2* values consistently lower than CSE-R2*. Higher agreement was observed when PDFF < 14%.
MEGE-R2* and CSE-R2* strongly agree, though at higher iron content, MEGE-R2* is consistently lower than CSE-R2*. In this preliminary dataset, a breaking point for agreement was found at R2* > 235. Lower agreement was observed in patients with moderate to severe liver steatosis.
探究多回波梯度回波（MEGE）与混杂校正化学位移编码（CSE）序列在广泛的 T2* / R2和质子密度脂肪分数（PDFF）值范围内进行肝脏 T2 / R2估计的检查内一致性。探索性地寻找一致性线中断的 T2 / R2*值，并检查低和高一致性区域之间的差异。
回顾性选择在 1.5T 同一检查中同时接受 MEGE 和 CSE 序列的连续患有肝脏铁过载风险的患者。在处理后的图像上，在右肝和左肝的一个区域上绘制感兴趣区，以进行 R2*（sec）和 PDFF（％）估计。使用组内相关系数（ICC）和 Bland-Altman 分析评估 MEGE-R2和 CSE-R2之间的一致性。计算了 95％置信区间（CI）。进行分段回归分析以找到序列之间一致性中断的点。使用基于树的分区分析检查低和高一致性区域。
共纳入 49 例患者。MEGE-R2的平均值为 94.2s（范围：31.0-737.1），CSE-R2的平均值为 87.7（29.7-748.1）。CSE-PDFF 的平均值为 9.12％（0.1-43.3）。 R2估计的一致性很强（ICC：0.992，95％CI 0.987，0.996），但关系是非线性的，可能存在异方差。当 MEGE-R2＞235s 时，一致性较低，MEGE-R2值始终低于 CSE-R2。当 PDFF＜14％时，一致性更高。
MEGE-R2和 CSE-R2高度一致，尽管在更高的铁含量下，MEGE-R2始终低于 CSE-R2。在这个初步数据集，一致性的转折点出现在 R2*＞235。在中重度肝脂肪变性的患者中观察到较低的一致性。
