Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
Christian Doppler Laboratory for Clinical Molecular Imaging, MOLIMA, MUW, Vienna, Austria.
Eur Radiol. 2022 May;32(5):3388-3397. doi: 10.1007/s00330-021-08439-y. Epub 2021 Dec 23.
T2 mapping of the liver is a potential diagnostic tool, but conventional techniques are difficult to perform in clinical practice due to long scan time. We aimed to evaluate the accuracy of a prototype radial turbo-spin-echo (rTSE) sequence, optimized for multi-slice T2 mapping in the abdomen during one breath-hold at 3 T.
A multi-sample (fat: 0-35%) agarose phantom doped with MnCl and 80 subjects (73 patients undergoing abdomen MR examination and 7 healthy volunteers) were investigated. A radial turbo-spin-echo (rTSE) sequence with and without fat suppression, a Cartesian turbo-spin-echo (Cart-TSE) sequence, and a single-voxel multi-echo STEAM spectroscopy (HISTO) were performed in phantom, and fat-suppressed rTSE and HISTO sequences were performed in in vivo measurements. Two approaches were used to sample T2 values: manually selected circular ROIs and whole liver analysis with Gaussian mixture models (GMM).
The rTSE-T2s values exhibited a strong correlation with Cart-TSE-T2s (R = 0.988) and with HISTO-T2s of water (R = 0.972) in phantom with an offset between rTSE and Cart-TSE maps (mean difference = 3.17 ± 1.18 ms). The application of fat suppression decreased T2 values, and the effect was directly proportional to the amount of fat. Measurements in patients yielded a linear relationship between rTSE- and HISTO-T2s (R = 0.546 and R = 0.580 for ROI and GMM, respectively).
The fat-suppressed rTSE sequence allows for fast and accurate determination of T2 values of the liver, and appears to be suitable for further large cohort studies.
•Radial turbo-spin-echo T2 mapping performs comparably to Cartesian TSE-T2 mapping, but an offset in values is observed in phantom measurements. •Fat-suppressed radial turbo-spin-echo T2 mapping is consistent with T2 of water as assessed by MRS in phantom measurements. •Fat-suppressed radial turbo-spin-echo sequence allows fast T2 mapping of the liver in a single breath-hold and is correlated with MRS-based T2 of water.
肝脏 T2 映射是一种有潜力的诊断工具，但由于扫描时间长，传统技术在临床实践中难以实施。我们旨在评估一种原型径向涡轮回波（rTSE）序列的准确性，该序列针对 3T 下腹部多切片 T2 映射进行了优化。
在多样本（脂肪：0-35%）琼脂糖体模中加入 MnCl，并对 80 名受试者（73 名接受腹部磁共振检查的患者和 7 名健康志愿者）进行了研究。在体模中进行了径向涡轮回波（rTSE）序列和带和不带脂肪抑制的笛卡尔涡轮回波（Cart-TSE）序列、单容积多回波 STEAM 光谱（HISTO），在体内测量中进行了带脂肪抑制的 rTSE 和 HISTO 序列。使用两种方法来采样 T2 值：手动选择圆形 ROI 和使用高斯混合模型（GMM）进行整个肝脏分析。
rTSE-T2 值与 Cart-TSE-T2 值（R = 0.988）以及体模中 HISTO 水的 T2 值（R = 0.972）具有很强的相关性，并且 rTSE 和 Cart-TSE 图谱之间存在偏移（平均差值 = 3.17 ± 1.18 ms）。应用脂肪抑制会降低 T2 值，并且该效果与脂肪量成正比。在患者中的测量结果表明，rTSE 和 HISTO-T2 值之间存在线性关系（ROI 和 GMM 的 R 值分别为 0.546 和 0.580）。
带脂肪抑制的 rTSE 序列允许快速准确地确定肝脏的 T2 值，并且似乎适合进一步的大型队列研究。
径向涡轮回波 T2 映射与笛卡尔 TSE-T2 映射具有可比性，但在体模测量中观察到值存在偏移。
体模测量中，带脂肪抑制的径向涡轮回波 T2 映射与 MRS 评估的水 T2 一致。
带脂肪抑制的径向涡轮回波序列允许在单次呼吸保持中快速进行肝脏 T2 映射，并与基于 MRS 的水 T2 相关。
