Department of Radiology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan.
Department of Radiological Technology, Yamaguchi University Hospital, Yamaguchi, Japan.
Eur Radiol. 2023 Oct;33(10):6844-6851. doi: 10.1007/s00330-023-10052-0. Epub 2023 Aug 8.
To determine the impact of fat on the apparent T1 value of the liver using water-only derived T1 mapping.
3-T MRI included 2D Look-Locker T1 mapping and proton density fat fraction (PDFF) mapping. T1 values of the liver were compared among T1 maps obtained by in-phase (IP), opposed-phase (OP), and Dixon water sequences using paired t-test. The correlation between T1 values of the liver on each T1 map and PDFF was assessed using Spearman correlation coefficient. The absolute differences between T1 value of the liver on Dixon water images and that on IP or OP images were also correlated with PDFF.
One hundred sixty-two patients (median age, 70 [range, 24-91] years, 90 men) were retrospectively evaluated. The T1 values of the liver on each T1 map were significantly different (p < 0.001). The T1 value of the liver on IP images was significantly negatively correlated with PDFF (r = - 0.438), while the T1 value of the liver on OP images was slightly positively correlated with PDFF (r = 0.164). The T1 value of the liver on Dixon water images was slightly negatively correlated with PDFF (r = - 0.171). The absolute differences between T1 value of the liver on Dixon water images and that on IP or OP images were significantly correlated with PDFF (r = 0.606, 0.722; p < 0.001).
Fat correction for the apparent T1 value by water-only derived T1 maps will be helpful for accurately evaluating the T1 value of the liver.
Fat-corrected T1 mapping of the liver with the water component only obtained from the 2D Dixon Look-Locker sequence could be useful for accurately evaluating the T1 value of the liver without the impact of fat in daily clinical practice.
• The T1 values of the liver on the conventional T1 maps are significantly affected by the presence of fat. • The apparent T1 value of the liver on water-only derived T1 maps would be slightly impacted by the presence of fat. • Fat correction for the apparent T1 values is necessary for the accurate assessment of the T1 values of the liver.
使用仅基于水的 T1 映射来确定脂肪对肝脏表观 T1 值的影响。
3-T MRI 包括 2D Look-Locker T1 映射和质子密度脂肪分数 (PDFF) 映射。使用配对 t 检验比较同相位 (IP)、反相位 (OP) 和 Dixon 水序列获得的 T1 图中肝脏的 T1 值。使用 Spearman 相关系数评估每个 T1 图中肝脏的 T1 值与 PDFF 之间的相关性。还将 Dixon 水图像上肝脏的 T1 值与 IP 或 OP 图像上的 T1 值之间的绝对差异与 PDFF 相关联。
回顾性评估了 162 名患者（中位年龄 70 [范围 24-91] 岁，90 名男性）。每个 T1 图中肝脏的 T1 值均有显著差异（p<0.001）。IP 图像上肝脏的 T1 值与 PDFF 呈显著负相关（r=−0.438），而 OP 图像上肝脏的 T1 值与 PDFF 呈轻度正相关（r=0.164）。Dixon 水图像上肝脏的 T1 值与 PDFF 呈轻度负相关（r=−0.171）。Dixon 水图像上肝脏的 T1 值与 IP 或 OP 图像上的 T1 值之间的绝对差异与 PDFF 显著相关（r=0.606、0.722；p<0.001）。
使用仅基于水的 T1 映射校正表观 T1 值将有助于准确评估肝脏的 T1 值。
使用二维 Dixon Look-Locker 序列获得的仅包含水的成分的肝脂肪校正 T1 映射可在日常临床实践中无脂肪影响的情况下，准确评估肝脏的 T1 值。
常规 T1 图中肝脏的 T1 值受脂肪存在的显著影响。
仅基于水的 T1 映射中肝脏的表观 T1 值会受到脂肪的轻微影响。
准确评估肝脏 T1 值需要对表观 T1 值进行脂肪校正。
