Ahn Jhii-Hyun, Yu Jeong-Sik, Park Kyu-Sang, Kang Seong Hee, Huh Ji Hye, Chang Jae Seung, Lee Jong-Han, Kim Moon Young, Nickel Marcel Dominik, Kannengiesser Stephan, Kim Jang-Young, Koh Sang-Baek
Department of Radiology, Wonju Severance Christian Hospital, Yonsei University College of Medicine, Republic of Korea.
Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
Magn Reson Imaging. 2021 Jul;80:1-8. doi: 10.1016/j.mri.2021.03.015. Epub 2021 Mar 30.
This study investigated whether T1 values in native T1 mapping of 3T magnetic resonance imaging (MRI) of the liver were affected by the fatty component.
This prospective study involved 340 participants from a population-based cohort study between May 8, 2018 and August 8, 2019. Data obtained included: (1) hepatic stiffness according to magnetic resonance elastography (MRE); (2) T1 value according to T1 mapping; (3) fat fraction and iron concentration from multi-echo Dixon; and (4) clinical indices of hepatic steatosis including body mass index, waist circumference, history of diabetes, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, and triglycerides. The correlations between T1 value and fat fraction, and between T1 value and liver stiffness were assessed using Pearson's correlation coefficient. The independent two-sample t-test was used to evaluate the differences in T1 values according to the presence or absence of hepatic steatosis, and the one-way analysis of variance was used to evaluate the difference in T1 value by grading of hepatic steatosis according to MRI-based proton density fat fraction (PDFF). In addition, univariate and multivariate linear regression analyses were performed to determine whether other variables influenced the T1 value.
T1 value showed a positive correlation with the fat fraction obtained from PDFF (r = 0.615, P < 0.001) and with the liver stiffness obtained from MRE (r = 0.370, P < 0.001). Regardless of the evaluation method, the T1 value was significantly increased in subjects with hepatic steatosis (P < 0.001). When comparing hepatic steatosis grades based on MRI-PDFF, the mean T1 values were significantly different in all grades, and the T1 value tended to increase as the grade increased (P < 0.001, P for trend <0.001). On multiple linear regression analysis, the T1 value was influenced by MRI-PDFF, calculated liver iron concentration, liver stiffness, and serum aspartate aminotransferase level.
The T1 value obtained by current T1 mapping of 3T MRI was affected by the liver fat component and several other factors such as liver stiffness, iron concentration, and inflammation.
本研究调查了3T磁共振成像（MRI）肝脏T1图谱中的T1值是否受脂肪成分影响。
这项前瞻性研究纳入了2018年5月8日至2019年8月8日期间一项基于人群的队列研究中的340名参与者。获取的数据包括：（1）根据磁共振弹性成像（MRE）得出的肝脏硬度；（2）根据T1图谱得出的T1值；（3）多回波狄克逊法得出的脂肪分数和铁浓度；（4）肝脏脂肪变性的临床指标，包括体重指数、腰围、糖尿病史、天冬氨酸转氨酶、丙氨酸转氨酶、γ-谷氨酰转肽酶和甘油三酯。使用Pearson相关系数评估T1值与脂肪分数之间以及T1值与肝脏硬度之间的相关性。采用独立两样本t检验评估有无肝脏脂肪变性时T1值的差异，采用单因素方差分析根据基于MRI的质子密度脂肪分数（PDFF）对肝脏脂肪变性进行分级来评估T1值的差异。此外，进行单变量和多变量线性回归分析以确定其他变量是否影响T1值。
T1值与从PDFF获得的脂肪分数呈正相关（r = 0.615，P < 0.001），与从MRE获得的肝脏硬度呈正相关（r = 0.370，P < 0.001）。无论评估方法如何，肝脏脂肪变性患者的T1值均显著升高（P < 0.001）。基于MRI-PDFF比较肝脏脂肪变性分级时，所有分级的平均T1值均有显著差异，且T1值随分级增加而升高（P < 0.001，趋势P < 0.001）。多线性回归分析显示，T1值受MRI-PDFF、计算得出的肝脏铁浓度、肝脏硬度和血清天冬氨酸转氨酶水平影响。
当前3T MRI的T1图谱所获得的T1值受肝脏脂肪成分以及肝脏硬度、铁浓度和炎症等其他几个因素影响。
