Quantification of pancreatic fat with dual-echo imaging at 3.0-T MR in clinical application: how do the corrections for T1 and T2* relaxation effect work and simplified correction strategy

Background Dual-echo imaging is a routine clinical magnetic resonance (MR) sequence affected by T1 and T2* relaxation effect in fat quantification. The separate impacts of T1 and T2* relaxation effect in pancreatic fat quantification using dual-echo imaging at 3.0-T MR have not been reported in detail. Purpose To demonstrate the separate T1 and T2* relaxation effect on pancreatic fat quantification by dual-echo imaging at 3.0-T MR and the simplified correction strategy is discussed for convenient clinical application. Material and Methods Twenty-one non-alcoholic fatty liver disease (NAFLD) participants with high risk of pancreatic steatosis were included. Pancreatic fat fractions (FF) by dual-echo imaging with different corrections were compared to that of proton magnetic resonance spectroscopy (¹H-MRS). Correlation analysis and Bland-Altman analysis were applied. Results The FF by ¹H-MRS was 5.9 ± 1.7%. Significant positive correlation (all P < 0.01) was found between FF by ¹H-MRS and each dual-echo imaging, in which T1 and T2* correction showed the best correlation (r = 0.95, FF = 6.2 ± 1.7%) and no correction showed the worst correlation (r = 0.86, FF = 5.2 ± 2.0%), and the simplified T1 and T2* correction manifested as r = 0.93 and FF = 6.3 ± 1.8%. FF by T1 and T2* correction showed the best agreement, while T1 correction showed the worst agreement as compared to that of ¹H-MRS. Conclusion T1 and T2* correction shows the best performance while no correction dual-echo imaging remains clinical available which may benefit from prior OP echo. Simplified correction using single T2* (32.6 ms) of water and fat is recommended for convenient clinical application in absence of obvious pancreatic iron overload.