T1 mapping for liver function evaluation in gadoxetic acid-enhanced MR imaging: comparison of look-locker inversion recovery and B1 inhomogeneity-corrected variable flip angle method

ObjectivesTo compare look-locker inversion recovery (LLIR) and B-1 inhomogeneity-corrected variable flip angle T1 mapping methods for estimation of liver function and prediction of hepatic insufficiency and decompensation on gadoxetic acid-enhanced MR imaging.MethodsIn this retrospective study, 248 patients with normal liver function, chronic liver disease, or cirrhosis underwent gadoxetic acid-enhanced liver MR imaging, including T1 mapping at 10-min and 20-min hepatobiliary phase (HBP) by using both methods. T1 relaxation times of the liver (T1(Liver-pre), T1(Liver-post)) and the spleen (T1(Spleen)) were correlated between two methods. T1(Liver) ([T1(Liver-pre) - T1(Liver-post)]/T1(Liver-pre)), adjusted T1(Liver) ([T1(Spleen) - T1(Liver-post)]/T1(Spleen)), and functional liver volume-to-weight ratio (liver volume on volumetric T1 map/[T1(Liver-post) x patient's weight]) were calculated. The diagnostic performance of T1 parameters and the predictive performance of models (serum marker, serum marker plus T1 parameter) were compared.ResultsT1(Liver-post) showed a strong correlation (r=0.93, p<0.001) between two methods but was significantly different. For depicting cirrhosis, LLIR-adjusted T1(Liver) at 10-min HBP showed the highest performance (p<0.025). For predicting hepatic insufficiency and decompensation, LLIR-adjusted T1(Liver) (Akaike information criterion (AIC), 58.37; C-index, 0.867) and LLIR-T1(Liver-post) (AIC, 48.82; C-index, 0.885) at 10-min HBP showed the best performance, respectively, when added to serum albumin level.ConclusionsT1(Liver-post) showed a strong correlation between two methods but with significant differences. T1 mapping using LLIR at 10-min HBP with obtainment of adjusted T1(Liver) and T1(Liver-post) may be the best approach for estimation of liver function and prediction of hepatic insufficiency and decompensation.Key Points center dot T1(Liver-post)showed a strong correlation between LLIR and B(1)inhomogeneity-corrected VFA methods, both at 10-min and 20-min HBP but with significant differences.center dot T1(Liver-post)at 10-min and 20-min HBP using LLIR and B(1)inhomogeneity-corrected VFA methods could not be used interchangeably during the follow-up in patients with chronic liver disease (CLD) or cirrhosis.center dot T1 mapping using LLIR at 10-min HBP with obtainment of adjusted T1(Liver)and T1(Liver-post)may be the most suitable method and parameter for estimation of global liver function and prediction of clinical outcomes in patients with CLD or cirrhosis.