Comparison of T1 Mapping on Gadoxetic Acid-Enhanced Magnetic Resonance Imaging With Conventional Functional Liver Reserve Indices and Technetium-99m Galactosyl Serum Albumin Scintigraphy

Background Gadoxetic acid (EOB)-enhanced magnetic resonance imaging (MRI) (EOB-MRI) can be used as a one-stop examination for detecting liver tumors and evaluating liver function. Purpose The study aimed to assess the functional liver reserve (FLR) using the T1 map from the hepatobiliary phase of EOB-MRI by conducting a comparison with the results of conventional FLR tests and the technetium-99m (99mTc)-galactosyl serum albumin (GSA) scintigraphy. Materials and methods The retrospective data from 43 patients were included in the study. The regions of interest covered the entire liver. The data acquired from each EOB-MRI slice were summed to derive voxel-by-voxel values. The average sum of the T1 values (pre- and post-enhancement), ∆T1, and ∆T1 ratios were calculated. The HH15, LHL15, and LU15 values were calculated from the GSA scintigraphy. The results of conventional FLR tests, such as the indocyanine green retention rate at 15 min (ICGR15), the Child-Pugh classification (CPC), and the albumin-bilirubin (ALBI) and albumin-indocyanine green evaluation (ALICE) scores, were obtained. Results The T1 pre- and post-sum values showed a weak correlation with the LHL15 (r=0.36 and 0.38, respectively). A strong correlation was observed between the liver volume and the T1 pre- and post-sum values (r=0.86 and 0.76, respectively). A moderate correlation was observed between the T1 mean and the ALBI and ALICE values (r=0.58 and 0.49, respectively) and between the ∆T1 ratio and the CPC, ALBI, and ALICE values (r=-0.40, 0.58, and -0.55, respectively). The T1 post-sum values showed a moderate correlation with the ALBI scores (r=0.47) and a weak correlation with the ALICE scores (r=0.38). Furthermore, the LU15 values showed a weak correlation with the ICGR15 and model for end-stage liver disease (MELD) scores (r=-0.32 and -0.34, respectively). Conclusions Representative indices, such as the T1 mean and ∆T1 ratio, demonstrated a better relationship with conventional FLR indices compared with volumetric radiological indices. Therefore, we propose that the T1 post-sum can be used as an FLR index.