Liver fibrosis staging using T1 mapping on gadoxetic acid-enhanced MRI compared with DW imaging

Abstract

To evaluate the utility of T1 mapping on gadoxetic acid-enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) for staging liver fibrosis. This retrospective study was approved by the institutional review board and included 145 patients (mean age: 54 years old; 115 men and 30 women). Necro-inflammatory activity grade (G) and liver fibrosis stage (S) were histopathologically determined. T1 relaxation time and apparent diffusion coefficient (ADC) of the liver were measured and the reduction rate of the T1 relaxation time (Δ%) was calculated. T1 relaxation time measurements were compared with ADC values according to S/G scores. Unenhanced hepatobiliary phase (HBP) and Δ% of T1 relaxation times showed significant correlations with S/G scores (rho: 0.28, 0.51, -0.35 for the S score, 0.26, 0.39, -0.26 for the G score, respectively, p<0.05). ADC values showed significant correlation with the S score (rho: -0.17, p = 0.04) and did not correlate significantly with the G score (rho: -0.07, p = 0.39). The areas under receiver operator characteristics (AUC) curve of unenhanced HBP, Δ% T1 relaxation time, and the ADC value were 0.68, 0.82, 0.71, 0.61 for the identification of S ≥ 3, and 0.63, 0.68, 0.62, 0.52 for the identification of G ≥ 3, respectively. The HBP T1 relaxation time was better than that of ADC for identification of S ≥ 3 (p = 0.0005) and G ≥ 3 (p = 0.014). The HBP T1 relaxation time measurement on gadoxetic acid-enhanced MRI images might be a potential biomarker in the staging of hepatic fibrosis, and was more accurate than the ADC measurement.