Assessing liver fibrosis in chronic hepatitis B using MR extracellular volume measurements: Comparison with serum fibrosis indices.

Objectives: To evaluate the diagnostic value of liver extracellular volume (ECV _liver ) measurement by equilibrium MR in staging liver fibrosis in chronic hepatitis B (CHB) patients, and to compare its performance with serum fibrosis indices.
Materials and Methods: 91 CHB patients were included and underwent gadopentetate dimeglumine-enhanced MRI with T1 mapping sequence before and 15-min after contrast. ECV _liver , aspartate aminotransferase-to-platelet ratio index (APRI) and fibrosis index based on the four factors (FIB-4) were calculated and compared between fibrosis subgroups, and the correlations between the three indices and fibrosis stage or inflammatory activity were measured by Spearman correlation analysis and stepwise multiple regression analysis. Diagnostic performance in evaluating liver fibrosis stage was assessed and compared using receiver operating characteristic analysis.
Results: Interobserver agreement showed an excellent interclass correlation coefficient of 0.895 for ECV _liver . ECV _liver , APRI and FIB-4 were different between fibrosis stages as a whole (F/H = 18.44-24.36, P ≤ 0.001). ECV _liver had the strongest correlation with fibrosis stage (r = 0.727, P < 0.001), while APRI and FIB-4 had weak correlations (r = 0.466 and 0.440, P < 0.001). Multivariate analysis showed that only ECV _liver was independently correlated with fibrosis stage (P < 0.001). The fibrosis stage was the only independent factor correlated with ECV _liver comparing to inflammatory activity (P < 0.001). AUCs of ECV _liver were larger than both APRI and FIB-4 in fibrosis staging, with significant differences in the diagnosis of advanced fibrosis (≥F3) and cirrhosis (F4) (P = 0.0024 to 0.0049).
Conclusion: MR ECV _liver provides a promising noninvasive tool in staging liver fibrosis for CHB patients, superior to the fibrosis indices of APRI and FIB-4.
(Copyright © 2019 Elsevier Inc. All rights reserved.)