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Updated: Oct 4, 2025
Author Spotlight: Advancing Hepatic Fibrosis Diagnosis Using Magnetic Resonance Elastography and AI
Published on: July 21, 2023
Two-Step Strategy, FIB-4 Followed by Magnetic Resonance Elastography, for Detecting Advanced Fibrosis in NAFLD
Nobuharu Tamaki1, Kento Imajo2, Suzanne R Sharpton3
1NAFLD Research Center, Division of Gastroenterology and Hepatology, Department of Medicine, University of California San Diego, La Jolla, California; Department of Gastroenterology and Hepatology, Musashino Red Cross Hospital, Tokyo, Japan.
Background & Aims:
A two-step strategy combining a serum marker and magnetic resonance elastography (MRE) for detecting advanced fibrosis (stage 3-4) among patients with nonalcoholic fatty liver disease (NAFLD) has been proposed, but its diagnostic accuracy has not been evaluated. In this multicenter study, we aimed to investigate the diagnostic accuracy of a two-step strategy including Fibrosis-4 (FIB-4) followed by MRE.
Methods:
In this multicenter study, 806 patients with biopsy-proven NAFLD who underwent contemporaneous MRE were enrolled and randomly assigned to training and validation cohorts. As a first step, patients with FIB-4 <1.3 were defined as test negative regardless of MRE. As a second step, among patients with FIB-4 ≥1.3, MRE <3.6 and ≥3.6 kPa were defined as test negative and positive. The primary outcome was the diagnostic accuracy for advanced fibrosis comparing MRE alone versus the two-step strategy.
Results:
Area under the receiver characteristic curves of MRE alone and the two-step strategy were 0.840 and 0.853 in the training cohort (P = .4) and 0.867 and 0.834 in the validation cohort (P = .2), respectively, and the diagnostic accuracy was comparable between the 2 methods. In the entire cohort, negative predictive value (NPV) and positive predictive value (PPV) of MRE for advanced fibrosis were 92.2% and 73.7%, respectively, whereas NPV at the first and second step and PPV at the second step were 90.9%, 84.4%, and 77.0%, respectively.
Conclusions:
The diagnostic accuracy of the two-step strategy was comparable to MRE and could reduce cost by reducing excessive MRE. Therefore, the two-step strategy could be used as a screening method in a large population.
