Noureddin M, Truong E, Gornbein JA, et al. - This study provides an accurate, MRI-serum-based score, the MAST (MRI aspartate aminotransferase) score, that showed better performance than previous scores in noninvasively identifying patients at higher risk of fibrotic nonalcoholic steatohepatitis (Fibro-NASH).

• A highly specific MRI-based score to detect Fibro-NASH patients was created in this study including derivation (n=103) and validation (n=244) cohorts from tertiary care centers who had MRI, liver biopsy, Transient elastography, and laboratory testing for non-alcoholic fatty liver disease from 2016-2020.

• A formula for Fibro-NASH detection was built based on magnetic resonance imaging derived proton density fat fraction), MR elastography, and a third variable with highest balanced accuracy per logistic regression.

• The MRI-AST (MAST) score was developed, and this score showed high performance and discrimination [ROC AUC 0.93 (0.88-0.97), 95% CI] in the validation cohort.

• Validation cohorts revealed that 90% specificity cutoff of 0.242 yielded sensitivity 75.0%, PPV (positive predictive value) 50.0% and NPV (negative predictive value) 96.5%, whereas the 90% sensitivity cutoff of 0.165 afforded specificity 72.2%, PPV 29.4%, and NPV 98.1%.

• Relative to NFS (NAFLD fibrosis score) and Fib-4 (fibrosis-4 index), MAST had fewer indeterminate score patients and overall higher AUC.

• Better ROC and overall better discrimination were offered by MAST vs FAST (FibroScan aspartate aminotransferase).