Quantitative Hepatobiliary MRI for Early Prognostic Assessment After Liver Transplantation: Survival Prediction Using the Contrast Enhancement Index

OBJECTIVES: To evaluate the feasibility and prognostic value of the contrast enhancement index (CEI) derived from gadobenate dimeglumine (Gd-BOPTA)-enhanced hepatobiliary-phase (HBP) magnetic resonance imaging (MRI) for early assessment of liver graft function after liver transplantation (LT). METHODS: This retrospective study included LT recipients undergoing Gd-BOPTA-enhanced MRI within 6 months after transplantation. CEI was calculated using liver-to-psoas signal intensity ratios on pre-contrast and HBP images acquired 90-120 minutes after contrast administration. ROC, Kaplan-Meier, and age-adjusted Cox regression analyses evaluated associations with mortality. RESULTS: Seventy patients (median age, 62 years; interquartile range [IQR], 48-74) were included. CEI was quantifiable in all cases (median, 1.27; IQR, 1.09-1.37). Non-survivors had significantly lower CEI values than survivors (median, 1.17 vs 1.31; p = 0.03; Cliff's δ = -0.28). ROC analysis showed moderate discrimination for mortality (AUC, 0.667; 95% CI, 0.529-0.793), with an optimal cutoff of 1.301 (sensitivity, 88%; specificity, 51.2%). Patients with CEI <1.301 had significantly lower overall survival (log-rank p = 0.028). After adjustment for recipient age, CEI remained associated with mortality (HR per 0.1-unit increase, 0.79; 95% CI, 0.64-0.98; p = 0.035). CONCLUSION: Quantitative CEI measurement on Gd-BOPTA HBP MRI is feasible after LT, and lower CEI values. ADVANCES IN KNOWLEDGE: This study links quantitative Gd-BOPTA-enhanced HBP MRI with overall survival after LT, supporting CEI as a potential non-invasive imaging biomarker for postoperative risk stratification.