Early detection of liver fibrosis in patients with Fontan circulation using multiparametric magnetic resonance imaging

Abstract Introduction Fontan procedure (FP), serving as the palliative intervention for complex congenital heart diseases characterized by single-ventricle physiology, precipitates a spectrum of late-stage complications. Fontan-associated liver disease (FALD) encompassing liver fibrosis (LF) which may progress to liver cirrhosis (LC) and thereby hepatocellular carcinoma (HCC) is among the most serious. Despite its importance, optimal surveillance of FALD remains undefined. Multiparametric Liver Multiscan (LMS) with corrected T1 (cT1) value emerges as a novel magnetic resonance (MRI) based non-invasive quantitative tool for liver inflammation and fibrosis evaluation. Aim of this study was to ascertain prevalence and severity of LF utilizing LMS, alongside identifying contributory risk factors for LF in adults post-FP. Material and methods Our cohort included 29 adult patients after FP who underwent LMS. Median age was 25y (20-43y) 54% were females. Liver morphology was assessed by ultrasound (USG) and MRI-based LMS protocol. Hepatic scoring systems, including the Aspartate Aminotransferase to Platelet Ratio Index (APRI), Fibrosis-4 (FIB-4) Index, and Model for End-Stage Liver Disease (MELD), were computed. Additionally, presence of fenestrations in the Fontan circulation, hemoglobin levels (Hb), and blood oxygen saturation both at rest and during exercise (SatO2%) were evaluated. Results Median cT1 was 914 (±207) ms, in 87% exceeding normal threshold . In those with elevated cT1, LF was undetected by USG in 38%. LC was identified in 27% of the cohort by USG. LC group exhibited significantly higher cT1 values (P<0.001) compared to non-LC group. cT1 value >933ms was associated with a sensitivity of 89% and a specificity of 80% for diagnosing LC (AUC 0.92). Significant correlation was found between cT1 values and Hb (P=0.01) and desaturation (SatO2 <90%/ interventional closure of fenestration, P=0.004). Conventional liver tests and hepatic scoring systems (APRI/FIB-4/MELD) did not predict cT1 nor LC. Conclusion Our study confirmed that LF is almost widely prevalentamong adult patients with single-chamber circulation. Risk factors for LF are systemic desaturation (SatO2 <90% or interventional closure of fenestration) and polyglobulia. However, reliable FALD surveillance remains challenging. Conventional liver assessments and scoring algorithms fall short in delineating the full scope of LF or LC. Consequently, the integration of non-invasive LMS into routine follow-up regimens is advocated, given its pronounced sensitivity for detecting subclinical FALD manifestations and predicting LC. The LMS-derived cT1 value >933ms is a critical predictor for LC, underscoring its importance in guiding further patient monitoring, treatment, and facilitating early HCC detection.