Inter-reader agreement and correlation of VAST, Fontan liver MRI score and MR elastography derived liver stiffness in children and young adults with Fontan-associated liver disease.

PURPOSE: (1) To assess inter-reader agreement of the varices, ascites, splenomegaly, thrombocytopenia (VAST) score and of the Fontan liver MRI scoring system and the correlation of each score with liver stiffness assessed by MR elastography in a cohort of children and young adults with Fontan associated liver disease (FALD).

METHODS

This is a retrospective study of children and young adults (< 21 years old) with FALD, at our institution, that underwent hepatic MRI with MRE between 2017 and 2024. VAST and MRI scores were assigned independently by two blinded radiologists (including on fellow). Inter-reader agreement was evaluated with Cohen's kappa (k). Linear regression analysis was performed using their mean scores to determine correlation with MRE-derived liver stiffness.

RESULTS

A total of 53 children with median age (interquartile range [IQR]) of 17.0 (14.0 to 18.0) years were included. Median (IQR) of the VAST and Fontan liver MRI scores were 0.5 (0 to 1) and 5 (3 to 6.5), respectively. The median (IQR) MRE liver stiffness calculated 4.0 (3.4 to 4.5) kPa. Inter-reader reliability for VAST and Fontan liver MRI scores were substantial (k = 0.66, 95% CI: [0.50-0.82]) and moderate (k = 0.53, 95% CI: [0.41-0.65]), respectively. MRE-derived liver stiffness correlated more with VAST (rho = 0.40, p = 0.003) than with MRI score (rho = 0.28, p = 0.05).

CONCLUSION

The VAST score has substantial inter-observer reliability and had a stronger correlation coefficient with MRE derived liver stiffness compared to the Fontan liver MRI scoring system in children and young adults, Radiologists should consider including the VAST score when interpreting Fontan liver MRI.