Purpose or Case Report: Fontan–associated liver disease (FALD) is associated with increased risk of liver cirrhosis and hepatocellular carcinoma. Liver biopsy is the current gold standard investigation for diagnosing liver fibrosis. Magnetic Resonance Elastography (MRE) is a non-invasive procedure assessing liver stiffness. To date, only limited published studies are available describing the correlation of MRE and biopsy in Fontan-associated pediatric patients. Further, longitudinal changes in MRE require an increase in hepatic stiffness of >22% to indicate true change in stiffness (95% CI). The purpose of this study is to determine the clinical implication of MRE in FALD.


Methods & Materials: Firstly, a retrospective review was performed of Fontan patients having an MRE study and percutaneous liver biopsy between 2015 and 2019 within a maximal time interval of 2 months. Targeted liver stiffness was measured via a freehand region of interest (ROI) in the area of biopsy as directed by reported liver segment and biopsy throw length. This and total liver stiffness was compared with a quantification of liver fibrosis measured by percentage Sirius red (%SR) staining of biopsy samples. Secondly, total liver stiffness was evaluated for patients with two or more MRE studies between 2016 and 2019 and compared. In the case of multiple MRE studies, the initial and most recent were compared. Clinical history, patient demographics, procedure reports, and pathology were reviewed.
Results: Eighteen Fontan patients were included from initial database triage, with a mean age of 15.2 years (SD=2.1, 14 males) and mean time interval since Fontan surgery being 12.6 years. There was no significant correlation between the %SR staining and total (r=-0.24, p=0.338) or targeted liver stiffness (r=-0.128, p=0.614). Seventeen patients were included from the second search, which showed a statistically significant increase in mean liver stiffness from 3.8 to 4.6 (21% increase) within an average period of 24±7 months (p=0.005).
Conclusions: Total and targeted MRE liver stiffness did not correlate with liver biopsy, the gold standard test. Although MRE stiffness is shown to increase longitudinally, the increase is insufficient to indicate true change in fibrosis. Thus, MRE has limited use in assessing liver fibrosis in Fontan patients. A possible underlying explanation is that congestion is a confounding factor in elastography assessment.