Imaging Findings in Fontan-Associated Liver Disease: Results of a Single Center Study

Fontan-associated liver disease (FALD) is a consequence of Fontan circulation causing liver fibrosis, cirrhosis, portal hypertension, and potentially hepatocellular carcinoma (HCC), with imaging essential to evaluation. To describe the cross-sectional imaging features of hepatic morphology and focal liver lesions (FLLs) in patients with FALD. This retrospective single-center study included patients post-Fontan procedure (10/2016-9/2022) who underwent CT or MRI and non-targeted liver biopsy for fibrosis staging. Two observers in consensus assessed CT/MRI for imaging findings of cirrhosis, portal hypertension, and FLL (>0.8cm) detection and characterization, including size, enhancement pattern, and MRI characteristics. A composite reference standard (pathology, multidisciplinary tumor board, imaging characteristics, or FLL stability) informed FLL diagnosis. Biopsies were staged using the Congestive Hepatic Fibrosis Score (CHFS) [range, 0(no fibrosis)-4 (cirrhosis)]. Associations between variables were analyzed using logistic regression and Fisher’s exact tests. Results from 41 patients [26M/15F, mean age=29.9y, MRI, n=24/CT, n=17] are presented. CHFS were 1(n=4)/2(n=19)/3(n=14)/4(n=4). Imaging signs of cirrhosis were common: liver surface nodularity (n=31) and volume redistribution (caudate lobe hypertrophy, n=35). Varices and ascites were observed in n=18 and n=16 patients. 62 FLL were identified in 15 patients (mean size=1.5±0.7cm). Diagnoses included benign-appearing enhancing lesions (n=52 lesions/10 patients), indeterminate (n=5 lesions/4 patients), HCC (n=4 lesions/3 patients), and sclerosing hemangioma (n=1). All HCC cases had CHFS=3. No association between laboratory, CHFS, and imaging findings of cirrhosis was found (p-values>0.12). Imaging findings of cirrhosis are discordant with fibrosis stage in FALD. Enhancing FLLs, including HCC, are common and frequently observed in noncirrhotic liver. • Imaging features of cirrhosis are common in FALD but did not correlate with histopathologic fibrosis stage. • Focal liver lesions (FLL) are frequent after Fontan, with most representing benign arterially enhancing nodules. • Hepatocellular carcinoma can occur in patients with FALD without overt cirrhosis and may be challenging to distinguish from other liver lesions on imaging. • Routine imaging surveillance and multidisciplinary evaluation in this FALD population is needed for assessment of liver parenchyma and FLL.