Imaging findings in Fontan-associated liver disease: Results of a single center study

Background: 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. Objectives: To describe the cross-sectional imaging features of hepatic morphology and focal liver lesions (FLLs) in patients with FALD. Methods: 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 (>0.8 cm) 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: 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 ± 0.7 cm). 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). Conclusions: Imaging findings of cirrhosis are discordant with fibrosis stage in FALD. Enhancing FLLs, including HCC, are common and frequently observed in noncirrhotic liver.