E2409. Fontan Associated Liver Disease: What the General Radiologist Needs to Know
  1. Stephanie Tan; University Health Network
  2. Ciara O'Brien; University Health Network
The Fontan operation is a palliative procedure for patients with single ventricle congenital heart disease where the systemic venous return is directed into the pulmonary circulation. The median age of survival of patients with the Fontan operation has increased from 17 years of age in 2000 to 25 years of age in 2010, therefore this is a growing population. Extracardiac complications are increasingly recognised. Given the change in cardiac dynamics and the rise in central venous pressure (CVP) from the Fontan circulation, these patients are predisposed to Fontan-associated liver disease (FALD). FALD is a spectrum of disease which includes hepatic parenchymal change, fibrosis, cirrhosis and hypervascular regenerative nodules

Educational Goals / Teaching Points
The purpose is to showcase the spectrum of disease that can occur with FALD and to demonstrate imaging pearls important for clinical management. This educational exhibit will discuss both the common generalised hepatic changes and the focal hepatic findings and malignancies that can occur with FALD. Diagnosing HCC in cirrhosis caused by vascular conditions is challenging due to the propensity for hypervascular regenerative nodules which can mimic HCC, therefore pearls for differentiating between the two will be discussed.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
There is a recognised correlation between hepatic surface nodularity and late-stage fibrosis. The diagnosis of early fibrosis is critical in the prevention of complications. Presence of numerous small hyperechoic lesions through the hepatic parenchyma without surface nodularity has been associated with early stage fibrosis. Diagnosing HCC in FALD can be challenging due to the presence of hyperenhancing nodules and vascular shunts. Hypervascular regenerative nodules are common in FALD. Histologically, these are focal nodular hyperplasia (FNH). These tend to follow FNH characteristics, with arterial hyperenhancement, minimal to no restriction and retention of contrast on hepatobiliary phase. Although hypervascular nodules can mimic HCC, the diagnosis of HCC can be made by assessing interval increase in size, washout on portal venous phase and associated increase in alpha feto-protein.

As the Fontan population ages, the extracardiac complications, including FALD are becoming more prevalent and can be seen in the community. Radiologists need to be able to recognize the associated findings such as cardiac cirrhosis and be able to confidently differentiate hypervascular nodules from HCC.