Computed Tomography in the Evaluation of Fontan Circulation

The Fontan procedure is a well-established surgical technique to improve survival in patients with univentricular heart disease. The procedure reroutes the systemic venous flow to the lungs, bypassing the right ventricle. The originally proposed method involved direct anastomosis of the right atrium to the pulmonary artery. Since then, several modifications have been made in the original technique leading to the modern Fontan, or total cavopulmonary connection. The modern Fontan technique has shown improved surgical outcomes and increased life expectancy in patients with univentricular disease. Due to the increased survival of these patients, long-term complications are becoming more prevalent. Common complications of Fontan procedure include right atrial dilatation and thrombosis; conduit stenosis and thrombosis; right-to-left and left-to-right shunts; hepatic congestion and cirrhosis; and lymphovascular. Computed tomography (CT) can reliably depict the normal Fontan anatomy and various postoperative complications. A fundamental understanding of the techniques of CT, including imaging protocols and common interpretive pitfalls, allows targeted imaging and precise reporting of clinically significant findings. Radiologists should be familiar with the multiple stages of single-ventricle palliation, normal Fontan anatomy, pathophysiology, and imaging features of common Fontan-related complications.