Purpose or Case Report: Truncus arteriosus is a rare congenital cardiac anomaly characterized by failure of conoseptal separation resulting in a single arterial trunk supplying both the pulmonary and systemic circulation. Diagnosis has historically been made with fetal echocardiography, and palliative surgery performed frequently in the neonatal period. Cross-sectional imaging is typically reserved for post-operative complications. However, due to lower dose radiation and faster scanners, preoperative CT angiography imaging is becoming more common with the increasing use of cardiac EKG-gated CT angiograms, requiring pediatric imagers to be familiar with the diagnosis of the truncus arteriosus spectrum.

Methods & Materials: This retrospective imaging review will describe the imaging features of truncus arteriosus, including the 2-D multiplanar reformatted images and 3-D volume rendered images. Various anatomical types of Truncus Arteriosus detailed in the widely used Van Praagh classification will be demonstrated. Illustrative examples will also detail variants not clearly defined by the current classification systems. Important imaging distinctions between truncus arteriosus and other similar appearing congenital cardiac anomalies, such as Tetralogy of Fallot or pulmonary atresia with major aorto-pulmonary collateral arteries, will be described.

Results:
Conclusions: This educational exhibit will provide viewers with a framework to recognize and classify truncus arteriosus, as well as provide vital distinction between truncus arteriosus and other similar appearing conotruncal anomalies.