Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) syndrome is a rare congenital coronary artery anomaly. There are two types of ALCAPA syndrome: the infant type and the adult type, each of which has different manifestations and outcomes. Infants experience myocardial infarction and congestive heart failure, and approximately 90% die within the 1st year of life. Rarely, ALCAPA syndrome manifests in adults; it may be an important cause of sudden cardiac death. Historically, ALCAPA syndrome was diagnosed at conventional angiography. However, the development of electrogardiographically gated multidetector computed tomographic (CT) angiography and magnetic resonance (MR) imaging enables accurate noninvasive imaging. At MR imaging and multidetector CT angiography, findings include direct visualization of the left coronary artery arising from the main pulmonary artery. Reversed flow from the left coronary artery into the main pulmonary artery may be seen at steady-state free-precession cine and fast cine phase-contrast MR imaging. Because of its ability to assess myocardial viability, which can be used as a prognostic factor to direct the need for surgical repair, MR imaging plays an important role in patient treatment. Restoration of a dual-coronary-artery system is the ideal surgical treatment for ALCAPA syndrome.
(c) RSNA, 2009.