Cardiac shunts: ASD, VSD, PDA

Abstract

Atrial septum defects (ASDs), ventricular septum defects (VSDs), and patent ductus arteriosus (PDA) are common congenital heart defects in both children and adults (Webb and Gatzoulis, Circulation 114:1645-1653, 2006; Minette and Sahn, Circulation 114:2190-2197, 2006; Schneider and Moore, Circulation 114:1873-1882, 2006). Morphological classification of these anomalies is important for treatment decisions. Accurate morphological classification requires imaging technique that is able to identify the defect and define its site, size, and relationship to the structures forming its margins. Imaging technique should also be able to identify associated anomalies, the amount of shunt through the defect, and accurate analysis of the heart and valve functions. Echocardiography is a great method for diagnosis of intracardiac shunts with good resolution to image cardiac morphology in detail and can identify small intracardiac defects and measure the shunt volume. Cardiac MR provides a comprehensive assessment of intracardiac anatomy and accurately quantifies biventricular function and blood flow. Detections of small defects (i.e., apical VSD) may require high-resolution imaging and CT can be the preferred technique. Assessment of associated extracardiac anomalies such as anomalous venous return can be optimally done with CT. In this chapter, a complete review of the shunts and clinical applications of CT and MRI will be presented.