Fetal Cardiac US: Techniques and Normal Anatomy Correlated with Adult CT and MR Imaging

Congenital heart disease (CHD) is an important cause of childhood mortality. Despite the widespread use of ultrasonography (US) as a screening tool, the prenatal detection rate is suboptimal. Improvement of the initial screening examination, which is performed in low-risk populations and often interpreted by community radiologists, targets a point in the screening process that is likely to have the largest population effect. If the goal of community-based screenings is to detect cases that may be abnormal and refer those to specialized centers for complete assessment, it is logical to use a checklist to confirm normal anatomy. This article presents a stepwise process to evaluate fetal cardiac anatomy using comparison with computed tomography (CT) and magnetic resonance (MR) images, which are more familiar to radiologists in busy general practices. In addition, this article presents a checklist for assessment of the four-chamber view and demonstrates the expected normal appearance of the outflow tract views as well as the additional views required for complex obstetric US. These additional views include the aortic arch and bicaval views, three-vessel view (3VV), and three-vessel trachea view (3TV). CHD may be isolated, but it may indicate aneuploidy or a syndrome that, if present, determines the prognosis. In isolated CHD, the prognosis is determined by the exact nature of the abnormalities. In particular, duct-dependent disease if undiagnosed results in circulatory collapse in the infant once the ductus closes. If the heart does not look normal, the patient should be referred for detailed evaluation. Timely diagnosis of significant CHD allows for development of a personalized pregnancy management plan. (C) RSNA, 2017.