Imaging description

A routine prenatal ultrasound (US) demonstrated cardiac abnormality later determined at dedicated prenatal cardiac echo to be suggestive of tetralogy of Fallot (TOF) with severe pulmonary stenosis or atresia and a large patent ductus arteriosus (PDA). Arrangements were therefore made for delivery at a major medical center. The baby was born by normal vaginal delivery at 39 weeks’ gestation and was noted to be mildly cyanotic with a soft systolic ejection murmur at the left sternal border. A frontal chest radiograph demonstrated mild cardiomegaly with a concave main pulmonary artery (PA) segment and uplifted cardiac apex (Fig. 23.1a) consistent with TOF. Pulmonary vascularity appeared normal. TOF with pulmonary valve atresia and large PDA were confirmed on postnatal echocardiography. Prostaglandin therapy to maintain patency of the ductus arteriosus had been initiated in the delivery room because of the prenatal echo findings.

A gated CT angiogram (80 kVp, mean mAs 102, DLP 30, approximate effective dose 2.4 mSv) was obtained at 4 days of age to further define the size and appearance of the native pulmonary vessels and systemic collateral arterial supply to the lungs. CT images including multiplanar, maximum intensity projection (MIP) and 3D volumetric reconstructions demonstrated the typical cardiac anatomy of TOF (large outlet ventricular septal defect (VSD), overriding aorta, right ventricular hypertrophy, and right ventricular outflow stenosis, in this case atresia) (Fig. 23.1b). A large tortuous PDA (5 mm) was seen extending from the distal aortic arch to the proximal left PA (Fig. 23.1c). This was the only systemic arterial supply to the lungs, no additional aorticopulmonary or other collaterals were identified. The distal main PA and right and left branch PAs were normally patent (approximately 3–4 mm) without stenoses (Fig. 23.1d). There was mild kinking of the proximal left PA proximal to the PDA. There was mild anomalous branching of the left-sided aortic arch with a common origin of the right brachiocephalic and left common carotid arteries and separate left subclavian artery (Fig. 23.1c). The coronary arteries appeared normal. There was moderate left upper lobe and lingular atelectasis with partial compression of the left bronchus by the PDA (not shown).