Imaging description

A five-month-old female infant presented with persistent tachypnea and failure to thrive. Frontal and lateral chest radiographs (Fig. 32.1a, b) demonstrated marked cardiomegaly, hyperinflation, and pulmonary venous congestion consistent with cardiogenic pulmonary edema. An echocardiogram was obtained that demonstrated marked left ventricular dilatation with very poor contractility (Fig. 32.1c). No additional abnormality was found. Of note, the coronary origins were thought to be normal on Doppler ultrasound (US), with normal direction of flow (Fig. 32.1d). Additional history, clinical examination, and laboratory investigation failed to reveal an underlying cause for the cardiac dysfunction. A gated CT angiogram was obtained, primarily to confirm that the coronary arteries were indeed normal. The CTA, timed for optimal contrast in the aorta and coronary arteries, demonstrated a single right coronary artery arising from the densely contrast-filled aorta (Fig. 32.1e). The left coronary artery was shown to arise anomalously from the posterior aspect of the pulmonary artery (Fig. 32.1f, g). The relative lack of contrast opacification of the left coronary artery and its branches, similar to the pulmonary artery, confirmed the antegrade flow pattern seen on Doppler. It was hypothesized that chronic hypoxia and pulmonary hypertension resulted in this atypical flow pattern for aberrant left coronary artery arising from the pulmonary artery (ALCAPA). Furthermore, it appeared that the rightward and posterior course of the left circumflex branch close to the aorta produced the appearance mistaken on US for a normal aortic origin of the left coronary artery.