Diagnosis of hemi-truncus arteriosis by three-dimensional magnetic resonance angiography.

Two patients, aged 3 days (weight 2 kg) and 40 years (weight 80 kg) underwent gadolinium-enhanced magnetic resonance angiography (MRA) because of diagnostic uncertainty. The newborn infant was antenatally diagnosed with truncus arteriosis. Postnatal echocardiography confirmed the diagnosis. It was thought that the branch pulmonary arteries were confluent (type II); however, an MRA was requested to clarify this. The MR angiograms (Figure 1) showed the right pulmonary artery arising from the left side of the ascending aorta. The left pulmonary artery, which was disconnected from the right pulmonary artery, was supplied by the patent ductus arteriosis arising from the underside of the aortic arch. The MRA findings were confirmed at surgery. The adult patient had been diagnosed with pulmonary atresia and ventricular septal defect in childhood and had been managed conservatively. Nevertheless, he began to experience reduced exercise tolerance and became cyanotic. An MRA was requested to outline the source of his pulmonary blood supply. The MR angiograms (Figure 2) showed a large left pulmonary artery arising from the left side of the ascending aorta, with pruning of its distal branches. On the right side, the patient had a number of small pulmonary arteries that were not supplied by the aorta or its main branches. A double aortic arch was also discovered. The patient is being assessed for heart-lung transplantation.