Diagnosis of Ductal Aneurysm Using Three-Dimensional CT Reconstruction

Abstract

The prevalence of ductal aneurysms is approximately 8.8% [2]. Ductal aneurysms are associated with serious complications, which makes accurate diagnosis prudent. Diagnosis is traditionally made by echocardiography, however, additional imaging modalities are sometimes required for a definitive diagnosis. Our patient, D.C., is a full-term newborn male who was transferred from an outside hospital to our Neonatal Intensive Care Unit secondary to respiratory failure and dysmorphism. His physical examination was significant for hypertelorism and low-set ears. He had increased precordial activity and a 3/6 holosystolic murmur heard throughout the precordium. An echocardiogram was performed on day of life 5, which showed a primum atrial septal defect (ASD) with left-to-right shunt, a secundum ASD with left-to-right shunt, and atrioventricular canaltype ventricular septal defect with no physiologic shunt secondary to atrioventricular valve tissue filling the defect. At that time echocardiography demonstrated significant left pulmonary artery stenosis. A follow-up echocardiogram was performed to further evaluate the caliber of the left pulmonary artery. A 1.6 9 1.8-cm cystic mass was noted anterior to and to the left of the main pulmonary artery/left pulmonary artery junction. There appeared to be a connection via a small communication to the main pulmonary artery (Fig. 1). A CT angiogram was performed, which showed a well-circumscribed contrast-filled structure measuring 1.7 9 1.4 9 1.2 cm arising from the anterior aspect of the proximal portion of the descending thoracic aorta, located anterolateral to the left main pulmonary artery branch, most consistent with a pseudoaneurysm. However, the exact anatomy was still difficult to precisely delineate. Therefore, we used three-dimensional reconstruction of the CT angiogram to show the aneurysm in connection with the ductus arteriosus and to demonstrate compression of the left pulmonary artery by the aneurysm (Fig. 2). Ductal aneurysms are rare and are more frequently associated with patients who have had surgical ligation of the ductus arteriosus or in association with connective tissue disorders [1]. One study demonstrated a prevalence of 8.8% in all newborn infants [2]. Ductal aneurysms usually are asymptomatic and incidentally discovered on routine echocardiographic evaluation or diagnosed by fetal echocardiogram. Although rare, ductal aneurysms are associated with serious complications, which include thromboembolism, infection, rupture, and death [3]. The conventional method to identify ductal aneurysm anatomy is by two-dimensional echocardiogram with color Doppler. However, some patients require additional imaging with CT angiography or MRI to further define the anatomy [1]. In our patient, the connection between the aneurysm and the artery was difficult to isolate on two-dimensional echocardiogram and CT angiogram. Therefore, three-dimensional reconstruction of the CT angiogram was necessary to make the exact diagnosis. Additionally, the three-dimensional reconstruction replicated the exact area of aneurysmal connection to the pulmonary artery. Three-dimensional CT has been described more often in the adult literature for diagnosis of aneurysms. The most common use is as a diagnostic tool for circle of Willis aneurysms. However, three-dimensional CT angiography has been used to diagnose aortic aneurysms in the adult population. In pediatrics, three-dimensional CT angiography Deneen Heath and Russell Cross contributed equally to this work.