Aortic arch anomalies usually require surgical intervention preceded by precise anatomic definition. We studied 20 patients to evaluate the feasibility and accuracy of using intravascular ultrasound catheters from a transesophageal approach with 3-dimensional image reconstruction for the diagnosis of aortic arch anomalies in infants and children. All patients had transthoracic echocardiograms and/or angiograms or magnetic resonance imaging. A 12.5-MHz intravascular ultrasound catheter was positioned in the esophagus and withdrawn by using an electrocardiogram and a respiratory gated pullback device to acquire the mediastinal images. All patients with arch anomalies underwent surgical repair. Reconstructed images were analyzed in the "anyplane" mode and with surface rendering. Intravascular ultrasound 3-dimensional imaging was successfully accomplished without complications. Anatomy was correctly identified in all patients by both blinded and unblinded observers, thus confirming the sensitivity and accuracy of the technique. We foresee this new technique to be useful as an adjunctive imaging modality applicable at the bedside or in the cardiac imaging laboratory.