Surgical treatment of patients with double-outlet right ventricle (DORV) depends on the spatial relation between the associated ventricular septal defect (VSD) and the arterial valves. This study was performed to refine the magnetic resonance (MR) imaging characteristics of VSD in DORV. Ten patients with DORV underwent MR imaging. Coronal, transverse, and oblique images were obtained with an electrocardiographic-gated multiple-section spin-echo technique. The transverse plane was the most valuable in defining the spatial relation of the VSD to the arterial valves. The site of fusion of the outlet septum with the VSD margin was diagnostically the most important feature in differentiating subaortic from subpulmonary VSD. The outlet septum fused with the anterior margin in subaortic VSD and the posterior margin in subpulmonary VSD; it was absent in doubly committed VSD. This study suggests that MR imaging can demonstrate the pertinent features of VSD and may be an indispensable adjunct to echocardiography in the preoperative evaluation of patients with DORV.
