Evaluation of a large atrial septal occluder with cardiac MR imaging

Magnetic resonance (MR) imaging was used to evaluate the position of a large atrial septal occluder (ASO) with regard to adjacent cardiac valves and veins and to assess any negative effects of the ASO on these vital structures. A total of 26 pediatric patients (mean age, 4.5 years; mean interval after implantation, 18.8 months) were evaluated with cardiac MR imaging. The position of the ASO was best depicted with two-dimensional cine fast low-angle shot imaging. The authors observed impingement of the ASO on the right superior pulmonary vein in 14 patients, on the right inferior pulmonary vein in three patients, on the right superior vena cava in 13 patients, and on the right inferior vena cava in nine patients. In two patients, protrusion of the ASO into the right inferior vena cava was associated with coronary sinus prominence. The ASO was in contact with the mitral valve in 10 patients. Deformation of the aortic valve and root was evident at the onset of the R wave in 19 patients and persisted throughout the cardiac cycle in five of these patients. Cardiac MR imaging reliably depicted the position of the ASO with regard to vital structures. Despite the protrusion of the ASO, no significant effects on venous structures or cardiac valves were observed.