MR findings in Shone's complex of left heart obstructive lesions

Background. Shone's complex is a series of four obstructive or potentially obstructive left-sided cardiac lesions (supravalvular mitral ring, parachute deformity of the mitral value, subaortic stenosis, and coarctation of the aorta). Both the complete form (all four lesions) and incomplete forms (less than four lesions) have been described. Objective. To determine which abnormalities of Shone's complex could be characterized by MR. Materials and methods. MR examinations in three patients (one complete, two incomplete) were retrospectively reviewed. Results. A supravalvular mitral ring, found at surgery in one patient, was not identified. Regurgitant and stenotic flow across the mitral valve, abnormal motion of the valve leaflets and abnormalities of the papillary muscles were identified. Individual chordal attachments were difficult to resolve. Narrowing in the subaortic region and abnormal flow from the subaortic region through the valve plane were demonstrated. A discrete subaortic diaphragm in one patient was not resolved. Both focal and diffuse types of coarctation of the aorta were well characterized. Conclusion. MR imaging is suited to evaluation of patients with Shone's complex. Individual chordal attachments and thin diaphragms of the mitral and aortic valves were difficult to resolve.