[Diagnosis of mitral valve prolapse by X-ray CT and MRI].

To evaluate the usefulness of enhanced X-ray CT and gating magnetic resonance imaging (MRI) for diagnosing mitral valve prolapse, three patients with this abnormality and several controls were examined by these two methods. The mitral valve was not recognized by X-ray CT except a few cases with thickened mitral valve. However, MRI could demonstrate clearly the mitral leaflets and annulus in many subjects. In transverse MR imaging of the subjects without valvular disease, the closed mitral valve showed V-shaped appearance in the left ventricle during systole. In a patient with marked mitral valve prolapse, MRI revealed buckling of the posterior mitral leaflet into the left atrium, and in two other patients with mild mitral valve prolapse, MRI demonstrated displacement of coaptation of the anterior leaflet toward the left atrium. These results suggest MRI is a useful method for diagnosing mitral valve prolapse.