[Value of MRI with injection of gadolinium in the diagnosis of mitral ring abscess. Apropos of a case].

Transoesophageal echocardiography is the investigation of choice for the diagnosis of valvular vegetations in infectious endocarditis but the diagnosis of an associated ring abscess is sometimes difficult especially in patients with valvular prostheses or calcifications which are in important source of artefacts. The authors report a case of mitral annular abscess confirmed at surgery and comment on the diagnostic and prognostic value of cardiac MRI. MRI showed an abnormal cavity directly related to the mitral annulus and separated from the left ventricle by a low intensity signal which increased after injection of gadolinium suggesting an inflammatory origin and therefore arising from the abscess. The cavity was heterogeneous in T1 associating zones of low intensity with high intensity signals increasing in T2 on the second echo (thrombus and necrosis). Cine-MRI showed non communication between the abscess cavity and the left ventricle or atrium.