Computed tomographic CT findings of mitral annular calcification MAC : CT shows severe MAC at the mitral annulus, however, MAC located mainly at posterior mitral annuls.Mitral annular morphology, Drowing show variability in the extent of fibrous components thick lines of the mitral annulus. Angelini et al 3 demonstrated that a continuous fibrous ring or collar interposed between the left atrial and ventricular myocardium and providing the hinge of the mural leaflet of the mitral valve is uncommon.