The chest x-rays especially the lateral view show a C-shaped calcified area over the cardiac shadow in the mitral valve area. This appearance is very typical of mitral annular calcification.

Mitral annular calcification occurs in about 10 % of the elderly population. It appears as circular, ovoid, C shaped or J shaped calcification in the mitral annulus. It can lead to mitral incompetence. Its presence on the chest x-ray usually indicates higher risk of cardiovascular events and stroke.

Reference: Fundamentals of Diagnostic Radiology by Brant & Helm’s.