Calcification of the cardiac valves and adjacent tissues has long been known to both clinicians and pathologists. Previous rheumatic endocarditis has been considered the cause of the calcification, and this is of clinical importance. The incidence of calcification associated with rheumatic valvular disease has been examined on the basis of autopsy findings by Epstein (1940) among others; he found calcification that varied in size from microscopically small particles to large calcareous masses in 64 out of 148 cases. This calcification not only involves the cardiac valve leaflets, but may also appear in the annulus fibrosus, the wall of the left atrium, and the papillary muscles. Similar calcification may develop without previous rheumatic infection, especially after middle age. Simon and Liu (1954) found calcification of the mitral valve annulus in 10 per cent of 590 unselected, consecutive autopsies and, like some others, observed that the incidence increased with age. The occurrence of calcification within the heart at X-ray examination was noted fairly early. Thus, for instance, Klason (1921) described a case of partial calcification of the mitral ring observed by fluoroscopy. Saul (1932) was apparently the first to publish X-ray pictures of three cases of this kind. Subsequently isolated cases or small series have been reported (e.g. Sossman and
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