Quantative Analysis of Mitral Valvular Calcification in Mitral Stenosis

Park, Si Hoon; Chung, Namsik; Cho, Seung Yon; Shin, Dong Hwan; Kim, Sun Il

Abstract

BACKGROUND
Conventional echocardiography provides fundamental information about mitral valve morphology and function but is often subjective and has a relatively low specificity in evaluating valve calcific deposit, which is critical information for the preoperative decision. We hypothesized that mitral valvular calcification could be detected in standard two-dimensional echocardiograms of mitral valve in vivo by evaluating regional gray level(echo amplitude) using computerized image analysis so that we could overcome the subjectivity and low specificity of conventional echocardiography.
METHODS
We tested this hypothesis by performing standard 2.5MHz two-dimensional echoes on mitral valve and myocardium in 30 patients with mitral stenosis, scheduled to undergo mitral valve replacement. We compared gray level of each region of interest in mitral valve and myocardium in stop-frame images with the degree of calcifications identified by pathologic and radiographic examinations.
RESULTS
Ratio of mean gray level of mitral valve to mean gray level of myocardium was the most reliable value in evaluating degree of calcification. Quantitatively, region of calcification displayed the ratio of significantly higher value than that of no calcification. In case of anterior mitral valve, the ratio of the evident calcified region was greater than 3.11, that of the region without calcification was less than 2.42 and that of microcalcification was betwwn 2.42 and 3.11. For posterior mitral valve, the ratio of the evident calcified region was greater than 3.50, that of the region without calcification was less than 2.19 and that of microcalcification was between 2.19 and 3.50. The sensitivity and specificity of this method for assessment of degree of calcification was 75% and 100% for anterior mitral valve and 9% and 87.5% for posterior mitral valve.
CONCLUSION
Mitral valvular calcification could be detected quantitatively in standard two dimensional echocardiograms of mitral valve in vivo by evaluating regional gray level(echo amplitude) using computerized image analysis.