Measurement of coronary artery calcium with dual-slice helical CT compared with coronary angiography: evaluation of CT scoring methods, interobserver variations, and reproducibility.

This study was performed to evaluate new scoring methods for quantitating coronary artery calcifications with helical CT and to compare the results with those of quantitative coronary angiography in patients with suspected coronary artery disease.Unenhanced dual-slice helical CT and coronary angiography were performed within 24 hr of each other in 101 patients with symptoms of coronary artery disease. Coronary artery calcifications with a density above 90 H were identified on each slice and, with the same regions of interest, quantitative scoring was performed at thresholds of 90 H (new) 130 H (old). Two mathematical algorithms (one new and one old) were evaluated for both thresholds (yielding four scoring systems). By CT imaging, we defined disease as a score of greater than zero. By angiography, we defined disease as a 50% or greater reduction in the luminal diameter of any major vessel. Interobserver variations in calcification scoring were evaluated. Seventeen of our patients. also underwent a second,...