Spiral versus electron-beam CT for coronary artery calcium scoring

PURPOSE: To determine differences in coronary artery calcium detection, qua ntification, and reproducibility, as measured at electron-beam computed tom ography (CT) and subsecond spiral CT with retrospective electrocardiogram g ating in an asymptomatic adult population. MATERIALS AND METHODS: Seventy subjects asymptomatic for coronary heart dis ease underwent both electron-beam CT and subsecond spiral CT. In all subjec ts, two images each were obtained with both scanners. Two experienced reade rs using three different algorithms scored each of the four scans: one scor e for the electron-beam CT images and two scores for the spiral CT images. RESULTS: With a 130-HU threshold for the quantification of calcium, there w ere no significant differences in interscan and interobserver variation in calcium scores between the electron-beam CT and spiral CT images. There was greater interobserver (P < .001) and interscan (P < .03) variation in scor es when a 90-HU threshold was used for spiral CT images. With a 130-HU thre shold, when calcium scores were used for clinical risk stratification, ther e was a significant difference between the results obtained with electron-b eam CT and those obtained with spiral CT (P < .05). CONCLUSION: Spiral CT has not yet proved to be a feasible alternative to el ectron-beam CT for coronary artery calcium quantification. There are system atic differences between calcium scores obtained with single-detector array subsecond spiral CT and those obtained with electron-beam CT.