Coronary artery calcium score: influence of the reconstruction interval on cardiac risk stratification in asymptomatic patients using dual-source computed tomography.

ABSTRACT

PURPOSE: To evaluate the impact of the reconstruction interval on coronary calcium score and cardiac risk stratification using dual-source computed tomography (DSCT). MATERIALS AND METHODS: DSCT coronary calcium scoring was performed in 61 consecutive patients, and five data sets per patient were reconstructed within diastole (50 - 70 % of the R-R interval). The Agatston score, volumetric score and the relative variability were assessed for all reconstructions. To assess the individual cardiovascular risk, patients were assigned to risk groups based on age and gender-matched percentile ranks. RESULTS: The mean Agatston score was 184.8 ± 377.9 (relative variability 47 % ± 52 %). The mean volumetric score was 164.4 ± 310.1 (relative variability 49 % ± 58 %). There was a negative correlation between the total Agatston score and the relative variability (r = -0.37; p < 0.01). Depending on the reconstruction interval used, 18 predominantly young patients were assigned to more than one risk group. CONCLUSION: Despite the increased temporal resolution of DSCT examinations, the Agatston and volumetric scores depend on the reconstruction time within the cardiac cycle. The fact that the greatest relative variability for both the Agatston score and the volumetric score was found in young patients with small amounts of coronary calcium may result in different treatment strategies for young patients depending on the reconstruction used. Therefore, more accurate risk stratification may require the analysis of multiple reconstruction intervals.