Comparison of dual-source and electron-beam CT for the assessment of coronary artery calcium scoring.

OBJECTIVE: Cardiac CT allows the detection and quantification of coronary artery calcification (CAC). Electron-beam CT (EBCT) has been widely replaced by high-end CT generations in the assessment of CAC. The aim of this study was to compare the CAC scores derived from an EBCT with those from a dual-source CT (DSCT). METHODS: We retrospectively selected 92 patients (61 males; mean age, 60.7 ± 12 years) from our database, who underwent both EBCT and DSCT. CAC was assessed using the Agatston score by two independent readers (replicates: 1, 2; 3=mean of reading 1 and 2). RESULTS: EBCT scores were on average slightly higher than DSCT scores (281 ± 569 vs 241 ± 502; p<0.05). In regression analysis R(2)-values vary from 0.956 (1) to 0.966 (3). We calculated a correction factor as EBCT=(DSCT+1)(1.026)-1. When stratifying into CAC categories (0, 1-99, 100-399, 400-999 and ≥1000), 79 (86%) were correctly classified. From those with positive CAC scores, 7 out of 61 cases (11%, κ=0.81) were classified in different categories. Using the corrected DSCT CAC score, linear regression analysis for the comparison to the EBCT results were r=0.971 (p<0.001), with a mean difference of 6.4 ± 147.8. Five subjects (5.4%) were still classified in different categories (κ=0.84). CONCLUSION: CAC obtained from DSCT is highly correlated with the EBCT measures. Using the calculated correction factor, agreement only marginally improved the clinical interpretation of results. Overall, for clinical purposes, face value use of DSCT-derived values appears as useful as EBCT for CAC scoring.

Concomitant atherosclerotic disease detected by whole-body MR angiography in relation to coronary artery calcification in patients with coronary artery disease.

PURPOSE: Patients with coronary artery disease (CAD) show a high prevalence for concomitant atherosclerotic peripheral arterial disease (PAD). On the other hand, PAD seems to be an additional risk factor for cardiac events. We evaluated the correlation between arterial pathologies as found in whole-body MR angiography and coronary artery calcification (CAC) detected by electron beam computed tomography (EBCT) and multislice CT (MSCT). MATERIALS AND METHODS: Two hundred and twenty-eight patients (161 men; 67 women) with suspicion for CAD/known CAD underwent whole-body contrast-enhanced MR angiography (wb-ce-MRA) and EBCT/MSCT. An atherosclerosis index was calculated for each patient Index = (40)Sigma(n=1) w(i) with w(i) being the grading of the stenosis of the i (ten) of 40 arteria segments (grade: 0 - no plaque; 1 - plaque - < or = 50 % stenosis; 2 - > 50 % stenosis - < or = 90 % stenosis; 3 - > 90 % stenosis - < 100 % stenosis; 4 - occlusion). Correlations between CAC and atherosclerosis index were performed. RESULTS: Wb-ce MRA and CAC correlate only moderately in this population. An atherosclerosis index 8 renders a positive predictive value for a CAC 100 of 63.3 %. CONCLUSION: An atherosclerosis index as defined in this study does not fully correlate with the extent of CAD as revealed by catheter angiography or EBCT/MSCT, but it might theoretically mirror the increased risk by PAD. It thus might be a promising complementary parameter for the prediction of cardiac events. Future studies need to show its possible additional predictive impact.