Abstract 2200: Randomized Comparison of Dual Source Computed Tomography and 64-Slice Multi-Detector Computed Tomography for the Detection of Coronary Artery Stenoses
Multi-detector CT (MDCT) has been shown to permit evaluation of the coronary arteries. However, image quality and evaluability is frequently impaired at higher heart rates. Therefore the use of β-blockers is usually required. Dual Source CT (DSCT) provides increased temporal resolution (83 ms). We directly compared the diagnostic accuracy of DSCT coronary angiography (Definition, Siemens) without β-blocker pre-medication in comparison to 64-slice MDCT (Sensation 64, Siemens) with β-blocker administration.
Methods: 80 consecutive patients (43 female, 37 male, mean age 64 y) referred for invasive coronary angiography due to suspected coronary artery disease were prospectively randomised either to DSCT or MDCT. In the MDCT group (n = 40 pts.), all patients with a heart rate > 60/min (n = 37) received 100 mg atenolol p.o. one hour prior to the scan, followed by up to 20 mg metoprolol i.v. if heart rate was still > 60/min. No β-blocker medication was given in the DSCT group (n = 40 pts.). DSCT (two tubes, 330 ms gantry rotation, 120 kV, 380 mAs, collimation 64 x 0.6 mm each, 50 mL of contrast-agent) and MDCT coronary angiography (330 ms gantry rotation, 120 kV, 380 mAs, collimation 64 x 0.6 mm, 60 to 80 mL of contrast-agent,) were evaluated on a per-artery basis concerning presence of stenoses > 50% diameter reduction. Results were compared to quantitative coronary angiography.
Results: Heart rate during DSCT (68 ± 13 bpm) was higher compared to MDCT (60 ± 7 bpm, p = 0.03). In the MDCT group, 146 of 160 coronary arteries (left main, left anterior descending, left circumflex and right coronary artery, including side branches with a diameter of more than 1.5 mm in 40 patients) could be evaluated (91%), while in the DSCT group 97% of all arteries were evaluable (p = 0.033). In evaluable arteries, sensitivity, specificity, negative and positive predictive value were 88% (15/17), 96% (124/129), 98% (124/126) and 75% (15/20) in the MDCT group versus 90% (18/20), 95% (128/135), 98% (128/130) and 72% (18/25) in the DSCT group. Overall diagnostic accuracy (with unevaluable arteries classified as incorrect diagnosis) was 87 % (139/160) in MDCT versus 91% (146/160) in DSCT (p = 0.21).
Conclusion: The higher temporal resolution of DSCT may overcome the clinical limitations of 64-slice MDCT.