Radiation dose exposure in multislice computed tomography of the coronaries in comparison with conventional coronary angiography

Background Radiation dose exposure is increased in multislice spiral computed tomography (MSCT) compared to conventional coronary angiography (CXA). Methods Retrospective data analysis of 56 patients (66 ± 8 years, 49 males, body surface area 1.98 ± 0.18 m2, heart rate 64 ± 11 bpm) who underwent MSCT and CXA was performed (MSCT: 16-slice scanner, rotation time 0.375 s, 120 kV, ECG-pulsing; CXA: current technique system build in 2003). Ten patients with bypass grafts underwent bypass angiography in CXA and MSCT. To compare the radiation doses of both investigations, the effective dose (ED) was chosen as the analysis variable. Results The mean ED for MSCT was 9.76 ± 1.84 mSv (n = 46) for patients without bypass grafts; with calcium scoring the mean ED was 12.46 ± 2.23 mSv (n = 46). In comparison, the mean ED of CXA was 2.60 ± 1.27 mSv (n = 46) for patients without bypass grafts; with bypass grafts (n = 10) the mean ED for MSCT was 12.95 ± 1.75 mSv, for CXA of 6.27 ± 4.04 mSv, respectively. In MSCT heart rates of ≤ 60 bpm resulted in lower mean ED than heart rates of > 60 bpm (8.86 ± 1.24 mSv versus 10.53 ± 1.86 mSv). Conclusions MSCT is still associated with a higher radiation dose exposure than CXA. The radiation dose relation is more favorable for MSCT than for CXA in patients with bypass grafts in comparison to patients without bypass grafts. This study emphasizes the importance of dose reduction techniques.