Image Quality and Dose Reduction by Dual Source Computed Tomography Coronary Angiography: Protocol Comparison

Purpose: To compare image quality and radiation dose among different protocols in patients who underwent a 128-slice dual source computed tomography coronary angiography (DSCT-CTCA). Methods: Ninety patients were retrospectively grouped according to heart rate (HR): 26 patients (group A) with stable HR 60 bpm or stable HR >= 70 bpm by retrospective electrocardiogram pulsing acquisition. Signal to noise ratio (SNR) and contrast to noise ratio (CNR) were measured for the main vascular structures. Moreover, the dose-length product and the effective dose were assessed. Results: Both SNR and CNR were higher in group A compared to group C (18.27 +/- 0.32 vs I 1.22 +/- 0.50 and 16.75 +/- 0.32 vs 10.17 +/- 0.50; P = .001). The effective dose was lower in groups A and B (2.09 +/- 1.27 mSv and 4.60 +/- 2.78 mSv, respectively) compared to group C (9.61 +/- 5.95 mSv) P < .0001. Conclusion: The correct selection of a low-dose, HR-matched CTCA scan protocol with a DSCT scanner provides substantial reduction of radiation exposure and better SNR and CNR