64-Slice spiral computed tomography of the coronary arteries: dose reduction using an optimized imaging protocol including individual weight-adaptation of voltage and current-time product.

Radiation dose and image quality were compared between a standard protocol (40 patients, group A) and a weight-adapted protocol of voltage and current-time product (44 patients, group B) using 64-slice coronary multidetector computed tomography (MDCT). Effective dose estimate was lower by 37% in all patients of group B (9.2 +/- 2.5 mSv) compared with group A (14.6 +/- 2.3 mSv, P < 0.0001). Group B patients with a small body mass index (BMI) benefited most with a dose reduction of 53% (6.7 +/- 1.5 mSv in group B versus 14.1 +/- 1.8 mSv in group A, P < 0.0001). Moderate reductions of 32% and 20% were achieved for patients with a medium and large BMI, respectively. Reduction in radiation dose did not affect the image quality as assessed by image noise, signal-to-noise ratios, and number of coronary segments with good diagnostic image quality. Individual weight-adaptation of voltage and current-time product significantly reduces the radiation dose without loss of image quality.