Optimization of the scan protocol in the measurements of coronary artery calcium

The aim of this study was to evaluate the influence of the tube current applied for studies of calcium score. The research was carried out in a private clinic of Rio de Janeiro, using a 64-slice MDCT scanner and an anthropomorphic cardiac CT phantom. In all images, the Agatston score, the volume and mass of the calcifications, and the noise for each current tube was determined. The average CT attenuation number obtained for all tube currents was 261.6 ± 3.2 HU for the CaHA density insert and -0.2 HU ± 2.0 for the water insert. The images obtained at lower tube currents were noisier and grainier than those obtained at higher tube currents. However no significant differences were found in the calcium measurements, which suggest a high potential of patient dose reduction, around 50%, without compromising diagnostic information. (author)