Performance of iterative reconstruction and automated tube voltage selection on the image quality and radiation dose in abdominal CT scans

To study the impact of sinogram-affirmed iterative reconstruction (SAFIRE) and concurrent application of automated tube voltage selection (ATVS) on image quality (IQ) and radiation dose. A phantom was scanned using various computed tomography (CT) parameters (kV, 80-120; mAs, 50-200). Abdomen contrast-enhanced CT (CECTs) in 170 adults were performed using dose-modified protocols: in 145 patients (group I), ATVS was applied (mAs, 111-649); in 25 (group II), the kV was fixed at 120 (reference mAs, 150). In 95 patients, standard-dose (SD) scan was available. Two readers evaluated the IQ of filtered back projection (FBP) and SAFIRE (levels 1, 3, and 5) images. In phantom, nonlinear drop in noise with increasing strengths of IR (levels S1-S5) was noted. The dose-modified IR scan was rated diagnostic in all 170 patients, with IQ score comparable to that of SD-FBP (P = 0.3). Lower kV (100/80) was prescribed by ATVS in 70% examinations in group I. In comparison with SD-FBP, the mean dose in CT dose index in group I (IR, 3.2 mGy; SD-FBP, 13.02 mGy; P < 0.0001) and in group II (IR, 4.8 mGy; SD-FBP, 11.8 mGy; P < 0.001) was 75.4% and 59.3% lower. Use of SAFIRE and ATVS provides diagnostic quality images at 59.3% to 75.4% reduced dose compared with SD-FBP scan.