Single- and dual-energy CT of the abdomen: comparison of radiation dose and image quality of 2nd and 3rd generation dual-source CT

To compare single-energy (SECT) and dual-energy (DECT) abdominal CT examinations in matched patient cohorts regarding differences in radiation dose and image quality performed with second- and third-generation dual-source CT (DSCT). We retrospectively analysed 200 patients (100 male, 100 female; mean age 61.2 +/- 13.5 years, mean body mass index 27.5 +/- 3.8 kg/m(2)) equally divided into four groups matched by gender and body mass index, who had undergone portal venous phase abdominal CT with second-generation (group A, 120-kV-SECT; group B, 80/140-kV-DECT) and third-generation DSCT (group C, 100-kV-SECT; group D, 90/150-kV-DECT). The radiation dose was normalised for 40-cm scan length. Dose-independent figure-of-merit (FOM) contrast-to-noise ratios (CNRs) were calculated for various organs and vessels. Subjective overall image quality and reader confidence were assessed. The effective normalised radiation dose was significantly lower (P < 0.001) in groups C (6.2 +/- 2.0 mSv) and D (5.3 +/- 1.9 mSv, P = 0.103) compared to groups A (8.8 +/- 2.3 mSv) and B (9.7 +/- 2.4 mSv, P = 0.102). Dose-independent FOM-CNR peaked for liver, kidney, and portal vein measurements (all P > 0.0285) in group D. Subjective image quality and reader confidence were consistently rated as excellent in all groups (all 1.53 out of 5). With both DSCT generations, abdominal DECT can be routinely performed without radiation dose penalty compared to SECT, while third-generation DSCT shows improved dose efficiency. aEuro cent Dual-source CT (DSCT) allows for single- and dual-energy image acquisition. aEuro cent Dual-energy acquisition does not increase the radiation dose in abdominal DSCT. aEuro cent Third-generation DSCT shows improved dose efficiency compared to second-generation DSCT. aEuro cent Dose-independent figure-of-merit image contrast was highest with third-generation dual-energy DSCT. aEuro cent Third-generation DSCT shows improved dose efficiency for SECT and DECT.