Wide volume versus helical acquisition using 320-detector row computed tomography for computed tomography urography in adults

Purpose: To evaluate the best collimation used in wide volume (WV) mode to cover the abdomen in computed tomography (CT) urography in terms of radiation dose and image quality. Materials and methods: This study was performed on a 320 x 0.5 mm detector row CT unit. The first part identified the lowest volume CT dose index (CTDIvol) by using the topograms data of 25 medium size patients (13 men and 12 women; mean age: 52+9 [SD] years; age range: 46-68 years) using different collimations on WV from 6 cm to 16 cm and the one of the helical mode for the same coverage length. The second part consisted of a clinical evaluation result including 45 medium size patients (32 men and 13 women; mean age: 68 +/- 14 [SD] years; age range: 45-72 years). The qualitative evaluation included several items based on a 5-point Likert scale. Results: The first part of the study indicated that a collimation of 10cm (200 x 0.5mm) in WV mode with 5 volumes had the lowest CTDIvol (2.78 +/- 0.35 mGy; range: 2.35-3.21 mGy) compared to helical mode (4.38 +/- 0.48 mGy, range: 3.75-4.95 mGy). In the second part, the mean radiation dose reduction by comparison with helical mode was 44.03% +/- 0.36% (P< 0.001) and 51.16% +/- 1.22% (P< 0.005) for CTDIvol and DLP, respectively. Conclusion: Wide volume mode of the abdomen can be performed with a significant radiation dose reduction with a collimation of 10cm (200 x 0.5 mm) and five volumes. (C) 2018 Societe francaise de radiologie. Published by Elsevier Masson SAS. All rights reserved.