Computed tomography urography with iterative reconstruction algorithm in congenital urinary tract abnormalities in children – association of radiation dose with image quality

Abstract

PurposeTo assess the extent to which a radiation dose can be lowered without compromising image quality and diagnostic confidence in congenital urinary tract abnormalities in children by using a CT scanner with an iterative reconstruction algorithm.Material and methods120 CT urography image series were analysed retrospectively. Image series were divided into four study groups depending on effective radiation dose (group 1: 0.8-2 mSv; group 2: 2-4 mSv; group 3: 4-6 mSv; group 4: 6-11 mSv). Objective and subjective image quality were investigated. In objective analysis, measurements of attenuation and standard deviation (SD) in five regions of interest (ROIs) were performed in 109 excretory image series, and image noise was evaluated. In subjective analysis, two independent radiologists evaluated 138 kidney units for subjective image quality and diagnostic confidence.ResultsThere were no significant differences in image noise in objective evaluation between the following study groups: 2 vs. 3 and 3 vs. 4 in all ROIs (with the only exception in spleen SD measurement between study groups 2 vs. 3), while there was significantly more image noise in group 2 in comparison to group 4. For all other ROIs in all study groups, there was more image noise on lower dose images. There were no significant differences in pairwise comparisons between study groups in subjective image quality. Diagnostic confidence was not significantly different between all study groups.ConclusionsLow-dose CT urography can be a valuable method in congenital urinary tract abnormalities in children. Despite poorer image quality, diagnostic confidence is not significantly compromised in examinations performed with lower radiation doses.

Influence of furosemide on contrast medium distribution in computed tomography urography of high-grade hydronephrosis in children

“…First, scanning parameters were different between patients and radiation exposure assessment was not a goal of this study. However, our recent research already confirmed that there are no significant differences in subjective image quality and diagnostic confidence between lower dose and higher dose examinations [38]. Second, we did not perform objective density measurements of the collecting systems, as there were different doses of furosemide, adapted to patients' weight.…”

Split-bolus CT urography with synchronous nephrographic and excretory phase in dogs: comparison of image quality with three-phase CT urography and optimal allocation ratio of contrast medium

“…The provision of a high radiation dose is an important issue in CTU in human medicine. Many efforts to reduce the radiation dose have been attempted, including reducing the number of imaging phases through the use of dual-energy CT, applying a split-bolus technique, changing the scanning parameters employed such as by lowering tube voltage or applying several iterative reconstruction algorithms [ 17 18 19 ]. Radiation exposure may not be as big a concern in veterinary medicine as it is in humans; however, considering the increased use of CT for assessment of the urinary tract and other organs, as well as the wide availability of multi-detector CT devices, the split CTU technique can reduce radiation exposure.…”