yes / Introduction: Reducing tube voltage is an effective dose saving method in
computed tomography (CT) assuming tube current is not concurrently
increased. Recent innovations in scanner technology now enable CT tube
voltage reduction to 70 kV thereby increasing opportunities for dose reduction
in paediatric patients, but it is unclear if the increased image noise associated
with 70 kV impacts on ability to visualise renal stones accurately. The purpose
was to assess detectability of nephrolithiasis using a bespoke paediatric
phantom and low kV, non-contrast CT and to assess inter-observer agreement.
Methods: Forty-two renal stones of different size and chemical composition
were inserted into porcine kidneys and positioned in a bespoke, water-filled
phantom mimicking a 9-year-old child weighing approximately 33kg. The
phantom was scanned using 120 and 70 kV CT protocols, and the detectability
of the stones was assessed by three radiologists. Absolute agreement and Fleiss’
kappa regarding detectability were assessed. Results: The mean diameter of
renal stones as measured physically was 4.24 mm ranging from 1 to 11 mm.
Four stones were missed by at least one observer. One observer had a
sensitivity of 93 and 95% at 70 and 120 kV, respectively, while the sensitivity
for observers 2 and 3 was 98% at both kV levels. Specificity was 100% across
readers and kV levels. Absolute agreement between the readers at 70 kV was
92% (kappa = 0.86) and 98% (kappa = 0.96) at 120 kV indicating a strong
agreement at both kV levels. Conclusions: The results suggest that lowering the
kV does not affect the detection rate of renal stones and may be a useful dose
reduction strategy for assessment of nephrolithiasis in children.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/18540 |
| Date | 18 June 2021 |
| Creators | Mussmann, B., Hardy, Maryann L., Jung, H., Ding, M., Osther, P.J., Fransen, M.L., Greisen, P.W., Graumann, O. |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Article, Published version |
| Rights | © 2021 The Authors. Published by John Wiley & Sons Australia, Ltd on behalf of Australian Society of Medical Imaging and Radiation Therapy and New Zealand Institute of Medical Radiation Technology. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. |
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