Methods: Pelvic CT examinations in bladder cancer patients were reconstructed at different slice thicknesses (0.6 mm-5 mm) and intervals, and resulting VC images assessed. Quality indicators were ridging, holes, floaters and dimpling artefacts, tumour definition, and an overall score, ranked 1(best) to 7 (worst). CT number and standard deviation (SD) for bladder contents and bladder wall were recorded. The mean SD was used as a measure of noise, and the contrast to noise ratio (CNR) was calculated as the CT number difference between them divided by the average image noise. The mean CNR across the three levels was used for analysis. Each qualitative image quality measure was compared to CT number, noise and CNR measurements.
Results: Dimpling artefacts increased with thinner slice reconstruction and correlated with increased noise, often resulting in poor tumour definition. The best overall image quality score was seen for VC images reconstructed at 1.2 mm slice thickness, probably due to the competing effects of spatial resolution and CNR.
Conclusion: A slice thickness reconstruction less than 1.2 mm does not provide for better image quality at VC due to the presence of increased noise.
Written by:
Lalondrelle S, Sohaib SA, Castellano IA, Mears D, Huddart R, Khoo V. Are you the author?
Academic Urology Unit, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, London, UK.
Reference: Br J Radiol. 2012 Jan 3. Epub ahead of print.
PubMed Abstract
PMID: 22215882
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