Making renal stones change size—impact of CT image post processing and reader variability
- نوع فایل : کتاب
- زبان : انگلیسی
- مؤلف : Mats Lidén & Torbjِrn Andersson & Hهkan Geijer
- چاپ و سال / کشور: 2011
Description
Objectives The objectives of this study were to quantify the impact of image post-processing parameters on the apparent renal stone size, and to quantify the intra- and inter-reader variability in renal stone size estimation. Methods Fifty CT datasets including a renal or ureteral stone were included retrospectively during a prospective inclusion period. Each of the CT datasets was postprocessed in different ways regarding slice thickness, slice increment and window setting. In the first part of the study a single reader repeated size estimations for the renal stones using different post-processing parameters. In the intrareader variability experiment one reader reported size estimations for the same images with a one-week interval. The inter-reader variability data were obtained from 11 readers reporting size estimations for the same renal stones. Results The apparent stone size differed according to image post-processing parameters with the largest mean differences seen with regard to the window settings experiment (1.5 mm, p<0.001) and slice thickness (0.8 mm, p<0.001). Changes in parameters introduced a bias and a pseudorandom variability. The inter-reader variability was considerably larger than the intra-reader variability. Conclusion Our results indicate a need for the standardisation of making measurements on CT images.
Eur Radiol DOI 10.1007/s00330-011-2171-x Received: 18 January 2011 / Revised: 24 March 2011 / Accepted: 29 April 2011
