Skip to Content
Authors Bell JR, Posielski NM, Penniston KL, Lubner MG, Nakada SY, Pickhardt PJ
Author Profile(s)
Journal J. Endourol.
Publish Date 2018 Feb 21
PubMed ID 29466878

Introduction and Objective Stone size guides treatment decisions, yet there is no standard method for measuring stone size. Prior work has shown significant variability in manual stone measurements (Patel J Urol 2012). We tested a novel stone software program designed to provide an automated and objective comprehensive CT-based stone profile. Methods Urinary stones identified on CT imaging were manually measured to obtain linear size, maximal stone density (in HU). Manual stone volume was calculated using the formula 0.52 x Length x Width x Height. The same stones were assessed with computer software capable of automatically providing stone length, density, and volume. The percent difference was compared between the manual measurements and the automated software data. Results 85 stones were identified on 42 CT scans from 17 patients. Stones were an average of 8 mm (1.9-21mm) with an average maximal density of 686 HU (126-1492 HU) and average stone volume of 192 mm3 (2.9-2555 mm3). The mean percent differences were 14.3% for density, 21.0% for volume and 25.2% for length. Conclusion Automated stone measurements can be accomplished quickly and precisely with dedicated software which can assess stones as small as 1.9 mm as well as stones with complex geometry. This software eliminates interobserver variability and offers a comprehensive stone profile with which to make clinical decisions. Copyright © 2018 The Board of Regents of the University of Wisconsin System