EAU 2018: Automatic Measurement of Mean Stone Density by Three-dimensional Stone Images For Predicting Shock Wave Lithotripsy Success
In the study, 239 patients who underwent both pretreatment non-contrast computed tomography (CT) and SWL for upper urinary tract calculi were retrospectively enrolled. MSD and stone volume were automatically measured from CTs of those patients. Two manual methods of measurement were also included involving the abdominal windows and the pelvic windows. The first was to measure MSD through region of interest incorporation of stone without inclusion of adjacent soft tissues. The second was calculation of MSD based on three consistent, small, non-overlapping ROI chosen for each stone. Furthermore, successful SWL was determined to be absence of stones or residual fragments detected by CT within 3 months after first SWL.
In the results, patient demographics and stone parameters were provided, including 48.5% success in SWL treatment rate. When compared with the manual methods stated above, MSD in successful SWL group was significantly lower than that of unsuccessful SWL group. Additionally, of the 5 methods examined, the effect size of 3D imaging was the highest, with a matching rate of 74.9%. Multivariate regression model also showed that MSD was an independent contributor for residual stones.
In conclusion, Dr. Yamashita states that the automatic measurement of MSD by 3D stone images were more accurate and reproducible, therefore is more useful than previous manual measuring modalities for predicting SWL outcomes.
Speaker: Dr. Yamashita
Authors: Yamashita S., Kohjimoto Y., Iwahashi Y., Iguchi T., Iba A., Hara I.
Written by: Whitney Zhang, Department of Urology, University of California-Irvine, at the 2018 European Association of Urology Meeting EAU18, 16-20 March, 2018 Copenhagen, Denmark