EAU 2017: Validation Of Automated Kidney Stone Volumetry In Low Dose Computed Tomography

London, England (UroToday.com) Do we finally have a software that accurately measures the stone volume?

Stone size is the most significant factor that drives all surgical outcomes. Accurate and reliable measurement of stone size is so important for surgical planning and predicting postoperative outcomes. However, to this date there is a lack of means to measure the stone size. There are many radiology-based applications and tools but they are mostly cumbersome and not easily available for urologists to use during the busy clinic. Additionally, most of them require significant skills, which is associated with a steep learning curve.

Wilhelm and colleagues developed automated software to measure stone volume. In this presentation they reported their single center validation study.

They assessed the software in 109 human stones with a diameter of at least 5mm. Measurements were carried out by three urologists independently, assessing the maximum diameter using the automated software. All three urologists received equal amount of training for the software prior to starting the study. Results were recorded and interrater correlation with a Single Score Intraclass Correlation Modelwere performed to assess the reproducibility and reliability.

Authors presented that the interrater correlation for the reference measures was 0.99 for the diameter and volume which is excellent. The mean reference diameter was 13.3mm (5.2-32.1). The correlation of the automated radiologic diameter with the reference value was 0.91. The radiologic assessment by hand correlated significantly better (0.98, p=<0.001). The correlation of the reference value with the automated radiologic volume assessment was 0.99 and significantly better compared to the calculated values based on hand measurements (0.95, p=<0.001).

In conclusions, the automated measurement of stone volume based on CT scans is feasible and the accuracy is significantly higher as compared to volumetric calculations based on the diameter using the old methods. Such calculations depend on the shape of the stone. In order to avoid bias in clinical trials, size should be measured as volume or a combination of diameter and volume.

Authors speculated that this software is the first generation and future iterations will improve the measurements even more. We believe that this software will significantly help the urologists measure the stone volume in an easy and accurate manner.

Speaker(s): Karl Wilhelm, MD

Authors: Wilhelm K.1, Hein S.1, Schlager D.1, Adams F.1, Miernik A.1, Schoenthaler M.1, Hesse A.2, Neubauer J.3

Institution(s): 1Faculty of Medicine and Medical Center - University of Freiburg, Center For Surgery Department of Urology, Freiburg, Germany, 2University of Bonn, Department of Urology, Division of Experimental Urology, Bonn, Germany, 3Faculty of Medicine and Medical Center - University of Freiburg, Department of Radiology, Freiburg, Germany

at the #EAU17 - March 24-28, 2017- London, England