Bell John Roger, Posielski Natasza M, Penniston Kristina L, Lubner Meghan G, Nakada Stephen Y, Pickhardt Perry J
1 Department of Urology, University of Kentucky College of Medicine , Lexington, Kentucky.
2 Department of Urology, University of Wisconsin School of Medicine and Public Health , Madison, Wisconsin.
J Endourol. 2018 May;32(5):455-461. doi: 10.1089/end.2017.0787. Epub 2018 Apr 2.
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. We tested a novel stone software program designed to provide an automated and objective comprehensive CT-based stone profile.
Urinary stones identified on CT imaging were manually measured to obtain linear size and maximal stone density (in Hounsfield unit [HU]). Manual stone volume was calculated using the formula 0.52 × length × width × height. The same stones were assessed with computer software capable of automatically providing stone length, density, and volume. Computer measurements were compared with manual measurements.
Eighty-five stones were identified on 42 CT scans from 17 patients. Manual measurements showed an average length of 8 mm (range 1.9-21 mm), average maximal density of 686 HU (126-1492 HU), and average stone volume of 192 mm (2.9-2555 mm). Automated computer measurements did not differ from manual measurements for density (755 HU vs 686 HU, p = 0.18) and volume (183 mm vs 192 mm, p = 0.86. Automated length was slightly longer then manual length (10 mm vs 8 mm, p < 0.003). The mean percent differences between manual and automated metrics were 14.3% for density, 21.0% for volume, and 25.2% for length.
Automated stone measurements can be accomplished quickly and precisely with dedicated software that can assess stones of varying size as well as stones with complex geometry. This software eliminates interobserver variability and offers a comprehensive stone profile with which to make clinical decisions.
结石大小指导治疗决策，但目前尚无测量结石大小的标准方法。先前的研究表明，手动测量结石存在显著差异。我们测试了一种新型结石软件程序，旨在提供基于CT的自动化、客观的结石综合轮廓。
对CT成像上识别出的尿路结石进行手动测量，以获取线性尺寸和最大结石密度（以亨氏单位[HU]表示）。使用公式0.52×长×宽×高计算手动结石体积。使用能够自动提供结石长度、密度和体积的计算机软件对相同的结石进行评估。将计算机测量结果与手动测量结果进行比较。
在17例患者的42次CT扫描中识别出85颗结石。手动测量显示平均长度为8毫米（范围1.9 - 21毫米），平均最大密度为686 HU（126 - 1492 HU），平均结石体积为192立方毫米（2.9 - 2555立方毫米）。自动化计算机测量的密度（755 HU对686 HU，p = 0.18）和体积（183立方毫米对192立方毫米，p = 0.86）与手动测量无差异。自动化测量的长度略长于手动测量的长度（10毫米对8毫米，p < 0.003）。手动和自动化测量指标的平均百分比差异为：密度14.3%，体积21.0%，长度25.2%。
使用专用软件可以快速、精确地完成结石的自动化测量，该软件能够评估不同大小以及具有复杂几何形状的结石。该软件消除了观察者间的差异，并提供了用于临床决策的综合结石轮廓。
