1 Brady Urological Institute and Department of Urology, Johns Hopkins School of Medicine , Baltimore, Maryland.
2 Division of Urology, Department of Surgery, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania.
J Endourol. 2018 Aug;32(8):685-691. doi: 10.1089/end.2018.0326. Epub 2018 Jul 13.
CT is the gold standard for visualizing renal and ureteral calculi. CT three-dimensional reformatting allows for automatic, accurate, and reliable measurement of stone size, volume, density, and location. In this study, we aimed to develop and test a software platform capable of calculating a battery of clinically important urinary stone parameters at the point-of-care (POC).
The syngo Calcium Scoring (Siemens Corporation) algorithm was modified to identify calcium-based stones using an attenuation threshold (250 HU) within a region of interest. Information automatically obtained after reconstruction included voxel sum and calculated volume, maximum diameter, largest diameter in the x, y, and z planes, cumulative diameter, distribution of attenuation in HU, and position relative to the skin for calculation of the skin-to-stone distance (SSD). This algorithm was packaged into a stand-alone application (MATLAB 9.1). From April 2017 to May 2017, all patients undergoing a noncontrast CT of the abdomen or the abdomen and pelvis at the Johns Hopkins Hospital were eligible for inclusion in this validation cohort.
A total of 55 index renal stones were included. The mean volume calculated by voxel sum was 216.53 mm (standard deviation [SD] ±616.19, range 1.50-4060.13). The mean volume calculated using the Ackermann's formula and for a sphere was 232.96 mm (SD ± 702.65, range 1.24-4074.04) and 1214.63 mm (SD ± 4233.41, range 1.77-25,246.40), respectively. The mean largest diameter in any one direction was 6.95 mm (SD ± 7.31, range 1.50-36.40). The maximum density of the stones ranged from 164 to 1725 HU. The mean SSD at the shortest possible point was 14.19 cm (SD ± 6.13, range 6.67-31.28).
We developed a stand-alone platform with a simple easy-to-use interface, which will allow any user the ability to calculate a battery of clinically important urinary stone parameters from CT imaging at the POC. This program is now freely available online.
CT 是可视化肾和输尿管结石的金标准。CT 三维重建可自动、准确、可靠地测量结石的大小、体积、密度和位置。本研究旨在开发和测试一个能够在即时护理点（POC）计算一系列重要临床尿石参数的软件平台。
使用西门子公司的 syngo Calcium Scoring（钙评分）算法，通过感兴趣区内的衰减阈值（250 HU）识别含钙结石。重建后自动获得的信息包括体素总和和计算的体积、最大直径、在 x、y 和 z 平面的最大直径、累积直径、HU 衰减分布以及相对于皮肤的位置，以计算皮肤-结石距离（SSD）。该算法被封装到一个独立的应用程序（MATLAB 9.1）中。2017 年 4 月至 2017 年 5 月，约翰霍普金斯医院所有接受腹部或腹部和骨盆非对比 CT 的患者均有资格纳入本验证队列。
共纳入 55 个指数肾结石。体素和计算的平均体积为 216.53mm（标准差[SD]±616.19，范围 1.50-4060.13）。使用 Ackermann 公式和球体计算的平均体积分别为 232.96mm（SD±702.65，范围 1.24-4074.04）和 1214.63mm（SD±4233.41，范围 1.77-25246.40）。任意一个方向的最大直径平均值为 6.95mm（SD±7.31，范围 1.50-36.40）。结石的最大密度范围为 164-1725HU。最短可能点的平均 SSD 为 14.19cm（SD±6.13，范围 6.67-31.28）。
我们开发了一个具有简单易用界面的独立平台，任何用户都可以使用该平台在即时护理点（POC）从 CT 成像计算一系列重要的临床尿石参数。该程序现在可在网上免费获得。
