利用双源双能量CT鉴别尿路离体结石成分的研究

目的以尿路结石红外光谱分析为参照标准，评价双源双能量CT鉴别离体尿酸盐和非尿酸盐尿路结石成分的能力。材料与方法收集2011年7月-2012年6月期间共308例病人的离体尿路结石在第一代双源CT机上以双能量模式进行离体扫描，利用肾结石成分分析软件区分尿酸和非尿酸结石，其中尿酸结石被编码为红色，而非尿酸结石被编码为蓝色。各抽取30个尿酸和非尿酸结石进行不同管电压条件下CT值的测量。计算双能量CT区分尿酸和非尿酸结石的准确度。结果308例尿路结石病人中，60例为尿酸结石，248例为非尿酸结石。尿酸结石在80kV[（375．8±69．2）HU]和140kV[（374．1±69．4）HU]管电压下CT值的变化不大（t=-0．217，P=0．830），而非尿酸结石在80kV[（1455．1±312．4）Hu]的CT值明显高于140kV[（1039．6±194．4）HU]（t=-12．16，P〈0．001）。80kV、140kV和平均加权像上非尿酸结石的CT值[分别为（1455．1±312．4）HU、（1039．6±194.4）HU、（882．0±176．4）HU]高于尿酸结石[分别为（375．8＋69．2）HU、（374．1±69．4）HU、（366．3±80．1）HU]（均P〈0．001）。以红外线光谱结果为参照标准，双能量CT鉴别尿酸和非尿酸结石的准确度为100％。结论双源双能量CT能准确区分尿酸和非尿酸结石，在尿路结石治疗方案的制定中具有重要价值。

In vitro differentiation of renal stone composition using dual-source,dual-energy CT

Objective To evaluate the ability of dual-source, dual-energy CT in differentiating uric acid stones from non-uric acid stones with infrared spectroscopy as reference standard. Materials and Methods Urinary calculus from 308 patients were scanned in first generation dual-source CT with dual-energy mode between July 2011 and June 2012. Renal Stone application was used to analyze their composition. The uric acid stones color were coded red and non--uric acid stones were blue. CT values were measured in 60 selective urinary calculus including 30 uric acid stones and 30 non-uric acid stones. The accuracy of dual energy CT to differentiate uric acid and no-uric acid stones was calculated. Results Of 308 patients, 60 patients had uric acid stones and 248 non-uric acid stones. No difference was found for uric acid stone at 80 kV and 140 kV （375.8±69.2 HU vs. 374.1±69.4 HU; t=-0.217, P=0.830）, while CT values of non-uric acid stones were higher at 80 kV than those at 140 kV （1 455.1±312.4 HU vs. 1 039.6±194.4 HU; t=-12.16, P〈0.001）. CT values of non-uric acid stones at 80 kV, 140 kV, and average weighted images （1 455.1±312.4 HU, 1 039.6±194.4 HU, and 882.0±176.4 HU, respectively） were higher than those of uric acid stones （375.8±69.2 HU, 374.1±69.4 HU, and 366.3±80.1 HU, respectively; P〈0.001）. With infrared spectrum findings as reference standard, the accuracy of dual energy CT in differentiating uric acid stones from non-uric acid stones was 100%. Conclusions Dual-source, dual-energy CT can accurately differentiate uric acid stones from non-uric acid stones, and plays an important role in treatment planning of renal stones.