双源CT双能量成像对泌尿系统结石成分分析的初步研究

Dual-source dual-energy CT for the differentiation of urinary stone composition： preliminary study

目的评价双源CT双能量成像区分泌尿系统结石成分的应用价值。方法对97枚经内镜碎石后取出的泌尿系统结石行双源cT双能量扫描。以红外光谱仪测定的结石成分为参考标准，将结石分为6组：尿酸结石组、胱氨酸结石组、磷酸镁铵结石组、草酸钙结石组、混合尿酸结石组和混合含钙结石组。测量计算80和140kV结石的HU差值、HU比值和双能量指数（DEI），并采用方差分析比较上述指标的差异。使用双能量软件定性诊断结石成分，并与红外光谱仪测定的成分结果比较。结果尿酸结石组（10枚）、胱氨酸结石组（5枚）、磷酸镁铵结石组（6枚）、草酸钙结石组（22枚）、混合尿酸结石组（7枚）和混合含钙结石组（47枚）的HU差值分别为（-17±13）、（229±34）、（309±45）、（512±97）、（201±64）和（530±71）HU，HU比值分别为0．96±0．03、1．34±0．04、1．41±0．03、1．47±0．03、1．30±0．07和1．49±0．03，DEl分另0为-0．006±0．004、0．064±0．007、0．080±0．007、0．108±0．011、0．055±0．014和0．112±0．008，差异有统计学意义（F值分别为124．894、407．028、322．864，P值均〈0．01）。尿酸结石组与其他结石组HU差值、HU比值和DEI差异有统计学意义（P值均〈0．01）。草酸钙结石组、混合含钙结石组分别与其他4组结石HU差值、HU比值和DEI差异有统计学意义（P值均〈0．01）。胱氨酸结石组与磷酸镁铵结石组HU比值差异有统计学意义（P〈0．01）。磷酸镁铵结石组与混合尿酸结石组HU差值、HU比值和DEI差异有统计学意义（P值均〈0．05）。双能量软件正确定性诊断10枚尿酸结石、4枚胱氨酸结石、22枚草酸钙结石和6枚混合尿酸结石。2枚磷酸镁铵结石被诊断为含胱氨酸成分。1枚胱氨酸结石、1枚混合尿酸结石、4枚磷酸镁铵结石和47枚混合含钙结石被诊断为含草酸盐成分。结论双源cT双能量成像对于区分泌尿系统结石成分有-定价值。双能量软件可以较好地区分尿酸结石、胱氨酸结石、混合尿酸结石与其他类型结石。

Objective To evaluate dual-source dual-energy CT （DSCT） for the differentiation of urinary stone composition in vitro. Methods Ninety-seven urinary stones were obtained by endoscopic lithotripsy and scanned using dual-source dual-energy CT. The stones were divided into six groups according to infrared spectroscopy stone analysis ： uric acid （ UA ） stones （ n = 10 ）, cystine stones （ n = 5 ）, struvite stones（n = 6）, calcium oxalate （CaOx） stones （ n = 22）, mixed UA stones （ n = 7） and mixed calcium stones（n =47）. Hounsfield units （HU） of each stone were recorded for the 80 kV and the 140 kV datasets by hand-drawing method. HU difference, HU ratio and dual energy index （DEI） were calculated and compared among the stone groups with one-way ANOVA. Using dual energy software to determine the composition of all stones, results were compared to infrared spectroscopy analysis. Results There were statistical differences in HU difference [ （ - 17 ± 13）, （229 ±34）, （309 ±45）, （512 ±97）, （201 ±64） and （530±71） HU respectively] , in HU ratio （0.96 ±0.03, 1.34 ±0.04, 1.41 ±0.03, 1.47 ±0.03, 1.30 ± 0.07, and 1.49 ± 0. 03 respectively ）, and DEI （ - 0. 006 ± 0. 004, 0. 064 ± 0. 007, 0. 080 ± 0. 007, 0. 108 ±0. 011 ,0. 055 ±0. 014 and 0. 112 ±0. 008 respectively） among different stone groups（F = 124. 894, 407. 028, 322. 864 respectively, P 〈 0. 01 ）. There were statistical differences in HU difference, HU ratio and DEI between UA stones and the other groups（P 〈0. 01 ）. There were statistical differences in HU difference, HU ratio and DEI between CaOx or mixed calcium stones and the other four groups （P 〈 0. 01 ）. There was statistical difference in HU ratio between cystine and struvite stones （P 〈0. 01 ）. There were statistical differences in HU difference,HU ratio and DEI between struvite and mixed UA stones （P 〈 0. 05）. Dual energy software correctly characterized 10 UA stones, 4 cystine stones, 22 CaOx stones and 6 mixed UA stones. Two struvite stones were considered to contain cystine. One cystine stone, 1 mixed UA stone, 4 struvite stones and 47 mixed calcium stones were considered to contain oxalate. Conclusions DSCT has the ability to differentiate urinary stone composition in vitro. With dual energy software, the UA, cystine and mixed UA stones can be differentiated from other types of stones.