体内泌尿系结石的双源CT双能量成像

Dual-Source Dual-Energy CT for the Differentiation of Urinary Stone Composition: In Vivo Study

目的初步探讨双源CT双能量成像区分体内泌尿系结石成分的可行性。方法对64例泌尿系结石患者行双源CT双能量检查,男41例,女23例,年龄20～82岁,平均年龄(53±16)岁。测量计算80 kV和140 kV图像结石的HU差值、HU比值和双能量指数(DEI)。使用双能量软件分析结石成分。收集结石患者治疗后的结石标本进行红外光谱分析,以此结果为标准,运用方差分析比较不同结石之间上述指标的差异,并进行两两比较。软件分析结果与红外光谱分析结果进行比较。结果共收集到55例患者治疗后的体外结石标本。尿酸结石、胱氨酸结石、磷酸镁铵结石、磷酸钙结石、草酸钙结石和混合含钙结石的HU差值分别为18±12、214±21、329±35、360±49、458±97和497±110,HU比值分别为1.04±0.02、1.36±0.02、1.49±0.04、1.50±0.08、1.52±0.05和1.53±0.04,DEI分别为0.006±0.004、0.062±0.002、0.089±0.006、0.095±0.013、0.107±0.011和0.112±0.012,上述指标有统计学差异(F值分别为20.185、121.574、69.480,P<0.001)。组间两两比较,尿酸结石与其他结石的HU差值、HU比值和DEI有统计学差异(P<0.05);胱氨酸结石与其他结石的HU比值和DEI有统计学差异(P<0.05);磷酸镁铵结石与草酸钙结石、混合含钙结石的HU差值和DEI有统计学差异(P<0.05);胱氨酸结石与草酸钙结石、混合含钙结石的HU差值有统计学差异(P<0.05);磷酸钙结石与混合含钙结石的DEI有统计学差异(P<0.05);其余组间两两比较无统计学差异(P>0.05)。与红外光谱分析结果比较,双能量软件正确诊断4例尿酸结石、1例混合尿酸结石、2例胱氨酸结石和11例草酸钙结石;另外,2例磷酸钙结石、29例混合含钙结石、1例尿酸铵和草酸钙混合结石、1例混合尿酸结石和4例磷酸镁铵结石均识别为草酸盐成分。结论 DSCT双能量成像分析体内结石成分具有可行性,使用双能量软件可以较好地区分体内的尿酸结石、混合尿酸结石、胱氨酸结石和含钙结石,但区分磷酸镁铵结石以及不同成分的含钙结石尚存在困难。

Objective To evaluate the ability of dual-source dual-energy CT to differentiate urinary stone of different compositions in vivo.Methods Sixty-four patients with known urinary stone disease were scanned using a DSCT scanner in the dual-energy mode.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 DEI were calculated.Urinary stones were classified as UA stones,mixed UA stones,cystine stones and calcium stones based on dual energy software,the results compared with the infrared spectroscopy analysis of stone samples.Use one-way ANOVA to compare HU difference,HU ratio and DEI of different stones groups according to infrared spectroscopy.Results In 55 patients,stones were sampled.Dual energy software correctly characterized 4 UA stones,1 mixed UA stone,2 cystine stone,and 42 calcium stones.4 struvite stones,1 mixed ammonium urate and calcium stone,1 mixed UA stone were classified as calcium stones.Statistical differences in HU difference（18±12）,（214±21）,（329±35）,（360±49）,（458±97） and（497±110） HU respectively,HU ratio（1.04±0.02,1.36±0.02,1.49±0.04,1.50±0.08,1.52±0.05 and 1.53±0.04 respectively）,and DEI（0.006±0.004,0.062±0.002,0.089±0.006,0.095±0.013,0.107±0.011 and 0.112±0.012 respectively） among UA stones,cystine stone,struvite stones,CaP stones,CaOx stones and mix calcium stones（P0.001）.There were statistical differences in HU difference,HU ratio and DEI between UA stones and the other groups,in HU ratio and DEI between cystine stones and the other groups,in HU difference and DEI between struvite stones and CaOx or mix calcium stones,in HU difference between cystine stones and CaOx or mix calcium stones,in DEI between CaP stones and mix calcium stones（P0.05）.Conclusion Dual-source dual-energy CT has the ability to differentiate UA stones,cystine stones,mixed UA stones and calcium stones in vivo,but it could not distinguish struvite stones and subtypes of calcium stones.