Objective       To evaluate the forecasting accuracy of dual-energy CT scanning to differentiate different compositions of urinary stone in vivo.       Methods       Fifty patients with known urinary stone disease admitted in the Southwest Hospital from March 2011 to September 2012 were enrolled in this study. They all underwent scanning preoperatively using a DSCT scanner in the dual-energy mode. CT value

CT different value and CT ratio value of each stone were recorded for the 80 kV and the 140 kV datasets. Based on dual energy software

stone composition was predicted. And these stone samples collected through surgery were analyzed by the infrared spectroscopy as the gold standard. ANOVA was used to compare CT value

CT value difference and CT ratio value of different stone compositions. Meanwhile

the 2 different methods were assessed by Kappa analysis to study their consistency.       Results       Among 50 stones

there were 4 cases of uric acid (UA) stones and 46 cases of non-UA acid ones (5 cystine

2 hydroxyapatite

33 CaOx stone

and 6 mixed stones). There were statistical differences in CT value

CT difference value and CT ratio value

compared UA stones with other stones (P＜0.05). But such differences were seen among the cystine

hydroxyapatite

CaOx

and mixed stones (P0.05). Compared the results analyzed by infrared spectrometer

dual energy software correctly diagnosed 4 cases of UA stones

4 of cystine stones

33 of CaOx stones

and 2 of mixed stones of UA and CaOx

but misdiagnosed 7 cases

including 1 case of cystine stone and 2 of hydroxyapatite stones misdiagnosed as CaOx stones

and 4 of mixed stones of UA and hydroxyapatite misdiagnosed as mixed ones of cystine and hydroxyapatite. Kappa analysis that the dual energy software and infrared spectroscopy had a test value of 0.705

indicating high consistency.       Conclusion       Dual-source dual-energy CT scanning has the ability to differentiate UA stones

cystine stones and calcium stones

but it can not distinguish subtypes of calcium stones and hydroxyapatite stones.