| [Objective] To investigate the clinical value of determination of upper urinary stone chemical composition by dual-source computed tomography processing software (kidney stones) in comparison with the standard control infrared spectroscopy.[Materials and methods]153patients with urinary stone were selected from October2010to April2012and69stones were collected through operation.97cases stones in vitro were collected. The stones in vivo were performed on DSCT dual energy scan, while the stones in vitro were placed on fresh swine kidneys, which were placed into a tray filled with saline, and then were done by DSCT, using the same scan mode as in vivo. The mean CT values were measured on the soft-tissue window at80kV.120kV.140kV and stone composition were analyzed by dual-energy Software (kidney stones). The stones were collected through surgical, percutaneous nephrolithotomy lithotomy and ureteroscopic. The stones composition were analysed by infrared spectroscopy as the gold standard. Statistical analyses were made to find the CT values ranges of different stone minerals and investigate the change characteristics of CT values at different kV and analyse the sensitivity, specificity of determination of urinary stone chemical composition by dual-source computed tomography dual energy kidney stones software.[Result]1. Among97cases stones in vitro,83stones were identified as pure stone (55calcium oxalate.13hydroxyapatite.9uric acid,4cystine and2struvite included) and14mixed stones. Among69cases stones in vivo.63stones were identified as pure stone (44calcium oxalate.9hydroxyapatite.7uric acid.3cystine) and6mixed stones. The two struvite stones and14mixed stones didn't involve in the statistical analysis.2.Compare the difference of mean CT values of all stones in vivo and iv vitro. No statistically significant difference was seen between in vivo and in vitro(P>0.05).3.Analysis of the stones in vitro:Compare the mean CT values of the different components of stones at different kV. The mean CT values of urinary stones gradually descreased with increasing kV. At the same scan kV. the CT values of calcium oxalate was the largest, followed by hydroxyapatite. cystine and the smallest was uric acid stones. At80kV. the mean CT values of calcium oxalate. hydroxyapatite. cystine stones, uric acid stones were1986.46±121.59HU.1545.36±242.00HU,750.00±112.48HU,509.67±179.47HU.respectively.At120kV.1497.08±214.86HU.1162.20±195.53HU.715.00±140.89HU.398.67±136.19HU.At140kV:1326.00±78.32HU.1060.67±149.79HU.590.00±165.89HU,360.33±94.93HU.Compare the range of CT values of urinary stones at different kV. At80kV. the range of CT value of calcium oxalate, hydroxyapatite wasn't overlap, while uric acid and cystine was partly overlap. At120kV, the range of CT value of uric acid and cystine wasn't overlap, while calcium oxalate and hydroxyapatite was partly overlap. At140kV, the range of CT value of uric acid and cystine. calcium oxalate and hydroxyapatite were partly overlap. However, at80,120.140kV. the range of CT values of calcium oxalate and hydroxyapatite wasn't overlap with uric acid and cystine.Compare the mean CT value of urinary stones at different kV by F test. At80kV,120kV,140kV, the difference was statistically significant (P<0.05), which the mean CT value of calcium oxalate was the largest, followed by hydroxyapatite.cystine and the smallest was uric acid.5. Compare the mean CT value of the same component of stones at different kV by F-test. Among at80kV.120kV,140kV. the mean CT value of calcium oxalate was statistically significant (P<0.05), and hydroxyapatite was also. However, the mean CT value of uric acid wasn't statistically significant at80kV.120kV,140kV. and cystine also (P>0.05). 4.Compare the mean CT value of uric acid stones and non-uric acid stones:the difference between nine cases of uric acid stones and74cases non-uric acid stones was compared by independent sample t-test at80kV,120kV,140kV (t=-7.838,-7.059.-8.69, respectively, P value <0.05), which had statistically significant. Using <500HU for standard diagnosis of uric acid stones, the sensitivity at80kV,120kV,140kV were56%,89%,100%,respectively; and the pecificity were88%.5.Determination of urinary stone chemical composition by dual-source computed tomography dual-energy scanning:Comparative analysis of the difference value of80kV and140kV and DEI value. The difference value and DEI value were statistically significant(P<0.05).About the difference value, uric acid (175.88HU) wasn't statistically significant in comparison with cystine (159.50HU),which was statistically significant in comparison with calcium oxalate (660.46HU), hydroxyapatite. The DEI value of calcium oxalate (0.1241) and hydroxyapatite (0.1019) weren't statistically significant and uric acid (0.0591) and cystine (0.0489) either, however, the former two had statistically significance in comparison with the latter two. The DEI values of uric acid (0.0591) and cystine were significant smaller than calcium oxalate and hydroxyapatite.With dual source dual energy processing software, all the urinary stones were clearly visible. The standard control(infrared spectroscopy) found55cases calcium oxalate,13hydroxyapatite,9uric acid,4cystine.2struvite. While59cases calcium oxalate stones,11hydroxyapatite,9uric acid,4cystine were evaluated by dual-energy processing software. The difference of the two methods of determination of urinary stones was compared with X2test, which was not statistically significant differences (P>0.05). ROC curve analysis showed AUC=0.82, which can be considered stone composition by DSCT with high accuracy in comparison with Infrared spectroscopy method. The sensitivity for the detection of calcium oxalate stones, hydroxyapatite, uric acid, cystine were100%,84.6%,100%,100%, the specificity were85.7%.100%,100%.100%and the accuracy were95.18%,97.59%,100%,100%, respectively.6. Compare the radiation dose between routine scan and dual-energy scan byt-test. The difference in CTDIvol. DTP, ED were statistically significant (t values were-4.226,-3.032,-3.032, P<0.05). which CTDIvol. DTP.ED of dual energy scan group were higher than rontine scan. The radiation dose of ED in dual energy scan group was more1.7mGy than rountine during one scan.[Conclusion]1. The age of onset of urinary stone wasn't relevant to stones composition and the overall incidence of urinary stones in men was more than women.2. The mean CT value of calcium oxalate. hydroxyapatite. uric acid and cystine weren't statistically significant difference in vivo and in vitro. According to mean CT value, the stones composition can been speculated.3. The mean CT values of calcium oxalate. hydroxyapatite. uric acid and cystine gradually descreased with increasing kV. At80kV. the range of CT value of calcium oxalate, hydroxyapatite wasn't overlap, which was likely to differentiate calcium oxalate from hydroxyapatite. At140kV, the overlap range of CT value of uric acid and cystine were smaller than at80kV.120kV. Combined with different kV. the stones composition can been speculated.4. The difference between uric acid stones and non-uric acid stones had statistically significant. Using<500HU for standard diagnosis of uric acid stones, the sensitivity at80kV.120kV.140kV were56%,89%,100%, respectively; and the pecificity were all88%, and the accuracy were84,88,89%, respectively.The sensitivity and specificity of diagnosis of uric acid stones can be improved at140kV.5. The results of diagnosis of stones composition in vivo by DSCT was consistent with the stones in vitro. The stones of calcium oxalate stones, hydroxyapatite, uric acid, cystine can be differentiated by dual-energy post-processing software-kidney stones software.The sensitivity for the detection of calcium oxalate stones, hydroxyapatite, uric acid, cystine were100%,84.6%,100%,100%. the specificity were85.7%,100%.100%,100%and the accuracy were95,18%,97.59%,100%,100%, respectively.The radiation dose was only slightly higher than conventional plain.6. The uric acid stone composition may be analysed through CT value. While the accuracy of diagnosis of stone composition can be significantly improved through CT value measurement and dual-energy post-processing software-kidney stones. |
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