| Background and ObjectiveUrinary calculi are one of the most common diseases of the urinary system. With the continuous improvement of living standards and dietary changes, the incidence of the disease is on the rise year by year. The complicated or secondary changes of Urinary tract stones, such as obstruction, infection, polyps, tumors, and impaired renal function and even loss are also increased. The components of Stones have great significance in the choice of treatment, efficacy, and prevention of recurrence. Moreover, stone analysis is helpful to analysis of the etiology of urolithiasis. Currently, in vitro analysis method is commonly used in judging the components of stone. The samples of stone all come from lithotripsy surgery or autologous stones, There is no a method that can know clearly the composition of stone before the treatment. Imaging is a reliable method of clinical diagnosing urolithiasis. But it is limited to know the location, morphology, size and number of stones. If there is a method that can not only diagnose the stones but also know the components of urolithiasis, it will play an important role in choosing a reasonable treatment method. Thus it can improve the efficacy of the treatment and avoid unnecessary trauma. Meanwhile it will reduce the occurrence of complications.This study aims to explore the ability to differentiate urinary calculi of different compositions by using dual-source CT before the treatment. The composition of urinary calculi was compared with results of reference standard (ex vivo infrared spectroscopy).Subjects and Methods1.1Clinical data:106urinary calculi were collected from December2011to May2012, including78men and28women. The ratio of men to women is2.79:1. The age was from21to69years and the average was35.6years. All patients were clinically diagnosed as urinary tract stones and signed the informed consent before the inspection. There were95cases of upper urinary stones,11cases of lower urinary stones.1.2CT examination and stone analysis:A Siemens Somatom Definition Flash DSCT protocol(A tube A’s voltage and effective tube current-time product,Snl40kV and162mAs, tube B’s voltage and effective tube current-time product,100kV and210mAs;tube rotation time0.5s;collimation,32x0.6mm;pitch,0.7; scanning slice thickness,5mm;image reconstruction thickness,1.5mm;reconstraction interval,0.5mm;convolution value,B30f medium smooth; integration factor,0.5reconstruction fused image) was implemented. The check sequence is dual energy kidney stones under the dual-energy mode. After examination, all collected data were transmitted to workstation. This study used syngo multimodality workplace of Siemens Company. Two experienced radiologists analyzed the stones on the standard window width of renal tissue, and each radiologist measured the CT value of Region of interest (ROI) of the largest stone. The ROI was placed at the1/2-2/3of the cross-sectional area of the largest stone.The same stone was measured four times, and take the average. Open the Dual Energy software and run the program of Kidney stone. The reconstructed data were transmitted to workstation and analyzed the composition of the stone.1.3Stone analysis of infrared Spectroscopy:Samples of106patients with Urinary calculi were analyzed by LIIR-20infrared spectroscopy.1.4Statistical analysis:SPSS17.0software for data processing. Comparison of the CT values, Ratio and DEI value in each group used Kruskal-Wallis H test. Pairwise comparison used Bonferroni. The Infrared Spectroscopy was the reference standard. The sensitively and specificity of Dual Source CT Dual Energy technology in the diagnosis of urolithiasis were calculated.Results106patients with urinary calculi were examined with a dual-source CT system. A total of106stone samples were collected. The dual-energy stone analysis software was implemented. The results of as dual-source CT follows:Calcium oxalate stones (n=61), calcium phosphate stones (n=19), cystine stones (n=17), uric acid stones (n=9).106stone samples were collected. All samples were inspected by infrared spectroscopy. The results of infrared spectroscopy as follows:Calcium oxalate monohydrate stones (n=44), cases of calcium oxalate dehydrate stones (n=32), calcium phosphate stones (n=16), cystine stones (n=5), uric acid stones (n=9). Thus, the sensitivity, specificity of Dual Source CT Dual Energy technology for diagnosing uric acid stones and non-uric acid stones were both100%; the sensitivity, specificity of Dual Source CT Dual Energy technology for diagnosing calcium oxalate stones were74.24%,67.86%, respectively; the sensitivity, specificity of Dual Source CT Dual Energy technology for diagnosing phosphate stones were73.33%,89.87%, respectively; the sensitivity, specificity of Dual Source CT Dual Energy technology for diagnosing cystine stones were;60%,84.27%,respectively.ConclusionDual Source CT Dual Energy stone analysis is a convenient, fast and non-invasive analysis method. It can know clearly the composition of urinary tract stones before treatment. It is very useful to the clinical diagnosis and treatment of urinary tract stone. |
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