How spiral computed tomography can be helpful in the evaluation of urinary stones composition?

Introduction: knowing the composition of a urinary calculus is frequently a key factor in determining its most appropriate management. helical computed tomography (ct) can provide helpful information on stone size and stone composition.objectives: we sought to determine the urinary stone composition by ct characteristics.materials and methods: since march 2008 till august 2009, 120 renal stones were obtained from patients who had undergone pyelolithotomy or nephrolithotomy at the imam-ali hospital, zahedan, iran. stones with the largest diameter more than or equal to 5 mm were studied. each calculus was placed inside the chicken lean meat. the radiologist was unaware of the exact chemical composition of the stones. we used independent sample t test for comparison of the absolute hounsfield unit (hu) values of the different types of calculi.results: of total 120 participated patients, 67 (55.8%) were male and 53 of them (44.2%) were female. the mean age of cases was 35.8 ± 12.4 years. according to hu in ct scan and final confirmation with chemical analysis, the calculi were classified into several groups. of 120 stones, 112 were chemically pure and 8 were mixed. there were 59 calcium oxalate, 27 calcium phosphate, 17 uric acid, 5 struvite, 4 cysteine and 8 mixed stones with variable ratios. in the analysis of the stones, overall difference between densities of the stones was statistically significant (p < 0.001).conclusion: according to the result of our study, we concluded that the use of non-contrast ct can be helpful in the prediction of urinary stone composition