Dual energy can accurately differentiate XXXX -containing urinary calculi from @entity460 stones.

@entity1 @entity2073 @entity460 @entity1791 @entity414
PURPOSE: To retrospectively evaluate the accuracy of dual-energy CT (DECT) in the detection of the chemical composition of urinary calculi in correlation with infrared spectroscopic stone analysis. METHODS: We reviewed the CT scans of 255 @entity1 who underwent DECT due to a clinical suspicion of @entity1791 . Out of this group, we included 64 @entity1 with clinically symptomatic @entity1791 requiring stone removal. After surgical removal of the stone by ureterorenoscopy, chemical composition was analyzed with infrared spectroscopy. We correlated DECT stone characterization results with chemical stone composition based on dual-energy indices (DEI). A total of 213 renal and ureteral stones could be removed and chemically analyzed. RESULTS: A total of 213 calculi were evaluated. Thirty eight out of sixty four (59  %) @entity1 had >1 stone. DECT was used to differentiate stones by using DEI. Stones harboring @entity460 (CA) were color-coded in blue, while stones containing @entity414 (UA) were colored red. Median DEI in UA-containing stones were 0.001. Non-UA-containing stones had a DEI between 0.073 for pure CA stones and 0.077 containing CA and other substances (p  =  0.001; p  =  0.03, respectively). Sensitivity of DECT was 98.4  % for differentiation of UA from non-UA-containing calculi. Specificity was 98.1  %. Mean effective radiation dose of DECT was 4.18  @entity2073 (0.44-14.27  @entity2073 ), thus comparable to conventional CT scans of the abdomen. Conventional measurement of Hounsfield units did not correlate with stone composition. CONCLUSION: DECT with image post-processing reliably discriminates UA-containing calculi from all other stones, but the study offered limitations. Discrimination within the non-UA stones cannot be reliably achieved but is clinically insignificant.
