The Efficiency of Non-Contrast Computed Tomography in the Estimation of Urinary Stone Composition

Abstract

Background: Prior knowledge of stone composition is key to determining stone brittleness as well as treatment management and prophylactic approach. The present study seeks to visualize stone type on non-contrast computed tomography on the basis of Hounsfield Unit (HU) values.

Methods: A retrospective evaluation was performed of non-contrast computed tomography scans of patients who underwent urinary system operation to remove stones which were subjected to biochemical analysis. The localization and size of the stones were determined and their HU values, mean attenuation/size (HUD) and maximum attenuation/size ratios were calculated.

Results: The results of stone analysis revealed 34 calcium phosphate, 11 calcium oxalate, 5 triple phosphate (struvite) stones. On the basis of measurement results, a significant difference was identified among HU values of the three stone types (P = 0.002). When the stones were compared in pairs, this difference was established to be due to the difference between the densities of calcium phosphate and struvite stones. No significant difference was observed among the stone groups with regard to HUD and maximum attenuation/size ratios.

Conclusions: HU values are a useful parameter to distinguish between calcium phosphate and struvite stones. The inclusion of HU values in reports will set the right course for treatment.




doi:10.4021/wjnu4e