OBJECTIVE:
To examine whether the Hounsfield Unit value predicts calcium oxalate monohydrate stones in patients who are undergoing percutaneous nephrolithotomy.
METHOD:
119 patients who underwent percutaneous nephrolithotomy were prospectively evaluated between February 2012 and August 2014. Using thin cuts, the highest single-energy computed tomography attenuation value within a pixel was measured for each stone. Data regarding age and gender were assessed before surgery. The extracted stones were analyzed using infrared spectrophotometry.
RESULTS:
By receiver operating characteristics analysis, a cutoff value of 1548 Hounsfield Unit and an age of 42.5 years were used to determine the likelihood of a stone being composed of calcium oxalate monohydrate. A higher Hounsfield Unit value and increased age augmented the chances of a stone being composed of calcium oxalate monohydrate. In general, females had a greater likelihood of harboring calcium oxalate monohydrate stones than males.
CONCLUSION:
The maximum Hounsfield Unit value, as determined by unenhanced single-energy computed tomography in association with gender, predicts the presence of calcium oxalate monohydrate stones in patients who are undergoing percutaneous nephrolithotomy.
KEYWORDS:
Urinary Calculi; Lithotripsy; Tomography; Hounsfield Unit
