Correlation between Hounsfield Unit Value and Stone Composition in Nephrolithiasis

• Autor(a) principal: Silva,Tennyson Rene
• Data de Publicação: 2016
• Outros Autores: Lima,Marcelo Lopes de
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: MedicalExpress (São Paulo. Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S2358-04292016000300003
• topic: Urinary Calculi; Lithotripsy; Tomography; Hounsfield Unit

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.