title: The comparative survey of Hounsfield units of stone composition in urolithiasis patients.
abstract: BACKGROUND
  Non-contrast computed tomography (NCCT) is the diagnostic choice for renal stone disease. Knowing the composition of a stone before passage can help to choose a better management. We sought to determine whether the Hounsfield unit (HU) measured by NCCT can predict the composition.
  
  
  METHODS
  180 urinary stones from patients seen at Shariati, Kashani and Alzahra CT centers, were submitted to stone analysis, 2012. All scans had been interpreted for HU. Primitive statistical findings showed an effect of size on the HU. To avoid confounding bias, Hounsfield Density (HD: HU/largest transverse diameter) was calculated. Statistical comparisons were performed between composition with HU and HD.
  
  
  RESULTS
  Calcium stones had specific ranges for HD and HU. No non-calcium stone had HU more than 448 and HD greater than 50 HU/mm.
  
  
  CONCLUSIONS
  NCCT can differentiate just Calcium from non-calcium stones.
authors.affiliation: Department of Radiology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Parisa Sotoodeh
authors.initials: PS
authors.lastname: Shahnani
authors.affiliation: Department of Radiology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Karami
authors.affiliation: Department of Urology, Azad university, Isfahan, Iran.
authors.forename: Bahman
authors.initials: B
authors.lastname: Astane
authors.affiliation: Health, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Janghorbani
keywords: Hounsfield density; Hounsfield unit; noncontrast computed tomography; urinary stone type