title: The use of non-contrast computed tomography and color Doppler ultrasound in the characterization of urinary stones - preliminary results.
abstract: OBJECTIVE
  To investigate the role of density value in computed tomography (CT) and twinkling artifact observed in color Doppler analysis for the prediction of the mineral composition of urinary stones.
  
  
  METHODS
  A total of 42 patients who were operated via percutaneous or endoscopic means and had undergone abdominal non-contrast CT and color Doppler ultrasonography examinations were included in the study. X-ray diffraction method was utilized to analyze a total of 86 stones, and the correlations between calculated density values and twinkling intensities with stone types were investigated for each stone.
  
  
  RESULTS
  Analyses of extracted stones revealed the presence of 40 calcium oxalate monohydrate, 12 calcium oxalate dihydrate, 9 uric acid, 11 calcium phosphate, and 14 cystine stones. The density values were calculated as 1499±269 Hounsfield Units (HU) for calcium oxalate monohydrate, 1505±221 HU for calcium oxalate dihydrate, 348±67 HU for uric acid, 1106±219 HU for calcium phosphate, and 563±115 HU for cystine stones. The artifact intensities were determined as grade 0 in 15, grade 1 in 32, grade 2 in 24, and grade 3 in 15 stones.
  
  
  CONCLUSIONS
  In case the density value of the stone is measured below 780 HU and grade 3 artifact intensity is determined, it can be inferred that the mineral composition of the stone tends to be cystine.
authors.affiliation: Department of Radiology, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Mesut
authors.initials: M
authors.lastname: Bulakçı
authors.affiliation: Department of Urology, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Tzevat
authors.initials: T
authors.lastname: Tefik
authors.affiliation: Department of Urology, Haseki Training and Research Hospital, İstanbul, Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Akbulut
authors.affiliation: Department of Radiology, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Mehmet Tolgahan
authors.initials: MT
authors.lastname: Örmeci
authors.affiliation: Department of Urology, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Caner
authors.initials: C
authors.lastname: Beşe
authors.affiliation: Department of Urology, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Öner
authors.initials: Ö
authors.lastname: Şanlı
authors.affiliation: Department of Urology, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Tayfun
authors.initials: T
authors.lastname: Oktar
authors.affiliation: Department of Radiology, İstanbul University İstanbul Faculty of Medicine, İstanbul, Turkey.
authors.forename: Artür
authors.initials: A
authors.lastname: Salmaslıoğlu
keywords: Color Doppler; Hounsfield unit; computed tomography; twinkling artifact; urinary stones