title: Unenhanced CT findings can predict the development of urinary calculi in stone-free patients.
abstract: OBJECTIVE
  To determine if calcium deposits in the papillae can be identified by unenhanced computed tomography (uCT) even before renal stones develop.
  
  
  METHODS
  A retrospective review of 413 patients with calculi identified 31 patients (stone-forming group) with a history of urinary tract calculi with a calculus demonstrated by uCT and a stone-free uCT before calculi had developed. The control group (n = 31) was composed of live kidney donors with no history of calculi and a stone-free uCT. CT attenuation was measured in all CTs using two regions of interest of 0.05 cm(2) and 0.1 cm(2) over the tip and the neighbouring area of the papillae. Student's and Wilcoxon t-tests were used for comparing results in the two groups.
  
  
  RESULTS
  The attenuation of the tip of the papilla was higher in the stone-forming group when compared to the controls after (45.2 HU versus 32.1 HU, P = 0.001) and even before frank calculi had developed (44.2 HU versus 32.1 HU, P = 0.003). There was no significant difference in papillary attenuation in the stone group before and after calculi had developed (45.2 HU versus 44.2 HU, P = 0.82).
  
  
  CONCLUSIONS
  Stone-forming patients exhibit higher papillary density even before calculi develop. This could define a population at risk of developing calculi.
authors.affiliation: Urology Department, Hospital Clínic Barcelona, Calle Villarroel 170, 08036 Barcelona, Spain. alexciudin@yahoo.com
authors.forename: Alexandru
authors.initials: A
authors.lastname: Ciudin
authors.forename: Maria Pilar
authors.initials: MP
authors.lastname: Luque Galvez
authors.forename: Rafael
authors.initials: R
authors.lastname: Salvador Izquierdo
authors.forename: Agustin
authors.initials: A
authors.lastname: Franco de Castro
authors.forename: Eduardo
authors.initials: E
authors.lastname: Garcia-Cruz
authors.forename: Juan
authors.initials: J
authors.lastname: Alcover García
authors.forename: Jose Ricardo
authors.initials: JR
authors.lastname: Alvarez-Vijande García
authors.forename: Carlos
authors.initials: C
authors.lastname: Nicolau
authors.forename: Antonio
authors.initials: A
authors.lastname: Alcaraz Asensio
mesh_terms: D000293:Adolescent; D000328:Adult; D003287:Contrast Media; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011856:Radiographic Image Enhancement; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013030:Spain / Q000453:epidemiology; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data*; D014545:Urinary Calculi / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D003287:Contrast Media