title: The evolution of CT diagnosed papillae tip microcalcifications: can we predict the development of stones?
abstract: OBJECTIVE
  To determine the incidence of computed tomography (CT) identifiable Randall plaques in a CT explored population; to determine the clinical relevance of this radiological finding by a 7-year follow-up; to determine a cut point to identify a population with high risk of developing calcium stone disease (SD).
  
  
  METHODS
  Retrospective study of all patients explored by abdominal CT in our center between January and March 2005.
  
  
  METHODS
  age 30-60 years and no SD. Papillae attenuation was measured on nonenhanced CT in Hounsfield units (HU) and the mean of all papillae was calculated. Patients were re-evaluated after 7 years to identify calcium stone formers. Anamnesis and already available CT, ultrasound, kidney, ureter, and bladder radiograph (KUB) or intravenous urography (IVU) images performed as part of their follow-up were used. In patients with no follow-up, ultrasound and KUB were to be performed. Pearson correlation, Student t-test, and the receiver operator curve were used for statistical analysis.
  
  
  RESULTS
  A total of 362 patients fulfilled the inclusion criteria and were analyzed; 12 developed calcium SD after 7 years. A significant difference was encountered between the papillae attenuation of stone formers (SF) versus non-SF (47.2HU vs. 35.5HU, p=0.001). There was good correlation between papillae attenuation and the possibility of developing SD (R=0.87). An optimal cut point of 43HU with a sensitivity of 81% and specificity of 97%, area under the curve 0.91, separated SF and non-SF.
  
  
  CONCLUSIONS
  Patients with high papillae density have a higher risk of developing SD. A cut point of 43HU could accurately be used to identify a high-risk population.
authors.affiliation: 1 Urology Department, Hospital Clínic Barcelona , Barcelona, Spain .
authors.forename: Alexandru
authors.initials: A
authors.lastname: Ciudin
authors.forename: Maria Pilar
authors.initials: MP
authors.lastname: Luque
authors.forename: Rafael
authors.initials: R
authors.lastname: Salvador
authors.forename: Mihai Gabriel
authors.initials: MG
authors.lastname: Diaconu
authors.forename: Agustin
authors.initials: A
authors.lastname: Franco
authors.forename: Antonio
authors.initials: A
authors.lastname: Collado-Belvis
authors.forename: Javier
authors.initials: J
authors.lastname: Sanchez
authors.forename: Vlad
authors.initials: V
authors.lastname: Constantin
authors.forename: Ricardo
authors.initials: R
authors.lastname: Alvarez-Vijande
authors.forename: Carlos
authors.initials: C
authors.lastname: Nicolau
authors.forename: Antonio
authors.initials: A
authors.lastname: Alcaraz
mesh_terms: D000328:Adult; D002114:Calcinosis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007668:Kidney / Q000000981:diagnostic imaging; D007669:Kidney Calculi / Q000737:chemistry / Q000000981:diagnostic imaging* / Q000209:etiology*; D007679:Kidney Medulla / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014513:Ureter / Q000000981:diagnostic imaging; D001743:Urinary Bladder / Q000000981:diagnostic imaging