title: Comparison between ultrasound and noncontrast helical computed tomography for identification of acute ureterolithiasis in a teaching hospital setting.
abstract: OBJECTIVE
  Recent studies have shown noncontrast computed tomography (NCT) to be more effective than ultrasound (US) for imaging acute ureterolithiasis. However, to our knowledge, there are few studies directly comparing these techniques in an emergency teaching hospital setting. The objectives of this study were to compare the diagnostic accuracy of US and NCT performed by senior radiology residents for diagnosing acute ureterolithiasis; and to assess interobserver agreement on tomography interpretations by residents and experienced abdominal radiologists.
  
  
  METHODS
  Prospective study of 52 consecutive patients, who underwent both US and NCT within an interval of eight hours, at Hospital São Paulo.
  
  
  METHODS
  US scans were performed by senior residents and read by experienced radiologists. NCT scan images were read by senior residents, and subsequently by three abdominal radiologists. The interobserver variability was assessed using the kappa statistic.
  
  
  RESULTS
  Ureteral calculi were found in 40 out of 52 patients (77%). US presented sensitivity of 22% and specificity of 100%. When collecting system dilatation was associated, US demonstrated 73% sensitivity, 82% specificity. The interobserver agreement in NCT analysis was very high with regard to identification of calculi, collecting system dilatation and stranding of perinephric fat.
  
  
  CONCLUSIONS
  US has limited value for identifying ureteral calculi in comparison with NCT, even when collecting system dilatation is present. Residents and abdominal radiologists demonstrated excellent agreement rates for ureteral calculi, identification of collecting system dilatation and stranding of perinephric fat on NCT.
authors.affiliation: Diagnostic Imaging Department, Universidade Federal de São Paulo - Escola Paulista de Medicina, São Paulo, Brazil. luisronan@gmail.com
authors.forename: Luís Ronan Marquez Ferreira
authors.initials: LR
authors.lastname: de Souza
authors.forename: Suzan Menasce
authors.initials: SM
authors.lastname: Goldman
authors.forename: Salomão
authors.initials: S
authors.lastname: Faintuch
authors.forename: Juliano Ferreira
authors.initials: JF
authors.lastname: Faria
authors.forename: Daniel
authors.initials: D
authors.lastname: Bekhor
authors.forename: Dario Ariel
authors.initials: DA
authors.lastname: Tiferes
authors.forename: Valdemar
authors.initials: V
authors.lastname: Ortiz
authors.forename: Peter
authors.initials: P
authors.lastname: Choyke
authors.forename: Jacob
authors.initials: J
authors.lastname: Szejnfeld
mesh_terms: D000208:Acute Disease; D004812:Epidemiologic Methods; D006784:Hospitals, Teaching; D006801:Humans; D007396:Internship and Residency; D015588:Observer Variation; D011361:Professional Competence; D011860:Radiography, Abdominal; D011871:Radiology; D036542:Tomography, Spiral Computed / Q000592:standards*; D014463:Ultrasonography; D014514:Ureteral Calculi / Q000000981:diagnostic imaging*