title: CT in detecting urinary tract calculi: influence on patient imaging and clinical outcomes.
abstract: OBJECTIVE
  To determine changes in examination patterns and effectiveness of care since the introduction of unenhanced helical computed tomography (CT) for examination of patients presenting to the emergency department (ED) with symptoms of urinary tract calculi (UTC).
  
  
  METHODS
  Hospital clinical and radiology information systems were used to retrospectively identify patients presenting with UTC symptoms from January to December 1997 (before introduction of unenhanced CT) and from January to December 1999 (after introduction of unenhanced CT). Chart abstraction was used to confirm the identification of patients with presenting symptoms suggestive of UTC and assess patient outcomes. Two hundred sixty-five patients presented before (1997) and 602 after (1999) unenhanced CT was introduced. Distributions of dichotomous variables were compared between the 1997 and 1999 groups by using logistic regression. Means were compared between the groups by using analysis of variance and mean total numbers of imaging studies by using Poisson regression.
  
  
  RESULTS
  Total number of imaging studies increased by 26.7% per patient visit (P <.001). Rates of admission following the initial ED visit (13.7% in 1997 vs 13.4% in 1999), as well as percentage of patients who subsequently returned to the ED (12.0% in 1997 vs 13.7% in 1999) or subsequently were admitted to the hospital (4.5% in 1997 vs 5.3% in 1999) in the month following the initial ED visit, were similar between the two groups. Unsuspected unenhanced CT findings that could affect acute patient care were observed at 5.9% of examinations.
  
  
  CONCLUSIONS
  Use of imaging for suspected UTC has increased markedly since the introduction of unenhanced CT, with little effect on acute care of patients in the ED.
authors.affiliation: Dept of Radiology, Univ of Rochester Medical Ctr, NY 14642, USA. ronald_gottlieb@urmc.rochester.edu
authors.forename: Ronald H
authors.initials: RH
authors.lastname: Gottlieb
authors.forename: Thao Christine
authors.initials: TC
authors.lastname: La
authors.forename: Erdal N
authors.initials: EN
authors.lastname: Erturk
authors.forename: Jenny L
authors.initials: JL
authors.lastname: Sotack
authors.forename: Susan L
authors.initials: SL
authors.lastname: Voci
authors.forename: Robert G
authors.initials: RG
authors.lastname: Holloway
authors.forename: Labib
authors.initials: L
authors.lastname: Syed
authors.forename: Igor
authors.initials: I
authors.lastname: Mikityansky
authors.forename: A Temel
authors.initials: AT
authors.lastname: Tirkes
authors.forename: Rania
authors.initials: R
authors.lastname: Elmarzouky
authors.forename: Frank L
authors.initials: FL
authors.lastname: Zwemer
authors.forename: Jean V
authors.initials: JV
authors.lastname: Joseph
authors.forename: Delphine
authors.initials: D
authors.lastname: Davis
authors.forename: William J
authors.initials: WJ
authors.lastname: DiGrazio
authors.forename: Edward M
authors.initials: EM
authors.lastname: Messing
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D004636:Emergency Service, Hospital; D005260:Female; D005500:Follow-Up Studies; D006784:Hospitals, Teaching; D006801:Humans; D008297:Male; D008875:Middle Aged; D009518:New York; D010343:Patient Admission; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014545:Urinary Calculi / Q000000981:diagnostic imaging* / Q000628:therapy