title: Non-contrast thin-section helical CT of urinary tract calculi in children.
abstract: BACKGROUND
  Non-contrast thin-section helical CT has gained acceptance for the diagnosis of urinary tract calculi in adults, but experience with the technique in children is limited.
  
  
  OBJECTIVE
  To evaluate the utility of non-contrast thin section helical CT for the diagnosis of urinary tract calculi in children.
  
  
  METHODS
  Radiology databases at three pediatric institutions were searched to identify all pediatric patients evaluated by "renal stone" protocol CT scans (no oral or intravenous contrast, scans covering the entire urinary tract obtained in helical mode with narrow collimation (< 5 mm)). CT scans were reviewed for the primary finding of urinary tract calculi, for secondary signs of acute urinary tract obstruction and for evidence of alternative diagnoses. Medical records were reviewed to determine clinical presentation and to confirm the eventual diagnosis.
  
  
  RESULTS
  One hundred thirty-seven scans of 113 children (mean age: 11.2 years) were studied. Thirty-eight of 94 examinations (40%) performed on 82 children for acute pain and/or hematuria showed ureteral calculi. Alternative diagnoses were suggested by CT on 16 scans (17%). Twenty-eight scans were performed on 10 asymptomatic children with known calculus disease confirming renal stone burden on 21 scans (75%) and persistent ureteral calculi on 6 scans (21%). Upper tract calculi were demonstrated on 10 of 15 scans (67%) performed to evaluate for calculi in patients with known non-calculus genitourinary tract abnormalities.
  
  
  CONCLUSIONS
  Non-contrast thin section helical CT is a useful method to diagnose urinary tract calculi in children. Radiation dose in this retrospective study may exceed the lowest possible radiation dose for diagnostic accuracy. Further research is needed to optimize CT imaging parameters, while maintaining diagnostic accuracy and minimizing radiation dose.
authors.affiliation: Section of Pediatric Radiology, C.S. Mott Children's Hospital, University of Michigan Medical Center, 1500 East Medical Center Drive, Ann Arbor 48109-0252, USA. pstrouse@umich.edu
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Strouse
authors.forename: D Gregory
authors.initials: DG
authors.lastname: Bates
authors.forename: David A
authors.initials: DA
authors.lastname: Bloom
authors.forename: Mitchell M
authors.initials: MM
authors.lastname: Goodsitt
mesh_terms: D000293:Adolescent; D002648:Child; D002669:Child Welfare; D002675:Child, Preschool; D003287:Contrast Media; D004307:Dose-Response Relationship, Radiation; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D006417:Hematuria / Q000150:complications; D006801:Humans; D007223:Infant; D007229:Infant Welfare; D008297:Male; D010146:Pain / Q000150:complications; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014545:Urinary Calculi / Q000175:diagnosis*
chemical_list: D003287:Contrast Media