title: Retrograde urethrocystography impairs computed tomography diagnosis of pelvic arterial hemorrhage in the presence of a lower urologic tract injury.
abstract: BACKGROUND
  There is controversy about the appropriate sequence of urologic investigation in patients with pelvic fracture. Use of retrograde urethrography or cystography may interfere with regular pelvic CT scanning for arterial extravasation.
  
  
  METHODS
  We performed a retrospective study at a regional trauma center in Toronto, Canada. Included were adult blunt trauma patients with pelvic fractures and concomitant bladder or urethral disruption who underwent initial pelvic CT before operation or hospital admission. Exposure of interest was whether retrograde urethrography (RUG) and cystography were performed before pelvic CT scanning. Main outcomes measures were indeterminate or false negative initial CT examinations for pelvic arterial extravasation.
  
  
  RESULTS
  Sixty blunt trauma patients had a pelvic fracture and either a urethral or bladder rupture. Forty-nine of these patients underwent initial CT scanning. Of these 49 patients, 23 had RUG or conventional cystography performed before pelvic CT scanning; 26 had cystography after regular CT examination. Performing cystography before CT was associated with considerably more indeterminate scans (9 patients) and false negatives (2 patients) for pelvic arterial extravasation (11 of 23 versus 0 of 26, p < 0.001) compared with performing urologic investigation after CT. In the presence of pelvic arterial hemorrhage, indeterminate or false negative CT scans for arterial extravasation were associated with a trend toward longer mean times to embolization compared with positive scans (p=0.1).
  
  
  CONCLUSIONS
  Extravasating contrast from lower urologic injuries can interfere with the CT assessment for pelvic arterial extravasation, delaying angiographic embolization.
authors.affiliation: Trauma Program, Department of Surgery, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Fernando Antonio Campelo
authors.initials: FA
authors.lastname: Spencer Netto
authors.forename: Paul
authors.initials: P
authors.lastname: Hamilton
authors.forename: Ron
authors.initials: R
authors.lastname: Kodama
authors.forename: Sandro
authors.initials: S
authors.lastname: Scarpelini
authors.forename: Sarah Joy
authors.initials: SJ
authors.lastname: Ortega
authors.forename: Peter
authors.initials: P
authors.lastname: Chu
authors.forename: Sandro Baleotti
authors.initials: SB
authors.lastname: Rizoli
authors.forename: Lorraine Norah
authors.initials: LN
authors.lastname: Tremblay
authors.forename: Frederick
authors.initials: F
authors.lastname: Brenneman
authors.forename: Homer Chin-Nan
authors.initials: HC
authors.lastname: Tien
mesh_terms: D000328:Adult; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D005260:Female; D050723:Fractures, Bone / Q000150:complications / Q000000981:diagnostic imaging*; D006470:Hemorrhage / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000000981:diagnostic imaging* / Q000293:injuries*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014521:Urethra / Q000000981:diagnostic imaging / Q000293:injuries; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000293:injuries; D014546:Urinary Catheterization; D014567:Urography / Q000379:methods*; D014949:Wounds, Nonpenetrating / Q000000981:diagnostic imaging