title: Detection of urothelial tumors: comparison of urothelial phase with excretory phase CT urography--a prospective study.
abstract: OBJECTIVE
  To compare contrast material-enhanced computed tomographic (CT) urography 60 seconds after injection of contrast material (urothelial phase [UP]) after intravenous administration of a diuretic with the standard 5-minute delayed excretory phase (EP) in a high-risk population for upper tract tumors.
  
  
  METHODS
  Institutional review board approval and informed consent were obtained. Eighty CT urographic examinations in 77 patients known to have or at high risk for urothelial malignancy were included. After intravenous administration of a diuretic, dual-phase CT urography was performed at 60 seconds (UP) and 5 minutes (EP) after intravenous administration of contrast material. Two experienced abdominal radiologists independently interpreted each phase more than 1 month apart to minimize recall bias. Urinary tract distention and location and size of all lesions suspected of being urothelial tumors were recorded. Standard of reference was obtained from prospective study interpretation and surgical histopathologic findings. Generalized estimating equations for logistic regression were used to compare performance measures and adjust for the correlation of repeated measures within patients.
  
  
  RESULTS
  There were 23 upper and 61 lower urinary tract tumors confirmed in 15 and 32 patients, respectively. For detection of bladder tumors, there was higher sensitivity for the UP than the EP (89.3% [109 of 122] vs 70.5% [86 of 122], respectively; P<.0001). For detection of upper tract tumors, there was higher sensitivity for the UP than the EP (82.6% [38 of 46] vs 69.6% [32 of 46], respectively; P=.0194). Distention of all upper urinary tract segments was better during the EP than the UP (P<.0001).
  
  
  CONCLUSIONS
  UP CT urography after injection of a diuretic has a higher lesion detection rate than the EP for both upper and lower urinary tract tumors, which suggests its possible use as a single-phase protocol for evaluation of the entire urinary tract in patients at high risk for urothelial tumors.
authors.affiliation: Joint Department of Medical Imaging, Princess Margaret Hospital, University of Toronto, 610 University Ave, Suite 3-960, Toronto, ON, Canada M5G 2M9. ur.metser@uhn.ca
authors.forename: Ur
authors.initials: U
authors.lastname: Metser
authors.forename: Mark A
authors.initials: MA
authors.lastname: Goldstein
authors.forename: Tanya P
authors.initials: TP
authors.lastname: Chawla
authors.forename: Neil E
authors.initials: NE
authors.lastname: Fleshner
authors.forename: Lindsay M
authors.initials: LM
authors.lastname: Jacks
authors.forename: Martin E
authors.initials: ME
authors.lastname: O'Malley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D004232:Diuretics / Q000008:administration & dosage; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014283:Triiodobenzoic Acids; D001749:Urinary Bladder Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014567:Urography / Q000379:methods*; D019459:Urothelium / Q000473:pathology*
chemical_list: D003287:Contrast Media; D004232:Diuretics; D014283:Triiodobenzoic Acids; C044834:iodixanol