title: A prospective randomized trial comparing 2 diuresis renography techniques for evaluation of suspected upper urinary tract obstruction in children.
abstract: OBJECTIVE
  We compare the diagnostic impact of 2 diuresis renography techniques for evaluation of suspected upper urinary tract obstruction in children.
  
  
  METHODS
  A total of 72 children were randomly assigned to 1 of 2 standardized diuresis renography protocols. The protocols were identical, except for the time of furosemide (F) injection. In the F+20 scans furosemide was given 20 minutes after the 99mtechnetium pentetic acid radiopharmaceutical. With the modified F-15 scans furosemide was injected 15 minutes before renography. Hydration, bladder catheterization, urine output determination, radiopharmaceutical injection and scan acquisition were identical. Renography outcomes (obstructed, nonobstructed or equivocal) were analyzed for the investigated side(s) and for the contralateral side, which was used as a control in children with suspected unilateral obstruction. Chi-square test was used to compare the percentage of obstructed and nonobstructed scans of both protocols. Fisher's exact test was used to compare the nonobstructed scans and equivocal results of both protocols.
  
  
  RESULTS
  Of the 96 scans performed 8 were excluded because of technical problems. The remaining scans included 44 F+20 and 44 F-15. Of the 88 scans 10 were used to evaluate possible bilateral obstruction. A total of 48 boys and 24 girls were evaluated. Because 2 children had a solitary kidney each, the total number of renal units studied for outcome was 174. The F-15 scan showed 7 times more obstruction than the F+20 scan on the investigated side, and this difference was statistically significant. No obstruction was diagnosed on the contralateral side with either technique when used to investigate cases of suspected unilateral obstruction.
  
  
  CONCLUSIONS
  The timing of the furosemide injection (F-15 scan versus F+20) has a significant impact on the obstructive versus nonobstructive renography results when evaluating children with suspected upper urinary tract obstruction.
authors.affiliation: Department of Radiology, Children's Hospital of Eastern Ontario, Ottawa, Canada.
authors.forename: M M
authors.initials: MM
authors.lastname: Foda
authors.forename: C T
authors.initials: CT
authors.lastname: Gatfield
authors.forename: M
authors.initials: M
authors.lastname: Matzinger
authors.forename: V
authors.initials: V
authors.lastname: Briggs
authors.forename: G
authors.initials: G
authors.lastname: Wells
authors.forename: S
authors.initials: S
authors.lastname: Walker
authors.forename: J F
authors.initials: JF
authors.lastname: Schillinger
mesh_terms: D002675:Child, Preschool; D004232:Diuretics / Q000008:administration & dosage; D005260:Female; D005665:Furosemide / Q000008:administration & dosage; D006801:Humans; D008297:Male; D011446:Prospective Studies; D011866:Radioisotope Renography / Q000379:methods*; D014570:Urologic Diseases / Q000000981:diagnostic imaging*
chemical_list: D004232:Diuretics; D005665:Furosemide