title: Dynamic renal scintigraphy in children with vesicoureteral reflux and suspected coexisting ureteropelvic junction obstruction.
abstract: OBJECTIVE
  We evaluated whether findings on voiding cystourethrography suggesting ureteropelvic junction (UPJ) obstruction coexists with vesicoureteral reflux (VUR) are associated with parameters on dynamic renal scintigraphy that support significant obstruction.
  
  
  METHODS
  We reviewed records of 44 patients referred for scintigraphy after voiding cystourethrography performed at age 1 day to 9.4 years (mean 7 months, median 1.7 months) showed VUR and findings suggestive of UPJ obstruction (blockage of contrast material at the UPJ, contrast dilution in the renal pelvis, slow renal pelvic drainage). Results were correlated with Society for Fetal Urology hydronephrosis grade and ureteral morphology.
  
  
  RESULTS
  Halftime was in the obstructive range (20 minutes or greater) for 7 of 47 kidneys (15%). The prevalence of a post-furosemide pelvicaliceal drainage halftime in the obstructive range increased with hydronephrosis grade (0% grade 1, 17% grade 2, 50% grade 3 to 4, p = 0.002) but did not vary with ureteral morphology (p = 0.08). In 12 of 38 cases (31%) where suspected UPJ obstruction was unilateral and a contralateral kidney was present differential uptake of the affected kidney was less than 45%. The prevalence of differential uptake less than 45% was higher in patients with than without ureteral dilatation (48% vs 12%, p = 0.02) but did not vary with hydronephrosis grade (p = 0.93).
  
  
  CONCLUSIONS
  In children with VUR and suspected coexisting UPJ obstruction dynamic renal scintigraphy may support significant obstruction when hydronephrosis is at least moderate in degree or ureteral dilatation is present but is unlikely to do so if neither is observed.
authors.affiliation: Department of Radiology, Division of Nuclear Medicine, Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Jan
authors.initials: J
authors.lastname: Stauss
authors.forename: Leonard P
authors.initials: LP
authors.lastname: Connolly
authors.forename: Susan A
authors.initials: SA
authors.lastname: Connolly
authors.forename: David
authors.initials: D
authors.lastname: Zurakowski
authors.forename: S Ted
authors.initials: ST
authors.lastname: Treves
authors.forename: Craig A
authors.initials: CA
authors.lastname: Peters
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000175:diagnosis / Q000503:physiopathology; D007223:Infant; D007231:Infant, Newborn; D007682:Kidney Pelvis / Q000503:physiopathology; D008297:Male; D011866:Radioisotope Renography; D014463:Ultrasonography; D014517:Ureteral Obstruction / Q000175:diagnosis* / Q000503:physiopathology; D014563:Urodynamics / Q000502:physiology*; D014567:Urography; D014718:Vesico-Ureteral Reflux / Q000175:diagnosis* / Q000503:physiopathology