title: Supranormal differential renal function in unilateral hydronephrotic kidney: insights from functional MR urography.
abstract: OBJECTIVE
  To retrospectively assess supranormal differential renal function (DRF) in unilateral hydronephrotic kidney by functional MR urography (fMRU).
  
  
  METHODS
  The ethics committees granted exempt status for this study and also waived the need for informed consent. A retrospective analysis was performed of all patients undergoing fMRU from January 2008 to November 2011. DRF was measured by both the area under the curve method and Rutland-Patlak plot. Glomerular DRF per unit of volume and kidney volumes were analyzed. Kidney volumes were compared with nomograms.
  
  
  RESULTS
  Of 170 children, 3 patients (2, 12, and 14 years) with a left ureteropelvic junction obstruction were included. Glomerular DRF per unit of volume was slightly higher on the dilated side but remained within normal range (<55%). Dilated kidney volumes were higher on the dilated side (≥55%). The volumes of nondilated kidneys were within normal range.
  
  
  CONCLUSIONS
  The data support the fact that the dilated kidney was not hyperfunctioning and that the nondilated kidney was not hypofunctioning. Based on these three patients, it could be assumed that supranormal DRF on the dilated side might be explained by a slight kidney volume asymmetry, in association with higher DRF per unit of volume, remaining within normal physiological range. J. Magn. Reson. Imaging 2014;40:577-582. © 2013 Wiley Periodicals, Inc.
authors.affiliation: CHU C. Nicolle, Service d'imagerie pédiatrique et fœtale, Rouen, Cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Sanavi
authors.forename: Jean-Nicolas
authors.initials: JN
authors.lastname: Dacher
authors.forename: Jérome
authors.initials: J
authors.lastname: Caudron
authors.forename: Michael
authors.initials: M
authors.lastname: Dolores
authors.forename: Agnès
authors.initials: A
authors.lastname: Liard
authors.forename: Pierre-Hugues
authors.initials: PH
authors.lastname: Vivier
mesh_terms: D000293:Adolescent; D002648:Child; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000151:congenital* / Q000503:physiopathology; D007090:Image Interpretation, Computer-Assisted; D007223:Infant; D007677:Kidney Function Tests; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D021782:Multicystic Dysplastic Kidney / Q000503:physiopathology*; D012189:Retrospective Studies; D014517:Ureteral Obstruction / Q000503:physiopathology*
keywords: MR urography; children; differential renal function; kidney; magnetic resonance imaging; obstructive uropathy