title: Reproducibility of contrast enhanced magnetic resonance renography in adolescents.
abstract: OBJECTIVE
  We sought to determine the reproducibility of magnetic resonance imaging renography using 3 different mathematical models and 2 different approaches to convert the relative signal intensity into quantitative indices. Furthermore, we wanted to examine the influence of fluid intake on the obtained renal parameters.
  
  
  METHODS
  A total of 10 healthy volunteers 13 to 16 years old were subjected to magnetic resonance imaging 3 times within 10 weeks, including an examination where fluid intake was increased. At each examination 0.1 mmol/kg gadolinium diethylenetriamine pentaacetic acid was administrated intravenously as a rapid bolus during a fast magnetic resonance renography sequence. Images were acquired in the coronal plan, and 1,200 images were recorded during approximately 7 minutes. Cortical data were analyzed to estimate absolute and differential function of renal parameters by converting signal intensities into quantitative units.
  
  
  RESULTS
  Using the simple approach that a change in magnetic resonance imaging signal is linearly related to the change in gadolinium diethylenetriamine pentaacetic acid concentration, we found reproducibility in the range of 1% to 5% of all estimations of the differential renal function. The relative glomerular ultrafiltration (ml per minute per cm(3) kidney cortex) was calculated and a reproducibility of 7% was observed for relative glomerular ultrafiltration (using the model based on deconvolution). Increased hydration caused a significant change in most parameters.
  
  
  CONCLUSIONS
  Contrast enhanced magnetic resonance renography is reproducible in the normal human kidney but excessive water intake has a significant influence on these parameters. Further studies are required to elucidate whether similar measurements can be applied to a kidney with impaired function.
authors.affiliation: Institute of Clinical Medicine, Aarhus University Hospital, Skejby Sygehus, Brendstrupgaardsvej, 8200 Aarhus, Denmark. bettina.jorgensen@ki.au.dk
authors.forename: Bettina
authors.initials: B
authors.lastname: Jørgensen
authors.forename: Anna Krarup
authors.initials: AK
authors.lastname: Keller
authors.forename: Eva
authors.initials: E
authors.lastname: Radvanska
authors.forename: Søren
authors.initials: S
authors.lastname: Rittig
authors.forename: Finn
authors.initials: F
authors.lastname: Taagehøj-Jensen
authors.forename: Jørgen
authors.initials: J
authors.lastname: Frøkiaer
authors.forename: Troels Munch
authors.initials: TM
authors.lastname: Jørgensen
authors.forename: Michael
authors.initials: M
authors.lastname: Pedersen
mesh_terms: D000293:Adolescent; D003287:Contrast Media; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011866:Radioisotope Renography / Q000379:methods*; D015203:Reproducibility of Results
chemical_list: D003287:Contrast Media