title: Quantitative assessment of glomerular filtration rate with MR gadolinium slope clearance measurements: a phase I trial.
abstract: OBJECTIVE
  To prospectively demonstrate the feasibility of quantifying the glomerular filtration rate (GFR) by assessing the renal clearance of gadolinium-based contrast medium from the extracellular fluid volume in healthy volunteers.
  
  
  METHODS
  The study was approved by the ethics committee and the governmental drug administration department (registration number 4030139, EudraCT number 2004-002969-20, study protocol number 318/2004). Informed consent was obtained from 16 healthy volunteers (six female, 10 male; mean age, 24.5 years +/- 2.8 [standard deviation]). Thirteen volunteers (four women, nine men; mean age, 24.8 years +/- 2.7; range, 23-30 years) successfully contributed to the study. The GFR was assessed by recording the renal clearance of gadobutrol (3.75 mL, approximately 0.05 mmol per kilogram of body weight) at navigator-gated turbo fast low-angle shot magnetic resonance (MR) imaging. Time-signal intensity curves were constructed from manually drawn regions of interest in the liver, spleen, and renal cortex, and the GFR was calculated by using exponential fitting. Simultaneously obtained iopromide clearance measurements were the reference standard. Statistical evaluations included Bland-Altman plotting and analysis of the relative deviation from iopromide clearance.
  
  
  RESULTS
  Evaluation of liver regions of interest revealed the lowest mean of paired differences from the iopromide clearance measurements (-5.9 mL/min per 1.73 m(2) +/- 14.6), with a mean GFR of 109.0 mL/min per 1.73 m(2) +/- 17.1 (134.1 mL/min per 1.73 m(2) +/- 35.4 for spleen, 100.7 mL/min per 1.73 m(2) +/- 25.1 for renal cortex) compared with a mean GFR of 103.1 mL/min per 1.73 m(2) +/- 9.4 measured by using iopromide clearance. The maximum deviation of MR-determined gadobutrol clearance values from iopromide clearance values was 29.2%. The mean disposition half-life of gadobutrol measured in the liver was 83.0 minutes +/- 14.2 (72.4 minutes +/- 20.2 in spleen, 92.6 minutes +/- 23.7 in renal cortex).
  
  
  CONCLUSIONS
  The described MR imaging method enables absolute quantification of the GFR after routine contrast material-enhanced MR imaging.
authors.affiliation: Section of Experimental Radiology, Department of Diagnostic Radiology, Eberhard-Karls University of Tübingen, Hoppe Seyler Strasse 3, 72076 Tübingen, Germany. andreas.boss@med.uni-tuebingen.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Boss
authors.forename: Petros
authors.initials: P
authors.lastname: Martirosian
authors.forename: Michael
authors.initials: M
authors.lastname: Gehrmann
authors.forename: Ferruh
authors.initials: F
authors.lastname: Artunc
authors.forename: Teut
authors.initials: T
authors.lastname: Risler
authors.forename: Niels
authors.initials: N
authors.lastname: Oesingmann
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Fritz
authors.initials: F
authors.lastname: Schick
authors.forename: Klaus
authors.initials: K
authors.lastname: Küper
authors.forename: Heinz-Peter
authors.initials: HP
authors.lastname: Schlemmer
mesh_terms: D000328:Adult; D003287:Contrast Media / Q000493:pharmacokinetics; D005240:Feasibility Studies; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007668:Kidney / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol