title: Evaluation of intrarenal oxygenation at 3.0 T using 3-dimensional multiple gradient-recalled echo sequence.
abstract: OBJECTIVE
  The objective of this study was to validate quantitation of R2* and DeltaR2* measurements obtained with a 3-dimensional (3-D) multiple gradient-recalled echo (mGRE) sequence for evaluating intrarenal oxygenation in humans.
  
  
  METHODS
  Validation was accomplished (1) by comparing R2* values with previously established 2-D techniques (n = 5, mean age = 33.6 years) and (2) by measuring change in DeltaR2* after furosemide (20 mg intravenously) administration (n = 5, mean age = 22 years). Additional pre- and postfurosemide scans were done at 1.5 T for comparison purposes.
  
  
  RESULTS
  R2* measurements with the 3-D technique showed good agreement with the 2-D techniques. The baseline medullary R2* at 3.0 T was about twice the value found at 1.5 T. Furosemide-induced change in R2* was observed within 5 minutes after administration.
  
  
  CONCLUSIONS
  R2* measurements with 3-D mGRE were comparable with those reported using 2-D techniques. The 3-D implementation facilitates observation of temporal changes in the medullary oxygenation without compromising spatial coverage.
authors.affiliation: Biomedical Engineering Department, Northwestern University, Evanston, Illinois, USA.
authors.forename: Santosh
authors.initials: S
authors.lastname: Tumkur
authors.forename: Anthony
authors.initials: A
authors.lastname: Vu
authors.forename: Luping
authors.initials: L
authors.lastname: Li
authors.forename: Pottumarthi V
authors.initials: PV
authors.lastname: Prasad
mesh_terms: D000328:Adult; D004232:Diuretics / Q000494:pharmacology*; D017352:Echo-Planar Imaging; D005260:Female; D005665:Furosemide / Q000494:pharmacology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007668:Kidney / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000097:blood*
chemical_list: D004232:Diuretics; D005665:Furosemide; D010100:Oxygen