title: Evaluation of the reproducibility of intrarenal R2* and DeltaR2* measurements following administration of furosemide and during waterload.
abstract: OBJECTIVE
  To estimate the reproducibility of BOLD MRI measurements in the evaluation of intrarenal oxygenation levels.
  
  
  METHODS
  In this study, the reproducibility of semiquantitative BOLD MRI measurements performed on a 1.5 T scanner with a multiple gradient-echo sequence in the renal medulla and cortex, and their response to furosemide and waterload, were assessed in eight healthy young subjects (25.6 +/- 4.1 years). Each subject underwent an identical experimental procedure on two separate days.
  
  
  RESULTS
  Renal R2* measurements were shown to be reproducible within approximately 12% from day to day based on a coefficient of variance (CV) analysis. The changes in R2* (DeltaR2*) following administration of furosemide were statistically significant, as shown by ANOVA and a paired Student's t-test, and were deemed reliable based on the reliable change index (RCI). However, DeltaR2* values following waterload were not statistically significant, and were not deemed reliable.
  
  
  CONCLUSIONS
  R2* measurements were reproducible over 270 days within 12%. Furosemide produced a significant and reliable change (approximately 30%), and the magnitude of change (5.7 s(-1)) was reproducible and consistent with our previous data. The response to waterload, however, did not reach statistical significance, and the magnitude did not reach the level that we had previously reported.
authors.affiliation: Department of Radiology, Evanston Northwestern Healthcare, Evanston, Illinois 60201, USA. LLi2@enh.org
authors.forename: Lu-Ping
authors.initials: LP
authors.lastname: Li
authors.forename: Pippa
authors.initials: P
authors.lastname: Storey
authors.forename: Linda
authors.initials: L
authors.lastname: Pierchala
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Jason
authors.initials: J
authors.lastname: Polzin
authors.forename: Pottumarthi
authors.initials: P
authors.lastname: Prasad
mesh_terms: D000328:Adult; D004231:Diuresis / Q000187:drug effects* / Q000502:physiology; D004232:Diuretics / Q000008:administration & dosage*; D004326:Drinking / Q000502:physiology*; D005260:Female; D005665:Furosemide / Q000008:administration & dosage*; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000502:physiology*; D007672:Kidney Cortex / Q000187:drug effects / Q000502:physiology; D007679:Kidney Medulla / Q000187:drug effects / Q000502:physiology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D013997:Time Factors
chemical_list: D004232:Diuretics; D005665:Furosemide