title: Using BOLD imaging to measure renal oxygenation dynamics in rats injected with diuretics.
abstract: OBJECTIVE
  we used blood oxygenation level-dependent magnetic resonance imaging (BOLD MRI) to measure renal oxygenation dynamics in rats injected with diuretics and evaluated diuretic effect on renal oxygenation.
  
  
  METHODS
  we performed BOLD MRI studies in 32 rats using a 1.5-tesla MR imaging system for animal experiments. We intravenously injected rats with saline (n=7), furosemide (n=7), acetazolamide (n=6), or mannitol (n=6). For controls, 6 rats were not injected with drugs. We estimated the apparent transverse relaxation rate (R(2)*) from the apparent transverse relaxation time (T(2)*)-weighted images and measured the time course of R(2)* at 4-min intervals over approximately 30 min.
  
  
  RESULTS
  compared with preadministration values, the R(2)* value did not change significantly in either the cortex or medulla in the control and mannitol groups but decreased significantly in the saline group; the R(2)* value significantly decreased in the medulla but did not change significantly in the cortex in the furosemide group; and the R(2)* value significantly increased in the medulla and significantly decreased in the cortex in the acetazolamide group.
  
  
  CONCLUSIONS
  our study results suggest that BOLD MRI is useful for evaluating the dynamics of renal oxygenation in response to various diuretics in the renal cortex and in the medulla.
authors.affiliation: Department of Medical Physics and Engineering, Division of Medical Technology and Science, Faculty of Health Science, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kusakabe
authors.forename: Taro
authors.initials: T
authors.lastname: Matsushita
authors.forename: Saori
authors.initials: S
authors.lastname: Honda
authors.forename: Sakie
authors.initials: S
authors.lastname: Okada
authors.forename: Kenya
authors.initials: K
authors.lastname: Murase
mesh_terms: D000086:Acetazolamide / Q000008:administration & dosage; D000704:Analysis of Variance; D000818:Animals; D004232:Diuretics / Q000008:administration & dosage*; D005665:Furosemide / Q000008:administration & dosage; D007275:Injections, Intravenous; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008353:Mannitol / Q000008:administration & dosage; D010101:Oxygen Consumption; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000008:administration & dosage
chemical_list: D004232:Diuretics; D008353:Mannitol; D012965:Sodium Chloride; D005665:Furosemide; D000086:Acetazolamide