title: Noninvasive evaluation of renal oxygenation in diabetic nephropathy by BOLD-MRI.
abstract: OBJECTIVE
  To evaluate the renal oxygenation in type 2 diabetes by blood oxygenation level dependent magnetic resonance imaging (BOLD-MRI).
  
  
  METHODS
  Forty-eight patients with type 2 diabetes and 67 healthy controls were recruited. All patients were further divided into four subgroups based on renal functional level. Bilateral renal cortical R2* (CR2*) and medullary R2* (MR2*) values were extracted and quantified on BOLD-MRI, then R2* ratio between medulla and cortex (MCR) was calculated. CR2*, MR2* and MCR were compared among the groups separately. The relationships were analyzed between R2* values and clinical index of renal function.
  
  
  RESULTS
  Compared with controls, MR2* and CR2* in diabetes were significantly increased. The positive relationship was found between MR2* and estimated glomerular filtration rate (eGFR), and CR2* was negatively correlated with eGFR. Interestingly, the MCR increased in early stage of diabetes and decreased along with the aggravation of diabetic nephropathy (DN).
  
  
  CONCLUSIONS
  BOLD-MRI can non-invasively detect and assess the renal hypoxia in diabetes. Our findings suggest that hypoxia in medulla is more apparent and earlier than in cortex. During the progression of DN, a reversion of corticomedullary oxygenation gradient can be detected, thus, MCR would be adopted to suppose the progression and prognosis of DN.
authors.affiliation: Department of Radiology, West China Hospital of Sichuan University, No 37 Guoxue Street, Wuhou District, Chengdu, Sichuan 610041, China.
authors.forename: Wen-Jie
authors.initials: WJ
authors.lastname: Yin
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Li
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
authors.forename: Shuang
authors.initials: S
authors.lastname: Zhao
authors.forename: Zi-Xing
authors.initials: ZX
authors.lastname: Huang
authors.forename: You-Qun
authors.initials: YQ
authors.lastname: Huang
authors.forename: Rong-Bo
authors.initials: RB
authors.lastname: Liu
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001706:Biopsy; D003928:Diabetic Nephropathies / Q000378:metabolism* / Q000473:pathology*; D005260:Female; D006801:Humans; D007677:Kidney Function Tests; D016014:Linear Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*
chemical_list: D010100:Oxygen