title: Application of BOLD MRI and DTI for the evaluation of renal effect related to viscosity of iodinated contrast agent in a rat model.
abstract: To evaluate the effects of viscosity of contrast agent (CA) on intrarenal oxygenation and diffusion as measured by blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) in a rat model.
  
  
  
  Radiocontrast iodixanol formulated in three viscosities were designated 270, 320, and 350 (mg iodine/mL). Sixty-three male Wistar rats were divided into four groups. Saline and iodixanol (4 g iodine/kg) were administered. MR images were acquired on a 3.0T scanner at baseline and at 1 hour, 24 hours, 48 hours, and 72 hours postinjection of solutions. BOLD-MRI was performed with a multiple gradient-recalled-echo sequence. The changes in R2*, apparent diffusion coefficient (ADC), fractional anisotropy (FA), histology, and hypoxia-inducible factor-1α (HIF-1α) immunoexpression were evaluated. The R2*, ADC, and FA values were normalized to baseline to calculate ΔR2*, ΔADC, and ΔFA.
  
  
  
  Compared with baseline levels, distinct elevation of ΔR2* (P < 0.05) and obvious decrease in ΔADC (P < 0.01) and ΔFA (P < 0.05) were observed in all the anatomical compartments at 1 hour after administration of CA. The absolute values in ΔR2*, ΔADC, and ΔFA increased with increases in CA viscosity, and differed significantly between the CA groups in renal cortex (CO), outer stripe of outer medulla (OSOM), and inner stripe of outer medulla (ISOM) (all P < 0.05). A significant positive correlation was observed between ΔR2* and HIF-1α expression (P < 0.001, r = 0.75). Significant negative correlations were observed between ΔADC, ΔFA, and pathologies in CO, OSOM, ISOM (all P < 0.001, r = -0.68-0.87; all P < 0.001, r = -0.60-0.66).
  
  
  
  The effect of CA viscosity on intrarenal oxygenation and diffusion was viscosity-dependent, and was identified using BOLD-MRI and DTI.
  
  
  
  1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1320-1331.
authors.affiliation: Department of Radiology, First Hospital of China Medical University, Shenyang, P.R. China.|Key Laboratory of Imaging Diagnosis and Interventional Radiology of Liaoning Province, Shenyang, P.R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Radiology, First Hospital of China Medical University, Shenyang, P.R. China.
authors.forename: Ke
authors.initials: K
authors.lastname: Ren
authors.affiliation: Department of Radiology, First Hospital of China Medical University, Shenyang, P.R. China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Radiology, First Hospital of China Medical University, Shenyang, P.R. China.
authors.forename: Wen-Ge
authors.initials: WG
authors.lastname: Sun
authors.affiliation: Department of Radiology, First Hospital of China Medical University, Shenyang, P.R. China.
authors.forename: Jia-Huan
authors.initials: JH
authors.lastname: Wang
authors.affiliation: Department of Radiology, First Hospital of China Medical University, Shenyang, P.R. China.|Key Laboratory of Imaging Diagnosis and Interventional Radiology of Liaoning Province, Shenyang, P.R. China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Radiology, First Hospital of China Medical University, Shenyang, P.R. China.|Key Laboratory of Imaging Diagnosis and Interventional Radiology of Liaoning Province, Shenyang, P.R. China.
authors.forename: Cheng-Hua
authors.initials: CH
authors.lastname: Wu
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000737:chemistry*; D056324:Diffusion Tensor Imaging; D004195:Disease Models, Animal; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007455:Iodine / Q000737:chemistry*; D007668:Kidney / Q000000981:diagnostic imaging* / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar; D014283:Triiodobenzoic Acids / Q000737:chemistry; D014783:Viscosity
chemical_list: D003287:Contrast Media; C497444:Hif1a protein, rat; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D014283:Triiodobenzoic Acids; D007455:Iodine; C044834:iodixanol; D010100:Oxygen
keywords: BOLD-MRI; DTI; contrast agent; kidney; renal oxygenation; viscosity