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Application of BOLD MRI and DTI for the evaluation of renal effect related to viscosity of iodinated contrast agent in a rat model
Author(s) -
Wang Yi,
Ren Ke,
Liu Yi,
Sun Wenge,
Wang Jiahuan,
Zhang Xin,
Wu Chenghua
Publication year - 2017
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25683
Subject(s) - iodixanol , fractional anisotropy , effective diffusion coefficient , diffusion mri , magnetic resonance imaging , nuclear medicine , chemistry , medicine , renal cortex , rat model , white matter , oxygenation , nuclear magnetic resonance , kidney , endocrinology , contrast medium , radiology , physics
Purpose 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. Materials and Methods 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. Results 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). Conclusion The effect of CA viscosity on intrarenal oxygenation and diffusion was viscosity‐dependent, and was identified using BOLD‐MRI and DTI. Level of Evidence: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2017;46:1320–1331.