Evaluation of Renal Pathophysiological Processes Induced by an Iodinated Contrast Agent in a Diabetic Rabbit Model Using Intravoxel Incoherent Motion and Blood Oxygenation Level-Dependent Magnetic Resonance Imaging

Abstract

Objective To examine the potential of intravoxel incoherent motion (IVIM) and blood oxygen level-dependent (BOLD) magnetic resonance imaging for detecting renal changes after iodinated contrast-induced acute kidney injury (CI-AKI) development in a diabetic rabbit model. Materials and Methods Sixty-two rabbits were randomized into 2 groups: diabetic rabbits with the contrast agent (DCA) and healthy rabbits with the contrast agent (NCA). In each group, 6 rabbits underwent IVIM and BOLD imaging at 1 hour, 1 day, 2 days, 3 days, and 4 days after an iohexol injection while 5 rabbits were selected to undergo blood and histological examinations at these specific time points. Iohexol was administrated at a dose of 2.5 g I/kg of body weight. Further, the apparent transverse relaxation rate (R2 * ), average pure molecular diffusion coefficient (D), pseudo-diffusion coefficient (D * ), and perfusion fraction (f) were calculated. Results The D and f values of the renal cortex (CO) and outer medulla (OM) were significantly decreased compared to baseline values in the 2 groups 1 day after the iohexol injection ( p < 0.05). A marked reduction in the D * values for both the CO and OM was also observed after 1 hour in each group ( p < 0.05). In the OM, a persistent elevation of the R2 * was detected for 4 days in the DCA group ( p < 0.05). Histopathological changes were prominent, and the pathological features of CI-AKI aggravated in the DCA group until day 4. The D, f, and R2 * values significantly correlated with the histological damage scores, hypoxia-inducible transcription factor-1α expression scores, and serum creatinine levels. Conclusion A combination of IVIM and BOLD imaging may serve as a noninvasive method for detecting and monitoring CI-AKI in the early stages in the diabetic kidney.

The Application of Functional Magnetic Resonance Imaging in Type 2 Diabetes Rats With Contrast-Induced Acute Kidney Injury and the Associated Innate Immune Response

“…The BOLD images in Figure 3 show the fMRI data used in our study to evaluate renal blood oxygen content and to predict CI-AKI. Upon comparing Groups A and C (or B and D), we concluded that the renal damage is induced by CM and that the main condition is hypoxia-related oxidative stress, which has been supported in various previous experiments ( Caiazza et al, 2014 ; Wang et al, 2019 ; Kusirisin et al, 2020 ). Some clinical studies on CKD have obtained similar outcomes ( Khatir et al, 2015 ; Hirakawa et al, 2017 ; Li et al, 2019 ).…”

Non-invasive investigation of early kidney damage in streptozotocin-induced diabetic rats by intravoxel incoherent motion diffusion-weighted (IVIM) MRI

“…The limitations of the single exponential model become more apparent due to the complexity of the renal structure and function, including vascular flow, tubular flow and passive diffusion [ 11 , 12 ]. The application of IVIM has been reported in research articles on diabetic renal injury [ 9 , 13 – 15 ]. On this basis, our team also conducted a pilot study using IVIM to evaluate the kidneys of patients with early DN [ 9 ].…”

Magnetic resonance diffusion tensor imaging applied to rat model of contrast-induced acute kidney injury

“…Biotin-labeled goat anti-mouse IgG served as secondary antibody, using diaminobenzidine (DAB) as chromogenic substrate. The brownish precipitates at points of peroxidase localization were interpreted using the smart segmentation tool of ImageJ (National Institutes of Health, Bethesda, MD, USA) open-source software ( Wang et al, 2019 ).…”

“…Renal hypoxia and direct nephrotoxicity of CA are the universally acknowledged causes of CIAKI. Given the well-known fact that tubular vacuolar, tubulointerstitial fibrosis, and tubular damage occur in CIAKI, the hypoxia-inducible transcription factor-1α (HIF-1α) is also highly expressed in CIAKI ( Wang et al, 2019 ). We hypothesize that DTI is able to detect pathological changes of CIAKI and determine the correlation of FA to the degree of renal pathologies and HIF-1α expression.…”