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Liu Y.-P.,Chinese Traditional Medicine Hospital | Liang C.-H.,Southern Medical University | Zhang S.-X.,Southern Medical University | Liu B.,Chinese Traditional Medicine Hospital | Ran P.-C.,Chinese Traditional Medicine Hospital
Chinese Journal of Radiology | Year: 2010

Objective: To evaluate blood oxygen level-dependent (BOLD) MRI on assessing renal damage after injection of iodine contrast medium with a 3.0 T system. Methods: Routine MRI examination, including T 1WI and T 2WI, and BOLD MRI were performed in 29 SD rats with a 3.0 T system before the injection of iodine contrast agent and 20 min, 24 h, 48 h, 72 h after the injection, respectively. T 2* and R 2* (= 1/T 2*) measurements were obtained in the cortex, inner and outer medulla of kidney, respectively. The results obtained before contrast agent administration were considered as the self-controls. AVONA test were used for the comparison of R 2* values in different parts of both kidneys before contrast agent administration. Two-sample t test was used to compare R 2* values before and at each time point after contrast agent administration, and R 2* values in different parts of the kidneys. Results: Before contrast agentadministration, R 2* values in outer medulla in both sides of kidney [R 2* left OM = (31.76±2.73)/s, R 2* right OM = (32-77±3.07)/s] were higher than those in cortex [R 2* left C = (30.20±3.48)/s, R 2* right c = (28.84±3.11)/s] and in inner medulla [R 2* left IM = (29.54±2.42)/s, R 2* right IM = (28.37±2.80)/s] (F = 3.357 and 14.961, P<0.05). There was no statistical significance in R 2* values in the three parts between left and right kidney, including cortex, outer and inner medulla (P>0.05). After contrast agent administration, R 2* values in outer medulla changed obviously, which reached to the peak values at 20 minutes after contrast agent administration [R 2* left OM = (43-57±3.84)/s, R 2* right OM = (44.58±3.13)/s] and dropped from 24 hours [R 2* left OM = (42.07±4.82)/s, R 2* right OM = (42-89±3.40)/s]. R 2* values in inner medulla and cortex only presented slight changes. Conclusion: R 2* values reflected the changes of oxygen content in renal cortex and medulla quantitatively, which helped for detecting medullar ischemia and hypoxia. BOLD MR imaging could offer a feasible method for evaluating oxygen metabolism and renal injury in cortex and medulla. © 2010 by the Chinese Medical Association.

PubMed | Chinese Traditional Medicine Hospital
Type: Journal Article | Journal: American journal of physiology. Renal physiology | Year: 2012

A multitude of evidence suggests that iodinated contrast material causes nephrotoxicity; however, there have been no previous studies that use arterial spin labeling (ASL) blood flow functional magnetic resonance imaging (fMRI) to investigate the alterations in effective renal plasma flow between normointensive and hypertensive rats following injection of contrast media. We hypothesized that FAIR-SSFSE arterial spin labeling MRI may enable noninvasive and quantitative assessment of regional renal blood flow abnormalities and correlate with disease severity as assessed by histological methods. Renal blood flow (RBF) values of the cortex and medulla of rat kidneys were obtained from ASL images postprocessed at ADW4.3 workstation 0.3, 24, 48, and 72 h before and after injection of iodinated contrast media (6 ml/kg). The H&E method for morphometric measurements was used to confirm the MRI findings. The RBF values of the outer medulla were lower than those of the cortex and the inner medulla as reported previously. Iodinated contrast media treatment resulted in decreases in RBF in the outer medulla and cortex in spontaneously hypertensive rats (SHR), but only in the outer medulla in normotensive rats. The iodinated contrast agent significantly decreased the RBF value in the outer medulla and the cortex in SHR compared with normotensive rats after injection of the iodinated contrast media. Histological observations of kidney morphology were also consistent with ASL perfusion changes. These results demonstrate that the RBF value can reflect changes of renal perfusion in the cortex and medulla. ASL-MRI is a feasible and accurate method for evaluating nephrotoxic drugs-induced kidney damage.

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