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| Evaluation of secondary functional changes in rats with spinal cord injury using BOLD-fMRI at 7.0T |
| WANG Lei1, WANG Yu-qing2, CHEN Yu-shu1, WANG Ting-hua1, GAO Fa-bao1 |
1. West China Hospital of Sichuan University, Chengdu 610041, China; 2. CAS Key Laboratory for Biomedical Effects of
Nanomaterials and Nanosafety, National Center for Nanoscience and Technology of China, Beijing 100190, China |
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Abstract Objective: To explore the imaging trends of secondary brain function changes in resting state and task state after spinal cord injury(SCI) in rats using the blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI). Methods: Complete spinal cord transected injury model was established in 12 SD rats, and categorized as Stage A, B and C according to the stimulation time after modeling. Stage A, as a control, performed after 5 minutes of modeling, the electrodes were inserted into the muscle at 2 mm on the right side of the spinal cord. Stage B, after 30 minutes of modeling, the electrodes were inserted into the lower section of the spinal cord at about 2 mm. Stage C, after 24 hours of modeling, the electrodes were inserted into the lower section of the spinal cord at about 2 mm. The resting and task state 7.0T fMRI was performed for all stages of the rats, and the electrical stimulation(0.5 A, 1 Hz) in task state lasted about 320 seconds. SPM8 and DPARSF software were used to analyze the task state and resting state fMRI data. Results: There were significant differences in the resting state and task state brain activity for the three stages. The resting brain activity areas of rats were mainly located in the prefrontal lobe, anterior cingulate gyrus and hippocampus. The number of active voxels in stage B increased by 10% compared with that in stage A, and the fractional amplitude of low-frequency fluctuations(fALFF) increased by 21%; the number of active voxels in stage C decreased by 4.4% compared with that in stage A, fALFF decreased by 6%. The brain activation areas of the task states in the three periods included the precentral gyrus, the postcentral gyrus, and the striatum. The number of active voxels in stage B decreased by 64% compared with that in stage A, and the mean value of t value decreased by 49%. The number of active voxels in stage C increased by 61% compared with that in stage A, and the mean value of t value decreased by 9%. Conclusion: BOLD-fMRI can dynamically, quantitatively and noninvasively evaluate the secondary changes of brain function activity in resting and task state after SCI in rats in vivo. After SCI, there is a stress effect in the static brain function, which disappears after 24 hours. After SCI, the activation of the brain function in the task state is from low level to high level.
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Received: 11 July 2017
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