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Updated: Jun 1, 2026
Non-invasive Imaging and Analysis of Cerebral Ischemia in Living Rats Using Positron Emission Tomography with 18F-FDG
Published on: December 28, 2014
[Functional connectivity analysis of super acute cerebral ischemia in rats: a resting-state functional MRI empirical
Qun-li Yao1, Hong-ying Zhang, Fang Fang
1Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing 210009, China.
Objective:
To investigate the change of low-frequency blood-oxygenation-level-dependent fluctuation (LFBF) after cerebral ischemia by functional connectivity analysis in the resting state.
Methods:
Super acute stroke rat-models with middle cerebral artery occlusion (MCAO) were employed in this study. Spontaneous fluctuations were recorded using a series of gradient-recalled echo-planar imaging (EPI) images before creation of the MCAO, and the same scan protocols were duplicated at the time of 60 min, 2 h after creation of the MCAO. FMRI signal time series from the different ROIs of ischemic cortex and normal cortex were preprocessed and low pass filtered. After preprocessing, the serial fMRI data was obtained by fast Fourier transformation to calculate the amplitude of the low-frequency fluctuations. Meanwhile, time course signal changes from a seed voxel of normal cortex were correlated with every voxel in the brain. Statistical analysis was performed across all rats to determine the extent of spatial correlation between regions.
Results:
The amplitude of LFBF in the ischemic cortex between 0.01 and 0.1 Hz was lightly decreased during the super acute ischemic stroke. Howerever, the amplitude of LFBF in contralateral cortex was increased after 2 hours. Spatial distribution of LFBF, from cross-correlation analysis, indicates that the substantial inter-hemispheric synchrony of ischemic region was decreased and of contralateral cortex was enhanced during the super acute ischemic stroke.
Conclusion:
The contrast behavior of the resting state BOLD signal fluctuations and a intra-hemispheric symmetry in the LFBF with similar phase characteristics in most other regions during super acute ischemic stroke can be implied a new approach to detect the physiological activity functions and the distinct resting neural networks after the acute ischemic stroke takes place.
