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Updated: Jul 11, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
MRI of spontaneous fluctuations after acute cerebral ischemia in nonhuman primates
Yutong Liu1, Helen D'Arceuil, Julian He
1Martinos Center, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts.
Purpose:
To study the spontaneous low-frequency blood oxygenation level-dependent (BOLD) functional MRI (fMRI) signal fluctuations during hyperacute focal cerebral ischemia.
Materials And Methods:
A stroke model in nonhuman primates (macaques) was used in this study. Spontaneous fluctuations were recorded using a series of gradient-recalled echo (GRE) echo-planar imaging (EPI) images. Fast Fourier transformation (FFT) was performed on the serial EPI data to calculate the frequency and magnitude of the spontaneous fluctuations. Diffusion tensor imaging (DTI) and perfusion-weighted imaging (PWI) were preformed to detect the ischemic lesion.
Results:
The frequency of these fluctuations decreased in the periinfarct tissue in the ipsilateral hemisphere, while their magnitude increased. This area of abnormal signal fluctuations often extended beyond the hyperacute diffusion/perfusion abnormality.
Conclusion:
This study suggests that measurement of the spontaneous fMRI signal fluctuations provides different information than is available from diffusion/perfusion or T2-weighted MRI.
Insights
Studying spontaneous blood oxygenation level-dependent (BOLD) functional MRI (fMRI) signal fluctuations in hyperacute stroke reveals altered frequencies and magnitudes in periinfarct tissue, offering insights beyond standard imaging.
Area of Science:
- Neuroimaging
- Cerebrovascular Research
- Functional Magnetic Resonance Imaging (fMRI)
Background:
- Hyperacute focal cerebral ischemia presents diagnostic challenges.
- Understanding early BOLD signal changes is crucial for stroke management.
- Spontaneous low-frequency fluctuations offer potential biomarkers.
Purpose of the Study:
- To investigate spontaneous low-frequency BOLD fMRI signal fluctuations in hyperacute focal cerebral ischemia.
- To characterize the frequency and magnitude of these fluctuations.
- To compare fMRI findings with diffusion and perfusion imaging.
Main Methods:
- Utilized a nonhuman primate stroke model.
- Recorded spontaneous BOLD fMRI signal fluctuations using gradient-recalled echo echo-planar imaging.
- Analyzed signal fluctuations with Fast Fourier Transformation.
- Assessed ischemic lesions using Diffusion Tensor Imaging and Perfusion-Weighted Imaging.
Main Results:
- Observed decreased fluctuation frequency in periinfarct tissue.
- Noted increased fluctuation magnitude in the ipsilateral hemisphere.
- Found that abnormal signal fluctuation areas often exceeded diffusion/perfusion abnormalities.
Conclusions:
- Spontaneous fMRI signal fluctuation measurement provides unique information.
- This method offers complementary data to diffusion/perfusion MRI.
- Findings suggest fMRI fluctuations may detect subtle ischemic changes.
