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Multislice diffusion mapping for 3-D evolution of cerebral ischemia in a rat stroke model
W Reith1, Y Hasegawa, L L Latour
1Department of Neurology, Medical Center of Central Massachusetts-Memorial, Worcester 01605-2982.
Abstract:
Diffusion-weighted magnetic resonance imaging (DWI) can quantitatively demonstrate cerebral ischemia within minutes after the onset of ischemia. The use of a DWI echo-planar multislice technique in this study and the mapping of the apparent diffusion coefficient (ADC) of water, a reliable indicator of ischemic regions, allow for the detection of the three-dimensional (3-D) evolution of ischemia in a rat stroke model. We evaluated 13 time points from 5 to 180 minutes after occlusion of the middle cerebral artery (MCA) and monitored the 3-D spread of ischemia. Within 5 minutes after the onset of ischemia, regions with reduced ADC values occurred. The core of the lesion, with the lowest absolute ADC values, first appeared in the lateral caudoputamen and frontoparietal cortex, then spread to adjacent areas. The volume of ischemic tissue was 224 +/- 48.5 mm3 (mean +/- SEM) after 180 minutes, ranging from 92 to 320 mm3, and this correlated well with the corrected infarct volume at postmortem (194 +/- 23.1 mm3, r = 0.72, p < 0.05). This experiment demonstrated that 3-D multislice diffusion mapping can detect ischemic regions noninvasively 5 minutes after MCA occlusion and follow the development of ischemia. The distribution of changes in absolute ADC values within the ischemic region can be followed over time, giving important information about the evolution of focal ischemia.
Insights
Diffusion-weighted imaging (DWI) detects early cerebral ischemia within 5 minutes of onset. This study maps the 3-D spread of stroke evolution in rats using apparent diffusion coefficient (ADC) mapping.
Area of Science:
- Neuroimaging
- Cerebrovascular Research
- Medical Physics
Background:
- Cerebral ischemia requires rapid detection for effective treatment.
- Diffusion-weighted magnetic resonance imaging (DWI) offers quantitative insights into ischemic changes.
- Understanding the spatiotemporal evolution of ischemia is crucial for stroke modeling.
Purpose of the Study:
- To evaluate the capability of 3-D multislice DWI and apparent diffusion coefficient (ADC) mapping for early detection and monitoring of ischemic evolution.
- To characterize the 3-D spread and development of cerebral ischemia in a rat stroke model.
Main Methods:
- Utilized diffusion-weighted echo-planar multislice magnetic resonance imaging (DWI).
- Mapped apparent diffusion coefficient (ADC) values to identify and quantify ischemic regions.
- Monitored 13 time points from 5 to 180 minutes post-middle cerebral artery (MCA) occlusion in a rat model.
Main Results:
- Reduced ADC values, indicative of ischemia, were detected as early as 5 minutes after MCA occlusion.
- The ischemic core initially appeared in the lateral caudoputamen and frontoparietal cortex, subsequently spreading.
- A strong correlation was observed between the 180-minute DWI-derived ischemic volume and postmortem infarct volume (r = 0.72, p < 0.05).
Conclusions:
- 3-D multislice diffusion mapping noninvasively detects cerebral ischemia within 5 minutes of MCA occlusion.
- This technique allows for monitoring the 3-D evolution and spread of focal ischemia over time.
- ADC value changes provide critical information regarding the dynamic development of ischemic brain injury.