Prediction of delayed ischemic injury with diffusion-weighted MRI following temporary middle cerebral artery occlusion in rats
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Updated: Oct 24, 2026
Focal Cerebral Ischemia Model by Endovascular Suture Occlusion of the Middle Cerebral Artery in the Rat
Published on: February 5, 2011
A Mancuso1, T Nimura, P R Weinstein
1Department of Neurological Surgery, Veterans Administration Medical Center and School of Medicine, University of California, San Francisco 94121, USA. anthman@itsa.ucsf.edu
Abstract:
Early reductions in the apparent diffusion coefficient of water (ADC) during focal cerebral ischemia are often reversible with reperfusion. With sustained ischemia, the magnitude of the ADC reduction generally increases with time, which could reflect increased severity of ischemic damage. Thus, a threshold in ADC reduction may exist beyond which damage can not be reversed with reperfusion. The goal of this study was to determine if such a threshold exists that is independent of the duration of ischemia in a rat model. Rats were subjected to either 30, 60, or 90 min of temporary middle cerebral artery occlusion. ADC maps acquired just before and 30 min after reperfusion were compared to histology performed after a 72 h survival period to determine the relationship between ADC reduction and final ischemic injury. Significant variability in tissue recovery was observed for the 30 min group. Regions with ADC reductions of up to 45% often recovered, while some regions not exhibiting any change in ADC during occlusion showed ischemic injury at 72 h. Similar observations were made in cortical regions of the 60 min group. In the caudate-putamen, reduced ADC was often associated with ischemic injury. For the 90 min group, results for the caudate-putamen were similar to those for the 60 min group, while reduced ADC was a much better predictor of final ischemic injury in cortical regions than it was in both the 30 and 60 min groups. Thus, no single threshold of ADC reduction that was independent of the duration of ischemia was associated with irreversible injury.
Insights
No single threshold of apparent diffusion coefficient (ADC) reduction predicts irreversible ischemic injury. The relationship between ADC changes and final damage varies with ischemia duration and brain region, highlighting the complexity of predicting stroke outcomes.
Area of Science:
- Neuroscience
- Radiology
- Pathology
Background:
- Early reductions in apparent diffusion coefficient (ADC) during focal cerebral ischemia are often reversible.
- Sustained ischemia leads to increased ADC reduction, potentially indicating greater damage.
- A critical ADC reduction threshold for irreversible injury is hypothesized.
Purpose of the Study:
- To determine if a duration-independent threshold of ADC reduction exists for irreversible ischemic injury.
- To investigate the relationship between ADC changes and histological damage after temporary middle cerebral artery occlusion in rats.
Main Methods:
- Rats underwent 30, 60, or 90 minutes of middle cerebral artery occlusion.
- ADC maps were acquired before and after reperfusion.
- Histology was performed after 72 hours to assess final ischemic injury.
Main Results:
- Variable tissue recovery observed, especially in shorter occlusion groups (30-60 min).
- ADC reduction up to 45% sometimes recovered; some areas with no ADC change showed injury.
- Reduced ADC was a better predictor of injury in cortical regions for longer occlusions (90 min).
Conclusions:
- No single ADC reduction threshold reliably predicts irreversible ischemic injury across all durations.
- The predictive value of ADC reduction for final injury is dependent on ischemia duration and brain region.
- ADC changes alone are insufficient to determine the extent of irreversible damage post-reperfusion.
