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Updated: Apr 6, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
MRI Susceptibility Changes Suggestive of Iron Deposition in the Thalamus after Ischemic Stroke
Ellis S van Etten1, Jeroen van der Grond, Eve M Dumas
1Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
Background:
Iron accumulation has been linked to neuronal injury following cerebral ischemia. In animals, a hypointense signal on T2*-weighted (T2*-w) MRI correlated with iron deposits in remote brain regions following ischemic stroke. We aim to assess whether such signal changes are present in remote brain structures following ischemic stroke in humans.
Methods:
We analyzed T2*-w images of 36 patients with unilateral ischemic stroke and 36 healthy controls. Regions of interest (ROIs) consisted of the thalamus, putamen, globus pallidus, caudate nucleus and white matter. To quantify signal intensity in ROIs ipsilateral to the infarct, signal intensity was measured in the ROIs in both hemispheres and a ratio of signal intensity was calculated. Signal asymmetry was compared between patients and controls and its relation with time after stroke onset was assessed.
Results:
In 34 (94%) patients, the thalamus ipsilateral to the infarct was hypointense compared to the contralateral thalamus. Ipsilateral thalamic signal hypointensity was significantly different between patients and controls (p < 0.001) and was present as early as 1 day after stroke onset. In other ROIs, no difference was found between patients and controls. No association was found between intensity asymmetry and time.
Conclusion:
We demonstrated that, as early as days after ischemic stroke, T2*-w signal intensity was decreased in the ipsilateral thalamus. This finding might indicate pathophysiologic changes in regions outside the infarcted area, possibly reflecting toxic iron accumulation.
Insights
Following ischemic stroke, T2*-weighted MRI shows reduced signal in the ipsilateral thalamus, suggesting potential iron accumulation in remote brain regions. This early change may indicate widespread neuronal injury after stroke.
Area of Science:
- Neuroimaging
- Neurology
- Biomedical Engineering
Background:
- Iron accumulation is implicated in neuronal damage after cerebral ischemia.
- Animal studies show T2*-weighted MRI hypointensity correlates with iron deposits in remote brain areas post-ischemic stroke.
- This study investigates if similar signal changes occur in human remote brain structures.
Purpose of the Study:
- To assess T2*-weighted magnetic resonance imaging (MRI) signal changes in remote brain regions following ischemic stroke in humans.
- To determine if ipsilateral thalamic hypointensity is a marker of post-stroke pathophysiology.
Main Methods:
- Analyzed T2*-weighted MRI scans from 36 ischemic stroke patients and 36 healthy controls.
- Measured signal intensity in regions of interest (thalamus, putamen, globus pallidus, caudate nucleus, white matter) in both hemispheres.
- Calculated signal intensity ratios to quantify asymmetry and compared between patients and controls.
Main Results:
- Significant thalamic signal hypointensity ipsilateral to the infarct was observed in 94% of stroke patients compared to controls (p < 0.001).
- This hypointensity was detectable as early as 1 day post-stroke onset.
- No significant signal differences were found in other analyzed regions (putamen, globus pallidus, caudate nucleus, white matter).
Conclusions:
- T2*-weighted MRI demonstrates decreased signal intensity in the ipsilateral thalamus within days of ischemic stroke.
- This finding suggests pathophysiological alterations in non-infarcted brain areas.
- The observed hypointensity may indicate toxic iron accumulation in remote brain regions after stroke.
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