Brain diffusion changes in carotid occlusive disease treated with endarterectomy

Area of Science:

• Neuroimaging
• Cerebrovascular Disease
• Diffusion-Weighted MRI

Background:

• Unilateral high-grade carotid stenosis is associated with ipsilateral leukoaraiosis and ischemic lesions.
• These lesions impact apparent diffusion coefficient (ADC) values measured by diffusion-weighted MRI (DWI).
• The effect of carotid endarterectomy on ADC values remains underexplored.

Purpose of the Study:

• To determine hemispheric differences in average ADC (ADC(av)) values.
• To assess if carotid endarterectomy alters brain tissue diffusion detectable by serial DWI.
• To compare diffusion changes between asymptomatic and symptomatic carotid stenosis patients.

Main Methods:

• Diffusion-weighted MRI (DWI) was performed on 45 patients with unilateral high-grade carotid stenosis (22 asymptomatic, 23 symptomatic) before and after carotid endarterectomy (3 and 100 days).
• 45 age- and sex-matched healthy controls underwent single DWI scans.
• ADC(av) values were analyzed in normal-appearing gray and white matter, watershed regions (WsR), and thalamus.

Main Results:

• Ipsilateral white matter and WsR showed higher ADC(av) values than contralateral, and both were higher than in controls.
• Carotid endarterectomy reduced these differences, though values remained elevated compared to controls.
• Gray matter and thalamus ADC(av) values were unaffected; no significant differences were found between asymptomatic and symptomatic patient groups.

Conclusions:

• Carotid stenosis affects white matter diffusion in the ipsilateral hemisphere.
• This diffusion alteration is partially reversible following carotid endarterectomy.
• The findings suggest a potential link to "preleukoaraiosis" development.