Dynamics of Water Diffusion Changes in Different Tissue Compartments From Acute to Chronic Stroke-A Serial Diffusion...

Area of Science:

• Neuroimaging
• Cerebrovascular Diseases
• Biophysics

Background:

• Acute ischemic stroke is characterized by a rapid decrease in apparent diffusion coefficient (ADC).
• Limited data exists on the temporal diffusion parameter changes within different tissue compartments of cerebral ischemia.

Purpose of the Study:

• To investigate the time course of diffusion parameters in various tissue compartments of acute ischemic stroke.
• To differentiate between persistent core, lesion growth, and reversible lesions using diffusion tensor imaging (DTI).

Main Methods:

• Longitudinal DTI study of 21 acute ischemic stroke patients at multiple time points (within 5h, 3h later, 2 days, 1 month).
• Defined volumes of interest (VOIs) for persistent core, lesion growth, and reversible lesions based on acute diffusion and FLAIR imaging.
• Calculated ratios of ADC, fractional anisotropy, and eigenvalues between stroke lesions and contralateral mirror regions.

Main Results:

• Persistent core showed reduced ADC and eigenvalues ratios initially, with partial normalization at 1 month.
• Regions of infarct growth exhibited similar but delayed diffusion parameter changes.
• Reversible lesions showed partial normalization but retained altered diffusion signatures at 1 month.

Conclusions:

• DTI effectively demonstrates characteristic temporal diffusion changes across different tissue compartments in acute ischemic stroke.
• Even areas with reversible diffusion lesions exhibit persistent tissue alterations, indicating long-term effects.