Differences between gray matter and white matter water diffusion in stroke: diffusion-tensor MR imaging in 12...

Area of Science:

• Neuroimaging
• Stroke research
• Diffusion MRI

Background:

• Stroke significantly impacts brain tissue, affecting both white matter (WM) and gray matter (GM).
• Understanding differential tissue response to ischemia is crucial for early diagnosis and treatment.
• Diffusion-tensor imaging (DTI) offers advanced insights into tissue microstructure compared to conventional diffusion-weighted imaging (DWI).

Purpose of the Study:

• To compare water diffusion changes in WM and GM in acute to early subacute stroke patients.
• To evaluate the sensitivity of DTI in detecting ischemia in different brain tissue types.

Main Methods:

• Diffusion-tensor echo-planar MR imaging was performed on 12 patients with middle cerebral artery infarcts.
• Isotropic diffusion coefficient (D) and diffusion anisotropy (Aσ) were computed to quantify diffusion.
• D values were measured in ischemic and contralateral WM and GM, differentiating tissue types using Aσ.

Main Results:

• Infarcted WM exhibited significantly greater diffusion reduction (46%) than infarcted GM (31%).
• DTI revealed two distinct levels of diffusion reduction within the infarct, predominantly in WM.
• DWI underestimated the extent and magnitude of WM diffusion abnormalities compared to DTI.

Conclusions:

• White matter is more severely affected by isotropic diffusion reduction than gray matter in acute stroke.
• Diffusion-tensor imaging demonstrates superior sensitivity for detecting white matter ischemia compared to diffusion-weighted imaging.