Microstructure of Strategic White Matter Tracts and Cognition in Memory Clinic Patients with Vascular Brain Injury

Area of Science:

• Neuroimaging
• Neurology
• Cognitive Science

Background:

• White matter injury is a key contributor to cognitive impairment in patients attending memory clinics.
• Vascular brain injury often involves white matter damage, impacting cognitive functions.

Purpose of the Study:

• To assess the added value of diffusion tensor imaging (DTI) in explaining cognitive variance in memory clinic patients with vascular brain injury.
• To identify specific white matter tracts crucial for cognitive functions using DTI.

Main Methods:

• Included 159 patients with vascular brain injury.
• Utilized conventional MRI markers (white matter hyperintensity volume, lacunes, infarcts, atrophy, microbleeds) and DTI metrics (fractional anisotropy, mean diffusivity) of global white matter and 18 specific tracts.
• Employed linear regression and Bayesian network analysis to correlate MRI/DTI findings with cognitive performance (executive functioning, speed, memory).

Main Results:

• Mean diffusivity (MD) of whole brain white matter explained additional variance in executive functioning (3.4%), speed (7.8%), and memory (1.2%).
• Bayesian analysis identified strategic tracts: right superior longitudinal fasciculus for executive functioning, left corticospinal tract for speed, and left uncinate fasciculus for memory.
• MD within these strategic tracts further explained additional variance in executive functioning (3.4%), speed (3.8%), and memory (2.1%) beyond conventional and global DTI markers.

Conclusions:

• Diffusion tensor imaging of strategic white matter tracts provides significant added value in explaining cognitive functioning variance.
• DTI enhances the understanding of white matter injury's impact on cognition in memory clinic patients with vascular brain injury.