Changes in Bihemispheric Structural Connectivity Following Middle Cerebral Artery Infarction

Area of Science:

• Neuroscience
• Neurology
• Radiology

Background:

• Middle cerebral artery infarction can lead to long-term neurological deficits.
• Understanding brain structural connectivity changes post-stroke is crucial for rehabilitation.
• Mild motor impairment following stroke may still involve significant brain network alterations.

Purpose of the Study:

• To investigate longitudinal changes in bilateral brain structural connectivity after middle cerebral artery infarction.
• To compare connectivity patterns in subacute and chronic stroke phases.
• To assess the impact of stroke on brain hemispheres even in cases of mild motor impairment.

Main Methods:

• Retrospective analysis of 18 subacute and 9 chronic stroke patients with mild upper extremity motor impairment.
• Acquisition of T1-weighted and diffusion tensor imaging (DTI).
• Tract-based spatial statistics (TBSS) of fractional anisotropy (FA) to analyze structural connectivity.

Main Results:

• Subacute phase: Decreased structural connectivity in the affected hemisphere's corticospinal tract, and in the unaffected hemisphere's corpus callosum and corona radiata.
• Chronic phase: Increased structural connectivity in bilateral frontal lobe motor association areas and the anterior corpus callosum.
• Significant alterations in bilateral hemispheric structural connectivity were observed, differing between subacute and chronic stages.

Conclusions:

• Middle cerebral artery infarction affects structural connectivity in both hemispheres, irrespective of motor impairment severity.
• Brain structural connectivity undergoes dynamic changes over time post-stroke.
• These findings highlight the widespread neural reorganization following even mild stroke.