Bilateral common carotid artery occlusion induced brain lesions in rats: A longitudinal diffusion tensor imaging study

Bilateral common carotid artery occlusion (BCCAO) has been widely used to reproduce the white matter (WM) and gray matter (GM) damage associated with chronic cerebral hypoperfusion (CCH). This study investigated whether diffusion tensor imaging (DTI) could be used at the early stages of disease to assess brain damage induced by BCCAO. To this end, DTI, together with histological methods, was used to evaluate the progression of WM lesions and GM neurodegeneration following BCCAO. The DTI was sufficiently sensitive to detect WM abnormalities in selected regions of the brain at 4 weeks after BCCAO. These abnormalities may indicate damage to the myelin and axons in the optic nerve (ON) and optic tract (OT). Our longitudinal results showed that DTI could be used to detect abnormalities of the WM and GM in select regions of the brain as early as 2 days after ligation. The DTI parameter patterns of change were region-specific throughout the detection time course. Lesions of the external capsule (EC) and periventricular hypothalamic nucleus (Pe) have not been thoroughly studied before. We found that the EC and Pe were both vulnerable to BCCAO and that the associated lesions could be detected using DTI. The current study demonstrated that in vivo DTI could potentially be used to measure WM damage evolution in a BCCAO rat model as well as early brain injury following CCH.