Cerebral Collateral Circulation

Abstract

Collateral circulation plays a decisive role in the pathophysiology of cerebral ischemia. However, knowledge regarding collateral circulation remains scarce due to the limitations of various assessment methods.

Anatomical descriptions of collateral circulation often focus on the more proximal anastomoses within the Circle of Willis and neglect the secondary pathways of collateral circulation provided by leptomeningeal anastomoses. The final formation of collateral circulation is likely dependent on the operation of multiple compensatory hemodynamic, metabolic, and neural mechanisms, as the subsequent formation of these protective vascular pathways can determine the severity of ischemic damage. Currently, the assessment of collateral circulation is performed using various instrumental studies, most frequently including CT angiography, MRI angiography, and digital angiography.

The assessment of collateral circulation will continue to be refined in the future with various neuroimaging methods, but one thing is clear—it represents one of the most important factors for the outcome of acute ischemic stroke.