The cerebral collateral circulation is a network of blood vessels designed to preserve cerebral blood flow when primary routes fail. Though recognized for hundreds of years, the beneficial influence of collateral flow has now gained significant attention due to widely available, rapid, and real-time non-invasive imaging techniques. Multimodal CT and MRI based techniques, with angiographic and perfusion assessments, are becoming mainstays in the care of patients with ischemic brain disease. These methods allow for precise delineation of the structural and functional aspects of cerebral blood flow and as such provide valuable information that can inform the diagnosis and treatment of cerebral ischemia, in both the acute and chronic setting.
Keywords: CT; MRI; advances in neuro-imaging; angiography; collateral; intracranial stenosis; moyamoya; perfusion; stroke; thrombectomy.