Fig. 1

Pathophysiology of Intracranial Atherosclerosis. Intracranial atherosclerotic disease (ICAD) is a chronic inflammatory disorder affecting arterial segments with high endothelial shear stress, such as bifurcations and curvatures. Early in atherogenesis, oxidized low-density lipoproteins (LDL) accumulate in the arterial intima, activating endothelial and smooth muscle cells (SMCs). This prompts monocytes to become macrophages and dendritic cells, which then differentiate into foam cells. As atherosclerosis progresses, immune cell infiltrates contribute to the thinning of the fibrous cap. Lipid accumulation and foam cell necrosis eventually form a necrotic core. At advanced stages of atherosclerosis, neovascularization from the adventitial vasa vasorum may lead to intraplaque hemorrhage and plaque instability. Image created with Biorender