You can see atheroma plaque in basal artery, vertebral artery and in the Willis polygon (circle of Willis). An atheroma is an accumulation of degenerative material in the inner layer of an artery wall. The material consists of mostly macrophage cells, or debris, containing lipids, calcium and a variable amount of fibrous connective tissue.These structural and functional changes in the vascular wall eventually leads to the narrowing of the arterial lumen and restricting the cerebral blood flow. The plaque build-up can be visualized with an angiogram and is usually done with MRI to quantify the plaque anatomy and composition. Given the symptoms, anti-coagulation medications reduce the likelihood of further buildup while also trying to break down the current build up on the surface without an embolism forming. Patients with severe stenosis that are at risk for impending stroke endovascular treatment is used. These include angioplasty, stent insertion, or bypass the blocked area.Photo by @Medizzy app.