Small Vessels, Big Problems: The New England Journal of Medicine:
"The impressive gains in stroke prevention and treatment seen over the past decade have not been evenly distributed across all types of stroke. Most advances have pertained to the approximately two thirds of symptomatic strokes that are caused by disease of the large arteries (those more than 0.1 mm in diameter) that run from the neck into the skull, the circle of Willis, and the surface of the brain. These large-vessel subtypes of stroke include atherosclerotic narrowing and occlusion of the large neck vessels, aneurysmal rupture and subarachnoid hemorrhage over the brain surface, and thromboembolic occlusion of the major vessel . . ."