Which type of stroke would most likely result from occlusion of a small penetrating artery?

A lacunar infarct is a specific type of ischemic stroke that occurs when there is occlusion of a small penetrating artery that supplies deep structures of the brain such as the basal ganglia, thalamus, or internal capsule. This occlusion typically results from chronic hypertension or lipohyalinosis, leading to small, deep brain lesions.

In contrast, a transient ischemic attack (TIA) is characterized by temporary symptoms without permanent damage, thus it does not involve infarction. Subarachnoid hemorrhage involves bleeding between the brain and the tissue covering it, generally due to a ruptured aneurysm or arteriovenous malformation, rather than an occlusion of an artery. Thrombotic strokes can involve larger arteries and typically result from a thrombus that forms directly on the site of atherosclerotic plaque in larger arteries rather than the small penetrating arteries leading to lacunar infarcts.

Therefore, the distinct mechanism leading to lacunar infarcts, linked to small vessel disease, clearly identifies it as the type of stroke most likely resulting from occlusion of a small penetrating artery.