Charcot-Bouchard aneurysms are microaneurysms that are less than 1 mm in diameter. They occur in the small penetrating arterioles that perfuse the basal ganglia, pons and subcortical white matter. These aneurysms occur due to long-standing hypertension and are prone to rupture. Hemorrhagic stroke would be evident on the intial CT scan as a focus of intraparenchymal hyperdensity.
Lacunar infarcts are small ischemic infarcts ( less than 15 mm in diameter), usually involving the basal ganglia, pons, internal capsule, or deep white matter of the brain. Lacunar infarcts occur most often due to hypertensive arteriolosclerosis of small, penetrating arterioles.