What disease primarily affects the intima and may extend into the media of blood vessels?

Atherosclerosis is the correct answer because it specifically involves the buildup of plaque—comprised of fats, cholesterol, and other substances—within the intima, which is the innermost layer of the blood vessel wall. Over time, this can lead to narrowing and hardening of the arteries, and in some cases, the disease can also extend into the media, the middle layer of the blood vessel, leading to further complications. The process of atherosclerosis is a progressive one that can lead to significant cardiovascular risks, including heart attacks and strokes.

In contrast, aneurysms are characterized by localized bulging in the wall of a blood vessel, usually affecting all three layers of the vessel wall rather than being confined primarily to the intima. Thrombosis refers to the formation of a blood clot within a blood vessel, which may occur in the context of atherosclerosis but does not primarily damage the vessel wall itself. Vasculitis is the inflammation of blood vessels, which affects the vessel wall more broadly and does not specifically target the intima in the same manner as atherosclerosis.