Saccular Aneurysm

An aneurysm is an abnormal dilatation or bulging in a blood vessel due to the intrinsic weakness of the vessel wall.Aneurysms can affect any blood vessel, but they are most commonly seen in arteries rather than veins. An aneurysm can be a true aneurysm or a false aneurysm. A true aneurysm has all 3 layers of the arterial wall (intima, media, and adventitia). A false aneurysm, also known as a pseudoaneurysm, involves only the artery's outer layer (adventitia). Depending on their shape, aneurysms can be saccular or fusiform. Cerebral aneurysms are 90% saccular aneurysms (also known as berry aneurysms), unlike aortic aneurysms, which are about 94% fusiform. Aneurysms can be classified based on their location in the body. Depending on the etiology, they can be dissecting or mycotic aneurysms.  This review focuses on saccular cerebral and aortic aneurysms. Saccular cerebral aneurysms can also be classified by size: Small: 5 mm or less . Medium: 6 mm to 14 mm. Large: 15 mm to 25 mm . Giant: greater than 25 mm . Most saccular aortic aneurysms are located in the descending thoracic aorta. Most cerebral aneurysms are asymptomatic and small, and they are incidentally found during brain imaging or an autopsy. About 85% of cerebral aneurysms are located in the anterior circulation at the arterial bifurcations on the circle of Willis and the middle cerebral artery bifurcation.