A fusiform aneurysm is a type of aneurysm characterized by a uniform, circumferential dilation of the entire vessel wall, giving the affected segment a spindle or sausage-like shape. This contrasts with a saccular aneurysm, which is a localized outpouching from only one side of the vessel wall. On ultrasound, a fusiform aneurysm appears as a smooth, symmetrical widening of the vessel that gradually tapers back to normal diameter at both ends. Fusiform aneurysms are most commonly found in the abdominal aorta and popliteal artery and are typically caused by atherosclerosis. The sonographer measures the maximum diameter of the aneurysm and documents any thrombus within it.
Sonography Term