Angioplasty is an interventional radiology treatment. A small balloon on the tip of a catheter is inserted into a blood vessel to widen up a narrowed or obstructed artery, often caused by atherosclerosis.

Three tissue layers called tunicae, or coats, surround the lumen of an artery. The adventitia (outer coat) is the outermost layer of an arterial wall and is composed of connective tissue containing elastic fibers and another layer of protein called the external basement membrane. Smooth muscle cells comprise the tunica media, or middle coat. The muscle cells contract or relax to constrict or dilate the artery.

See also Coronary Angiogram, Angiography, Angioplasty, and Cardiac Catheterization.

Interventional radiology is an area of clinical subspecialty which uses various radiology techniques (such as fluoroscopy, ultrasound, computed tomography, and MRI procedures) to guide procedures such as a biopsy, inserting catheters, place wires, draining fluids, dilating or stenting narrowed ducts or vessels to diagnose or treat different conditions.

See also CT Guided Biopsy, Angioplasty, Coronary Angiogram and Interventional Ultrasound.