Sonography's Role in the Diagnosis of May-Thurner Syndrome

May-Thurner syndrome (MTS), also known as Cockett syndrome or iliac vein compression syndrome, is a condition in which patients develop swelling, deep vein thrombosis (DVT), venous insufficiency, and other symptoms of the left lower extremity due to an anatomic variant in which the right common iliac artery overlies and compresses the left common iliac vein against the lumbar spine. Although it is an uncommonly diagnosed condition, it is estimated to compose up to half of cases of left lower extremity venous disease. Although having some degree of iliac vein compression is considered a normal anatomic variant in an asymptomatic patient, those who experience severe swelling, venous reflux, and DVT often have anatomically abnormal veins with a spur formation. With proper technique and proficiency, transabdominal sonography can be used as a valuable diagnostic tool in the discovery and to facilitate treatment of May-Thurner syndrome. Diagnostic ultrasound also can monitor the development of recurring DVT and identify symptoms of postthrombotic syndrome.