May-Thurner syndrome (MTS), also called iliocaval compression syndrome, Cockett’s syndrome, or non-occlusive iliac vein lesion, occurs secondary to compression of the left iliac vein by the overriding right iliac artery. From autopsy studies, MTS accounts for 2-3% of lower limb deep vein thrombosis. However; it is often underreported and miss-diagnosed in accident and emergency, resulting in long-term complication (post thrombotic syndrome) with its detrimental effect. Possible mechanisms include vascular trauma to the vein from repetitive compression from the overlying pulsating artery, causing elastin and collagen deposition in the iliac vein, which eventually leads to spur formation.
Usually doppler ultrasound will detect if a deep vein thrombosis is present in the iliac vessels, but is unable to visualize iliac vein compression and spurs. Diagnostic modalities include helical abdominal computed tomography (CT), magnetic resonance venography (MRV), intravenous ultrasound (IVUS) and conventional venography would allow accurate diagnosis and facilitate in management planning.