The purpose of our educational exhibit is to review the role of contrast-enhanced time-resolved MR Angiography (TR-MRA) in the evaluation of vascular thoracic outlet syndrome (TOS). After reviewing this exhibit, the reader will be able to recognize (1) the characteristic findings of vascular TOS on TR-MRA, (2) the pathology underlying vascular TOS, and (3) the strengths and weaknesses of TR-MRA for evaluating TOS.

Thoracic outlet syndrome (TOS) is caused by compression of either the subclavian vessels (vascular TOS) or the brachial plexus (neurogenic TOS), most commonly in the costoclavicular area. Among the three TOS etiologies, the neurogenic subtype is most common. Of the two vascular TOS etiologies, the venous subtype is more common than the arterial subtype. Serious complications can develop from vascular TOS, including pulmonary embolism, venous gangrene, primary effort thrombosis, digital ischemia and stroke. Therefore, early diagnosis and treatment is important.

Definition: Thoracic outlet syndrome (TOS) is a group of clinical syndromes caused by position-dependent compression of the subclavian vessels (vascular TOS) or the brachial plexus (neurogenic TOS), most commonly in the costoclavicular space. Neurogenic TOS is much more common than vascular TOS, and venous TOS, which is due to subclavian vein compression, is more common than arterial TOS, which is due to subclavian artery compression. TOS is most common in younger women. Compression Locations: The three most common sites of neurovascular compression in TOS are:...

Thoracic outlet syndrome (TOS) is caused by positional impingement of either the subclavian vessels (vascular TOS) or the brachial plexus (neurogenic TOS), most commonly in the costoclavicular area. Neurogenic TOS is the most common form. Venous TOS, which is due to subclavian vein compression, is the second most common form; arterial TOS, which is due to subclavian artery compression, is the rarest form. Vascular TOS can lead to pulmonary embolism, venous gangrene, primary effort thrombosis, digital ischemia and rarely stroke. Early diagnosis and treatment are...

Aralasmak A, Karaali K, Cevikol C, Uysal H, Senol U. MR imaging findings in brachial plexopathy with thoracic outlet syndrome. AJNR Am J Neuroradiol 2010;31(3):410–417. Beygui RE, Olcott C 4th, Dalman RL. Subclavian vein thrombosis: outcome analysis based on etiology and modality of treatment. Ann Vasc Surg 1997;11(3):247–255 Bilbey JH, Müller NL, Connell DG, Luoma AA, Nelems B. Thoracic outlet syndrome: evaluation with CT. Radiology 1989;171(2):381–384. Brewin J, Hill M, Ellis H. The prevalence of cervical ribs in a London population. Clin Anat 2009;22(3):331–336. Chang...