Type:
Educational Exhibit
Keywords:
Arteries / Aorta, Vascular, MR, MR-Angiography, Diagnostic procedure, Haemodynamics / Flow dynamics
Authors:
S. Wassef, A. Stolpen; Iowa City, IA/US
DOI:
10.1594/ecr2018/C-2932
Conclusion
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 important.
The diagnosis of TOS is made by history,
physical exam,
which includes provocative tests,
radiography,
electrodiagnostic tests,
brachial plexus neurography,
duplex studies and conventional digital subtraction angiography (DSA).
Time-resolved 3D MR Angiography (TR-MRA) has recently become an excellent,
robust and reliable noninvasive alternative to DSA for evaluating patients with suspected vascular TOS.
Provocative arm positions are employed to determine the presence,
severity and site of vascular impingement and any associated complications.
For unilateral arterial TOS studies,
the contralateral arm is injected with undiluted gadolinium-based contrast agent.
For unilateral venous TOS studies,
the ipsilateral arm is injected with dilute gadolinium-based contrast.
The latter technique,
which is known as direct MR venography,
can be performed on one or both arms.
Venous TOS can also be evaluated using the arterial TOS technique,
but allowing TR-MRA image acquisition to continue through the venous phase.