Which imaging modalities provide definitive assessment for arterial TOS?

• A. CT alone
• B. CT and MRI
• C. X-ray
• D. Doppler ultrasound

Answer: (B)

Definitive assessment of arterial thoracic outlet syndrome relies on imaging that clearly shows the subclavian artery and how it is affected during provocative positioning, along with the surrounding structures that may cause compression. CT angiography and MR angiography provide the most detailed cross‑sectional views, letting you see the arterial lumen for stenosis, occlusion, or aneurysm and also assessing the bones and soft tissues that contribute to compression. This combination of precise vascular visualization and anatomic context makes CT and MRI the best choices for a definitive evaluation. X‑ray mainly shows bone anatomy and doesn’t reveal arterial status, while Doppler ultrasound can assess blood flow but is operator‑dependent and may miss deeper or complex proximal lesions, so it isn’t typically definitive on its own.