Dynamic CT angiography assessment of the suprascapular artery in thoracic outlet syndrome: anatomy, anatomical variants, and dynamic stenosis.

OBJECTIVES: To evaluate the anatomy and dynamic behavior of the suprascapular artery (SSA) in patients undergoing dynamic CT angiography (DCTA) for thoracic outlet syndrome (TOS) and to investigate its relationship with subclavian artery (SCA) stenosis. METHODS: In this retrospective single-center study, consecutive DCTA examinations performed for suspected TOS between March 2023 and December 2024 were reviewed. SSA origin, course relative to the costoclavicular space (CCS), relationship with the brachial plexus, and the presence of SSA stenosis or occlusion were independently assessed by two blinded radiologists across five dynamic acquisition volumes. Associations between SSA abnormalities and symptom type, scapulalgia, and SCA stenosis were analyzed. RESULTS: A total of 193 thoracic outlets were included. The SSA originated from the thyrocervical trunk in 77.7% of cases and coursed through the CCS in 77.7%. Contact between the SSA and brachial plexus was observed in 30.6% of thoracic outlets, although no neural compression was identified. At least one SSA stenosis or occlusion was detected in 25.9% of thoracic outlets and was significantly associated with symptomatic outlets (odds ratio [OR], 4.16; P = 0.006), scapulalgia (OR, 2.44; P = 0.012), CCS course (OR, 2.56; P = 0.049), thyrocervical trunk origin (OR, 4.31; P = 0.005), concomitant SCA stenosis (OR, 7.20; P < 0.001), and acquisition volume (P < 0.001). CONCLUSIONS: The SSA frequently traverses the CCS and commonly demonstrates dynamic stenosis or occlusion in patients with suspected TOS. Its association with symptoms, scapulalgia, and SCA stenosis suggests that the SSA may represent a previously underrecognized imaging marker of thoracic outlet hemodynamics.