Thoracic outlet: Assessment with MR imaging in asymptomatic and symptomatic populations

PURPOSE: To compare the dynamic modifications of the thoracic outlet in asymptomatic volunteers and symptomatic patients and assess the presence and location of vasculonervous compressions in these two populations. MATERIALS AND METHODS: Thirty-five healthy volunteers and 54 patients with clinical symptoms of thoracic outlet syndrome (TOS) underwent magnetic resonance (MR) imaging of the thoracic outlets with their arms alongside their bodies and after a postural maneuver. Measurements were obtained at the interscalene triangle (thickness of anterior scalene muscle, interscalene angle), at the costoclavicular space (minimum costoclavicular distance, distance between inferior border of subclavius muscle and the anterior chest wall, maximum thickness of subclavius muscle, angle between first rib shaft and horizontal), and at the retropectoralis minor space (distance between posterior border of pectoralis minor muscle and posterior lining of axilla at the passage of the axillary vessels, thickness of pectora...