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Ultrasonographic Assessment of Arterial Cross‐sectional Area in the Thoracic Outlet on Postural Maneuvers Measured With Power Doppler Ultrasonography in Both Asymptomatic and Symptomatic Populations

Objective. The purpose of this study was to evaluate the feasibility and potential usefulness of power Doppler ultrasonography (PDU) in the assessment of changes in arterial cross‐sectional area in the thoracic outlet during upper limb elevation. Methods. Forty‐four volunteers and 28 patients with a clinical diagnosis of arterial thoracic outlet syndrome were evaluated by B‐mode imaging and PDU. Arterial cross‐sectional area was assessed in the 3 compartments of the thoracic outlet with the arm alongside the body and at 90°, 130°, and 170° of abduction. The percentage of arterial stenosis was calculated for each of these arm positions. Nineteen of the 28 patients were also assessed by magnetic resonance (MR) imaging. Results. No significant arterial stenosis was shown in the interscalene triangle and in the retropectoralis minor space of the volunteers and patients. A significant difference (P < .01) in stenosis between volunteers and patients was seen for all degrees of abduction in the costoclavicular space. The 130° hyperabduction maneuver appeared to be the most discriminating postural maneuver. Seven patients assessed with MR imaging did not have any arterial stenosis on MR images, whereas an appreciable degree of arterial stenosis was shown with ultrasonography. Conclusions. Arterial compression inside the thoracic outlet can be detected and quantified with B‐mode imaging in association with PDU.