Soft-tissue lesions, such as lung neoplasms [27], may also be evaluated, although the negative predictive value of chest radiographs is low, such that cross-sectional imaging is a necessary part of a complete TOS workup. In the postoperative setting, radiographs may be useful to confirm osseous changes and evaluate for postoperative complications, such as pneumothorax. US Duplex Doppler Subclavian Artery and Vein US is widely used as an imaging modality in the initial evaluation of patients with suspected arterial or venous pathology. Although many patients with nTOS have additional symptoms due to arterial or venous compression, US is not as valuable in assessing direct neurological involvement. Real-time duplex US can be used to evaluate the cross-sectional area of the costocervical space with and without provocative maneuvers [28]. Diagnosis of compressive effects upon the brachial plexus is a challenge [29], and symptoms of TOS may unmask a deeper regional pathology such as a Pancoast tumor or cervical spondylopathy, requiring further imaging. If there is reason to believe that symptoms could be related to hypertrophy of the anterior scalene muscles, US could be used for guidance to inject anesthetic in an attempt to confirm nTOS [30]. The procedure is considered diagnostic of nTOS if the patient experiences relief of symptoms after the injection. In the postoperative setting, US can be useful to evaluate vessel patency and complications such as postoperative hematoma or fluid collection. Variant 2: Venous thoracic outlet syndrome. Initial imaging and follow-up imaging after surgery or intervention. Arteriography Upper Extremity Selective upper-extremity arteriography may be used to evaluate extrinsic compression of the subclavian artery; however, it does not provide diagnostic assessment of the subclavian vein. This procedure is therefore not considered a first-line test for vTOS.
Thoracic Outlet Syndrome. Soft-tissue lesions, such as lung neoplasms [27], may also be evaluated, although the negative predictive value of chest radiographs is low, such that cross-sectional imaging is a necessary part of a complete TOS workup. In the postoperative setting, radiographs may be useful to confirm osseous changes and evaluate for postoperative complications, such as pneumothorax. US Duplex Doppler Subclavian Artery and Vein US is widely used as an imaging modality in the initial evaluation of patients with suspected arterial or venous pathology. Although many patients with nTOS have additional symptoms due to arterial or venous compression, US is not as valuable in assessing direct neurological involvement. Real-time duplex US can be used to evaluate the cross-sectional area of the costocervical space with and without provocative maneuvers [28]. Diagnosis of compressive effects upon the brachial plexus is a challenge [29], and symptoms of TOS may unmask a deeper regional pathology such as a Pancoast tumor or cervical spondylopathy, requiring further imaging. If there is reason to believe that symptoms could be related to hypertrophy of the anterior scalene muscles, US could be used for guidance to inject anesthetic in an attempt to confirm nTOS [30]. The procedure is considered diagnostic of nTOS if the patient experiences relief of symptoms after the injection. In the postoperative setting, US can be useful to evaluate vessel patency and complications such as postoperative hematoma or fluid collection. Variant 2: Venous thoracic outlet syndrome. Initial imaging and follow-up imaging after surgery or intervention. Arteriography Upper Extremity Selective upper-extremity arteriography may be used to evaluate extrinsic compression of the subclavian artery; however, it does not provide diagnostic assessment of the subclavian vein. This procedure is therefore not considered a first-line test for vTOS.