Diagnostic imaging modalities for vascular Thoracic Outlet Syndrome (TOS); a topical review and proposed diagnostic pathway

OBJECTIVE: This topical review aims to provide an overview of current literature on diagnostic modalities for vascular thoracic outlet syndrome (TOS) and evaluates their clinical applicability. Additionally, a structured diagnostic pathway is proposed for the assessment of arterial TOS (ATOS) and venous TOS (VTOS). METHODS: Given the absence of standardized guidelines, limited high-quality evidence, and heterogeneous cohorts, this review adopts a topical rather than a systematic approach. A comprehensive literature search of peer-reviewed articles between 2000 and 2006 was conducted in Pubmed. The available literature is summarized to assess the advantages, limitations, and clinical utility of each modality. RESULTS: Imaging plays a vital role in the evaluation of vascular TOS, although protocols vary substantially between centers. For suspected ATOS, computed tomography arteriography (CTA), using a dedicated TOS protocol is proposed as the preferred initial modality, while computed tomography venography (CTV) with TOS protocol is recommended for suspected VTOS. In patients presenting with suspected upper-extremity deep vein thrombosis (UEDVT), duplex ultrasound is recommended for initial assessment. Contrast angiography is reserved for selected cases when non-invasive imaging is inconclusive, or when endovascular intervention is anticipated. Chest radiography (CR) and photoplethysmography (PPG) appear to have limited additional diagnostic value. Intravascular ultrasound (IVUS) may offer complementary information in selected patients with VTOS. CONCLUSION: The diagnostic complexity of vascular TOS underscores the importance of an integrated approach combining clinical evaluation and imaging, preferably within specialized expert centers. The proposed diagnostic pathway provides a practical framework, and may serve as a step toward uniformity in clinical practice across different centers.