Abstract: Materials and methods: From 2009 to 2013 we performed 38 MRA studies for clinically suspected TOS (13 M, 25 F; mean age, 35.9 years; σ = 11.13). Twin peripheral 20G intravenous catheters were placed in a cubital vein in both arms and connected to a single power injector by two lines joined with a connector. A 3T MR system with a wide gantry was used. Two groups of four radiologists assessed all the images. Group A judged the full examinations, Group B had only the late acquisitions. Differences were evaluated using the Chi square test. TOS was confirmed only after integration with the clinical history.Abstract: Results: Seventeen (45 %) patients were diagnosed with predominant venous TOS (VTOS), nine (24 %) with predominant arterial TOS (ATOS) and 12 (32 %) had an indeterminate or nonvascular condition. Group A radiologists identified significantly more VTOS than group B (p = 0.049). Interobserver agreement was very high.Abstract: Conclusions: SB-MRA is a safe and reliable protocol for the study of TOS. It provides a supplementary early acquisition that allows for separate assessment of veins and arteries, permits the investigation of the collateral venous flow with a single injection of contrast material and provides a higher diagnostic power for VTOS. SB-MRA is helpful for the diagnosis of TOS of vascular origin.Abstract: Purpose: This paper presents a new magnetic resonance angiography (MRA) protocol for the evaluation of thoracic outlet syndrome (TOS) that allows for a separate assessment of veins and arteries while using a single, simultaneous and bilateral (SB-MRA) single contrast injection, valid for both abduction and adduction acquisitions.