Track Sign Distal to Internal Carotid Artery Occlusion

Nothing to report. Video S1. Track sign distal to internal carotid artery occlusion. Digital subtraction angiography showing total occlusion at the left internal carotid artery (ICA). Retrograde blood flow reached the carotid bulb via a collateral vessel originating from the external carotid artery at the pharyngeal region (circle). The flow then formed a U-shaped turn, transitioning into slow antegrade blood flow into the distal ICA (black arrows). The two arteries with opposing flow directions paralleling at the cervical region created a track sign at the late arterial phase. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.