Angiographic Reversed Flow Ratio as an Indicator of High-Grade Internal Carotid Stenosis

Identification of deranged differential flow between the ICA and ECA circulations is an insensitive but highly specific marker for high-grade stenosis. Therefore, if flow reversal is identified but the apparent carotid stenosis is mild, further angiographic projections should be used to uncover a highly probable severe carotid stenosis.