Table 2:

Ultrasound-specific mimics of near-occlusion

Cause	Mimic	Reason for Mimic
Imaging protocol	NrOc mistaken for occlusion	Small low-flow channel not visualized
Interpretation	NrOc mistaken for intracranial disease	Low flow with systolic spikes could be either
	NrOc mistaken for no stenosis	Normal velocities with tight stenosis on B-mode
Limitation of ultrasound	NrOc mistaken for stenosis	NrOc without full collapse has high flow velocities

Note:—NrOc indicates near-occlusion.