Bunny waveform sign

Last revised by Francis Deng on 2 Jan 2020

Bunny waveform sign refers to the biphasic morphology of the pulsed wave Doppler spectral waveform in the vertebral artery in early (occult/latent or partial) subclavian steal phenomenon (sometimes called a "presteal" state, before it progresses to frank flow reversal). There is a sharp deceleration of flow during peak systole due to a drop in pressure in the stenotic segment of the subclavian artery when flow is fastest 2. Different depictions differ as to whether the bunny is facing to the left 2-7 or right 8,9.

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