Pseudoaneurysm spectral Doppler at pedicle?

• A. Systolic inflow high-velocity with diastolic outflow (to-and-fro)
• B. Continuous flow with no variation
• C. No flow
• D. Only diastolic flow

Answer: (A)

A pseudoaneurysm neck shows a to-and-fro waveform on spectral Doppler. Blood is driven into the sac during systole when arterial pressure peaks, and then flows back out through the neck toward the parent vessel during diastole. This bidirectional, high-velocity pattern at the pedicle is the hallmark of a pseudoaneurysm, reflecting the ongoing communication between the arterial lumen and the sac.

This pattern helps distinguish it from other findings. Continuous flow without variation typically suggests a high-flow lesion like a fistula rather than a pseudoaneurysm neck. No flow would indicate thrombosis or occlusion within the sac, not active communication. Diastolic flow alone lacks the systolic inflow component and wouldn’t match the classic pulsatile, bidirectional pattern seen at the neck.