Aliasing in Doppler ultrasound is a common artifact where blood flow velocity is underestimated or displayed in the wrong direction, appearing as a “wrap-around” of the Doppler spectrum. This occurs when the Nyquist limit, which is half the pulse repetition frequency, is exceeded by high-velocity blood flow. It’s a crucial concept for sonographers to understand as it can lead to misinterpretation of hemodynamics.
This artifact can be mitigated by increasing the pulse repetition frequency (PRF), adjusting the baseline, or switching to a lower frequency transducer. Proper recognition and correction of aliasing are essential for accurate diagnosis and clinical decision-making in medical ultrasound imaging, ensuring reliable assessment of blood flow in various vascular studies.