The role of the acoustic radiation force in color Doppler twinkling artifacts

PURPOSE: The aim of this experimental study was to evaluate whether the acoustic radiation force (ARF) is a potential source of twinkling artifacts in color Doppler images. METHODS: Color Doppler images were obtained using a clinical ultrasonic scanner (Voluson e, GE Healthcare) for a high contrast (+15 dB) circular scattering phantom at pulse repetition frequencies (PRFs) ranging from 0.1 to 13 kHz. Ultrasound transmissions resulting in ARF were measured using a hydrophone at the various PRFs considered. The influence of ARF on the appearance of twinkling colors was examined via the common parameter PRF. This methodology is based on the fact that alternating positive and negative Doppler shifts induced by the ARF are centered at a PRF twice the maximum Doppler frequency on the color scale bar, whereas the twinkling color aliasing is expected to remain similar regardless of PRF. RESULTS: Color twinkling artifacts were observed to be most conspicuous at the lowest PRF of 0.1 kHz. The extent of twinkling rapidly decreased as the PRF increased, eventually disappearing when the PRF ≥0.6 kHz. The measured ultrasound transmissions, however, were found to be insensitive to the PRF, and therefore it can be inferred that the PRF was insensitive to the ARF. CONCLUSION: Based on our experimental observations, the ARF may not be a source of color Doppler twinkling artifacts.