Adaptive acoustic power and frequency adjustment in color Doppler imaging
Automated, real-time adjustment of ultrasound imaging parameters could speed up scanning sessions, decrease operator dependence, and improve reproducibility. This study examines adaptive frequency and acoustic output adjustment in color Doppler imaging to ensure high resolution, accurate velocity estimation while observing ALARA (As Low As Reasonably Achievable) output recommendations. Temporal signal-to-noise ratio (SNR) in clutter-filtered Doppler data was considered for guiding parameter selection. A SNR threshold of 20 dB was established based on simulation results showing this SNR enabled velocity estimation within 5% of the noise-free estimate. During in vivo scanning of the uterine artery in four pregnant volunteers, frequency and acoustic output sweeps were performed while SNR was calculated. In half of acquisitions, the maximum system frequency of 4 MHz was recommended based on the 20 dB threshold. Acoustic output sweeps at 4 MHz showed Thermal Index (TI) could be further reduced to 0.2-0.3 from the system maximum of 1.2 while still meeting the 20 dB threshold. These results motivate the use of temporal SNR for guiding adaptive frequency and acoustic output adjustment.
