Beamforming and Imaging Approaches for Array-Based Dual-Frequency Acoustic Angiography

Acoustic angiography (AA) using dual frequency (DF) ultrasound systems enables high-resolution and high-contrast imaging of the microvasculature within tissue. AA has been used to detect changes in vasculature due to cancerous tumours, and it has the potential to aid the evaluation of treatment outcomes. DF ultrasound imaging uses conventional frequency ultrasound transducers (~2-4 MHz, LF) on transmit (Tx), and high frequency (HF) transducers on receive (Rx) to detect higher order harmonics (~10-20 MHz) from microbubble contrast agents. In this paper, we show a DF array, with LF and HF arrays integrated within the probe head that overcomes limitations of the previously used single channel DF probes such as the limited focal depth. The integrated DF array has been connected to a configurable micro-US beamforming system to allow plane wave on Tx and parallel Rx in both HF and DF imaging modes. This work presents DF and HF imaging modes with plane wave imaging techniques to visualize a contrast-filled channel within a tissue-mimicking phantom.