Image-guided Application and Monitoring of Transcranial Focused Ultrasound in Realistic Human Head Phantom

Dual-mode ultrasound arrays (DMUAs) have been used for monitoring and delivery of transcranial focused ultrasound (tFUS) in small-animal models in vivo. Synthetic-aperture (SA) imaging can be used for stereotaxic guidance, while high frame rate imaging modes, such as single-transmit focus (STF) imaging, can provide feedback for thermal and mechanical closed-loop control of lesion formation and neuromodulation. The objective of this study is to demonstrate the feasibility of DMUA guidance and control of tFUS application in a realistic human head phantom. A DMUA was used to image through the temporal bone of the phantom in SA and STF modes. Results from the SA imaging mode demonstrates the ability to image fine targets such as vessels with aneurysms. Additionally, subaperture processing of SA data shows it is possible to reduce reverberation. Results from the STF imaging mode show the feasibility of speckle tracking using transranial echo data, both with and without subaperture processing. These results demonstrate the value of judicial design of subaperture beamforming for identifying tissue structure and improving speckle statistics for high fidelity thermography and elastography. Results from tFUS-monitoring experiments will be given.