A wearable, steerable, transcranial Low-Intensity Focused Ultrasound system

A bstract Objectives Transcranial Low-Intensity Focused Ultrasound (LIFU) offers unique opportunities for precisely neuromodulating small and/or deep targets within the human brain, which may be useful for treating psychiatric and neurological disorders. This paper presents a novel ultrasound system that delivers focused ultrasound through the forehead to anterior brain targets and evaluates its safety and usability in a volunteer study. Methods The ultrasound system and workflow are described, including neuronavigation, LIFU planning, and ultrasound delivery components. Its capabilities are analyzed through simulations and experiments to establish its safe steering range. A cohort of 20 healthy volunteers received a LIFU protocol aimed at the anterior medial prefrontal cortex (amPFC), using imaging and questionnaires to screen for adverse effects. Results Simulations and hydrophone readings agreed with less than 5% error, and the safe steering range was found to encompass a 1.8cm x 2.5cm x 2cm volume. There were no adverse effects evident on qualitative assessments, nor any signs of damage in susceptibility-weighted imaging scans. All participants tolerated the treatment well, and the users found the interface effective as the system was capable of accurately targeting the amPFC in all participants. A post hoc analysis showed that “virtual fitting” could aid in steering the beams around subjects’ sinuses. Conclusions The presented system was successfully used to safely deliver LIFU through the forehead to the amPFC in all volunteers, and was well-tolerated. With the capabilities validated here and positive results of the study, this technology appears well-suited to explore LIFU’s efficacy in clinical neuromodulation contexts.