Navigated Transcranial Focused Ultrasound (tFUS)  

Key Challenges 

Precise Targeting of Deep Brain Structures

The ability to reach deep targets is one of tFUS's greatest strengths, but it also introduces a critical challenge. Effective stimulation requires highly accurate positioning of the transducer on the scalp. Even small placement errors can substantially alter the acoustic focus and reduce targeting accuracy.

Diverse Transducer Designs

tFUS transducers are available with a wide range of acoustic characteristics, focal depths, beam geometries, and physical configurations. Navigation systems must accommodate these differences while maintaining accurate visualization and targeting.

Multimodal Research Protocols

Many studies investigating the effects of tFUS rely on multimodal approaches, combining ultrasound stimulation with techniques such as EEG, TMS, MRI, or other physiological measurements. Efficient integration across modalities is essential for streamlined workflows and synchronized data collection.

Limited Dedicated Navigation Solutions

While neuronavigation has become standard practice for TMS, dedicated navigation tools for tFUS remain limited. Researchers often lack the specialized software and workflows needed to achieve reliable and reproducible stimulation targeting.

The visor2™ Solution 

Building on our extensive experience in navigated TMS, visor2™ now provides dedicated support for transcranial focused ultrasound workflows.

The new Transducer Target workflow enables precise targeting of deep brain structures by allowing users to define both the intended anatomical target and the optimal transducer position on the scalp. visor2 displays the distance between the scalp and the target, helping users verify that the selected target lies within the effective focal range of the transducer. Users can also account for the thickness of coupling media, such as gel pads, by applying a transducer offset, ensuring that the acoustic focus remains aligned with the intended brain target while maintaining optimal acoustic coupling.

visor2 also supports customizable transducer profiles with user-defined focal depths and beam geometries. The resulting acoustic focus and stimulation volume are visualized directly within the participant's anatomy, enabling researchers to assess target accessibility, optimize transducer placement, and better understand the spatial relationship between the focal zone and the intended brain target.

Session recording and review capabilities allow researchers to document transducer positioning, tilt, and acoustic focus placement throughout the experiment. These tools support reproducibility, quality assurance, and longitudinal study designs by providing a complete record of stimulation delivery.

By combining subject-specific anatomical targeting, acoustic focus visualization, and real-time navigation feedback, visor2 helps improve targeting consistency and reproducibility across sessions and participants.

Integrated Multimodal Navigation 

For studies combining tFUS with TMS, visor2 enables seamless switching between stimulation modalities within the same neuronavigation session. Users can move between TMS and tFUS workflows without interrupting the session or losing data.

Session data from both modalities are stored within a unified workflow, allowing researchers to visualize stimulation locations, access stimulation histories, and export synchronized datasets for downstream analysis and reporting.

For electrophysiological monitoring, the eego™ mylab platform integrates seamlessly with visor2 and supports high-density EEG recordings at sampling rates up to 16,384 Hz, enabling advanced tFUS-EEG and TMS-EEG research workflows.

Publications