Flexible ultrasound array for subcortical brain stimulation in humans: a simulation study.

Area of Science:

• Neurosurgery
• Biomedical Engineering
• Acoustics

Background:

• Transcranial focused ultrasound (tFUS) is a promising non-invasive neuromodulation technique for neuropsychiatric disorders.
• Current clinical hemispherical arrays face challenges with skull acoustic properties, leading to energy loss and reduced efficacy.
• Steering ultrasound beams exacerbates wave reflection and refraction at the skull interface.

Purpose of the Study:

• To introduce a flexible ultrasound array designed to conform to individual skull shapes for improved tFUS.
• To investigate the impact of flexible array configuration compared to traditional semi-spherical arrays.
• To enhance the therapeutic efficiency of tFUS for targeting subcortical regions.

Main Methods:

• Development of a flexible ultrasound array adaptable to patient-specific cranial geometry.
• Numerical simulations comparing the flexible array's performance against a standard semi-spherical array.
• Evaluation of focusing performance, including full width at half maximum (FWHM) and focal peak pressure, with and without beam steering.

Main Results:

• The flexible array demonstrated a 29.4% reduction in FWHM and a 44.4% increase in focal peak pressure compared to the semi-spherical array without steering.
• The flexible array achieved a wide steering range (30 × 20 mm²) while maintaining focusing performance.
• Improved acoustic energy transmission through the skull was observed with the flexible configuration.

Conclusions:

• The proposed flexible ultrasound array offers a significant improvement over traditional designs for tFUS applications.
• This technology provides a theoretical framework for enhancing the therapeutic efficacy of tFUS in treating neuropsychiatric conditions.
• Customizable flexible arrays hold potential for more precise and effective non-invasive neuromodulation.