Probing phased-array focused ultrasound transducers using realistic 3D in-silico trabecular skull models: A numerical...

Area of Science:

• Biomedical Engineering
• Acoustics
• Neuroscience

Background:

• Transcranial focused ultrasound (tFUS) is a promising neuromodulation technique for brain diseases.
• Skull's complex structure can interfere with ultrasound wave propagation.
• Accurate modeling is needed to predict tFUS device performance.

Purpose of the Study:

• To investigate the effect of human skull trabecular structure and porosity on tFUS transducer performance.
• To compare the pressure fields generated by two different phased-array transducers in porous skull models.
• To highlight the importance of incorporating realistic skull models in tFUS simulations.

Main Methods:

• Numerical simulations using realistic 3D skull models with varying porosities (0%, 50%, 60%).
• Comparison of pressure fields from two 96-element phased-array transducers (f-number=0.8 and f-number=1.1).
• Analysis of pressure distribution maps and -6dB isosurfaces to quantify focal/scattered volumes and focus shifts.

Main Results:

• Porous skull models introduce significant ultrasound scattering and off-target hotspots, missed by non-porous models.
• Both transducers showed focus shifts; transducer 2 exhibited lower selectivity and substantially increased scattering (450-1000%) in porous models.
• Skull porosity critically affects tFUS pressure field predictions.

Conclusions:

• Accurate modeling of skull porosity is essential for reliable tFUS simulations and accurate pressure predictions.
• Simplified non-porous models can lead to distorted performance predictions and obscure critical scattering effects.
• This study provides insights for optimizing tFUS transducer design for improved precision and safety in therapeutic applications.