TY - JOUR
T1 - Effects of skull properties on continuous-wave transcranial focused ultrasound transmission
AU - Li, Han
AU - Barnard, Isla
AU - Halliwell, Tyler
AU - Zhang, Xinyu
AU - Melzer, Andreas
AU - Huang, Zhihong
N1 - Publisher Copyright:
© 2025 Acoustical Society of America.
PY - 2025/4
Y1 - 2025/4
N2 - Transcranial low-intensity focused ultrasound can deliver energy to the brain in a minimally invasive manner for neuromodulation applications. However, continuous sonication through the skull introduces significant wave interactions, complicating precise energy delivery to the target. This study presents a comprehensive examination of intracranial acoustic fields generated by focused ultrasound transducers and assesses the characteristics of cranial bone that affect acoustic transmission. Acoustic field maps were generated at 88 regions of interest across 10 historical and 2 Thiel-embalmed human skull specimens with sonication at frequencies of 220, 650, and 1000 kHz. The average peak pressure insertion losses for historical skulls were 3.6 ± 3.4, 9.3 ± 3.3, and 14.8 ± 5.8 dB, respectively, and for Thiel skulls, the respective losses were 2.9 ± 1.8, 9.4 ± 2.6, and 17.0 ± 5.5 dB. The effects of skull thickness, skull density ratio, and skull curvature on intracranial peak pressure, power, and focal area were investigated and linear fits produced. Several unfavorable focusing performances were observed in regions with excessive thickness variation. The effects of angulation and spacing between the transducer and the skull were also investigated. Preliminary findings indicate that wave superposition resulting from skull and transducer spacing could lead to a 30%-40% uncertainty in peak recorded intracranial pressure.
AB - Transcranial low-intensity focused ultrasound can deliver energy to the brain in a minimally invasive manner for neuromodulation applications. However, continuous sonication through the skull introduces significant wave interactions, complicating precise energy delivery to the target. This study presents a comprehensive examination of intracranial acoustic fields generated by focused ultrasound transducers and assesses the characteristics of cranial bone that affect acoustic transmission. Acoustic field maps were generated at 88 regions of interest across 10 historical and 2 Thiel-embalmed human skull specimens with sonication at frequencies of 220, 650, and 1000 kHz. The average peak pressure insertion losses for historical skulls were 3.6 ± 3.4, 9.3 ± 3.3, and 14.8 ± 5.8 dB, respectively, and for Thiel skulls, the respective losses were 2.9 ± 1.8, 9.4 ± 2.6, and 17.0 ± 5.5 dB. The effects of skull thickness, skull density ratio, and skull curvature on intracranial peak pressure, power, and focal area were investigated and linear fits produced. Several unfavorable focusing performances were observed in regions with excessive thickness variation. The effects of angulation and spacing between the transducer and the skull were also investigated. Preliminary findings indicate that wave superposition resulting from skull and transducer spacing could lead to a 30%-40% uncertainty in peak recorded intracranial pressure.
UR - https://www.scopus.com/pages/publications/105002175739
U2 - 10.1121/10.0036344
DO - 10.1121/10.0036344
M3 - Article
C2 - 40172281
SN - 0001-4966
VL - 157
SP - 2336
EP - 2349
JO - Journal of the Acoustical Society of America
JF - Journal of the Acoustical Society of America
IS - 4
ER -