Sonicating deep brain regions with pulsed focused ultrasound using magnetic resonance imaging–guided neuronavigation single-element piezoelectric transducers is a new area of exploration for neuromodulation. Upper cranial nerves such as the trigeminal nerve and other nerves responsible for sensory/motor functions in the head may be potential targets for ultrasound pain therapy. The location of upper cranial nerves close to the skull base poses additional challenges when compared with conventional cortical or middle brain targets. In the work described here, a series of computational and empirical testing methods using human skull specimens were conducted to assess the feasibility of sonicating the trigeminal pathway near the sphenoid bone region. The results indicate a transducer with a focal length of 120 mm and diameter of 85 mm (350 kHz) can deliver sonication to upper cranial nerve regions with spatial accuracy comparable to that of focused ultrasound brain targets used in previous human studies. Temperature measurements in cortical bone and in the skull base with embedded thermocouples yield evidence of minimal bone heating. Conventional pulse parameters were found to cause reverberation interference patterns near the cranial floor; therefore, changes in pulse cycles and pulse repetition frequency were examined for reducing standing waves. Limitations and considerations for conducting ultradeep focal targeting in human applications are discussed.
|Number of pages||13|
|Journal||Ultrasound in Medicine and Biology|
|Publication status||Published - 2022 Jun|
Bibliographical noteFunding Information:
The authors thank Mark Green, MD (Icahn School of Medicine at Mount Sinai), for his input and discussions on various pathophysiologies related to cranial nerves. All authors have nothing to declare.
© 2022 World Federation for Ultrasound in Medicine & Biology
All Science Journal Classification (ASJC) codes
- Radiological and Ultrasound Technology
- Acoustics and Ultrasonics