Ultrasound Neuromodulation as a New Brain Therapy

Abstract

Within the last decade, ultrasound has been "rediscovered" as a technique for brain therapies. Modern technologies allow focusing ultrasound through the human skull for highly focal tissue ablation, clinical neuromodulatory brain stimulation, and targeted focal blood-brain-barrier opening. This article gives an overview on the state-of-the-art of the most recent application: ultrasound neuromodulation as a new brain therapy. Although research centers have existed for decades, the first treatment centers were not established until 2020, and clinical applications are spreading rapidly.

Keywords: brain stimulation; brain therapy; focused ultrasound; transcranial pulse stimulation.

Figure 1

Treatment setting for one of the current state‐of‐the‐art navigated and highly focused neuromodulation systems (TPS system). Reproduced with permission. Copyright 2022, Storz Medical AG.

Figure 2

Example for a very small ultrasound neuromodulation focus. A,B) Reproduced with permission.^{[ 9 ]} Copyright 2021, American Neurological Association. Ultrasound pressure field. A) Acoustic intensity profile of the 0.5 MHz transducer with focus 30 mm measured in free water. The white line in the longitudinal maps (left) indicates the focal plane where the spatial peak pulse average intensity of the acoustic field was measured. Acoustic beam cross‐section of the focal plane is illustrated at right. B) Line plots illustrate the lateral (x, left) and vertical (y, middle) peak normalized acoustic intensity profiles for the acoustic beam in the focal plane. The lateral and vertical dimensions of acoustic beam cross‐sections measured at the intensity full width at half maximum (FWHM) were 5.8 and 5.6 mm. The line plot for the axial (z, right) peak normalized intensity profiles shows a near‐field peak at 12 mm and a far‐field peak at 33 mm (close to the focal length of 30 mm).