Transcranial Focused Ultrasound: Established and Emerging Applications in Neurosciences

Transcranial MR-guided high-intensity focused ultrasound (HIFU) thermoablation is an established incisionless image-guided treatment for movement disorders; however, neuroradiologist involvement in clinical decision-making and procedural workflows is highly variable and site-specific. Transcranial low-intensity focused ultrasound (LIFU) is a rapidly evolving non-invasive, image-guided technology for neuromodulation and blood-brain barrier disruption. Compared with HIFU, the optimal protocol, therapeutic mechanism, and safety limits remain uncertain for LIFU. Despite these gaps, LIFU has significant potential for neuropsychiatric and neuro-oncologic diseases. Familiarity with transcranial ultrasound principles and the pivotal role of CT and MR imaging for targeting and evaluating outcomes is increasingly important for neuroradiologists. This review uses HIFU as a clinical model to illustrate the integration of imaging into focused ultrasound workflows. We then discuss LIFU with respect to technical factors, imaging considerations, safety, and limitations. We highlight its emerging applications, including neuromodulation, targeted drug delivery, and liquid biopsy. Finally, we conclude by summarizing key knowledge gaps, outlining future directions, and proposing strategies to more actively engage neuroradiologists in this emerging field.