A Review of the Current Therapies, Challenges, and Future Directions of Transcranial Focused Ultrasound Technology: Advances in Diagnosis and Treatment

IMPORTANCE: Magnetic resonance imaging–guided focused ultrasound ablation has been approved for the treatment of refractory essential tremor and is being studied for other neurological indications, including dyskinesias and tremor in Parkinson disease, dystonia, neuropathic pain, obsessive-compulsive disorder, epilepsy, and brain tumors. OBJECTIVE: To review the scientific foundations of FUS technology, existing neurological applications, and future advances. EVIDENCE REVIEW: PubMed was searched for the past 10 years using the terms “transcranial ultrasound,” “focused ultrasound,” and “neurological applications.” Relevant references were selected from the author's reference collection. From the 2855 unique records, 243 publications were screened. After excluding abstracts detailing in vitro studies or non-neurological applications, 86 full texts were retrieved for qualitative review. FINDINGS: Advances in the transducer design and electronic phase correction have allowed efficient focusing of ultrasounds for transcranial treatment. The mid-frequency (650 kHz) transducer can make small (4-6 mm in diameter) and precise (accuracy of