Magnetic resonance–guided focused ultrasound in movement disorders: technical and clinical series of 80 patients

Abstract

Background: magnetic resonance–guided focused ultrasound (MRgFUS) has emerged as a noninvasive alternative for the treatment of movement disorders. However, given the relative novelty of this technique, the specific technical and stereotactic parameters for its application across different pathologies have not yet been clearly defined in the literature. Although international series have reported technical parameters and clinical outcomes, data from Latin America remains limited.

Objectives: to report the technical parameters, targeting strategies, and early clinical outcomes of MRgFUS in a cohort of 80 patients treated at the only center in our country.

Methods: we analyzed 80 consecutive MRgFUS procedures performed between December 2024 and October 2025. The cohort included patients with Parkinson’s disease (n = 49), essential tremor (n = 28), and other rare movement disorders (n = 3). Therapeutic targets included the ventral intermediate nucleus (VIM, n = 54), the subthalamic nucleus (STN, n = 21), and others. Technical parameters recorded included skull density ratio (SDR), number of sonications, maximum energy, and peak temperature achieved. Subjective and objective clinical outcomes, as well as adverse events, were assessed.

Results: the mean age was 70.2 years (range, 25-88), and 57.5% of patients were male. Median subjective improvement was 95% (range, 70-100%), with a median objective improvement of 90%. Procedures targeting the VIM required slightly higher energy than those targeting the STN (22,936 J vs. 19,699 J), while achieving similar maximum temperatures (58.8 °C vs 59.2 °C). SDR was negatively correlated with maximum energy (r = −0.58). Adverse events occurred in 30% of patients, most of which were transient; permanent adverse events occurred in 10%. The most frequent complications were headache, gait instability, and paresthesias.

Conclusion: this series demonstrates that MRgFUS targeting VIM and STN is safe, effective, and technically reproducible. SDR remains a key factor in energy planning. Our findings provide a reference framework for centers in Latin America adopting MRgFUS and support its integration into routine clinical practice.