Introduction: Stereotactic lesioning has proven effective for the treatment of movement disorders, but it fell out of favor with the discovery of dopamine replacement and DBS. Therapeutic uses of ultrasound have long been of interest but never applied to the brain because of limitations with transcranial sonication. Today advances in ultrasound technology with CT-correction algorithms and phased array transducers are enabling precise delivery of acoustic waves through the skull while MRI allows for precise targeting and continuous monitoring of the treatment. MR guided focused ultrasound may also enable noninvasive modulation of neural circuits.
Methods: An FDA-approved (IDE#G100169), phase 1 clinical trial is underway to test the safety and potential efficacy of MR guided focused ultrasound thalamotomy for the treatment of medically-refractory essential tremor. A series of incremental sonications to the Vim nucleus is targeted with MRI while patients are continuously monitored clinically and with realtime MR thermography imaging. Standard assessments of tremor, potential adverse events, and MR imaging is obtained at baseline and posttreatment: 1 day, 1 week, 1 month, 3 months.
Results: We report the initial case of a 74 yo male with ET who was successfully treated without complication. His clinical rating scale for tremor decreased from 55 to 5. The treatment was noninvasive, painless, and without sedation. Intraoperative testing allowed for an adjustment of the sonication from the sensory thalamus. Other patients preparing for treatment will be presented.
Conclusions: MR guided focused ultrasound technology allows for precise targeting of subcortical structures. The treatment is noninvasive and can be monitored continuously with clinical assessment and MR thermal imaging. Neuromodulation of deep brain targets is likely possible prior to lesioning. This phase 1 clinical trial of MRgFUS for the treatment of ET continues.
Patient Care: This is a phase 1 clinical trial assessing the safety and potential efficacy of noninvasive lesioning with MR guided focused ultrasound for the treatment of essential tremor and potentially other movement disorders.
Learning Objectives: By the conclusion of this presentation, participants should be aware of the potential advantages of MR guided focused ultrasound where noninvasive lesioning can be precisely delivered with real-time MR and clinical monitoring.