Initiating a Magnetic Resonance-Guided Focused Ultrasound Program: Comprehensive Workflow and Lessons Learned from the Initial 116 Cases

Abstract

<b><i>Introduction:</i></b> Magnetic resonance-guided focused ultrasound (MRgFUS) represents an incisionless treatment option for essential or parkinsonian tremor. The incisionless nature of this procedure has garnered interest from both patients and providers. As such, an increasing number of centers are initiating new MRgFUS programs, necessitating development of unique workflows to optimize patient care and safety. Herein, we describe establishment of a multi-disciplinary team, workflow processes, and outcomes for a new MRgFUS program. <b><i>Methods:</i></b> This is a single-academic center retrospective review of 116 consecutive patients treated for hand tremor between 2020 and 2022. MRgFUS team members, treatment workflow, and treatment logistics were reviewed and categorized. Tremor severity and adverse events were evaluated at baseline, 3, 6, and 12 months post-MRgFUS with the Clinical Rating Scale for Tremor Part B (CRST-B). Trends in outcome and treatment parameters over time were assessed. Workflow and technical modifications were noted. <b><i>Results:</i></b> The procedure, workflow, and team members remained consistent throughout all treatments. Technique modifications were attempted to reduce adverse events. A significant reduction in CRST-B score was achieved at 3 months (84.5%), 6 months (79.8%), and 12 months (72.2%) post-procedure (<i>p</i> < 0.0001). The most common post-procedure adverse events in the acute period (<1 day) were gait imbalance (61.1%), fatigue and/or lethargy (25.0%), dysarthria (23.2%), headache (20.4%), and lip/hand paresthesia (13.9%). By 12 months, the majority of adverse events had resolved with a residual 17.8% reporting gait imbalance, 2.2% dysarthria, and 8.9% lip/hand paresthesia. No significant trends in treatment parameters were found. <b><i>Conclusions:</i></b> We demonstrate the feasibility of establishing an MRgFUS program with a relatively rapid increase in evaluation and treatment of patients while maintaining high standards of safety and quality. While efficacious and durable, adverse events occur and can be permanent in MRgFUS.

Magnetic Resonance-Guided Focused Ultrasound without Anesthesiologist Support

“…We noted similar findings 3 months post-MRgFUS compared to the above-mentioned studies which utilized systemic anesthesia, including gait/balance changes (20.6%) and paresthesia (10.3%). As we recently reported, these adverse events decreased to 17.8% ataxia and 8.9% paresthesia at 12-month follow-up, suggesting that lack of anesthesiologist support does not increase the likelihood of long-term adverse events [14].…”

“…The treatment target, ventral intermediate nucleus of the thalamus (VIM), was identified using the AC-PC targeting system, as described previously [14]. After the alignment sonications, clinical testing was performed after each treatment sonication to assess tremor improvement and to inquire about side effects.…”