Magnetic resonance-guided focused ultrasound for essential tremor:a prospective,single center,single-arm study

The safety and effectiveness of magnetic resonance-guided focused ultrasound thalamotomy has been broadly established and validated for the treatment of essential tremor.In 2018,the first magnetic resonance-guided focused ultrasound system in Chinese mainland was installed at the First Medical Center of the PLA General Hospital.This prospective,single center,open-label,single-arm study was part of a worldwide prospective multicenter clinical trial(ClinicalTrials.gov Identifier:NCT03253991)conducted to confirm the safety and efficacy of magnetic resonance-guided focused ultrasound for treating essential tremor in the local population.From 2019 to 2020,10 patients with medication refractory essential tremor were recruited into this open-label,single arm study.The treatment efficacy was determined using the Clinical Rating Scale for Tremor.Safety was evaluated according to the incidence and severity of adverse events.All of the subjects underwent a unilateral thalamotomy targeting the ventral intermediate nucleus.At the baseline assessment,the estimated marginal mean of the Clinical Rating Scale for Tremor total score was 58.3±3.6,and this improved after treatment to 23.1±6.4 at a 12-month follow-up assessment.A total of 50 adverse events were recorded,and 2 were defined as serious.The most common intraoperative adverse events were nausea and headache.The most frequent postoperative adverse events were paresthesia and equilibrium disorder.Most of the adverse events were mild and usually disappeared within a few days.Our findings suggest that magnetic resonance-guided focused ultrasound for the treatment of essential tremor is effective,with a good safety profile,for patients in Chinese mainland.

Predicting tremor improvement after MRgFUS thalamotomy in essential tremor from preoperative spontaneous brain activity:A machine learning approach

Magnetic resonance-guided focused ultrasound surgery(MRgFUS)thalamotomy is an emerging technique for medication-refractory essential tremor(ET),but with variable outcomes.This study used pattern regression analysis to identify brain signatures predictive of tremor improvements.Fifty-four ET patients(mean age=63.06 years,standard deviation(SD)=10.55 years,38 males)underwent unilateral MRg FUS thalamotomy and were scanned for resting-state functional magnetic resonance imaging(rsf MRI).Seventy-four healthy controls(mean age=58.09 years,SD=10.30 years,38 males)were recruited for comparison.Tremor responses at 12 months posttreatment were evaluated by the Clinical Rating Scale for Tremor.The fractional amplitude of low-frequency fluctuations(f ALFF)was calculated from rs-f MRI data.Two-sample t-test was used to generate a disease-specific mask,within which Multivariate Kernel Ridge Regression analyses were conducted.Predicted and actual clinical scores were compared using Pearson's correlation coefficient(r)and normalized mean squared error(Norm.MSE).Permutation test and leave-one-out strategy were applied for results validation.KRR identified f ALFF patterns that significantly predicted the hand tremor improvement(r=0.23,P=0.025;Norm.MSE=0.05,P=0.026)and the postural tremor improvement(r=0.28,P=0.025;Norm.MSE=0.06,P=0.023),but not action tremor improvement.Lobule VI of right cerebellum(Cerebelum_6_R),right superior occipital gyrus(Occipital_Sup_R)and lobule X of vermis(Vermis_10)contributed most for hand tremor prediction(normalized weights(NW):2.77%,2.40%,2.34%)while Vermis_10,left supplementary motor area(Supp_Motor_Area_L)and right hippocampus(Hippocampus_R)for postural tremor prediction(NW:2.69%,2.12%,2.05%).The low contributing NW of the individual brain regions suggested that the f ALFF pattern as a whole is an overall predicting feature.Preoperative f ALFF pattern predicts tremor benefits induced by MRg FUS thalamotomy.Clinical Trials.gov number:NCT04570046.