Technical and operative factors affecting magnetic resonance imaging–guided focused ultrasound thalamotomy for essential tremor: experience from 250 treatments

2021 ◽  
pp. 1-9
Author(s):  
Myung Ji Kim ◽  
So Hee Park ◽  
Kyung Won Chang ◽  
Yuhee Kim ◽  
Jing Gao ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Multivariate Analysis ◽  
Magnetic Resonance ◽  
Low Temperature ◽  
Essential Tremor ◽  
Focused Ultrasound ◽  
Rating Scale ◽  
Resonance Imaging ◽  
Temperature Group

OBJECTIVE Magnetic resonance imaging–guided focused ultrasound (MRgFUS) provides real-time monitoring of patients to assess tremor control and document any adverse effects. MRgFUS of the ventral intermediate nucleus (VIM) of the thalamus has become an effective treatment option for medically intractable essential tremor (ET). The aim of this study was to analyze the correlations of clinical and technical parameters with 12-month outcomes after unilateral MRgFUS thalamotomy for ET to help guide future clinical treatments. METHODS From October 2013 to January 2019, data on unilateral MRgFUS thalamotomy from the original pivotal study and continued-access studies from three different geographic regions were collected. Authors of the present study retrospectively reviewed those data and evaluated the efficacy of the procedure on the basis of improvement in the Clinical Rating Scale for Tremor (CRST) subscore at 1 year posttreatment. Safety was based on the rates of moderate and severe thalamotomy-related adverse events. Treatment outcomes in relation to various patient- and sonication-related parameters were analyzed in a large cohort of patients with ET. RESULTS In total, 250 patients were included in the present analysis. Improvement was sustained throughout the 12-month follow-up period, and 184 (73.6%) of 250 patients had minimal or no disability due to tremor (CRST subscore < 10) at the 12-month follow-up. Younger age and higher focal temperature (Tmax) correlated with tremor improvement in the multivariate analysis (OR 0.948, p = 0.013; OR 1.188, p = 0.025; respectively). However, no single statistically significant factor correlated with Tmax in the multivariate analysis. The cutoff value of Tmax in predicting a CRST subscore < 10 was 55.8°C. Skull density ratio (SDR) was positively correlated with heating efficiency (β = 0.005, p < 0.001), but no significant relationship with tremor improvement was observed. In the low-temperature group, 1–3 repetitions to the right target with 52°C ≤ Tmax ≤ 54°C was sufficient to generate sustained tremor suppression within the investigated follow-up period. The high-temperature group had a higher rate of balance disturbances than the low-temperature group (p = 0.04). CONCLUSIONS The authors analyzed the data of 250 patients with the aim of improving practices for patient screening and determining treatment endpoints. These results may improve the safety, efficacy, and efficiency of MRgFUS thalamotomy for ET.

Bilateral Magnetic Resonance Imaging-Guided Focused Ultrasound Thalamotomy for Essential Tremor

2021 ◽  
pp. 1-9
Author(s):  
Kenji Fukutome ◽  
Hidehiro Hirabayashi ◽  
Yosuke Osakada ◽  
Yoshihiro Kuga ◽  
Hideyuki Ohnishi
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Adverse Events ◽  
Essential Tremor ◽  
Focused Ultrasound ◽  
Rating Scale ◽  
Resonance Imaging ◽  
Clinical Rating ◽  
The Mean ◽  
Clinical Rating Scale

<b><i>Introduction:</i></b> Essential tremor is the most common movement disorder in adults. Bilateral symptoms are typical; however, bilateral thalamotomy for essential tremor is associated with a high probability of adverse events. We retrospectively investigated the efficacy and safety of staged bilateral ventral intermediate nucleus thalamotomy for refractory essential tremor using magnetic resonance imaging-guided focused ultrasound. <b><i>Methods:</i></b> We enrolled 5 consecutive patients with refractory essential tremor between September 2016 and March 2020. Patients underwent a second operation at least 1 year after the first operation. The second lesion was created asymmetrically to the first lesion. <b><i>Results:</i></b> Mean patient age was 57.6 years, and the mean interval between the 2 operations was 27.8 months. The second lesion center was superior to the first lesion in all patients. The mean baseline, second preoperative, and second postoperative Clinical Rating Scale for Tremor total scores were 63.6, 49.2, and 21.8, respectively. The mean baseline, second preoperative, and second postoperative Clinical Rating Scale for Tremor part C scores were 18.4, 8.2, and 2.6, respectively. One patient had permanent adverse events of slight dysarthria and discomfort in the tongue. No patient experienced dysphagia or cognitive dysfunction after the second operation. Four of the 5 patients were satisfied with the results of the bilateral treatment, including the patient who had permanent adverse events. <b><i>Conclusions:</i></b> Magnetic resonance imaging-guided focused ultrasound is an effective method for bilateral thalamotomy when adhering to the following considerations: (1) asymmetrical lesions are created and (2) sufficient interval (&#x3e;1 year) between operations.

scholarly journals What factors impact the clinical outcome of magnetic resonance imaging–guided focused ultrasound thalamotomy for essential tremor?

2020 ◽  
pp. 1-6 ◽  
Author(s):  
Kenji Fukutome ◽  
Yoshihiro Kuga ◽  
Hideyuki Ohnishi ◽  
Hidehiro Hirabayashi ◽  
Hiroyuki Nakase
Keyword(s):  
Magnetic Resonance Imaging ◽  
Treatment Outcome ◽  
Magnetic Resonance ◽  
Essential Tremor ◽  
Focused Ultrasound ◽  
Maximum Temperature ◽  
Resonance Imaging ◽  
Improvement Rate ◽  
Lower Baseline ◽  
Younger Age

OBJECTIVEMagnetic resonance imaging–guided focused ultrasound (MRgFUS) is a novel and useful treatment for essential tremor (ET); however, the factors impacting treatment outcome are unknown. The authors conducted this study to determine the factors affecting the outcome of MRgFUS.METHODSFrom May 2016 through August 2017, 15 patients with ET were admitted to Ohnishi Neurological Center and treated with MRgFUS. To determine the factors impacting treatment outcome, the authors retrospectively studied correlations between the Clinical Rating Scale for Tremor (CRST) improvement rate and age, disease duration, baseline CRST score, skull density ratio (SDR), skull volume, maximum delivered energy, or maximum temperature.RESULTSThe mean CRST score was 18.5 ± 5.8 at baseline and 4.6 ± 5.7 at 1 year. The rate of improvement in the CRST score was 80% ± 22%. Younger age and lower baseline CRST score were correlated with a higher CRST improvement rate (p = 0.025 and 0.007, respectively). To obtain a CRST improvement rate ≥ 50%, a maximum temperature ≥ 55°C was necessary. There was no correlation between SDR and CRST improvement rate (p = 0.658). A lower SDR and higher skull volume required significantly higher maximum delivered energy (p = 0.014 and 0.016, respectively). A higher maximum temperature was associated with a significantly larger lesion volume (p = 0.026).CONCLUSIONSYounger age and lower baseline CRST score were favorable outcome factors. It is important to assess predictive factors when applying MRgFUS.

scholarly journals Transcranial magnetic resonance imaging–guided focused ultrasound: noninvasive central lateral thalamotomy for chronic neuropathic pain

2012 ◽  
Vol 32 (1) ◽  
pp. E1 ◽  
Author(s):  
Daniel Jeanmonod ◽  
Beat Werner ◽  
Anne Morel ◽  
Lars Michels ◽  
Eyal Zadicario ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Neuropathic Pain ◽  
Magnetic Resonance ◽  
Mr Imaging ◽  
Real Time ◽  
Focused Ultrasound ◽  
Resonance Imaging ◽  
Mr Thermometry ◽  
Chronic Neuropathic Pain

Object Recent technological developments open the field of therapeutic application of focused ultrasound to the brain through the intact cranium. The goal of this study was to apply the new transcranial magnetic resonance imaging–guided focused ultrasound (tcMRgFUS) technology to perform noninvasive central lateral thalamotomies (CLTs) as a treatment for chronic neuropathic pain. Methods In 12 patients suffering from chronic therapy-resistant neuropathic pain, tcMRgFUS CLT was proposed. In 11 patients, precisely localized thermal ablations of 3–4 mm in diameter were produced in the posterior part of the central lateral thalamic nucleus at peak temperatures between 51°C and 64°C with the aid of real-time patient monitoring and MR imaging and MR thermometry guidance. The treated neuropathic pain syndromes had peripheral (5 patients) or central (6 patients) origins and covered all body parts (face, arm, leg, trunk, and hemibody). Results Patients experienced mean pain relief of 49% at the 3-month follow-up (9 patients) and 57% at the 1-year follow-up (8 patients). Mean improvement according to the visual analog scale amounted to 42% at 3 months and 41% at 1 year. Six patients experienced immediate and persisting somatosensory improvements. Somatosensory and vestibular clinical manifestations were always observed during sonication time because of ultrasound-based neuronal activation and/or initial therapeutic effects. Quantitative electroencephalography (EEG) showed a significant reduction in EEG spectral overactivities. Thermal ablation sites showed sharply delineated ellipsoidal thermolesions surrounded by short-lived vasogenic edema. Lesion reconstructions (18 lesions in 9 patients) demonstrated targeting precision within a millimeter for all 3 coordinates. There was 1 complication, a bleed in the target with ischemia in the motor thalamus, which led to the introduction of 2 safety measures, that is, the detection of a potential cavitation by a cavitation detector and the maintenance of sonication temperatures below 60°C. Conclusions The authors assert that tcMRgFUS represents a noninvasive, precise, and radiation-free neurosurgical technique for the treatment of neuropathic pain. The procedure avoids mechanical brain tissue shift and eliminates the risk of infection. The possibility of applying sonication thermal spots free from trajectory restrictions should allow one to optimize target coverage. The real-time continuous MR imaging and MR thermometry monitoring of targeting accuracy and thermal effects are major factors in optimizing precision, safety, and efficacy in an outpatient context.

Neurological adverse event profile of magnetic resonance imaging-guided focused ultrasound thalamotomy for essential tremor

2018 ◽  
Vol 33 (5) ◽  
pp. 843-847 ◽  
Author(s):  
Paul S. Fishman ◽  
W. Jeffrey Elias ◽  
Pejman Ghanouni ◽  
Ryder Gwinn ◽  
Nir Lipsman ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Adverse Event ◽  
Magnetic Resonance ◽  
Essential Tremor ◽  
Focused Ultrasound ◽  
Resonance Imaging ◽  
Adverse Event Profile ◽  
Neurological Adverse Event
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