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

Introduction: 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. Methods: 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. Results: 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. Conclusions: 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 (>1 year) between operations.

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

Journal of Neurosurgery ◽

10.3171/2020.11.jns202580 ◽

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.

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Impact of skull density ratio on efficacy and safety of magnetic resonance–guided focused ultrasound treatment of essential tremor

Journal of Neurosurgery ◽

10.3171/2019.2.jns183517 ◽

2020 ◽

Vol 132 (5) ◽

pp. 1392-1397 ◽

Cited By ~ 5

Author(s):

Marissa D’Souza ◽

Kevin S. Chen ◽

Jarrett Rosenberg ◽

W. Jeffrey Elias ◽

Howard M. Eisenberg ◽

...

Keyword(s):

Magnetic Resonance ◽

Adverse Events ◽

Essential Tremor ◽

Focused Ultrasound ◽

Rating Scale ◽

Density Ratio ◽

Target Temperature ◽

Efficacy And Safety ◽

Significant Difference ◽

Clinical Rating Scale

OBJECTIVESkull density ratio (SDR) assesses the transparency of the skull to ultrasound. Magnetic resonance–guided focused ultrasound (MRgFUS) thalamotomy in essential tremor (ET) patients with a lower SDR may be less effective, and the risk for complications may be increased. To address these questions, the authors analyzed clinical outcomes of MRgFUS thalamotomy based on SDRs.METHODSIn 189 patients, 3 outcomes were correlated with SDRs. Efficacy was based on improvement in Clinical Rating Scale for Tremor (CRST) scores 1 year after MRgFUS. Procedural efficiency was determined by the ease of achieving a peak voxel temperature of 54°C. Safety was based on the rate of the most severe procedure-related adverse event. SDRs were categorized at thresholds of 0.45 and 0.40, selected based on published criteria.RESULTSOf 189 patients, 53 (28%) had an SDR < 0.45 and 20 (11%) had an SDR < 0.40. There was no significant difference in improvement in CRST scores between those with an SDR ≥ 0.45 (58% ± 24%), 0.40 ≤ SDR < 0.45 (i.e., SDR ≥ 0.40 but < 0.45) (63% ± 27%), and SDR < 0.40 (49% ± 28%; p = 0.0744). Target temperature was achieved more often in those with an SDR ≥ 0.45 (p < 0.001). Rates of adverse events were lower in the groups with an SDR < 0.45 (p = 0.013), with no severe adverse events in these groups.CONCLUSIONSMRgFUS treatment of ET can be effectively and safely performed in patients with an SDR < 0.45 and an SDR < 0.40, although the procedure is more efficient when SDR ≥ 0.45.

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Magnetic resonance–guided focused ultrasound thalamotomy for tremor: a report of 30 Parkinson's disease and essential tremor cases

Journal of Neurosurgery ◽

10.3171/2016.10.jns16758 ◽

2018 ◽

Vol 128 (1) ◽

pp. 202-210 ◽

Cited By ~ 70

Author(s):

Menashe Zaaroor ◽

Alon Sinai ◽

Dorith Goldsher ◽

Ayelet Eran ◽

Maria Nassar ◽

...

Keyword(s):

Quality Of Life ◽

Parkinson’S Disease ◽

Parkinson's Disease ◽

Adverse Events ◽

Essential Tremor ◽

Focused Ultrasound ◽

Rating Scale ◽

Innovative Technology ◽

The Mean

OBJECTIVEThalamotomy of the ventral intermediate nucleus (VIM) is effective in alleviating medication-resistant tremor in patients with essential tremor (ET) and Parkinson's disease (PD). MR-guided focused ultrasound (MRgFUS) is an innovative technology that enables noninvasive thalamotomy via thermal ablation.METHODSPatients with severe medication-resistant tremor underwent unilateral VIM thalamotomy using MRgFUS. Effects on tremor were evaluated using the Clinical Rating Scale for Tremor (CRST) in patients with ET and by the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS) in patients with PD and ET-PD (defined as patients with ET who developed PD many years later). Quality of life in ET was measured by the Quality of Life in Essential Tremor (QUEST) questionnaire and in PD by the PD Questionnaire (PDQ-39).RESULTSThirty patients underwent MRgFUS, including 18 with ET, 9 with PD, and 3 with ET-PD. The mean age of the study population was 68.9 ± 8.3 years (range 46–87 years) with a mean disease duration of 12.1 ± 8.9 years (range 2–30 years). MRgFUS created a lesion at the planned target in all patients, resulting in cessation of tremor in the treated hand immediately following treatment. At 1 month posttreatment, the mean CRST score of the patients with ET decreased from 40.7 ± 11.6 to 9.3 ± 7.1 (p < 0.001) and was 8.2 ± 5.0 six months after treatment (p < 0.001, compared with baseline). Average QUEST scores decreased from 44.8 ± 12.9 to 13.1 ± 13.2 (p < 0.001) and was 12.3 ± 7.2 six months after treatment (p < 0.001). In patients with PD, the mean score of the motor part of the UPDRS decreased from 24.9 ± 8.0 to 16.4 ± 11.1 (p = 0.042) at 1 month and was 13.4 ± 9.2 six months after treatment (p = 0.009, compared with baseline). The mean PDQ-39 score decreased from 38.6 ± 16.8 to 26.1 ± 7.2 (p = 0.036) and was 20.6 ± 8.8 six months after treatment (p = 0.008). During follow-up of 6–24 months (mean 11.5 ± 7.2 months, median 12.0 months), tremor reappeared in 6 of the patients (2 with ET, 2 with PD, and 2 with ET-PD), to a lesser degree than before the procedure in 5. Adverse events that transiently occurred during sonication included headache (n = 11), short-lasting vertigo (n = 14) and dizziness (n = 4), nausea (n = 3), burning scalp sensation (n = 3), vomiting (n = 2) and lip paresthesia (n = 2). Adverse events that lasted after the procedure included gait ataxia (n = 5), unsteady feeling (n = 4), taste disturbances (n = 4), asthenia (n = 4), and hand ataxia (n = 3). No adverse event lasted beyond 3 months. Patients underwent on average 21.0 ± 6.9 sonications (range 14–45 sonications) with an average maximal sonication time of 16.0 ± 3.0 seconds (range 13–24 seconds). The mean maximal energy reached was 12,500 ± 4274 J (range 5850–23,040 J) with a mean maximal temperature of 56.5° ± 2.2°C (range 55°–60°C).CONCLUSIONSMRgFUS VIM thalamotomy to relieve medication-resistant tremor was safe and effective in patients with ET, PD, and ET-PD. Current results emphasize the superior adverse events profile of MRgFUS over other surgical approaches for treating tremor with similar efficacy. Large randomized studies are needed to assess prolonged efficacy and safety.

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

Journal of Neurosurgery ◽

10.3171/2020.2.jns192814 ◽

2020 ◽

pp. 1-6 ◽

Cited By ~ 2

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.

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Evaluation of Parkinson’s disease by neuromelanin-sensitive magnetic resonance imaging and 123I-FP-CIT SPECT

Acta Radiologica ◽

10.1177/0284185117722812 ◽

2017 ◽

Vol 59 (5) ◽

pp. 593-598 ◽

Cited By ~ 12

Author(s):

Keita Kuya ◽

Toshihide Ogawa ◽

Yuki Shinohara ◽

Mana Ishibashi ◽

Shinya Fujii ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Parkinson’S Disease ◽

Parkinson's Disease ◽

Magnetic Resonance ◽

Rating Scale ◽

Substantia Nigra Pars Compacta ◽

Emission Computed Tomography ◽

Resonance Imaging ◽

The Mean ◽

The Relationship

Background Both neuromelanin-sensitive magnetic resonance imaging (NmMRI) and 123I-FP-CIT single photon emission computed tomography (SPECT) (DaTSCAN) assist the diagnosis of Parkinson’s disease (PD). However, there have been few studies investigating a correlation between them. Purpose To correlate the utility of NmMRI and DaTSCAN and to evaluate the relationship between both imaging findings and the Unified PD rating scale part III (UPDRS III) score for the diagnosis and management of PD. Material and Methods Seventeen patients with PD who underwent both NmMRI and DaTSCAN were included. We measured the volume of the neuromelanin-positive substantia nigra pars compacta (SNc volume) on NmMRI and measured the specific binding ratio (SBR) on DaTSCAN. The asymmetry index (AI) of the SNc volume and SBR were also calculated. We evaluated the relationship between the UPDRS III score and the SNc volume and SBR, respectively. Results The SNc volume showed a significant correlation with the SBR. The AIs of them also showed a significant correlation. Both the mean of the bilateral SBR and the mean of the bilateral SNc volume showed significant negative correlations with the UPDRS III score. However, the correlation between the SBR and the UPDRS III score was stronger than that between the SNc volume and the UPDRS III score. Conclusion Both NmMRI and DaTSCAN are helpful for PD diagnosis. However, we conclude that DaTSCAN is more suitable for the evaluation of the clinical motor severity and would be more useful for the management of PD patients than NmMRI.

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Two year data from a preliminary study of double lesion site MRgFUS treatment of Essential Tremor targeting the thalamus and the posterior subthalamic area

10.1101/2020.12.27.20248723 ◽

2021 ◽

Author(s):

Ayesha Jameel ◽

Wladyslaw Gedroyc ◽

Dipankar Nandi ◽

Bryn Jones ◽

Olga Kirmi ◽

...

Keyword(s):

Quality Of Life ◽

Essential Tremor ◽

Focused Ultrasound ◽

Rating Scale ◽

Severity Scores ◽

The Mean ◽

Preliminary Study ◽

Clinical Rating Scale

AbstractBackgroundMR-guided focused ultrasound (MRgFUS) is an effective treatment for essential tremor (ET). However, the optimal intracranial target sites remain to be determined.ObjectiveTo assess MRgFUS induced sequential lesions in (anterior-VIM/VOP nuclei) the thalamus and then posterior subthalamic area (PSA) performed during the same procedure for alleviating ET.Methods14 patients had unilateral MRgFUS lesions placed in anterior-VIM/VOP then PSA. Bain-Findley Spirals were collected during MRgFUS from the treated arm (BFS-TA) and throughout the study from the treated (BFS-TA) and non-treated (BFS-NTA) arms and scored by blinded assessors. Although, the primary outcome was change in the BFS-TA from baseline to 12 months we have highlighted the 24 month data.Secondary outcomes included the Clinical Rating Scale for Tremor (CRST), Quality of Life for ET (QUEST) and PHQ-9 depression scores.ResultsThe mean improvement in the BFS-TA from baseline to 24 months was 41.1% (p<0.001) whilst BFS-NTA worsened by 8.8% (p<0.001). Intra-operative BFS scores from the targeted arm showed a mean 27.9% (p<0.001) decrease after anterior-VIM/VOP ablation and an additional 30.1% (p<0.001) reduction from post anterior-VIM/VOP to post-PSA ablation.Mean improvements at 24 month follow-up in the CRST-parts A, B and C were 60.7%, 30.4% and 65.6% respectively and 37.8% in QUEST-tremor score (all p<0.05). Unilateral tremor severity scores decreased in the treated arm (UETTS-TA) 72.9% (p=0.001) and non-treated arm (UETTS-NTA) 30.5% (p=0.003). At 24 months residual adverse effects were slight unsteadiness (n=1) and mild hemi-chorea (n=1).ConclusionUnilateral anterior-VIM/VOP and PSA MRgFUS significantly diminished contralateral arm tremor with improvements in arm function, tremor related disability and quality of life, with an acceptable adverse event profile.

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