Multimodal MRI for MRgFUS in essential tremor: post-treatment radiological markers of clinical outcome

Kapadia, Anish; Elias, Gavin J B; Boutet, Alexandre; Germann, Jürgen; Pancholi, Aditiya; Chu, Powell; Zhong, Jidan; Fasano, Alfonso; Munhoz, Renato P.; Chow, Chung‐Wai; Kucharczyk, Walter; Schwartz, Michael L.; Hodaie, Mojgan; Lozano, Andrés M.

doi:10.1136/jnnp-2020-322745

Cited by 39 publications

(37 citation statements)

References 29 publications

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“…Although the Vim is a small thalamic nucleus, substantially invisible to imaging even using advanced MR sequences, and indirect targeting using stereotactic coordinates still represents the gold-standard approach, MR imaging has a non-marginal role in the planning and follow-up of patients undergoing MRgFUS thalamotomy [ 20 , 28 , 29 ]. Tractography of the dentato-rubro-thalamic fibers using DTI sequencing is recognized as a valid method for directly identifying the treatment target at the level of the thalamus, and its interruption was demonstrated to be associated with clinical improvement [ 21 , 22 ].…”

Section: Discussionmentioning

confidence: 99%

Comprehensive Evaluation of Factors Affecting Tremor Relapse after MRgFUS Thalamotomy: A Case-Control Study

et al. 2021

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Objective: To identify possible relevant factors contributing to tremor relapse after MRgFUS thalamotomy in patients with essential tremor (ET) and Parkinson’s disease (PD). Methods: We identified patients with tremor relapse from a series of 79 treatments in a single institution. The demographic and clinical characteristics of the study group patients were compared to those of patients who did not relapse in the same follow-up period. Imaging and procedural factors were compared using a control group matched for clinical and demographic characteristics. Results: Concerning clinical and demographic characteristics, we did not find statistically significant differences in gender and age. Seventy-three percent of patients with tremor relapse were Parkinson’s disease patients. Using MRI, we found larger thalamotomy lesions at the 1-year follow-up in the control group with stable outcomes, compared to patients with tremor relapse. In the tractography evaluation, we found a more frequent eccentric position of the DRTt in patients with tremor relapse. Conclusions: The most relevant determining factors for tremor relapse after MRgFUS thalamotomy appear to be tremor from Parkinson’s disease and inaccurate thalamic targeting. Size of the thalamotomy lesion can also influence the outcome of treatment.

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Section: Discussionmentioning

confidence: 99%

Comprehensive Evaluation of Factors Affecting Tremor Relapse after MRgFUS Thalamotomy: A Case-Control Study

et al. 2021

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“…Last, we found no association between the 24-h MRgFUS lesion volume and clinically relevant post-treatment FC changes. Previous radiological studies on MRgFUS (mainly based on morphological data) suffer from some inconsistency, with most authors reporting fewer symptom recurrences with larger lesions (46,(102)(103)(104)(105)(106), while others were focusing more on lesion location (20,107) or topography (27,(108)(109)(110), rather than the lesion volume. Indeed, we observed some heterogeneity in the size and shape of Vim lesions in our sample, whereas lesion volumes did not differ significantly between GR and PR.…”

Section: Limitationsmentioning

confidence: 99%

Resting State Functional Connectivity Signatures of MRgFUS Vim Thalamotomy in Parkinson's Disease: A Preliminary Study

et al. 2022

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Magnetic Resonance-guided high-intensity Focused Ultrasound (MRgFUS) of the thalamic ventral intermediate nucleus (Vim) for tremor has increasingly gained interest as a new non-invasive alternative to standard neurosurgery. Resting state functional connectivity (rs-FC) correlates of MRgFUS have not been extensively investigated yet. A region of interest (ROI)-to-ROI rs-FC MRI “connectomic” analysis focusing on brain regions relevant for tremor was conducted on 15 tremor-dominant patients with Parkinson's disease who underwent MRgFUS. We tested whether rs-FC between tremor-related areas was modulated by MRgFUS at 1 and 3 months post-operatively, and whether such changes correlated with individual clinical outcomes assessed by the MDS-UPDRS-III sub items for tremor. Significant increase in FC was detected within bilateral primary motor (M1) cortices, as well as between bilateral M1 and crossed primary somatosensory cortices, and also between pallidum and the dentate nucleus of the untreated hemisphere. Correlation between disease duration and FC increase at 3 months was found between the putamen of both cerebral hemispheres and the Lobe VI of both cerebellar hemispheres, as well as between the Lobe VI of untreated cerebellar hemisphere with bilateral supplementary motor area (SMA). Drop-points value of MDS-UPDRS at 3 months correlated with post-treatment decrease in FC, between the anterior cingulate cortex and bilateral SMA, as well as between the Lobe VI of treated cerebellar hemisphere and the interpositus nucleus of untreated cerebellum. Tremor improvement at 3 months, expressed as percentage of intra-subject MDS-UPDRS changes, correlated with FC decrease between bilateral occipital fusiform gyrus and crossed Lobe VI and Vermis VI. Good responders (≥50% of baseline tremor improvement) showed reduced FC between bilateral SMA, between the interpositus nucleus of untreated cerebellum and the Lobe VI of treated cerebellum, as well as between the untreated SMA and the contralateral putamen. Good responders were characterized at baseline by crossed hypoconnectivity between bilateral putamen and M1, as well as between the putamen of the treated hemisphere and the contralateral SMA. We conclude that MRgFUS can effectively modulate brain FC within the tremor network. Such changes are associated with clinical outcome. The shifting mode of integration among the constituents of this network is, therefore, susceptible to external redirection despite the chronic nature of PD.

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“…[21][22][23]33) Lesion size and location are also important prognostic factors. 34,35) Pineda-Pardo et al reported that the greatest clinical improvement correlated with a larger lesion volume and a more inferior and posterior location, whereas the largest lesion accounted for the occurrence of gait disturbance. 34) From our experience, we realize that we can readily reach high temperatures if the SDR is high enough to generate larger lesions.…”

Section: Outcomes and Safety Of Mrgfus: Can Mrgfus Surpass Dbs?mentioning

confidence: 99%

Techniques, Indications, and Outcomes in Magnetic Resonance-guided Focused Ultrasound Thalamotomy for Tremor

Maesawa

Nakatsubo

Tsugawa

et al. 2021

Neurol. Med. Chir.(Tokyo)

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Magnetic resonance (MR)-guided focused ultrasound surgery (MRgFUS) is the latest minimally invasive stereotactic procedure, and thalamotomy using this novel modality has demonstrated its effectiveness and safety, especially for patients with essential tremor (ET) and Parkinson's disease (PD). In Japan, the application of MRgFUS to treat ET and PD has recently been covered by health insurance. Technically, the transducer with 1024 elements emits ultrasound beams, which are then focused on the target with a phase control, resulting in optimal ablation by thermal coagulation. The technical advantages of MRgFUS are continuous intraoperative monitoring of clinical symptoms and MR images and fine adjustment of the target by the steering function. Postoperative tremor control is compatible with other modalities, although long-term follow-up is necessary. The adverse effects are usually transient and acceptable. Prognostic factors for good tremor control include high temperature and large lesion size. A high skull density ratio is a factor to achieve high temperature and large lesioning, but it may not be necessary and sufficient for clinical outcomes. For patients with advanced symptoms such as bilateral tremor or head/neck tremor, deep brain stimulation may be recommended because of the adjustability of stimulation and the possibility of bilateral treatment. Patients have high expectations of MRgFUS because of its non-invasiveness. To perform this treatment safely and effectively, physicians need to understand the technological aspects, the physiological principles. To choose the appropriate modality, physicians also should recognize the clinical advantages and disadvantages of MRgFUS compared to other modalities.

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Multimodal MRI for MRgFUS in essential tremor: post-treatment radiological markers of clinical outcome

Cited by 39 publications

References 29 publications

Comprehensive Evaluation of Factors Affecting Tremor Relapse after MRgFUS Thalamotomy: A Case-Control Study

Comprehensive Evaluation of Factors Affecting Tremor Relapse after MRgFUS Thalamotomy: A Case-Control Study

Resting State Functional Connectivity Signatures of MRgFUS Vim Thalamotomy in Parkinson's Disease: A Preliminary Study

Techniques, Indications, and Outcomes in Magnetic Resonance-guided Focused Ultrasound Thalamotomy for Tremor

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