Focused ultrasound using a novel targeting method four-tract tractography for magnetic resonance–guided high-intensity focused ultrasound targeting

Feltrin, Fabrício Stewan; Chopra, Rajiv; Pouratian, Nader; Elkurd, Mazen; El-Nazer, Rasheda; Lanford, Lauren; Dauer, William T.; Shah, Bhavya

doi:10.1093/braincomms/fcac273

Cited by 17 publications

(10 citation statements)

References 32 publications

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“… 13 Four-tract tractography decreases treatment time, reduces AEs, decreases the thermal dose required to see an initial tremor response, and maintains extremity and axial tremor response from 3 months to 1 year. 13 , 25 …”

Section: Introductionmentioning

confidence: 99%

Improving tremor response to focused ultrasound thalamotomy

Holcomb

Chopra

Feltrin

et al. 2023

Brain Communications

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MRI-guided high-intensity focused ultrasound thalamotomy is an incisionless therapy for essential tremor. To reduce adverse effects, the field has migrated to treating at approximately 2 mm above the anterior commissure-posterior commissure plane. We perform MRI-guided high intensity focused ultrasound with an advanced imaging targeting technique, four tract tractography. Four tract tractography uses diffusion tensor imaging to identify the critical white matter targets for tremor control, the decussating and non-decussating dentatorubrothalamic tracts, while the corticospinal tract and medial lemniscus are identified to be avoided. In some patients, four tract tractography identified a risk of damaging the medial lemniscus or corticospinal tract if treating at 2 mm superior to the anterior commissure-posterior commissure plane. In these patients, we chose to target 1.2-1.5 mm superior to the anterior commissure-posterior commissure plane. In these patients, post-operative imaging revealed that the focused ultrasound lesion extended into the posterior subthalamic area. This study sought to determine if patients with focused ultrasound lesions that extend into the posterior subthalamic area have greater tremor improvement than those without. 20 essential tremor patients underwent MRI-guided high intensity focused ultrasound and were retrospectively classified into two groups. Group 1 included patients with extension of the thalamic focused ultrasound lesion into the posterior subthalamic area. Group 2 included patients without extension of the thalamic focused ultrasound lesion into the posterior subthalamic area. For each patient, the percent change in postural tremor, kinetic tremor, and Archimedes spiral scores were calculated between baseline and a three-month follow-up. Two-tailed Wilcoxon rank sum tests were used to compare improvement in tremor scores, total number of sonications, thermal dose to achieve initial tremor response, and skull density ratio between groups. Group 1 had significantly greater postural, kinetic, and Archimedes spiral score percent improvement than Group 2 (p-values: 5.41 × 10−5, 4.87 × 10−4, and 5.41 × 10−5, respectively). Group 1 also required significantly fewer total sonications to control the tremor and a significantly lower thermal dose to achieve tremor response (p-values: 6.60 × 10−4 and 1.08 × 10−5, respectively). No significant group differences in skull density ratio were observed (p-value = 1.0). We do not advocate directly targeting the posterior subthalamic area with MRI-guided high-intensity focused ultrasound because the shape of the focused ultrasound lesion can result in a high risk of adverse effects. However, when focused ultrasound lesions naturally extend from the thalamus into the posterior subthalamic area, they provide greater tremor control than those that only involve the thalamus.

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Section: Introductionmentioning

confidence: 99%

Improving tremor response to focused ultrasound thalamotomy

Holcomb

Chopra

Feltrin

et al. 2023

Brain Communications

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“…53,62,64 Although FUS-T enables real-time monitoring of both magnetic resonance-based thermometry and treatment effect and during thalamotomy, 12,53 further investigation into factors that could contribute to larger lesion volume, such as increased acceleration in power per sonication, higher skull density ratio, and increased distance between targets in multiple sonications, would improve an already efficacious incisionless thalamotomy option. Our analysis motivates future studies that model lesion size and use improved imaging techniques such as diffusion tractography imaging 69 to optimize lesion location, limit off-target side effects, and improve efficacy with FUS-T.…”

Section: Discussionmentioning

confidence: 77%

A Systematic Review Comparing Focused Ultrasound Surgery With Radiosurgery for Essential Tremor

2023

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BACKGROUND: Focused ultrasound (FUS-T) and stereotactic radiosurgery thalamotomy (SRS-T) targeting the ventral intermediate nucleus are effective incisionless surgeries for essential tremor (ET). However, their efficacy for tremor reduction and, importantly, adverse event incidence have not been directly compared. OBJECTIVE: To present a comprehensive systematic review with network meta-analysis examining both efficacy and adverse events (AEs) of FUS-T vs SRS-T for treating medically refractory ET. METHODS: We conducted a systematic review and network meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, using the PubMed and Embase databases. We included all primary FUS-T/SRS-T studies with approximately 1-year follow-up, with unilateral Fahn-Tolosa-Marin Tremor Rating Scale or Clinical Rating Scale for Tremor scores prethalamotomy/post-thalamotomy and/or AEs. The primary efficacy outcome was Fahn-Tolosa-Marin Tremor Rating Scale A+B score reduction. AEs were reported as an estimated incidence. RESULTS: Fifteen studies of 464 patients and 3 studies of 62 patients met inclusion criteria for FUS-T/SRS-T efficacy comparison, respectively. Network meta-analysis demonstrated similar tremor reduction between modalities (absolute tremor reduction: FUS-T: −11.6 (95% CI: −13.3, −9.9); SRS-T: −10.3 (95% CI: −14.2, −6.0). FUS-T had a greater 1-year adverse event rate, particularly imbalance and gait disturbances (10.5%) and sensory disturbances (8.3%). Contralateral hemiparesis (2.7%) often accompanied by speech impairment (2.4%) were most common after SRS-T. There was no correlation between efficacy and lesion volume. CONCLUSION: Our systematic review found similar efficacy between FUS-T and SRS-T for ET, with trend toward higher efficacy yet greater adverse event incidence with FUS-T. Smaller lesion volumes could mitigate FUS-T off-target effects for greater safety.

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“…A recent meta-analysis subsequently verified these findings and found a reduced risk of side effects (specifically the most common side effect, ataxia) when tractography was used to target VIM for focused ultrasound ablation [ 45 ]. The use of dMRI for tractography presurgical target planning can be standardized, as per one study, with FDA-approved software so that other institutions can utilize methods for improving target identification and reducing side effects [ 46 ].…”

Section: Dmri and Tractographymentioning

confidence: 99%

Diffusion and functional MRI in surgical neuromodulation

Silva,

Barrios-Martinez,

Yeh

et al. 2024

Neurotherapeutics

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Focused ultrasound using a novel targeting method four-tract tractography for magnetic resonance–guided high-intensity focused ultrasound targeting

Cited by 17 publications

References 32 publications

Improving tremor response to focused ultrasound thalamotomy

Improving tremor response to focused ultrasound thalamotomy

A Systematic Review Comparing Focused Ultrasound Surgery With Radiosurgery for Essential Tremor

Diffusion and functional MRI in surgical neuromodulation

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