# 3-D Tractography Focused Ultrasound Ablation for Essential Tremor

> **NIH NIH R01** · UNIV OF NORTH CAROLINA CHAPEL HILL · 2024 · $511,178

## Abstract

PROJECT SUMMARY
 Essential tremor (ET) is a common neurological disorder and a leading cause of functional and psychological
disabilities that can be difficult to suppress with oral medications, many of which have considerable side effects
limiting adequate dosing. As a result, up to 20% of ET patients cannot achieve satisfactory control of their
symptoms and must consider interventional options. Focused ultrasound ablation (FUSA) of the ventral
intermediate nucleus (Vim) is an FDA-approved and Medicare-reimbursed procedure for ET resistant to
medications that can selectively ablate the brain area associated with tremor without the need for surgical
incisions or anesthesia. The success of Vim-FUSA depends on the ability to accurately ablate 70% of the Vim
volume without lesioning neighboring structures, a goal that is complicated by technical challenges in three
critical phases of the procedure: planning (identifying the Vim location and extension); delivery (ablating the Vim
volume with adequate accuracy); and monitoring (confirming Vim ablation with reliable intraoperative imaging).
 We propose to advance Vim-FUSA with the support of 3-D tractography, a neuroimaging technique to visually
represent nerve tracts within the brain. We hypothesize that 3-D tractography Vim-FUSA will improve the Vim
ablation compared to standard Vim-FUSA and prove safe and feasible in the clinical setting. We also hypothesize
that intraoperative magnetic resonance (i-MR) monitoring will differentiate ablated tissue from immediate
perilesional edema and accurately predict the Vim-FUSA clinical outcomes.
 Aim 1. Estimate and characterize the improvement in Vim ablation achieved with 3-D tractography
Vim-FUSA vs. standard Vim-FUSA in an experimental controlled animal study. Through an experimental
animal study, we will characterize the Vim ablation delivered with 3-D tractography Vim-FUSA in one hemisphere
(experimental group) vs. standard Vim-FUSA in the opposite hemisphere (control group).
 Aim 2. Test safety, feasibility, and preliminary efficacy, and estimate effect size of 3-D tractography
Vim-FUSA in a phase-II, two-groups, pre-post interventional human study. In a human study, we will test
the safety and feasibility of ablating 70% of the Vim volume while checking for side effects with intraoperative
clinical testing. Tremor assessments will be videotaped at baseline and 12 weeks and compared, in a blinded
fashion, with age-sex matched controls randomly selected from the video repository of the two FDA-regulated
studies of standard Vim-FUSA at baseline and 12 weeks.
 Aim 3 (Exploratory). Assess the accuracy of i-MR in differentiating tissue ablation from immediate
perilesional edema and its utility in predicting Vim-FUSA clinical outcomes. In the experimental animal
study, we will estimate and compare the accuracy of conventional and non-conventional i-MR in differentiating
tissue necrosis from perilesional edema. In the interventional human study, we will evalua...

## Key facts

- **NIH application ID:** 10650282
- **Project number:** 5R01NS125386-02
- **Recipient organization:** UNIV OF NORTH CAROLINA CHAPEL HILL
- **Principal Investigator:** Vibhor Krishna
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $511,178
- **Award type:** 5
- **Project period:** 2022-07-01 → 2027-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10650282

## Citation

> US National Institutes of Health, RePORTER application 10650282, 3-D Tractography Focused Ultrasound Ablation for Essential Tremor (5R01NS125386-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10650282. Licensed CC0.

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