MRI-guided Focused Ultrasound Thalamotomy for Patients with Medically-refractory Essential Tremor.
Authors: Meng Y, Huang Y, Solomon B, Hynynen K, Scantlebury N, Schwartz ML, Lipsman N
Essential tremor (ET) is the most common type of tremor in adults. While ET does not result in decreased life expectancy, the disabilities associated with ET can have a significant impact on quality of life, mood, functional activities, and socialization. Patients suffering from ET not sufficiently treated with first line medications may be eligible for alternative strategies such as deep brain stimulation, radiofrequency ablation, and MRI guided focused ultrasound (MRgFUS). High-intensity MRgFUS is an emerging modality to treat ET, its attraction for patients being that it is noninvasive and associated with short recovery time, as patients are home the day after treatment. While MRgFUS centers are still limited, it will become important for clinicians to consider MRgFUS as a treatment alternative, particularly in the case of a patient for whom open surgery is contraindicated. This article outlines the steps of patient selection, equipment setup, sonication, and post-treatment follow-up, as well as critical steps to be aware of when performing a MRgFUS procedure.
Introduction
Purpose
thermal ablation or other (neuro ablation)
Study Objective
To describe the protocol for performing MRI-guided focused ultrasound thalamotomy for the treatment of medically refractory essential tremor.
Animal model / Human subject
human patients (characteristics not specified)
Disease model
with essential tremor (medically refractory)
MRI or image guidance method
3T MRI guidance with real-time thermometry
Targeted brain region(s)
Thalamus
Target coordinates
AC-PC based indirect coordinates: ~25% anterior to PC, lateral adjusted per patient anatomy
Outcomes and Safety
Summary of Outcomes
The described MRgFUS thalamotomy protocol provides a noninvasive, real-time image-guided method for creating therapeutic lesions in the Vim. Its clinical efficacy is comparable to traditional surgeries, with the unique advantages of immediate feedback, adjustability, and absence of cranial implants, though outcomes are modulated by patient-specific factors like skull density.
Duration of biological effect
durable at 12 months
Safety-related matter
the therapy may cause damage to surrounding tissue, with associated pain or neurologic injury if the lesions created by the MRgFUS is too superficial. In addition, the difficulty of this treatment is denpendent on patient's own physical conditions. Skull density, thickness, and shape would affect the needed acoustic energy required for the successful ablation. Skull and scalp heating can be a source of discomfort and may lead to long-term sequelae.
Brain Region
Ultrasound Parameters
Ultrasound instrument
a commercially available helmet transducer with 1024 independent elements, source not specified
FUS Frequency
650kHz
FUS Mode
continuous
Pulse duration
10-25s
Duration of a single FUS session
10-25s
Focal Characteristics
none (not specified)
Treatment frequency
12months
We are open to feedback. If you see a mistake or have a suggestion, please contact us.
← Back to Search