ExAblate Transcranial MR Guided Focused Ultrasound in the Treatment of Essential Tremor
The purpose of this study is to evaluate the safety and initial effectiveness of MRI-guided focused ultrasound thermal ablation of a designated area in the brain of patients suffering from medication-refractory Essential Tremor, using the ExAblate transcranial system.
The ExAblate system is a medical device that involves a focused ultrasound system and an MRI scanner. ExAblate delivers a pulse of focused ultrasound energy, or sonication, to the targeted tissue. In this particular study the targeted tissue is a unilateral thermal lesion created in the ventralis intermedius nucleus of the thalamus.
The treatment begins with a series of standard diagnostic MR images to identify the location and shape of tumor to be treated. The ExAblate computer uses the physician's designation of the target volume to plan the best way to cover the target volume with small spots called "sonications". These treatment spots are cylinder shaped. Their size depends on sonication power and duration. During the treatment, a specific MR scan, which can be processed to identify changes in tissue temperature, provides a thermal map of the treatment volume to confirm the therapeutic effect. The thermal map is used to monitor the treatment in progress, and confirm that the ablation is proceeding according to plan, thus closing the therapy loop.
The ExAblate transcranial operates a helmet-shaped transducer (currently utilizing 1000-element phased array transducer) positioned above the subject head. The ExAblate transcranial system also includes means to immobilize the subject head, cool the interface water, and software for CT analysis and phase correction computation.
The ExAblate transcranial system is an experimental device and is being investigated in this study.
|Study Design:||Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||A Feasibility Study to Evaluate Safety and Initial Effectiveness of ExAblate Transcranial MR Guided Focused Ultrasound for Unilateral Thalamotomy in the Treatment of Essential Tremor|
- Device or procedure related Adverse Events reported [ Time Frame: 3 Months ] [ Designated as safety issue: Yes ]Safety of the ExAblate transcranial treatment will be determined by an evaluation of the incidence and severity of device and procedure related complications from the first / treatment day visit through the 3-Months post-treatment time point. Alternative treatments resulting from post-surgical changes in neurological status will be reported.
- Tremor rating scales: the Clinical Rating Scale for Tremors [ Time Frame: 3 months ] [ Designated as safety issue: No ]Effectiveness will be evaluated using validated, tremor rating scales: the Clinical Rating Scale for Tremors (CRST) for ET patients, based upon patients in whom unilateral ExAblate lesioning is attempted (i.e., Intent-to-Treat analysis). Efficacy is defined as a reduction in contralateral symptoms at 3-months post-treatment.changes in neurological status will be reported.
|Study Start Date:||January 2011|
|Study Completion Date:||October 2012|
|Primary Completion Date:||October 2012 (Final data collection date for primary outcome measure)|
|Experimental: ExAblate Treatment||
Device: ExAblate Transcranial MRgFUS System
Treatment with the ExAblate Transcranial MRgFUS System.