MRI-guided transcranial focused ultrasound (ExAblate Neuro)
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Indications
- medication-refractory Parkinson's disease*[1][5]
- essential tremor*[1]
- Alzheimer's disease (low-intensity focused ultrasound)[2][3]
* high-intensity focused ultrasound
* improvement in 37/39 patients with duration of benefit > 1 year[1]
Contraindications
- contraindicated for patients who cannot have MRI imaging, including those with implanted metallic devices such as cardiac pacemaker
- contraindications to gadolinium
- body size limitations for MRI
- pregnancy
- renal failure those
- unstable heart conditions
- severe hypertension
- substance abuse
- bleeding disorder
- coagulopathy
- history of cerebrovascular disease (stroke)
- history of brain tumor
Procedure
- transcranial image (brain MRI)-guided focuses ultrasound
- unilateral pallidotomy[5] for treatment-resistant Parkinson's disease[5]
- helmet transducer
- patients wear a helmet that has ultrasound probes
- 1,000 separate ultrasound transducers angled in different orientations[2]
- low-intensity focused ultrasound
- MRI is used to visualize areas of the brain with amyloid plaques.
- ultrasound waves travel through the scalp & skull converging on the locations in the brain targeted with MRI with a high degree of plaques
- tiny spherical microbubbles injected into the bloodstream oscillate in areas targeted with ultrasound, resulting in a transient opening of the blood-brain barrier
- treatment takes ~2 hours
- patients undergo 3 treatments, each 2 weeks apart.
Mechanism of action
- transcranial focused ultrasound can open blood brain barrier
- MRI-guided low-intensity focused ultrasound with injected microbubbles to temporarily open the blood-brain barrier reduces beta-amyloid plaques & cognitive impairment in patients with mild Alzheimer's disease[3]
- ability to transiently open the blood-brain barrier on demand safely facilitates new therapeutic strategies for treating brain disease
More general terms
References
- ↑ 1.0 1.1 1.2 1.3 Susman E Focused Ultrasound Ablates Tremor Durable clinical improvement with non-invasive treatment in small study. MedPage Today. Dec 3, 2019 https://www.medpagetoday.com/meetingcoverage/rsna/83663
Bruno F et al Efficacy of tc-MRgFUS Thalamotomy in The Treatment of Essential Tremor and Parkinson Disease Tremor: Experience From 39 Patients in A Single Centre with Long Term Follow-Up. Radiological Society of North America RSNA 2019; Abstract NR438-SD-WEB7 - ↑ 2.0 2.1 2.2 Susman E Ultrasound Can Open Blood-Brain Barrier. Treatment could improve drug penetration and toxin removal in Alzheimer's patients. MedPage Today. Dec 5, 2019 https://www.medpagetoday.com/meetingcoverage/rsna/83712
Mehta R, et al Blood-Brain Barrier in the Hippocampus and Entorhinal Cortex Using MR-Guided Focused Ultrasound in Patients with Alzheimer's Disease Radiological Society of North America RSNA 2019; Abstract SSG11-06 - ↑ 3.0 3.1 3.2 Anderson P Low-Intensity Focused Ultrasound Safe, Effective in Mild Alzheimer's Disease. Medscape. August 30, 2021 https://www.medscape.com/viewarticle/957487
- ↑ FDA News Release. July 11, 2016 FDA approves first MRI-guided focused ultrasound device to treat essential tremor. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm510595.htm
- ↑ 5.0 5.1 5.2 5.3 George J Focused Ultrasound Approved for Advanced Parkinson's. Expanded indication includes medication-refractory PD patients with motor problems. MedPage Today November 5, 2021 https://www.medpagetoday.com/neurology/parkinsonsdisease/95458