High-Intensity Focused Ultrasound for PD: Hope or Hype?

Treatment for Parkinson disease has remained largely unchanged for decades. Conventional treatment has remained restricted to two main avenues: symptomatic medications and the use of deep brain stimulation for those who qualify. In recent years, a new therapy has been introduced which has the potential to radically change the landscape of Parkinson disease treatment. Like other therapies, focused ultrasound is still a symptomatic therapy – not a cure, and like other therapies it has its advantages and disadvantages. In this article, we will try to answer some of the most common questions and dispel some rumors and hype surrounding this new and promising therapy

What is High-Intensity Focused Ultrasound?

High-Intensity Focused Ultrasound (HiFU), which is also sometimes called MR-guided Focused Ultrasound (MRgFUS), is a relatively new non-invasive medical technology which uses beams of ultrasound waves to deliver therapies to various tissues in the body.

How does HiFU work? Focused ultrasound uses an array of over 1,000 transducers to produce ultrasound that are focused on a single point to create a lesion. In movement disorders such as Parkinson disease, the targeted point is within the brain, where the transducers are focused on a specific area to create heat leading to an ablative lesion. In other words, HiFU uses very high energy sound waves to heat up a tiny portion of the brain involved in the disease in order to disrupt its activity. Individually, the ultrasound beams do no damage to the tissues they pass through, and heat is only created at the tiny point where all the beams converge. How is HiFU used in the treatment of Parkinson Disease? HiFU was approved for the treatment of tremor predominant Parkinson disease in 2018. Focused ultrasound is used to create a lesion in the specific brain circuit which is responsible for producing tremor. There are clinical trials currently underway to investigate the use of HiFU for other symptoms of PD, but today the treatment is only available for tremor. Not all patients are candidates for this therapy, and there are very important considerations that patients must discuss with their physicians. Individuals with cognitive difficulties, balance problems, or high skull density ratios may not be considered good candidates.

What are the Pros and Cons of HiFU? One of the greatest advantages of this new technology is that it does not require any surgical incisions, and does not involve any hardware being implanted in the body. The ultrasound waves which create the lesion do no damage as they enter the body, and only at the targeted point of convergence do they create a lesion in the brain. This procedure can be done within a few hours, and patients are typically able to be home and enjoy its benefits the same evening. Like all medical treatments, it’s important to consider not only the benefits, but also the potential risks and drawbacks. While HiFU can be very effective for treatment of tremor, its current approved use falls short of treating any other PD symptoms such as rigidity, slowness or dyskinesia. Another very important consideration is that HiFU is currently only approved to be performed safely on one side, due to the risk of side effects if both sides of the brain are treated. This means that symptoms on only one side of the body can be treated using HiFU. In addition, since HiFU is a one-time procedure, its effects cannot be modified or adjusted as the disease progresses and symptoms change. Finally, since HiFU is a fairly new technology, it’s unclear exactly how long patients can expect to retain the benefits from the procedure.

Summary

• High-intensity focused ultrasound is a real and exciting new medical technology.

• Focused ultrasound waves are used to create a lesion without any surgical incisions or hardware implants.

• HiFU is currently only approved for treatment of tremor in PD and does not treat any other PD symptoms, although clinical trials are currently under way to expand its use.

• Focused ultrasound treatment can only be applied to one side of the brain currently, thus leaving the other side untreated.

• Like all treatments, HiFU is not right for everyone. Patients should discuss the risks and benefits with their doctor.

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About the Author:

Mazen Elkurd, DO is an instructor of Neurology at UT Southwestern Medical Center in Dallas, Texas.

Dr. Elkurd is a Dallas native who graduated from the University of Texas at Arlington, then went on to complete medical school at A.T. Still University in Mesa, Arizona. He completed neurology residency training at Georgetown University Medical Center in Washington, D.C. where he served in his final year as academic chief resident. Following residency, Dr. Elkurd returned to Dallas to complete a clinical fellowship in movement disorders at UT Southwestern Medical Center. He is now a diplomate of the American Board of Psychiatry and Neurology and a practicing movement disorder neurologist, caring for patients with various movement disorders including Parkinsonism, tremor, ataxia, myclonus, dystonia, chorea, functional neurological disorders and gait disorders. He has been author of several scientific publications in the field of movement disorders and has research interests in the field of Parkinson disease with a number of ongoing projects. Dr. Elkurd is also active in the teaching of residents and medical students, giving lectures to rotating medical students and supervising residents in the delivery of care to patients at the Ron J Anderson Ambulatory Clinic at Parkland. DAPS is excited to have Mazen as one of its newest members to the Medical Advisory Board.