Focused ultrasounds: How the noninvasive brain surgery works


Clinical trials around the world are brain surgery that doesn’t require an incision or involve any blood, but can dramatically improve the lives of people with essential tremors, depression and more. This procedure, known as focused ultrasound, aims sound waves at parts of the brain to disrupt faulty brain circuits that cause a signal.

“Focused ultrasound is a non-invasive medical technology,” said Dr. Neal Castle, founder and chairman of the Focused Ultrasound Foundation. “We’ve said that focused ultrasound is the most powerful sound you’ll ever hear, but one day it could save your life.”

Castle explains how it works, “similar to a magnifying glass for focusing light rays on a single point and burning a hole in a leaf.”

He added, “In focused ultrasound, instead of using an optical lens to focus light beams, an acoustic lens is used to focus more of the ultrasound energy beam on deep targets in the body with high accuracy and precision.” Adjacent normal tissue.

The procedure is useful for people with essential tremor, a neurological disorder that causes involuntary and pulsating tremors. The disease can affect any part of the body, but the tremors often occur in the hands – even during simple tasks such as eating, drinking or writing.

Essential tremor is usually localized to one part of the body and may be aggravated by movement. It is more common in people 40 and older, and affects about 25 million people worldwide, according to a 2021 study.

That was the case with 80-year-old Brenda Herrick, who recently pioneered the procedure at the University of Virginia.

Herrick’s tremors make her uncomfortable in social situations because she’s afraid of spilling or knocking something over, she told CNN.

But 44 seconds of focused ultrasound waves eliminated her tremors.

“I looked at my hand, and it wasn’t moving, and it was the first time I could see my fingers in 20 years,” Herrick said. “I think it’s definitely a miracle, and I thank the Lord for that.”

Focused ultrasound is a form of functional neurosurgery, aiming to alter precise structures deep within the brain, restoring function or, in this case, stopping a tumor. Experts say it’s an alternative treatment for people like Herrick’s who don’t respond to conventional drug therapy or stop hurting.

“Simply put, you can imagine that there are a lot of abnormal neurons in this target that are firing uncontrollably, causing tremors, tremors,” Cassel said.

Focused ultrasound technology uses a transducer to increase the temperature and force sound waves to destroy tissue.

Patients must shave their heads before receiving the high-intensity focused ultrasound needed to treat essential tremors, as air can sometimes enter the hair follicles.

The patient undergoes an MRI and CT scan so doctors can use the generated images to map the brain and target structures.

Pictured is a scan of Hric's brain.  Focused ultrasound significantly improved 80-year-old tremors.

The Insightec Exablate Neuro, a focused ultrasound platform, teaches how many beams should be used to perform the treatment, and then neurosurgeons, Dr. Jeff Elias, can do what they call “test shots just to make sure we’re focusing on the bull’s eye.” .

Elias, the UVA Health neurosurgeon who treated Herrick, is a pioneer in treating essential tremors using ultrasound waves. In the year In 2011, he led clinical trials that were critical to obtaining regulatory approval for this procedure in the United States.

“These (test shots) are really low energy, but we want to see if our treatment is exactly where we need it,” he said. This is your chance to see the gun.

Four doses of the 11-second treatment significantly improved Hric’s tremors. The entire process took less than two hours, most of which was spent brainstorming and testing the target.

At first, Herrick had trouble drawing in circles. A focused ultrasound helped color in the lines.

In general, anyone with essential tremor who doesn’t respond to medication is a good candidate for ultrasound therapy, says Dr. Nir Lipsman, a scientist at Sunnybrook Health Sciences Center in Toronto and director of neuromodulation at the Sunnybrook Harquill Center.

People who are claustrophobic or unable to undergo an MRI scan with metal in their bodies are not qualified for focused ultrasound, says Dr. Noah Phillips, professor of psychiatry and human behavior at Brown University’s Alpert School of Medicine. Philip is the lead for mental health research at the VA RR&D Center for Neurorehabilitation and Neurotechnology.

Ideally, the benefits of focused ultrasound are permanent, Lipsman said. “If you can destroy the part of the brain responsible for the tremors, it should be a permanent effect,” he said. “But within a year, some of these patients will relapse or the tremors will recur, and we don’t know why.

Although such regression can also occur with drug therapy—which is why some essential tremor patients turn to focused ultrasound in the first place.

But some patients experienced the benefits five years after undergoing focused ultrasound, according to a 2022 study by Elias.

The potential side effects of focused ultrasound are why the mapping and testing components of the process are so important. If the wrong area is targeted or over-treated, the patient’s balance and stability can be affected long-term.

“The most common side effects we see in patients are temporary numbness or tingling that can sometimes occur in the treated arm or around the lip,” Lipsman said. “It usually goes away with time.”

Other common, but usually temporary, concerns include slight instability in the legs after the procedure. But doctors do not use general anesthesia or take patients to the hospital for this procedure, he said.

Today, focused ultrasound technology is used worldwide at various levels, including clinical trials and approved regulatory use. There are more than 170 clinical uses — including for neurodegenerative disorders and brain tumors, breast, lung, prostate and more — and the field is growing, he said.

“With ultrasound, you can see the effects of the treatment in real time, whereas with radiation, the effects are invisible when the treatment is given,” Cassel said. “And the effects of radiation take weeks or months to show.”

According to a small study by Lipsman and a team of researchers in 2020, use for depression and obsessive-compulsive disorder is on the table. They found that focused ultrasound was safe and effective for improving symptoms in people with major depression and OCD. But more studies are needed.

A limitation of focused ultrasound is that not everyone’s skull is the same, Lipsman said.

“The density of the skull has a significant impact on the ability to travel through ultrasound,” he said. “It’s extremely rare, but there are some patients where, try as we might, we can’t do effective damage to the brain. The skull does not allow the passage of ultrasound. So this is a technical limitation of the technology, something we are actively working on.

Focused ultrasound isn’t available for every disease, but experts say it’s “medicine’s best-kept secret” and they hope it will one day become a standard treatment.

“My belief is that in 10 years,” Cassell said, “focused ultrasound will be a mainstream treatment affecting millions of patients worldwide every year. It will be widely accepted.”




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