MR-Guided Ultrasound for Essential Tremor & Parkinson's Disease
MR-guided focused ultrasound is a new procedure for treating essential tremor and Parkinson's disease. It uses high-intensity focused ultrasound energy, guided by magnetic resonance imaging (MRI), to heat a small targeted area of tissue in the brain, which can reduce the tremor and Parkinson's symptoms.
This procedure can be done while the patient is awake. It is also not a traditional surgery. It happens inside an MRI scanner. The scanner allows the physician to precisely plan, guide, and target a small, specific area of your brain. The scanner also measures, very precisely, the increased temperature in the brain caused by the ultrasound energy. This allows it to precisely treat only the intended target.
Your specialist will deliver ultrasound energy focused on an extremely small target in the brain (the VIM of the thalamus). This energy causes a small burn in the targeted tissue.
Because ultrasound can pass through skin, muscle, fat, and bone without incisions, it is an ideal treatment tool. Ultrasound energy is also non-ionizing, meaning that you are not exposed to potentially dangerous radiation during the procedure.
To start your treatment, you will meet the nurse who will be shaving and cleaning your scalp. This same nurse will be with you throughout the procedure. Comfort measures will be taken as you receive medications for anxiety and pain, and staff will place a urinary catheter in your bladder so you won’t have to go to the bathroom during the procedure.
You will be given numbing medication before a frame is placed on your head to prevent any movement during the procedure. A silicon membrane is then placed on the head to allow for circulation of cool water. This will minimize potential heating near the scalp.
Your heart rate, blood pressure, and blood oxygen levels will be monitored throughout the procedure.
Planning the Treatment
Next, you will lie on the bed that will move you in and out of the MRI device. You will be conscious throughout the procedure so you can communicate with the physicians and nurses, and your specialists will perform the procedure from a computer in the room next to the MRI suite. They will be able to monitor you through the window to the MRI suite as well as with a camera, and you will have a nurse in the MRI suite with you to monitor your vital signs and ensure you are doing well.
To plan the procedure, MRI images will be obtained so that your physician can locate the area to be treated. Small doses of ultrasound energy will be given to help confirm proper target in the brain.
You will be given a Stop button to hold during the procedure, so you can pause the treatment at any time. Cool water from your helmet will circulate around the top of your head to prevent heating from the ultrasound.
During the sonication treatment, your physician will ask you questions and have you perform tasks like writing or tracing lines to confirm the tremor is improving.
Once your physician is confident of the location, the focused ultrasound energy will be increased in the same location to make the improvement in tremor permanent.
The procedure typically lasts a few hours. The time depends on many factors associated with the shape and density of your skull.
After coming out of the MRI machine, we will remove the frame from your head before scanning a few more images to confirm the location of the treatment. After these images, you will be moved to a recovery room. Most patients will be able to go home later that day.
Before discharge, monitoring equipment will be removed and you will receive specific discharge instructions from your doctor. Usually nothing is required, although your doctor may recommend over-the-counter pain relief medication.
Your physician will let you know when you need to return for any follow-up visits. You will also be told whom to contact in case of an emergency after the procedure.
Most patients are able to return to work and normal activities within days.
Benefits of MR-Guided Focused Ultrasound
Patients who have had this procedure have immediately seen their tremor significantly reduced, which has improved their ability to perform daily activities, such as eating, drinking, and writing.
There are many benefits to undergoing a focused ultrasound procedure:
- It's a non-invasive therapy with almost immediate effect on symptoms.
- It offers a quick recovery time, allowing you to return to daily activities within days.
- It has reduced
riskof infection and damage to non-targeted areas of the brain.
- It does not require incisions (cuts), burr holes through the skull, or electrode insertion into the brain.
Risks & Side Effects of MR-Guided Focused Ultrasound
It is possible, but unlikely, that you will not gain any essential tremor relief or improvement in
You may experience the following complications and side effects:
- You may have short periods of dizziness, pain, headaches, or other sensations during treatment, which end shortly after treatment.
- You may have temporary or permanent tingling in your fingers or elsewhere in your body. These sensations are typically mild to moderate and can last as briefly as the length of the procedure or up to several days.
- You may have nausea or vomiting.
- You may have bruising in the area of the IV following the procedure, similar to that experienced after blood draws. Any bruising should heal within a week.
- You may have changes in sensation or strength on the side of the body treated. This is most common several days after the treatment and typically improves after several weeks.
There is also a chance that your tremor may return some months or years after treatment. You should discuss any questions concerning risks and/or complications of the procedure with your doctor.
Patient Requirements for MR-Guided Focused Ultrasound
You must have a confirmed diagnosis of essential tremor to be referred for an MR-guided focused ultrasound. Your doctors will also want to be sure that you have tried at least two medications and found that they do not help you and/or have undesirable side effects.
In addition, you must be at least 22 years old. Since the procedure is done in an MRI scanner, there is a physical weight limit, generally in the range of 350 pounds.
You may not be able to have treatment if you have the following conditions:
- Allergic to the contrast dye used during MRI imaging
- Not generally healthy enough to go through the treatment and lie still in the same position for about three hours
- Certain heart conditions
- Extensive scarring on your scalp
- Skull tumors
- Severe hematological, neurological, or other uncontrolled disease
- Metallic implants, including:
- spine or bone fixation devices,
- total joints,
- metal clips, or
Any metallic implants must be non-magnetic so you won’t be injured from the MRI’s strong magnetic field.
Your doctor can discuss all these conditions with you to determine if you are able to have the procedure.
To be evaluated for the MR-guided focused ultrasound treatment for essential tremor, make an appointment with one of our neurologists. At your appointment they will determine if they can refer you for the procedure.