Implementing MRI-Guided Focused Ultrasound: Challenges and Opportunities

Steven Lewis, MD

In the United States, Parkinson disease (PD) remains the second-most common neurodegenerative disease after Alzheimer disease (AD), with nearly 90,000 people diagnosed each year. The combined direct and indirect cost of PD, including treatment, social security payments and lost income, is estimated to be nearly $52 billion per year in the U.S. alone. Medications alone cost an average of $2500 a year and therapeutic surgery can cost up to $100,000.

Focused ultrasound is emerging as a promising treatment for PD, particularly for patients with tremors. It is a non-invasive procedure that uses sound waves to target and destroy specific areas of the brain involved with tremor control, like the thalamus. Over the years, more institutions, including Lehigh Valley Health Network (LVHN), have begun to adopt this therapeutic approach, allowing for greater treatment capabilities for patients with PD and essential tremor.

Behrang Saminejad, MD

Steven Lewis, MD, physician in chief of Lehigh Valley Fleming Neuroscience Institute and secretary-general of the World Federation of Neurology, was a part of the recent implementation of focused ultrasound at LVHN. Him, along with his other colleague, Behrang Saminejad, MD, a movement disorder doctor at Fleming Neuroscience Institute, sat down to provide insight on the novelty behind focused ultrasound, and the necessary steps for proper implementation. The duo provided commentary on the mechanism behind this approach, how it differs from other PD treatment options, and the ways to further optimize it going forward. In addition, Saminejad spoke on the safety of focused ultrasound and the pre-planning screening process to ensure patient success.

What goes into implementing focused ultrasound for essential tremor and PD? From an institutional perspective, how do you implement this type of tool successfully and efficiently?

Steven Lewis, MD: Putting together such a complex program requires an expert clinical team consisting of fellowship-trained movement disorder neurologists and a functional neurosurgeon, as well as a dedicated nurse navigator to seamlessly help guide patients through the process.

From an administrative perspective, it requires education to senior leadership, and their buy-in, as to the importance of the program. At LVHN, we were benefitted by having senior leadership who recognized the importance of supporting this program to benefit the many patients in our massive geographical region in the network (and beyond) for whom this therapeutic option is a consideration. Implementing this program also requires an excellent working relationship with the radiology department and its leadership, given that the focused ultrasound technology "lives" in an MRI suite and the installation of the technology, and each focused ultrasound procedure, competes with diagnostic MRI time.

Why is this such a promising approach for these patient groups? Discuss more about the mechanism behind focused ultrasound and what it brings to the patient community

Behrang Saminejad, MD: Prior to 2016 when high-frequency MRI guided focused ultrasound was FDA approved, the main way to treat refractory essential tremor (refractory essential tremor is a tremor that is not responding to the optimal dose of medication either because the patient cannot tolerate higher doses or the medication is ineffective in the treatment of the tremor) Deep Brain stimulation surgery (DBS) was the other main way to treat refractory tremors. Deep and simulation surgery involves placement of the lead into the brain and the area that could control the tremor called the ventral intermediate nucleus (VIM) of the thalamus; however, the procedure itself is invasive and also requires programming over time. Because of the neurosurgical procedure, that carries a higher risk. Patients who are older or had other medical comorbidities were usually excluded from deep brain stimulation surgery.

Since the approval of MRI guided focused ultrasound in 2016 the number of patients that have been able to be offered this therapy has increased. There are multiple reasons for this. First, this procedure is incision less so the overall risk of MRI guided focused ultrasound is much less than deep brain stimulation surgery. This by itself increases the number of candidates for FUS significantly. It can provide significant improvement in the tremor immediately or within a couple of days after the procedure and in most cases, there is minimal to no recovery time.Also patients who are older with a more complicated medical history are not excluded from focused ultrasound surgery while previously they would be excluded from consideration for deep brain stimulation surgery.

High-frequency MRI guided focused ultrasound especially when established in an area like Lehigh Valley can provide options for patients who are debilitated with a significant tremor who previously would have had no other options other than traveling for this procedure.

Are there any safety complications with this approach? And if so, how do we best manage or prevent them from happening?

Behring Saminejad, MD: All of the patients who are evaluated in our Medical Center for consideration for focused ultrasound surgery are seen by movement disorder specialists. Movement disorder specialists are neurologists with extra training focusing on essential tremor, and Parkinson's is another movement disorder.

This approach enables the movement disorder specialist to ensure the patient has been tried on medication and also is a reasonable candidate before they see our functional neurosurgeon. If the movement disorder specialist notices any speech changes or balance changes before the operation, these are brought up to collaborative rounds after the patient is seen by our neurosurgeon. Discussions are then had about the candidacy of the patient. MRI guided focused ultrasound can worsen balance and speech so patients who at baseline have balance challenges, speech challenges, or swallowing difficulty may need closer monitoring, or in some cases they may not be deemed candidates for high-frequency MRI guided ultrasound.

Going forward, are there ways in which the clinical community has thought about optimizing focused ultrasound? Whether that be for these patient populations or others.

Behring Saminejad, MD: From a community perspective, a reasonable approach is educating patients through support groups for essential tremor, local physician’s office, information luncheons or webinars to discuss essential tremor, and also would be a good candidate for high-frequency MRI guided focused ultrasound.

Education plays a very important role in expanding focused ultrasound and this always starts with community events to inform patients with essential tremor who have refractory tremors about the possible treatment options.