Transcranial Focused Ultrasound for Tremor: Next Generation Image-Guided Therapy for the Brain

Dr. Bhavya Shah is a neuroradiologist at UT Southwestern in Dallas, TX and the director of their transcranial-focused ultrasound lab. While in residency at Boston MIT, he studied the radiology applications for nerve regeneration and expanded his scope of practice during his fellowship at Stanford. Dr. Bhavya Shah explains the use of low intensity focused ultrasound (LIFU) and high intensity focused ultrasound (HIFU), particularly in the context of movement disorders including essential tremor and Parkinson’s disease. LIFU is used to identify the appropriate targets in the brain in relation to the disease and may be used to alter how neurons behave. In contrast, high intensity focused ultrasound (HIFU) is utilized to ablate and destroy tissues typically after the localization of the intended treatment area.

Dr. Shah developed a way to identify targets in the brain for treatment with focused ultrasound with the use of four-tract tractography in cadavers. Using this technology, the brain can be thinly sliced into sections which could then be registered off an MRI back to the path using block face photography, allowing the identification of white matter tracts that enter and leave the thalamus. With these tracts identified, neuroradiologists can first stimulate the localized area with LIFU to confirm the location, then ablate using HIFU. The procedure lasts approximately 30-45 minutes as the patient remains awake. Remarkably, patients with essential tremor usually experience benefit immediately following the procedure as patients with Parkinson’s have symptom improvement within days to weeks. After two hours of observation, patients are discharged assuming no side effects. Side effects are uncommon but can include numbness and tingling around the mouth or fingertips as well as muscle weakness.

Beyond its use for movement disorders, the adaptable nature of focused ultrasound technology shows promise for a broad range of applications, particularly for the use of neuropsychiatric conditions. Dr. Shah offers the potential for the use of HIFU as a wearable device that delivers constant stimulation modulated by biofeedback, potentially eliminating the need for MRI for the procedure. Dr. Shah and Dr. Fleming end the discussion with how radiology has evolved over the years and the importance of keeping an open mind working in a multidisciplinary team. They emphasize the gravity of patient engagement and the central goal of medicine and improving the standard of care should always be aimed at benefiting the patient.