Location is Everything

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Better brain treatment targeting improves outcomes for individuals with essential tremor.
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Improving clinical outcomes for patients with essential tremor requires specific targeting of areas in the brain, which can be aided by precise image-guided techniques.

Much like how location can directly affect the price of a home, targeting specific areas of the brain can have an effect on the success of certain brain treatments. However, delivering treatment to the exact location in the brain that will provide the most benefit remains a daunting challenge. 

To help address this challenge, researchers at Krembil Research Institute explored an emerging technique, known as magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy, for the treatment of essential tremor—a debilitating brain disorder that causes uncontrollable shaking. This study was done in collaboration with Sunnybrook Health Sciences Centre.

The approach uses high-resolution MR imaging to precisely target a tiny area of the brain called the thalamus. This brain region is responsible for relaying important motor and sensory signals in the brain and is a key target for essential tremor therapies.

By examining patients who underwent MRgFUS thalamotomy, the study found that clinical outcomes were largely dependent on the specific regions that were targeted within the thalamus. Just as in the real estate market, location seems to play a critical role in the clinical outcomes of these patients.

The researchers further mapped out areas that were associated with the best treatment responses, as well as those linked with an increased risk of detrimental side effects. Using standard assessment methods, the research team found that use of MRgFUS led to a ~42% improvement in tremor scores three months after treatment. The study also suggested that when smaller areas of the brain were targeted, side effects were less severe.

“These findings are a significant step toward improving the effectiveness of MRgFUS thalamotomy and will enable us to refine areas to target therapy so that we can improve outcomes and reduce adverse effects for patients,” says Dr. Andres M. Lozano, a neurosurgeon at Toronto Western Hospital and Krembil Senior Scientist.

This work was supported by Insightec and the Toronto General & Western Hospital Foundation. Dr. Lozano holds a Tier 1 Canada Research Chair in Neuroscience.

Boutet A, Ranjan M, Zhong J, Germann J, Xu D, Schwartz ML, Lipsman N, Hynynen K, Devenyi GA, Chakravarty M, Hlasny E, Llinas M, Lozano CS, Elias GJB, Chan J, Coblentz A, Fasano A, Kucharczyk W, Hodaie M, Lozano AM. Focused ultrasound thalamotomy location determines clinical benefits in patients with essential tremor. Brain. 2018 Dec 1. doi: 10.1093/brain/awy278.

Dr. Andres Lozano, Senior Scientist, Krembil Research Institute. Photo courtesy of the Globe and Mail.