Grant: Project Grant

Deep brain stimulation (DBS) is increasingly used to treat the behavioural symptoms of Parkinson's Disease and many other conditions, such as unmanageable depression. As the name suggests, DBS involves implanting metal electrodes into targets deep within the brain. A small device is also implanted underneath the skin, usually in the upper chest, to send electrical signals to the brain to treat the patient's symptoms. DBS is a very useful treatment, but the underlying mechanism of action is not well understood and requires further research. DBS patients also require monitoring in both the short and long term to check for possible side effects when the electrodes are implanted, and to make sure that the electrodes continue to work well over time. DBS patients may also go on to develop other diseases that require assessment by medical imaging methods. In all of these circumstances it is highly desirable for DBS patients to be assessed with magnetic resonance imaging (MRI). From a research context, MRI is a very versatile method that enables multiple aspects of brain structure and function to be assessed in one examination to unravel DBS mechanisms. MRI is also the main clinical method of imaging diseases and injury of the brain. However, MRI of DBS patients is limited by safety concerns that brain tissue near the implant could be permanently damaged from heating during the imaging procedure. This grant proposal investigates a promising MRI method called "parallel radiofrequency transmission (PTX)" for its ability to suppress heating near implanted DBS electrodes. PTX conditions that minimize heating will be determined, and methods will be demonstrated for optimized, safe PTX MRI of patients who have received DBS devices for depression. Ultimately, this work will lay the groundwork for conducting safe research MRI studies of DBS mechanisms, and safe and improved clinical MRI of DBS patients in the longer term.