Magnetic Resonance-Guided Focused Ultrasound Bilateral Capsulotomy for the Treatment of Refractory Bipolar Depression

This study is a prospective, single arm and nonrandomized phase l study. Participants will: * Undergo MRgFUS capsulotomy targeting the anterior limb of the internal capsule. * Be assessed before and after treatment for adverse events, symptom changes, and quality of life. * Complete a battery of clinical rating scales including the Hamilton Depression Rating Scale (HAMD), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Young Mania Rating Scale (YMRS), Yale-Brown Obsessive Compulsive Scale (YBOCS), and the Columbia-Suicide Severity Rating Scale (C-SSRS), along with the Quality of Life Enjoyment and Satisfaction Questionnaire (QLESQ). A total of 10 participants, all patients at Sunnybrook Hospital, are expected to enroll in the study. Each participant will be involved for approximately 26 months, including a 2-month pre-treatment period and 24 months of follow-up. The full study duration is estimated at 3 years, with primary results anticipated within 2 to 3 years.