Patient-specific targeting of VIM using THOMAS segmentation predicts post-MRgFUS side effects: a retrospective evaluation

Motivation: Precise and personalized targeting for MR-guided focused ultrasound (MRgFUS) is desired to ensure treatment efficacy and avoid side effect. Goal(s): To assess THalamus Optimized Multi Atlas Segmentation (THOMAS) on white-matter nulled MRI for targeting of the ventral intermediate (VIM) thalamic nucleus in MRgFUS for tremor patients. Approach: We retrospectively assessed the relationships of standard indirectly targeted coordinates, post-FUS lesions, and THOMAS segmentation with post-FUS side effects and tremor scores in patients who underwent VIM-MRgFUS. Results: In patients who exhibited side effects, FUS lesions had a smaller overlap with THOMAS-based VIM segmentation and were located more inferiorly. Impact: THOMAS is a novel automated thalamic segmentation tool which may aide in the targeting of the VIM nucleus, potentially reducing side effects and improving treatment outcomes in MRgFUS for patients with tremor.