Acute versus chronic ventral lateral thalamus intrinsic connectivity after MR-guided focused ultrasound thalamotomy for essential tremor

Motivation: To address the gap in understanding the longitudinal impact of MR-guided focused ultrasound (MRgFUS)-thalamotomy on motor network connectivity in essential tremor (ET). Goal(s): To elucidate the changes in functional connectivity within the motor network following MRgFUS thalamotomy, distinguishing between acute and chronic phases. Approach: Connectivity changes in the ventrolateral (VL) thalamus of 19 ET patients were tracked using fMRI at three intervals—pre-operation, one day, and three months post-MRgFUS. Results: Initially, both VLs showed diminished connectivity with sensorimotor regions. By three months, left VL had enhanced connections with associative and visual areas, while right VL demonstrated sustained reduced sensorimotor connectivity, reflecting hemisphere-specific functional reorganization. Impact: Mapping evolving connectivity of ventrolateral thalamus after MR-guided focused ultrasound (MRgFUS) thalamotomy enables tailored essential tremor treatments, potentially yielding better outcomes and informing treatment parameters, while also providing putative biomarkers for treatment efficacy and broader insights into neurological network management.