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Asymptomatic Transient MRI Signal Changes after Unilateral Deep Brain Stimulation Electrode Implantation for Movement Disorder

Deep brain stimulation (DBS) is an accepted treatment of movement disorders, but little research on tissue changes induced by these devices has been made. We report findings of MRI signal changes in patients with unilateral DBS implantation and no clinically detectable symptoms. A retrospective review of preoperative stereotactic MRI scans for staged placement of second-side DBS was performed in 38 patients to assess the frequency of signal changes along the previously implanted DBS track. No abnormal signal changes were noted in 23 patients (61%). Increased subcortical signals on T2-weighted fast spin echo MRI sequences along the DBS track were noted in 15 patients (39%) and varied from circumferential hyperintensity along the electrode track to significant involvement of the subcortical white matter. The changes were only detected in scans performed within 3 months of DBS implantation (15 of 27 patients). Despite these changes, the patients were totally asymptomatic. The etiology of the changes is unknown but may reflect a transient tissue response to the implantation of the electrode.