TY - JOUR T1 - Segmentation of the Globus Pallidus Internus Using Probabilistic Diffusion Tractography for Deep Brain Stimulation Targeting in Parkinson Disease JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 1127 LP - 1134 DO - 10.3174/ajnr.A5641 VL - 39 IS - 6 AU - E.H. Middlebrooks AU - I.S. Tuna AU - S.S. Grewal AU - L. Almeida AU - M.G. Heckman AU - E.R. Lesser AU - K.D. Foote AU - M.S. Okun AU - V.M. Holanda Y1 - 2018/06/01 UR - http://www.ajnr.org/content/39/6/1127.abstract N2 - BACKGROUND AND PURPOSE: Although globus pallidus internus deep brain stimulation is a widely accepted treatment for Parkinson disease, there is persistent variability in outcomes that is not yet fully understood. In this pilot study, we aimed to investigate the potential role of globus pallidus internus segmentation using probabilistic tractography as a supplement to traditional targeting methods.MATERIALS AND METHODS: Eleven patients undergoing globus pallidus internus deep brain stimulation were included in this retrospective analysis. Using multidirection diffusion-weighted MR imaging, we performed probabilistic tractography at all individual globus pallidus internus voxels. Each globus pallidus internus voxel was then assigned to the 1 ROI with the greatest number of propagated paths. On the basis of deep brain stimulation programming settings, the volume of tissue activated was generated for each patient using a finite element method solution. For each patient, the volume of tissue activated within each of the 10 segmented globus pallidus internus regions was calculated and examined for association with a change in the Unified Parkinson Disease Rating Scale, Part III score before and after treatment.RESULTS: Increasing volume of tissue activated was most strongly correlated with a change in the Unified Parkinson Disease Rating Scale, Part III score for the primary motor region (Spearman r = 0.74, P = .010), followed by the supplementary motor area/premotor cortex (Spearman r = 0.47, P = .15).CONCLUSIONS: In this pilot study, we assessed a novel method of segmentation of the globus pallidus internus based on probabilistic tractography as a supplement to traditional targeting methods. Our results suggest that our method may be an independent predictor of deep brain stimulation outcome, and evaluation of a larger cohort or prospective study is warranted to validate these findings.DBSdeep brain stimulationFGATIRfast gray matter acquisition T1 inversion recoveryGPeglobus pallidus externusGPiglobus pallidus internusM1primary motor cortexMNIMontreal Neurological InstitutePDParkinson diseaseSMA/PMCsupplementary motor area/premotor cortexSNsubstantia nigraSTNsubthalamic nucleusUPDRS IIIUnified Parkinson Disease Rating Scale, Part IIIVTAvolume of tissue activated ER -