Elsevier

NeuroImage: Clinical

Volume 20, 2018, Pages 1266-1273
NeuroImage: Clinical

Structural connectivity–based segmentation of the thalamus and prediction of tremor improvement following thalamic deep brain stimulation of the ventral intermediate nucleus

https://doi.org/10.1016/j.nicl.2018.10.009Get rights and content
Under a Creative Commons license
open access

Highlights

  • Pre-operative connectivity data may improve thalamic DBS targeting for tremor.

  • Tremor control was positively correlated with connectivity-based thalamic segmentation.

  • Stimulation of the SMA/PMC connected thalamic region correlated with tremor control.

Abstract

Objectives

Traditional targeting methods for thalamic deep brain stimulation (DBS) performed to address tremor have predominantly relied on indirect atlas-based methods that focus on the ventral intermediate nucleus despite known variability in thalamic functional anatomy. Improvements in preoperative targeting may help maximize outcomes and reduce thalamic DBS–related complications. In this study, we evaluated the ability of thalamic parcellation with structural connectivity–based segmentation (SCBS) to predict tremor improvement following thalamic DBS.

Methods

In this retrospective analysis of 40 patients with essential tremor, hard segmentation of the thalamus was performed by using probabilistic tractography to assess structural connectivity to 7 cortical targets. The volume of tissue activated (VTA) was modeled in each patient on the basis of the DBS settings. The volume of overlap between the VTA and the 7 thalamic segments was determined and correlated with changes in preoperative and postoperative Fahn-Tolosa-Marin Tremor Rating Scale (TRS) scores by using multivariable linear regression models.

Results

A significant association was observed between greater VTA in the supplementary motor area (SMA) and premotor cortex (PMC) thalamic segment and greater improvement in TRS score when considering both the raw change (P = .001) and percentage change (P = .011). In contrast, no association was observed between change in TRS score and VTA in the primary motor cortex thalamic segment (P ≥ .19).

Conclusions

Our data suggest that greater VTA in the thalamic SMA/PMC segment during thalamic DBS was associated with significant improvement in TRS score in patients with tremor. These findings support the potential role of thalamic SCBS as an independent predictor of tremor improvement in patients who receive thalamic DBS.

Keywords

Brain connectomics
Deep brain stimulation
Diffusion tensor imaging
Essential tremor
Ventral intermediate nucleus
Ventral thalamic nuclei

Abbreviations

DBS
deep brain stimulation
ET
essential tremor
FSL
Functional MRI of the Brain Software Library
HARDI
high angular resolution diffusion-weighted imaging
MRgFUS
magnetic resonance–guided focus ultrasonography
MRI
magnetic resonance imaging
MP-RAGE
magnetization-prepared rapid gradient-echo
PMC
premotor cortex
SCBS
structural connectivity–based segmentation
SMA
supplementary motor area
SRS
stereotactic radiosurgery
TRS
Tremor Rating Scale
VIM
ventral intermediate nucleus
VO
ventralis oralis
VTA
volume of tissue activated

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