title: The role of the pallidothalamic fibre tracts in deep brain stimulation for dystonia: A diffusion MRI tractography study.
abstract: Deep Brain Stimulation (DBS) of the Globus pallidus internus (GPi) is gold standard treatment in medically refractory dystonia. Recent evidence indicates that stimulation effects are also due to axonal modulation and affection of a fibre network. For the GPi, the pallidothalamic tracts are known to be the major motor efferent pathways. The aim of this study is to explore the anatomic vicinity of these tracts and DBS electrodes in dystonia applying diffusion tractography.
  
  
  
  Diffusion MRI was acquired in ten patients presenting for DBS for dystonia. We applied both a conventionally used probabilistic tractography algorithm (FSL) as well as a probabilistic streamline tracking approach, based on constrained spherical deconvolution and particle filtering with anatomic priors, to the datasets. DBS electrodes were coregistered to the diffusion datasets.
  
  
  
  We were able to delineate the pallidothalamic tracts in all patients. Using the streamline approach, we were able to distinguish between the two sub-components of the tracts, the ansa lenticularis and the fasciculus lenticularis. Clinically efficient DBS electrodes displayed a close anatomic vicinity pathway of the pallidothalamic tracts, and their course was consistent with previous tracer labelling studies. Although we present only anatomic data, we interpret these findings as evidence of the possible involvement of fibre tracts to the clinical effect in DBS. Electrophysiological intraoperative recordings would be needed to complement our findings. In the future, a clear and individual delineation of the pallidothalamic tracts could optimize the stereotactic process of optimal electrode localization. Hum Brain Mapp 38:1224-1232, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Neurology, Klinikum Grosshadern, University of Munich, Germany.
authors.forename: Verena Eveline
authors.initials: VE
authors.lastname: Rozanski
authors.affiliation: Department of Engineering, INESC TEC and Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, Porto, 4200-465, Portugal.
authors.forename: Nadia Moreira
authors.initials: NM
authors.lastname: da Silva
authors.affiliation: Department of Neurology, Klinikum Grosshadern, University of Munich, Germany.
authors.forename: Seyed-Ahmad
authors.initials: SA
authors.lastname: Ahmadi
authors.affiliation: Department of Neurosurgery, Klinikum Grosshadern, University of Munich, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Mehrkens
authors.affiliation: Department of Engineering, INESC TEC and Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, Porto, 4200-465, Portugal.
authors.forename: Joao
authors.initials: J
authors.lastname: da Silva Cunha
authors.affiliation: Department of Computer Science, Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science department, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Houde
authors.affiliation: Department of Neurology, Klinikum Grosshadern, University of Munich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Vollmar
authors.affiliation: Department of Neurology, Klinikum Grosshadern, University of Munich, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Bötzel
authors.affiliation: Department of Computer Science, Sherbrooke Connectivity Imaging Lab (SCIL), Computer Science department, Université de Sherbrooke, Sherbrooke, Québec, Canada.
authors.forename: Maxime
authors.initials: M
authors.lastname: Descoteaux
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D001931:Brain Mapping; D046690:Deep Brain Stimulation / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004421:Dystonia / Q000000981:diagnostic imaging / Q000628:therapy*; D005260:Female; D005917:Globus Pallidus / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D013788:Thalamus / Q000000981:diagnostic imaging / Q000502:physiology*
keywords: deep brain stimulation; diffusion MRI; movement disorders; neural networks