title: Imaging of Anterior Nucleus of Thalamus Using 1.5T MRI for Deep Brain Stimulation Targeting in Refractory Epilepsy.
abstract: BACKGROUND
  Deep brain stimulation (DBS) of the anterior nucleus of thalamus (ANT) is an evolving treatment option in refractory focal epilepsy. Due to poor visualization of ANT in traditional MRI sequences used for movement disorder surgery, targeting of ANT is mainly based on stereotactic atlas information. Sophisticated 3T MRI methods enable visualization of ANT, but 1.5T MRI is still preferred or more readily available in a large number of centers performing DBS.
  
  
  OBJECTIVE
  In the present study, we sought to determine whether ANT could be adequately visualized at 1.5T MRI pre- and postoperatively using imaging techniques similar to the ones visualizing ANT in 3T MRI. A total of 15 MRI examinations with short tau inversion recovery (STIR) and T1-weighted magnetization prepared gradient echo (MPRAGE) images were performed to visualize ANT in nonepileptic subjects (n = 2), patients with vagus nerve stimulator (VNS) (n = 3), stereotactic MRI (n = 3), patients with ANT-DBS (n = 7).
  
  
  RESULTS
  ANT was distinctly visualized in STIR and T1-weighted MPRAGE images in patients without implanted stimulators, with Leksell stereotactic frame and with fully implanted VNS. Postoperative 1.5T MRI was able to demonstrate some of the anatomical landmarks around ANT enabling assessment of electrode contact locations.
  
  
  CONCLUSIONS
  The visualization of ANT is possible in preoperative 1.5T MRI enabling direct targeting of ANT all examined situations. The use of indirect targeting and its inherent potential for lead misplacement due to anatomical variation may be avoided using these MRI methods. Furthermore, postoperative MRI with STIR and T1-weighted MPRAGE images enable detailed postoperative assessment of contact locations.
authors.affiliation: Department of Neurosurgery, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Elena
authors.initials: E
authors.lastname: Jiltsova
authors.affiliation: Department of Neurosciences and Rehabilitation, Tampere University Hospital, Tampere, Finland.
authors.forename: Timo
authors.initials: T
authors.lastname: Möttönen
authors.affiliation: Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden.
authors.forename: Markus
authors.initials: M
authors.lastname: Fahlström
authors.affiliation: Department of Neurosciences and Rehabilitation, Tampere University Hospital, Tampere, Finland.
authors.forename: Joonas
authors.initials: J
authors.lastname: Haapasalo
authors.affiliation: Department of Neurosciences and Rehabilitation, Tampere University Hospital, Tampere, Finland.
authors.forename: Timo
authors.initials: T
authors.lastname: Tähtinen
authors.affiliation: Department of Neurosciences and Rehabilitation, Tampere University Hospital, Tampere, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Peltola
authors.affiliation: Department of Neurosciences and Rehabilitation, Tampere University Hospital, Tampere, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Öhman
authors.affiliation: Department of Surgical Sciences, Radiology, Uppsala University, Uppsala, Sweden.
authors.forename: Elna-Marie
authors.initials: EM
authors.lastname: Larsson
authors.affiliation: Medical Imaging Centre, Tampere University Hospital, Tampere, Finland.
authors.forename: Tommi
authors.initials: T
authors.lastname: Kiekara
authors.affiliation: Department of Neurosurgery, Uppsala University Hospital, Uppsala, Sweden.|Department of Neurosciences and Rehabilitation, Tampere University Hospital, Tampere, Finland.
authors.forename: Kai
authors.initials: K
authors.lastname: Lehtimäki
mesh_terms: D020643:Anterior Thalamic Nuclei / Q000000981:diagnostic imaging* / Q000502:physiology*; D046690:Deep Brain Stimulation / Q000379:methods*; D000069279:Drug Resistant Epilepsy / Q000000981:diagnostic imaging / Q000628:therapy*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D014057:Tomography, X-Ray Computed
keywords: Deep brain stimulation; MRI; epilepsy; implant; stimulator