title: Visualisation of the zona incerta for deep brain stimulation at 3.0 Tesla.
abstract: OBJECTIVE
  Deep-brain stimulation (DBS) of the zona incerta (ZI) has shown promising results for medication-refractory neurological disorders including Parkinson's disease (PD) and essential tremor (ET). The success of the intervention is indispensably dependent on the reliable visualisation of the ZI.                         The aim of the study was to evaluate different promising new magnetic resonance imaging (MRI) methods at 3.0 Tesla for pre-stereotactic visualisation of the ZI using a standard installation the protocol.
  
  
  METHODS
  MRI of nine healthy volunteers was acquired (T1-MPRAGE, T2-FLAIR, T2*-FLASH2D, T2-SPACE and susceptibility-weighted imaging (SWI). Image quality and visualisation of the ZI for each sequence were analysed independently by two neuroradiologists using a 6-point scale. For T2*-FLASH2D the axial, coronal and sagittal planes were compared. The delineation of the ZI versus the internal capsule, the subthalamic nucleus and the pallidofugal fibres was evaluated in all sequences and compared to T2-FLAIR using a paired t-test. Inter-rater reliability, contrast-to-noise ratios (CNR), and signal-to-noise ratios (SNR) for the ZI were computed. For illustration, coronal T2*-FLASH2D images were co-registered with the corresponding section schema of the Schaltenbrand-Wahren stereotactic atlas.
  
  
  RESULTS
  Only the rostral part of the ZI (rZI) could be identified. The rZI was best and reliably visualised in T2*-FLASH2D (particularly coronal orientation; p < 0.05). No major artifacts in the rZI were observed in any of the sequences. SWI, T2-SPACE, and T2*-FLASH imaging offered significant higher CNR values for the rZI compared to T2-FLAIR imaging using standard parameters. The co-registration of the coronal T2*-FLASH2D images projected the ZI clearly into the boundaries of the anatomical sections.
  
  
  CONCLUSIONS
  The delineation of the rZI is best possible in T2*-FLASH2D (particularly coronal view) using a standard installation protocol at 3.0 T. The caudal ZI could not be discerned in any of the sequences.
authors.affiliation: Medical Faculty Mannheim, Department of Neuroradiology, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany.
authors.forename: H U
authors.initials: HU
authors.lastname: Kerl
authors.forename: L
authors.initials: L
authors.lastname: Gerigk
authors.forename: S
authors.initials: S
authors.lastname: Huck
authors.forename: M
authors.initials: M
authors.lastname: Al-Zghloul
authors.forename: C
authors.initials: C
authors.lastname: Groden
authors.forename: I S
authors.initials: IS
authors.lastname: Nölte
mesh_terms: D000328:Adult; D046690:Deep Brain Stimulation / Q000379:methods*; D006801:Humans; D053783:Magnetic Resonance Imaging, Interventional / Q000379:methods*; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020530:Subthalamus / Q000033:anatomy & histology* / Q000601:surgery