title: Positional brain deformation visualized with magnetic resonance morphometry.
abstract: OBJECTIVE
  To assess and visualize gravitational effects on brain morphology and the position of the brain within the skull by magnetic resonance (MR) morphometry in order to identify confounding effects and possible sources of error for accurate planning of neurosurgical interventions.
  
  
  METHODS
  Three-dimensional MR imaging data sets of 13 healthy adults were acquired in different positions in the scanner. With a morphometric approach, data sets were evaluated by deformation field analysis and the brain boundary shift integral. Distortions of the brain were assessed comparing right versus left and prone versus supine positioning, respectively.
  
  
  RESULTS
  Two effects could be differentiated: 1) greatest brain deformation of up to 1.7 mm predominantly located around central brain structures in the lateral direction and a less pronounced change after position changes in posterior-anterior direction, and 2) the brain boundary shift integral depicted position-dependent brain shift relative to the inner skull.
  
  
  CONCLUSIONS
  Position-dependent effects on brain structure may undermine the accuracy of neuronavigational and other neurosurgical procedures. Furthermore, in longitudinal MR volumetric studies, gravitational effects should be kept in mind and the scanning position should be rigidly controlled for.
authors.affiliation: Department of Neurology, Friedrich-Schiller-University, Jena, Germany.
authors.forename: Sonja
authors.initials: S
authors.lastname: Schnaudigel
authors.forename: Christoph
authors.initials: C
authors.lastname: Preul
authors.forename: Tarik
authors.initials: T
authors.lastname: Ugur
authors.forename: Hans Joachim
authors.initials: HJ
authors.lastname: Mentzel
authors.forename: Otto W
authors.initials: OW
authors.lastname: Witte
authors.forename: Marc
authors.initials: M
authors.lastname: Tittgemeyer
authors.forename: Georg
authors.initials: G
authors.lastname: Hagemann
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000473:pathology*; D001927:Brain Diseases / Q000473:pathology*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D013238:Stereotaxic Techniques; D055815:Young Adult