title: Intraoperative X-ray detection and MRI-based quantification of brain shift effects subsequent to implantation of the first electrode in bilateral implantation of deep brain stimulation electrodes.
abstract: OBJECTIVE
  After implantation of the first electrode in bilateral deep brain stimulation (DBS) lead implantation, brain shift effects in the target region and along the implantation trajectory of the second electrode are quantified with intraoperative magnetic resonance imaging (MRI). We investigated intraoperative X-ray imaging for its feasibility in indirect detection of brain shift.
  
  
  METHODS
  In 25 patients who underwent bilateral DBS lead implantation, X-ray and MRI were performed before and after implantation of the first electrode. Two parameters of brain shift were assessed with nonrigid free-form deformation field analysis of the MRI data: global brain shift along the anterior and posterior commissure (AC-PC) line and specific brain shift along the implantation trajectory of the second electrode. Pre- and intraoperative X-ray images were geometrically and intensity corrected for detection of significant signal changes through intracranial air accumulation during implantation of the first electrode.
  
  
  RESULTS
  After implantation of the first electrode, brain shift greater than 1 mm (maximum 1.3 mm) was observed at the AC and brain shift greater than 2 mm (maximum 2.5 mm) was observed along the planned implantation trajectory of the second electrode. In 1 patient, the implantation trajectory of the second electrode went through a sulcus after cortical brain shift. In 9 patients, intracranial air volume between 0.1 and 38.5 ml was observed with MRI after implantation of the first electrode. Significant X-ray absorption changes were induced by an intracranial air volume of greater than 8 ml.
  
  
  CONCLUSIONS
  In bilateral DBS implantation, brain shift effects can cause misallocation of the second electrode with the risk of adverse or no stimulation effects as well as unnecessary cortical damage. A lack of X-ray signal changes caused by intracranial air invasion during DBS lead implantation indicates a lack of clinically relevant brain shift.
authors.affiliation: Department of Stereotactic and Functional Neurosurgery, University of Cologne, Cologne, Germany. stefan.hunsche@uk-koeln.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Hunsche
authors.forename: Dieter
authors.initials: D
authors.lastname: Sauner
authors.forename: Mohammad
authors.initials: M
authors.lastname: Maarouf
authors.forename: Jörg
authors.initials: J
authors.lastname: Poggenborg
authors.forename: Klaus
authors.initials: K
authors.lastname: Lackner
authors.forename: Volker
authors.initials: V
authors.lastname: Sturm
authors.forename: Harald
authors.initials: H
authors.lastname: Treuer
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology; D046690:Deep Brain Stimulation / Q000295:instrumentation / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D011859:Radiography; D012189:Retrospective Studies; D014965:X-Rays