title: Estimation of brain deformation for volumetric image updating in protoporphyrin IX fluorescence-guided resection.
abstract: BACKGROUND
  Fluorescence-guided resection (FGR) of brain tumors is an intuitive, practical and emerging technology for visually delineating neoplastic tissue exposed intraoperatively. Image guidance is the standard technique for producing 3-dimensional spatially coregistered information for surgical decision making. Both technologies together are synergistic: the former detects surface fluorescence as a biomarker of the current surgical margin while the latter shows coregistered volumetric neuroanatomy but can be degraded by intraoperative brain shift. We present the implementation of deformation modeling for brain shift compensation in protoporphyrin IX FGR, integrating these two sources of information for maximum surgical benefit.
  
  
  METHODS
  Two patients underwent FGR coregistered with conventional image guidance. Histopathological analysis, intraoperative fluorescence and image space coordinates were recorded for biopsy specimens acquired during surgery. A biomechanical brain deformation model driven by intraoperative ultrasound data was used to generate updated MR images.
  
  
  RESULTS
  Combined use of fluorescence signatures and updated MR image information showed substantially improved accuracy compared to fluorescence or the original (i.e., nonupdated) MR images, detecting only true positives and true negatives, and no instances of false positives or false negatives.
  
  
  CONCLUSIONS
  Implementation of brain deformation modeling in FGR shows promise for increasing the accuracy of neurosurgical guidance in the delineation and resection of brain tumors.
authors.affiliation: Dartmouth Medical School, Dartmouth College, Hanover, N.H., USA.
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Valdés
authors.forename: Xiaoyao
authors.initials: X
authors.lastname: Fan
authors.forename: Songbai
authors.initials: S
authors.lastname: Ji
authors.forename: Brent T
authors.initials: BT
authors.lastname: Harris
authors.forename: Keith D
authors.initials: KD
authors.lastname: Paulsen
authors.forename: David W
authors.initials: DW
authors.lastname: Roberts
mesh_terms: D000368:Aged; D001921:Brain / Q000601:surgery*; D001932:Brain Neoplasms / Q000601:surgery*; D005909:Glioblastoma / Q000601:surgery; D018316:Gliosarcoma / Q000601:surgery; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007091:Image Processing, Computer-Assisted; D007432:Intraoperative Period; D008279:Magnetic Resonance Imaging; D008856:Microscopy, Fluorescence; D008959:Models, Neurological; D016343:Monitoring, Intraoperative / Q000379:methods; D019635:Neurosurgical Procedures / Q000379:methods*; D011524:Protoporphyrins; D025321:Surgery, Computer-Assisted / Q000379:methods*
chemical_list: D011524:Protoporphyrins; C028025:protoporphyrin IX