title: Clinical evaluation of a model-updated image-guidance approach to brain shift compensation: experience in 16 cases.
abstract: OBJECTIVE
  Brain shift during neurosurgical procedures must be corrected for in order to reestablish accurate alignment for successful image-guided tumor resection. Sparse-data-driven biomechanical models that predict physiological brain shift by accounting for typical deformation-inducing events such as cerebrospinal fluid drainage, hyperosmotic drugs, swelling, retraction, resection, and tumor cavity collapse are an inexpensive solution. This study evaluated the robustness and accuracy of a biomechanical model-based brain shift correction system to assist with tumor resection surgery in 16 clinical cases.
  
  
  METHODS
  Preoperative computation involved the generation of a patient-specific finite element model of the brain and creation of an atlas of brain deformation solutions calculated using a distribution of boundary and deformation-inducing forcing conditions (e.g., sag, tissue contraction, and tissue swelling). The optimum brain shift solution was determined using an inverse problem approach which linearly combines solutions from the atlas to match the cortical surface deformation data collected intraoperatively. The computed deformations were then used to update the preoperative images for all 16 patients.
  
  
  RESULTS
  The mean brain shift measured ranged on average from 2.5 to 21.3 mm, and the biomechanical model-based correction system managed to account for the bulk of the brain shift, producing a mean corrected error ranging on average from 0.7 to 4.0 mm.
  
  
  CONCLUSIONS
  Biomechanical models are an inexpensive means to assist intervention via correction for brain deformations that can compromise surgical navigation systems. To our knowledge, this study represents the most comprehensive clinical evaluation of a deformation correction pipeline for image-guided neurosurgery.
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Box 351631, Station B, Nashville, TN, 37235, USA.|Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.|Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Miga
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Box 351631, Station B, Nashville, TN, 37235, USA.
authors.forename: Kay
authors.initials: K
authors.lastname: Sun
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Box 351631, Station B, Nashville, TN, 37235, USA.
authors.forename: Ishita
authors.initials: I
authors.lastname: Chen
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Box 351631, Station B, Nashville, TN, 37235, USA. logan.clements@vanderbilt.edu.
authors.forename: Logan W
authors.initials: LW
authors.lastname: Clements
authors.affiliation: Department of Biomedical Engineering, Vanderbilt University, Box 351631, Station B, Nashville, TN, 37235, USA.
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Pheiffer
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, 10065, USA.
authors.forename: Amber L
authors.initials: AL
authors.lastname: Simpson
authors.affiliation: Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, 37232, USA.
authors.forename: Reid C
authors.initials: RC
authors.lastname: Thompson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging* / Q000601:surgery; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D016343:Monitoring, Intraoperative / Q000379:methods*; D009038:Motion; D019635:Neurosurgical Procedures / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D055815:Young Adult
keywords: Biomechanical model; Brain shift; Finite element; Image-guided surgery; Inverse model; Registration