title: Automated alignment of perioperative MRI scans: A technical note and application in pediatric epilepsy surgery.
abstract: Conventional image registration utilizing brain voxel information may be erroneous in a neurosurgical setting due to pathology and surgery-related anatomical distortions. We report a novel application of an automated image registration procedure based on skull segmentation for magnetic resonance imaging (MRI) scans acquired before, during and after surgery (i.e., perioperative). The procedure was implemented to assist analysis of intraoperative brain shift in 11 pediatric epilepsy surgery cases, each of whom had up to five consecutive perioperative MRI scans. The procedure consisted of the following steps: (1) Skull segmentation using tissue classification tools. (2) Estimation of rigid body transformation between image pairs using registration driven by the skull segmentation. (3) Composition of transformations to provide transformations between each scan and a common space. The procedure was validated using locations of three types of reference structural landmarks: the skull pin sites, the eye positions, and the scalp skin surface, detected using the peak intensity gradient. The mean target registration error (TRE) scores by skull pin sites and scalp skin rendering were around 1 mm and <1 mm, respectively. Validation by eye position demonstrated >1 mm TRE scores, suggesting it is not a reliable reference landmark in surgical scenarios. Comparable registration accuracy was achieved between opened and closed skull scan pairs and closed and closed skull scan pairs. Our procedure offers a reliable registration framework for processing intrasubject time series perioperative MRI data, with potential of improving intraoperative MRI-based image guidance in neurosurgical practice. Hum Brain Mapp 37:3530-3543, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Developmental Imaging, Clinical Sciences, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.|Stroke and Aging Research Group, Monash University, Melbourne, Victoria, Australia.
authors.forename: Richard
authors.initials: R
authors.lastname: Beare
authors.affiliation: Developmental Imaging, Clinical Sciences, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.|Department of Neurosurgery, Royal Children's Hospital, Melbourne, Victoria, Australia.|Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.|Neuroscience Research, Clinical Sciences, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.
authors.forename: Joseph Yuan-Mou
authors.initials: JY
authors.lastname: Yang
authors.affiliation: Department of Neurosurgery, Royal Children's Hospital, Melbourne, Victoria, Australia.
authors.forename: Wirginia J
authors.initials: WJ
authors.lastname: Maixner
authors.affiliation: Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.|Department of Neurology, Royal Children's Hospital, Melbourne, Victoria, Australia.
authors.forename: A Simon
authors.initials: AS
authors.lastname: Harvey
authors.affiliation: Developmental Imaging, Clinical Sciences, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kean
authors.affiliation: Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.|Child Neuropsychology, Clinical Sciences, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.|Department of Psychology, Royal Children's Hospital, Melbourne, Victoria, Australia.|School of Psychological Sciences, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Vicki A
authors.initials: VA
authors.lastname: Anderson
authors.affiliation: Developmental Imaging, Clinical Sciences, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia.|Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Marc L
authors.initials: ML
authors.lastname: Seal
mesh_terms: D000293:Adolescent; D001921:Brain / Q000000981:diagnostic imaging / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D000069279:Drug Resistant Epilepsy / Q000000981:diagnostic imaging* / Q000601:surgery; D004828:Epilepsies, Partial / Q000000981:diagnostic imaging* / Q000601:surgery; D005123:Eye / Q000000981:diagnostic imaging; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D019635:Neurosurgical Procedures / Q000295:instrumentation; D010363:Pattern Recognition, Automated / Q000379:methods*; D011184:Postoperative Period; D011300:Preoperative Care; D011446:Prospective Studies; D015203:Reproducibility of Results; D012535:Scalp / Q000000981:diagnostic imaging / Q000601:surgery; D012886:Skull / Q000000981:diagnostic imaging / Q000601:surgery
keywords: accuracy; automated registration; brain shift; children; epilepsy; intraoperative; magnetic resonance imaging; neurosurgery; postoperative; preoperative; skull segmentation