title: Three-dimensional localization of cortical electrodes in deep brain stimulation surgery from intraoperative fluoroscopy.
abstract: Electrophysiological recordings from subdural electrocorticography (ECoG) electrodes implanted temporarily during deep brain stimulation (DBS) surgeries offer a unique opportunity to record cortical activity for research purposes. The optimal utilization of this important research method relies on accurate and robust localization of ECoG electrodes, and intraoperative fluoroscopy is often the only imaging modality available to visualize electrode locations. However, the localization of a three-dimensional electrode position using a two-dimensional fluoroscopic image is problematic due to the lost dimension orthogonal to the fluoroscopic image, a parallax distortion implicit to fluoroscopy, and variability of visible skull contour among fluoroscopic images. Here, we present a method to project electrodes visible on the fluoroscopic image onto a reconstructed cortical surface by leveraging numerous common landmarks to translate, rotate, and scale coregistered computed tomography (CT) and magnetic resonance imaging (MRI) reconstructed surfaces in order to recreate the coordinate framework in which the fluoroscopic image was acquired, while accounting for parallax distortion. Validation of this approach demonstrated high precision with an average total Euclidian distance between three independent reviewers of 1.65±0.68mm across 8 patients and 82 electrodes. Spatial accuracy was confirmed by correspondence between recorded neural activity over sensorimotor cortex during hand movement. This semi-automated interface reliably estimates the location of temporarily implanted subdural ECoG electrodes visible on intraoperative fluoroscopy to a cortical surface.
authors.affiliation: Brain Modulation Laboratory, Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Randazzo
authors.affiliation: Brain Modulation Laboratory, Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Efstathios D
authors.initials: ED
authors.lastname: Kondylis
authors.affiliation: Brain Modulation Laboratory, Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Alhourani
authors.affiliation: Brain Modulation Laboratory, Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Wozny
authors.affiliation: Brain Modulation Laboratory, Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Witold J
authors.initials: WJ
authors.lastname: Lipski
authors.affiliation: Brain Modulation Laboratory, Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Crammond
authors.affiliation: Brain Modulation Laboratory, Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. Electronic address: richardsonrm@upmc.edu.
authors.forename: R Mark
authors.initials: RM
authors.lastname: Richardson
mesh_terms: D000368:Aged; D001931:Brain Mapping / Q000379:methods*; D046690:Deep Brain Stimulation / Q000379:methods*; D000069280:Electrocorticography / Q000379:methods; D004566:Electrodes; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000628:therapy*; D064847:Multimodal Imaging; D038361:Neuronavigation / Q000379:methods; D012984:Software
keywords: Deep brain stimulation (DBS) surgery; Electrocorticography (ECoG); Electrode localization; Fluoroscopy; Image coregistration; Movement disorders