title: Functional reorganization of the corticospinal tract in a pediatric patient with an arteriovenous malformation.
abstract: Presurgical mapping in a pediatric patient diagnosed with arteriovenous malformation in the left hemisphere revealed a case of apparent functional reorganization of a white matter tract. Magnetoencephalography (MEG) was used to identify the motor fields following hand movement. As expected, motor field activity for the left hand was detected in the right hemisphere. Surprisingly, MEG activity was also detected in the right hemisphere following movement of the right hand. MEG activations served as seeds from which to launch diffusion tensor imaging tractography to delineate the corticospinal tracts (CSTs). Using the MEG activation for movement of the right hand, we delineated a tract in the right hemisphere. A tract corresponding to motor function for the left hand was also delineated in the right hemisphere. For comparison, the CSTs of the patient were launched from anatomical landmarks at the precentral gyrus, and were successfully delineated in each hemisphere. Our findings suggest that the functional delineation of white matter pathways may be more sensitive than anatomical delineation for identifying reorganization of the developing brain in response to a lesion. This study is, to our knowledge, the first description of a functional reorganization of an existing tract to serve as a CST in children.
authors.affiliation: aProgram in Neurosciences and Mental Health bDepartment of Diagnostic Imaging cDivision of Neurosurgery dDivision of Haematology/Oncology, The Hospital for Sick Children eDepartments of Medical Imaging fSurgery gPaediatrics hPsychology, University of Toronto, Toronto iDepartment of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada jDepartment of Radiology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
authors.forename: Nadia
authors.initials: N
authors.lastname: Scantlebury
authors.forename: William
authors.initials: W
authors.lastname: Gaetz
authors.forename: Elysa
authors.initials: E
authors.lastname: Widjaja
authors.forename: James
authors.initials: J
authors.lastname: Rutka
authors.forename: Eric
authors.initials: E
authors.lastname: Bouffet
authors.forename: Conrad
authors.initials: C
authors.lastname: Rockel
authors.forename: Donald
authors.initials: D
authors.lastname: Mabbott
mesh_terms: D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000503:physiopathology*; D015225:Magnetoencephalography; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D011712:Pyramidal Tracts / Q000503:physiopathology*