title: Automatic detection of primary motor areas using diffusion MRI tractography: comparison with functional MRI and electrical stimulation mapping.
abstract: OBJECTIVE
  As an alternative tool to identify cortical motor areas for planning surgical resection in children with focal epilepsy, the present study proposed a maximum a posteriori probability (MAP) classification of corticospinal tract (CST) visualized by diffusion MR tractography.
  
  
  METHODS
  Diffusion-weighted imaging (DWI) was performed in 17 normally developing children and 20 children with focal epilepsy. An independent component analysis tractography combined with ball-stick model was performed to identify unique CST pathways originating from mouth/lip, finger, and leg areas determined by functional magnetic resonance imaging (fMRI) in healthy children and electrical stimulation mapping (ESM) in children with epilepsy. Group analyses were performed to construct stereotaxic probability maps of primary motor pathways connecting precentral gyrus and posterior limb of internal capsule, and then utilized to design a novel MAP classifier that can sort individual CST fibers associated with three classes of interest: mouth/lip, fingers, and leg. A systematic leave-one-out approach was applied to train an optimal classifier. A match was considered to occur if classified fibers contacted or surrounded true areas localized by fMRI and ESM.
  
  
  RESULTS
  It was found that the DWI-MAP provided high accuracy for the CST fibers terminating in proximity to the localization of fMRI/ESM: 78%/77% for mouth/lip, 77%/76% for fingers, 78%/86% for leg (contact), and 93%/89% for mouth/lip, 91%/89% for fingers, and 92%/88% for leg (surrounded within 2 cm).
  
  
  CONCLUSIONS
  This study provides preliminary evidence that in the absence of fMRI and ESM data, the DWI-MAP approach can effectively retrieve the locations of cortical motor areas and underlying CST courses for planning epilepsy surgery.
authors.affiliation: Carman and Ann Adams Department of Pediatrics, School of Medicine, Wayne State University, Detroit, Michigan 48201, USA. jeongwon@pet.wayne.edu
authors.forename: Jeong-Won
authors.initials: JW
authors.lastname: Jeong
authors.forename: Eishi
authors.initials: E
authors.lastname: Asano
authors.forename: Erik C
authors.initials: EC
authors.lastname: Brown
authors.forename: Vijay N
authors.initials: VN
authors.lastname: Tiwari
authors.forename: Diane C
authors.initials: DC
authors.lastname: Chugani
authors.forename: Harry T
authors.initials: HT
authors.lastname: Chugani
mesh_terms: D000293:Adolescent; D001921:Brain / Q000098:blood supply / Q000254:growth & development / Q000473:pathology; D001931:Brain Mapping; D002648:Child; D002675:Child, Preschool; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D038524:Diffusion Magnetic Resonance Imaging; D004525:Efferent Pathways / Q000098:blood supply / Q000473:pathology / Q000502:physiology; D004558:Electric Stimulation; D004828:Epilepsies, Partial / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood; D011712:Pyramidal Tracts / Q000473:pathology
chemical_list: D010100:Oxygen
keywords: Automatic detection; Corticospinal tract; Diffusion MRI tractography; Epilepsy; Presurgical planning; Primary motor cortex