title: Triple-layer appearance of Brodmann area 4 at thin-section double inversion-recovery MR imaging.
abstract: OBJECTIVE
  To investigate whether thin-section axial double inversion-recovery (DIR) brain magnetic resonance (MR) imaging at 3.0 T can help distinguish the primary motor cortex (PMC), or Brodmann area 4, from other selected cortical regions, including the primary sensory cortex (PSC), or Brodmann areas 1-3, on the basis of the presence of a "triple-layer" appearance.
  
  
  METHODS
  This prospective study was approved by the institutional review board; informed consent was obtained from patients. This study included 191 patients (94 female, age range, 5-80 years; 97 male, age range, 5-76 years) with normal findings at 3.0-T MR imaging. The presence or absence of a triple-layer appearance within selected cortical regions on DIR images was graded independently by two neuroradiologists as definitely present (grade 2), probably present (grade 1), or definitely absent (grade 0). Ten additional patients with tumors underwent DIR imaging and intraoperative cortical mapping for further validation of the PMC. A myelin-stained brain specimen image in a patient not imaged with DIR was correlated with a representative set of DIR images.
  
  
  RESULTS
  A triple-layer appearance was found in the PMC bilaterally in 184 of 191 patients; grade 0 was assigned in only seven patients, who were all younger than 10 years. Grades were significantly lower in patients younger than 10 years than in others (P < .0001) but were not significantly different between older age groups (P > .0018). Interobserver agreement was excellent (weighted kappa = 0.843). The PMC determined on DIR images was confirmed with cortical mapping in all 10 patients with tumors. Triple-layer appearance was not present in the other cortical regions examined, including the PSC (P < .01). The triple-layer appearance on DIR images corresponded to the myelin band within the PMC present on the myelin-stained specimen image.
  
  
  CONCLUSIONS
  A triple-layer appearance was found in the PMC at thin-section 3.0-T DIR imaging but not in other examined brain regions and therefore might be useful as an adjunct sign for identification of motor regions.
authors.affiliation: Department of Radiology, Research Institute of Radiological Science, Brain Research Institute, BK21 Project for Medical Sciences, Yonsei University College of Medicine, Seodaemun-gu, Seoul, Republic of Korea. eungykim@yuhs.ac
authors.forename: Eung Yeop
authors.initials: EY
authors.lastname: Kim
authors.forename: Dong-Hyun
authors.initials: DH
authors.lastname: Kim
authors.forename: Jong-Hee
authors.initials: JH
authors.lastname: Chang
authors.forename: Eunhye
authors.initials: E
authors.lastname: Yoo
authors.forename: Jae-Wook
authors.initials: JW
authors.lastname: Lee
authors.forename: Hae-Jeong
authors.initials: HJ
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000033:anatomy & histology* / Q000473:pathology; D011446:Prospective Studies