title: Essential features of Chiari II malformation in MR imaging: an interobserver reliability study--part 1.
abstract: OBJECTIVE
  Brain MR imaging is essential in the assessment of Chiari II malformation in clinical and research settings concerning spina bifida. However, the interpretation of morphological features of the malformation on MR images may not always be straightforward. In an attempt to select those features that unambiguously characterize the Chiari II malformation, we investigated the interobserver reliability of all its well-known MR features.
  
  
  METHODS
  Brain MR images of 79 children [26 presumed to have Chiari II malformation, 36 presumed to have no cerebral abnormalities, and 17 children in whom some Chiari II malformation features might be present; mean age 10.6 (SD 3.2; range, 6-16) years] were blindly and independently reviewed by three observers. They rated 33 morphological features of the Chiari II malformation as present, absent, or indefinable in three planes (sagittal, axial, and coronal). The interobserver reliability was assessed using κ statistics.
  
  
  RESULTS
  Twenty-three of the features studied turned out to be unreliable, whereas the interobserver agreement was almost perfect (κ value > 0.8) for nine features (eight in the sagittal plane and one in the axial plane, but none in the coronal plane).
  
  
  CONCLUSIONS
  This study presents essential features of the Chiari II malformation on MR images by ruling out the unreliable features. Using these features may improve the assessment of Chiari II malformation in clinical and research settings.
authors.affiliation: Department of Pediatric Neurology 801, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB Nijmegen, The Netherlands. n.geerdink@cukz.umcn.nl
authors.forename: Niels
authors.initials: N
authors.lastname: Geerdink
authors.forename: Ton
authors.initials: T
authors.lastname: van der Vliet
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Rotteveel
authors.forename: Ton
authors.initials: T
authors.lastname: Feuth
authors.forename: Nel
authors.initials: N
authors.lastname: Roeleveld
authors.forename: Reinier A
authors.initials: RA
authors.lastname: Mullaart
mesh_terms: D000293:Adolescent; D001139:Arnold-Chiari Malformation / Q000145:classification / Q000175:diagnosis*; D001921:Brain / Q000473:pathology*; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015203:Reproducibility of Results; D013116:Spinal Cord / Q000473:pathology