title: Predictive accuracy of standard computed tomography scanning in the diagnosis of Chiari malformation Type I in children.
abstract: OBJECTIVE
  In this study, retrospective data analysis was performed to analyze the utility of head computed tomography (CT) scanning in the diagnosis of Chiari malformation Type I (CM-I) in the pediatric population.
  
  
  METHODS
  The authors conducted a retrospective review of radiology charts describing head CT results obtained at Columbus Children's Hospital between January 2004 and January 2005. The records were searched for the key words "Chiari," "cerebellar ectopy," or "tonsillar ectopy." The exclusion criteria included patients with previously known Chiari malformation Type I or Type II or those who had undergone follow-up magnetic resonance (MR) imaging at other institutions. Head CT and MR images for the remaining patients were reviewed to verify accuracy.
  
  
  RESULTS
  Of the 72 patients with suspicious findings of tonsillar ectopy on CT, only 37 (51.4%) had MR imaging findings consistent with CM-I. The tonsillar ectopy in these patients ranged from 3 mm to 17 mm below the foramen magnum.
  
  
  CONCLUSIONS
  The authors' findings indicate that incidental standard CT scans of the head have limited value in identifying CM-I.
authors.affiliation: Division of Pediatric Neurosurgery, Department of Neurological Surgery, Columbus Children's Hospital and The Ohio State University Medical Center, Columbus, Ohio 43205, USA.
authors.forename: Mirza N
authors.initials: MN
authors.lastname: Baig
authors.forename: Ali
authors.initials: A
authors.lastname: Raza
authors.forename: Moumen
authors.initials: M
authors.lastname: Asbahi
authors.forename: Scott
authors.initials: S
authors.lastname: Elton
mesh_terms: D001139:Arnold-Chiari Malformation / Q000000981:diagnostic imaging* / Q000473:pathology; D002648:Child; D015331:Cohort Studies; D006801:Humans; D008279:Magnetic Resonance Imaging; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed