title: Morphometric analysis of foramen magnum dimensions and intracranial volume in pediatric Chiari I malformation.
abstract: OBJECTIVE
  Foramen magnum dimensions and intracranial volume in Chiari I malformations in children were studied, and the statistical relationship between patient demographics, radiological features and foramen magnum morphometry was investigated.
  
  
  METHODS
  Linear measurements were used to calculate the intracranial volume using preoperative magnetic resonance images and computed tomogram images. The area of the foramen magnum was obtained independently using computer imaging software and a regression formula. The result of 21 pediatric patients was compared with a matched control group.
  
  
  RESULTS
  The area of the foramen magnum was within the range of the expected value deduced using a formula based on the intracranial volume. There was no statistical difference in the area and linear dimensions of the foramen magnum in the study and control groups. Six patients (28%) had a foramen magnum in close proximity to a spherical shape.
  
  
  CONCLUSIONS
  The authors provide a simple, accurate and reproducible method of estimating foramen magnum area in the pediatric Chiari I group. The irregular shape of the foramen magnum is accentuated by developmental bony and soft tissue anomalies at the cranio-vertebral junction in Chiari malformation. Consequently, an individualized cross-sectional assessment of the foramen magnum in relation to the hindbrain tissue in the same plane is required to study the initiation and propagation of the Chiari I symptomatology.
authors: Department of Neurosurgery, Sri Satya Sai Institute of Higher Medical Sciences, EPIP Area, Whitefield, Bangalore 560066 Karnataka, India. sunilvf@gmail.com
authors: Sunil V
authors: SV
authors: Furtado
authors: Darpan J
authors: DJ
authors: Thakre
authors: Prasanna K
authors: PK
authors: Venkatesh
authors: Kalyan
authors: K
authors: Reddy
authors: A S
authors: AS
authors: Hegde
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000886:Anthropometry; D001139:Arnold-Chiari Malformation / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D001931:Brain Mapping / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D003388:Cranial Fossa, Posterior / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D004185:Disability Evaluation; D005260:Female; D005539:Foramen Magnum / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011237:Predictive Value of Tests; D011300:Preoperative Care; D012249:Rhombencephalon / Q000002:abnormalities / Q000473:pathology / Q000601:surgery; D012720:Severity of Illness Index; D013116:Spinal Cord / Q000002:abnormalities / Q000473:pathology / Q000601:surgery; D013595:Syringomyelia / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D014057:Tomography, X-Ray Computed / Q000379:methods*