title: Sonographic evaluation of optic nerve diameter in children with raised intracranial pressure.
abstract: OBJECTIVE
  The optic nerve is part of the central nervous system, and a rise in intracranial pressure (ICP) can directly affect the perioptic nerve space, leading to an increase in nerve diameter. Transorbital sonography is a safe and easy-to-perform method to measure optic nerve diameter for rapid diagnosis of increased ICP.
  
  
  METHODS
  The optic nerve diameter was measured in 3 individual occasions by transorbital sonography in the transverse view, 3 mm posterior to the papilla in both eyes, and the mean was calculated. Two groups were examined: a control group of children with normal ICP and normal ophthalmologic and optic nerve examination results and a case group with increased ICP as determined by an alternative method.
  
  
  RESULTS
  The sample consisted of 156 children, of which 78 (50%) were in the case group and 78 (50%) were in the control group. Eighty-four subjects (53.7%) were male, and 72 (46.1%) were female. The mean +/- SD ages were 6.9 +/- 5.6 years in the case group and 6.8 +/- 5.5 years in the control group. The mean optic nerve diameters were 5.6 +/- 0.6 mm (range, 4.55 +/- 0.7 to 7.6 +/- 0.6 mm) in the case group and 3.3 +/- 0.6 mm (range, 2 +/- 0.6 to 4.35 +/- 0.6 mm) in the control group. The difference in the means was significant at P < .001.
  
  
  CONCLUSIONS
  Optic nerve diameter, measured by transorbital sonography, was significantly greater in pediatric patients with increased ICP compared with a control group. Transorbital sonography can be used to identify pediatric patients with raised ICP.
authors.affiliation: Radiology Department, Tehran Hospital, Children Medical Center, Gharib Street, Keshavarz Boulevard, Tehran, Iran.
authors.forename: Ashkan Akhavan
authors.initials: AA
authors.lastname: Malayeri
authors.forename: Shirin
authors.initials: S
authors.lastname: Bavarian
authors.forename: Mehrzad
authors.initials: M
authors.lastname: Mehdizadeh
mesh_terms: D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D019586:Intracranial Hypertension / Q000503:physiopathology*; D007427:Intracranial Pressure; D008297:Male; D009900:Optic Nerve / Q000000981:diagnostic imaging*; D014463:Ultrasonography