title: Optic nerve sheath diameter on MR imaging: establishment of norms and comparison of pediatric patients with idiopathic intracranial hypertension with healthy controls.
abstract: OBJECTIVE
  IIH is a disorder associated with increased intracranial pressure with no clinical, laboratory, or radiologic evidence of an intracranial space-occupying lesion. The aim of this study was to establish ONSD standards of healthy pediatric subjects and compare the normal measurements with those of patients with  IIH.
  
  
  METHODS
  One hundred fifteen MR imaging studies of children 4 months to 17 years of age were blinded and reviewed by a pediatric neuroradiologist. A total of 230 optic nerves were measured. Eighty-six MR imaging examinations were performed in apparently healthy subjects. This control group included subjects who underwent MR imaging for various reasons, and their MR imaging findings were interpreted as normal. Twenty-nine MR imaging examinations were performed in patients with documented IIH. The ONSD was measured 1 cm anterior to the optic foramina on an axial T2 sequence. For statistical analysis, both patients and controls were stratified into 4 age groups (I, 0-3 years; II, 3-6 years; III, 6-12 years; IV, 12-18 years).
  
  
  RESULTS
  The mean ONSD of the control group in all age groups (I, 3.1 mm; II, 3.41 mm; III, 3.55 mm; IV, 3.56 mm) was significantly smaller than the mean ONSD of patients (I, 4.35 mm; II, 4.37 mm; III, 4.25 mm; IV, 4.69 mm). A positive correlation between age and ONSD (r = 0.414, P < .01) was found in the control group.
  
  
  CONCLUSIONS
  According to our study, in pediatric patients with IIH, the ONSD is significantly larger than that in healthy controls regardless of age group and sex. This measurement might prove to be an auxiliary tool in the diagnosis of increased intracranial pressure in pediatric patients.
authors: Department of Pediatric Neurosurgery, Dana Children's Hospital, Tel Aviv, Israel.
authors: B
authors: B
authors: Shofty
authors: L
authors: L
authors: Ben-Sira
authors: S
authors: S
authors: Constantini
authors: S
authors: S
authors: Freedman
authors: A
authors: A
authors: Kesler
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D009186:Myelin Sheath / Q000473:pathology*; D009900:Optic Nerve / Q000033:anatomy & histology / Q000473:pathology*; D011559:Pseudotumor Cerebri / Q000473:pathology*; D012016:Reference Values