title: Relationship Between Optic Nerve Protrusion Measured by OCT and MRI and Papilledema Severity.
abstract: OBJECTIVE
  To develop measures of optic nerve protrusion length (NPL) from optical coherence tomography (OCT) and magnetic resonance imagining (MRI) and compare these measures with papilledema severity in idiopathic intracranial hypertension (IIH).
  
  
  METHODS
  Optical coherence tomography and MRI scans were obtained from 11 newly diagnosed untreated IIH patients (30 ± 10 years; body mass index [BMI] 36 ± 4 kg/m2). Optic nerve protrusion length was measured for each eye using OCT and MRI independently. The relationship between the NPL measures and their association with the Frisen scale for papilledema severity were assessed. Two different OCT-based measures of NPL were derived to assess the influence of the retinal thickness on the association with papilledema severity. Additional OCT scans from 11 healthy subjects (38 ± 7 years) were analyzed to establish reliability of the NPL measurement.
  
  
  RESULTS
  Optical coherence tomography and MRI measurements of NPL were significantly linearly correlated (R = 0.79, P < 0.0001). Measurements of NPL from OCT and MRI were significantly associated with Frisen papilledema grade (P < 0.0001). Mean OCT measurement of NPL in the papilledema cohort was significantly larger than in the healthy cohort (0.62 ± 0.24 vs. 0.09 ± 0.03 mm, P < 0.0001).
  
  
  CONCLUSIONS
  Significant linear correlation between OCT and MRI measurements of NPL supports the reliability of the OCT-based measurements of NPL in papilledema. Significant association between the papilledema grade and OCT- and MRI-based measurements of NPL highlights the potential of NPL as an objective and more sensitive marker of papilledema severity than the Frisen scale.
authors.affiliation: Department of Radiology, University of Miami, Miami, Florida, United States.
authors.forename: Yu-Cherng C
authors.initials: YC
authors.lastname: Chang
authors.affiliation: Department of Radiology, University of Miami, Miami, Florida, United States.
authors.forename: Noam
authors.initials: N
authors.lastname: Alperin
authors.affiliation: Department of Radiology, University of Miami, Miami, Florida, United States.
authors.forename: Ahmet M
authors.initials: AM
authors.lastname: Bagci
authors.affiliation: Department of Radiology, University of Miami, Miami, Florida, United States.
authors.forename: Sang H
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States.
authors.forename: Potyra R
authors.initials: PR
authors.lastname: Rosa
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States.
authors.forename: Gregori
authors.initials: G
authors.lastname: Giovanni
authors.affiliation: Bascom Palmer Eye Institute, University of Miami, Miami, Florida, United States.
authors.forename: Byron L
authors.initials: BL
authors.lastname: Lam
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009900:Optic Nerve / Q000473:pathology*; D010211:Papilledema / Q000175:diagnosis*; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence / Q000379:methods*; D055815:Young Adult