Abnormal Optic Nerves Signals in Orbital MRI: a Rare Sign in Idiopathic Intracranial Hypertension

Background It is recognized that radiological examination is essential for the diagnosis of Idiopathic intracranial hypertension (IIH). The present study demonstrated a rare sign of IIH in optic nerves on MRI images. Methods Review the medical records and MRI images of 82 the patients with IIH referred to our neurology department from January 2017 to December 2018. Inclusion criteria were: 1) accorded with the IIH diagnostic criteria adapted from Friedman et al. [1], 2) abnormal optic nerve signal with enhancement on orbital MRI, 3) no better explanation for the optic nerve involvement. Results 12 patients are enrolled. The age of patients ranged from 16 to 55 years, median age 32.91±14.36 years, two patients were male and ten were female. The CSF opening pressures (OP) of all patients were all above 30 cmH2O. Enhancement of optic nerves sheaths (ONS) in retrobulbar segments were observed in all affected eyes showed on coronal orbital MRI gadolinium (Gd)-enhanced T1WI sequence. Conclusions Enhancement of ONS on MRI is a rare sign of IIH that clinicians should recognize in order to avoid misdiagnosis and mistreatment. Keywords: Idiopathic intracranial hypertension, Optic nerves sheaths, Orbital MRI