[Optic nerve subarachnoid space expansion in MR imaging: a etiology study]

Area of Science:

• Neuro-ophthalmology
• Radiology
• Medical Imaging

Background:

• Optic nerve subarachnoid space (ONSS) expansion is a condition requiring investigation into its underlying causes.
• Magnetic Resonance Imaging (MRI) is a key diagnostic tool for visualizing neuro-ophthalmic structures.

Purpose of the Study:

• To determine the spectrum of causes associated with optic nerve subarachnoid space (ONSS) expansion.
• To differentiate causes of ONSS expansion using MRI findings.

Main Methods:

• Retrospective study analyzing MRI and ophthalmologic data from 26 patients with ONSS expansion and 20 controls.
• Measurement of optic nerve diameter (OND) and optic nerve sheath diameter (ONSD) to calculate ONSS.
• Comparison of clinical features, MRI findings, and final diagnoses between groups.

Main Results:

• ONSS expansion was significantly larger in the patient group (1.9±0.4 mm) compared to controls (1.2±0.2 mm).
• Cerebral venous sinus thrombosis (CVST) was the most frequent cause of bilateral ONSS expansion (75%).
• Unilateral ONSS expansion was associated with compressive lesions on the anterior visual pathway (66.7%).

Conclusions:

• Cerebral venous sinus thrombosis (CVST) is strongly linked to bilateral optic nerve subarachnoid space (ONSS) expansion.
• Unilateral ONSS expansion may serve as an indicator for compressive lesions affecting the anterior visual pathway.