What the most common reasons for the optic nerve thickening?
Optic nerve glioma, meningioma, neuritis
What characteristic findings would agree with the most probable diagnosis?
Left optic nerve entrapment is very specific for the nerve sheath meningioma with tubular growth pattern.
The left optic nerve is entrapped by the homogeneous, slightly hyperintense on T2WI tissue, which strongly enhances on T1+C fat saturated series. The globe, extraocular muscles, lacrimal gland and retrobulbar tissue are normal.