Computed tomography and magnetic resonance imaging in the diagnosis of inflammatory disease of the optic nerve.

Enlargement of the optic nerve and chiasm as demonstrated by high-resolution CT scanning or magnetic resonance imaging is often assumed to indicate tumor. However, this is not always true. The mode of clinical presentation of the disease process must be correctly applied to the interpretation of the radiographic studies. In the case illustrated here, neuro-ophthalmologic evaluation prevented an unnecessary biopsy in a patient whose presentation was atypical for anterior visual pathway glioma and whose clinical course was otherwise compatible with optic neuritis.