Orbital Magnetic Resonance Imaging to unmask giant cell arteritis.

Optic nerve enhancement is a sign seen in different disease states; however, perineural enhancement is less common. This article presents the case of a patient with bilateral amaurosis in whom the diagnosis of giant cell arteritis was suggested by perineural enhancement on orbital magnetic resonance imaging (MRI) and confirmed by biopsy of the temporal artery. The clinical presentation of giant cell arteritis is occasionally nonspecific; patients can have visual symptoms, even blindness if the branches of the ophthalmic artery are affected; in these cases, orbital MRI can be very useful for early diagnosis. Although the MRI findings are uncommon, distinct patterns of enhancement have been reported, the most characteristic of which is perineural enhancement. The pattern of optic nerve involvement is relatively unknown, but important because it orients the diagnosis of a disease that can lead to permanent blindness.