Objective:

To determine the frequency of post-contrast enhancement on orbital MRI during acute optic neuritis(ON) in myelin oligodendrocyte glycoprotein antibody-associated disease(MOGAD).

Background:

ON is the most common manifestation of MOGAD. MRI is routinely used to evaluate relapses in MOGAD, however, the sensitivity of T1 post-contrast enhancement on orbital MRI in MOGAD associated acute ON has not been established.  

Design/Methods:

In this retrospective study, patients referred to the Mayo Clinic who met the diagnostic criteria for MOGAD, presented with acute ON, completed MRI with fat suppression of the orbit within 30 days of the onset of visual symptoms, and had adequate clinical data for review were included. Available clinical data and the presence of T1 post-contrast enhancement were evaluated.

Results:

This study included 122 patients with MOGAD (median age: 39 years [range, 6-72], 68% female) with 177 acute ON attacks. Bilateral ON occurred in 34/122(28%) of patients. MRIs were completed a median of 6 days (range, 0-26) after the onset of visual loss. Of included attacks, 119/170(70%) had a visual acuity 20/40 or worse, 77/170(45%) had a visual acuity 20/200 or worse, and 157/173(91%) had pain with eye movements during acute ON. Optic nerve T1 post-contrast enhancement was present in 173/177 ON attacks(97.7%). ON was confirmed in attacks without enhancement on MRI by at least one of the following: retinal nerve fiber layer swelling on optical coherence tomography(n=2), enhancement on a second MRI within the acute presentation(11 days later, n=1), and/or new T2 hyperintensity of the optic nerve on a follow-up MRI scan(n=2). 

Conclusions:

Contrasted MRI with fat suppression is highly sensitive for the detection of acute ON in MOGAD and can aid in diagnosis. In rare cases, enhancement may not be present in MOGAD acute ON and ancillary testing including OCT and follow-up MRI may be helpful for diagnosis.