Editing Optic neuritis (section)

=== MRI ===
[[Magnetic resonance imaging]] (MRI) is a robust and sensitive diagnostic modality for the detection of optic neuritis. Imaging of the optic nerve with MRI shows increased signal on the affected side. There is contrast enhancement of the symptomatic optic nerve and sheaths acutely or intrinsic signal increase (looking brighter) within ≥ 3 months. One study found that MRI of the orbits with fat suppression and gadolinium enhancement detected acute optic neuritis lesions in 95% of affected individuals within 20 days of vision loss.<ref>{{Cite journal |last1=Kupersmith |first1=Mark J. |last2=Alban |first2=Therese |last3=Zeiffer |first3=Barbara |last4=Lefton |first4=Daniel |date=April 2002 |title=Contrast-enhanced MRI in acute optic neuritis: relationship to visual performance |url=https://pubmed.ncbi.nlm.nih.gov/11912114 |journal=Brain: A Journal of Neurology |volume=125 |issue=Pt 4 |pages=812–822 |doi=10.1093/brain/awf087 |issn=0006-8950 |pmid=11912114}}</ref> Another study found that T2-weighted images with fat suppression and short tau inversion recovery (STIR) detected lesions in up to 89% of acute optic neuritis cases with abnormalities persisting for as long as 6 weeks in 92% of cases.<ref>{{Cite journal |last1=Miller |first1=D. H. |last2=Newton |first2=M. R. |last3=van der Poel |first3=J. C. |last4=du Boulay |first4=E. P. |last5=Halliday |first5=A. M. |last6=Kendall |first6=B. E. |last7=Johnson |first7=G. |last8=MacManus |first8=D. G. |last9=Moseley |first9=I. F. |last10=McDonald |first10=W. I. |date=February 1988 |title=Magnetic resonance imaging of the optic nerve in optic neuritis |url=https://pubmed.ncbi.nlm.nih.gov/3340276 |journal=Neurology |volume=38 |issue=2 |pages=175–179 |doi=10.1212/wnl.38.2.175 |issn=0028-3878 |pmid=3340276}}</ref>
 
[[File:Case-3-mri.png|thumb|Magnetic Resonnance Imaging (MRI) during an episode of optic neuritis.]]

Identification of optic nerve, orbital, brain, and meningeal involvement with MRI can also help to better characterize the underlying cause of optic neuritis upon initial evaluation. Unilateral optic nerve involvement is more common MS while bilateral optic nerve involvement is more common in NMOSD and MOGAD.<ref name=":35"/>  T2-hyperintense and gadolinium-enhancing lesions in multiple regions of the brain and/or spinal cord may be highly suggestive or diagnostic of MS. Such lesions found in the periependymal, fornix, and hypothalamic lesions may be more suggestive of NMOSD.<ref name=":35"/> Involvement of the optic chiasm or optic tract are more suggestive of NMOSD-optic neuritis; involvement of the retrobulbar optic nerve can be seen in both NMOSD and MOGAD, but more commonly in MOGAD; perineural optic nerve involvement is often suggestive of MOGAD-optic neuritis, but should not preclude the investigation of other autoimmune or infectious etiologies.<ref name=":35"/>