Intraorbital optic nerve and experimental optic neuritis. Correlation of fat suppression magnetic resonance imaging and electron microscopy.
To provide magnetic resonance imaging (MRI)-ultrastructural correlations of demyelinating lesions of the intraorbital optic nerve, the authors performed gadolinium-enhanced/T2-weighted fat-suppressed MRI and transmission electron microscopy of the optic nerves of animals with experimental allergic encephalomyelitis. Gadolinium enhancement of the optic nerve adjacent to the globe was seen on fat-suppressed T1-weighted MRI as early as 3 days after antigenic sensitization, increased in severity involving longer segments of nerve at 10 to 14 days, and persisted at 30 days. Gadolinium enhancement preceded T2-weighted signal aberrations. Ultrastructural evaluation of the intraorbital nerve revealed: (1) expansion of the extracellular space and inflammatory infiltrate that correlated with the intensity of gadolinium enhancement; (2) the degree of demyelination correlated with T2-weighted signal aberrations; (3) as deduced from gadolinium enhancement and T2 signal aberrations, breakdown of the blood-brain barrier preceded widespread demyelination; (4) lesions appeared to start at the optic nerve insertion into the globe and then progress toward the orbital apex.
Guy
J
J
Department of Ophthalmology, University of Florida, College of Medicine, Gainesville 32610-0284.
Fitzsimmons
J
J
Ellis
E A
EA
Beck
B
B
Mancuso
A
A
D000273:Adipose Tissue / Q000648:ultrastructure; D000818:Animals; D003287:Contrast Media; D004338:Drug Combinations; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000473:pathology*; D005682:Gadolinium; D019786:Gadolinium DTPA; D006168:Guinea Pigs; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008536:Meglumine; D009900:Optic Nerve / Q000648:ultrastructure; D009902:Optic Neuritis / Q000473:pathology*; D009915:Orbit; D009942:Organometallic Compounds; D004369:Pentetic Acid
D003287:Contrast Media; D004338:Drug Combinations; D009942:Organometallic Compounds; D008536:Meglumine; D004369:Pentetic Acid; D005682:Gadolinium; D019786:Gadolinium DTPA