LONG-TIME ECHO STIR SEQUENCE MAGNETIC-RESONANCE-IMAGING OF OPTIC NERVES IN OPTIC NEURITIS

Magnetic resonance imaging of optic nerves was obtained in 13 patients with acute optic neuritis and in 13 patients with a previous history of optic neuritis (ON), assessed by clinical, visual fields and visual evoked potentials evaluations. Results of the conventional short tau inversion recovery (STIR) sequence obtained with short time echo (STE- STIR: 22 ms) were compared with long time echo (LTE-STIR: 80 ms) seque nce. The conventional STE-STIR sequence revealed lesions in 78.5% of a cute ON and in 58.8% of optic nerves affected by previous ON. The LTE- STIR sequence was diagnostic in 92.8% of acutely symptomatic nerves, i n 94.1.% of nerves with previous ON. The calculated length of optic ne rve lesions was significantly longer in imaging obtained with the LTE- STIR sequence than with the conventional STE-STIR sequences, both in a cute and previous ON.