LONG ECHO TIME STIR SEQUENCE MRI OF OPTIC NERVES IN OPTIC NEURITIS

MRI of the optic nerves was obtained in 13 patients with acute optic n euritis and 13 with a previous optic neuritis (ON), assessed by clinic al features, visual fields and visual evoked potentials. Results of th e conventional short tau inversion recovery (STIR) sequence obtained w ith a short echo time (STE-STIR; 22 ms) were compared with those of a long echo time (LTE-STIR: 80 ms) sequence. The conventional STE-STIR s equence revealed lesions in the optic nerves in 78.5 % of acute and 58 .8 % of previous ON. The LTE-STIR se sequence showed abnormalities in 92.8 % of acutely symptomatic nerves and 94.1 % of nerves with previou s ON. The optic nerve lesions appeared significantly longer with the L TE-STIR sequence than with the conventional STE-STIR sequences, in bot h acute and previous ON.