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

Magnetic resonance images of optic nerves were obtained in 20 patients with acute optic neuritis (ON), and assessed by means of clinical, vi sual field and visual evoked potential evaluations; the imaging was re peated I year later The results of the conventional Short Tau Inversio n Recovery (STIR) sequence obtained using short time echo (STE-STIR: 2 2 msec) were compared with those of the long time echo sequence (LTE-S TIR: 80 msec). The conventional STE-STIR sequence revealed lesions in 57.2% cases of acute ON and in 42.9% of the optic nerves affected by p revious ON; the LTE-STIR sequence was diagnostic in 95.2% of acute ON cases and in 85% of patients with previous ON. The calculated length o f the optic nerve lesions was significantly longer in the images obtai ned using the LTE-STIR sequence than in those obtained using conventio nal STE-STIR sequences.