ABSTRACT
This study included 17 patients with an age ranged 17-42 years. They have thyroid eye disease. MR images of the thyroid gland and orbits were performed on 1.5 Tesla machine. TI weighted images were obtained with repetition time [TR] of about 500 ms and echo time [ET] of 20-25 ms. T2 weighted images were obtained with TR of 2000-2500 ms and TE of 30-80 ms. Excess fat deposition in the retro-bulbar space was reported in 9 cases and muscle involvement was reported in 11 cases. Five cases showed symmetrical enlargement of extra ocular muscles, while 5 cases were asymmetrical and one case was unilateral. The distribution of muscle involvement was in the following order: Inferior rectus 64.7%, medial rectus 52.9%, superior rectus 29.4% and least frequency was in the lateral rectus 17.6%. The enlarged muscles have fusiform expansion with tapering towards muscle tendon. They have signal intensity similar to normal signal intensity of the muscle on TI weighted images. On T2 weighted images, they were hypointense in 10 cases and hyperintense in one case. Lacrimal gland involvement was recorded in 2 cases