Extraocular mucle enlargement with tendon involvement in thyroid-aociated orbitopathy

Purpoe To evaluate the configuration of extraocular mucle and tendon enlargement in patient with thyroid-aociated orbitopathy (TAO). Deign Retropective, noncomparative cae erie. Method We retropectively evaluated the preoperative computed tomography (CT) or magnetic reonance imaging (MRI) can, or both, of 125 conecutive patient with previouly diagnoed TAO. Axial CT (n = 88) or MRI (n = 37) lice of the orbit were examined for tendon involvement of enlarged medial or lateral recti mucle. A ratio of tendon to mucle width greater than 0.5 wa conidered a tendon involvement. Reult Eight patient (6.4%) with TAO demontrated tendon involvement on axial CT or MRI. Thee patient had ignificantly greater diplopia in primary gaze than patient with no tendon involvement or patient with no mucle enlargement. Concluion The configuration of extraocular mucle enlargement on imaging tudie ha traditionally been ued to differentiate TAO from other inflammatory procee becaue the tendon i typically pared (fuiform configuration) in TAO. However, we found that the configuration of tendon involvement (cylindrical configuration) can occaionally be noted in TAO and may be more frequently aociated with primary gaze diplopia. Tendon involvement doe not eliminate the diagnotic poibility of TAO.