Ga-68-DOTA-NOC PET/CT Reveals Active Graves' Orbitopathy in a Single Extraorbital Muscle

Abstract

A 53-year-old woman with clinical history of multiple stroke presented with bilateral chemosis and vertical paresis of the right eye. Ophthalmologic examination showed partial atrophy of the right optical nerve, without exophthalmos. Sonography presented a pattern suggestive of autoimmune thyropathy. Laboratory revealed subclinical hyperthyroidism, and mildely elevated thyrotropin receptor antibody to 1.3 U/l. Graves' thyroid disease and concomitant ophthalmopathy was assumed. Head and neck Ga-68-DOTA-NOC PET/CT demonstrated marked accumulation at the thyroid and the right rectus inferior muscle. This finding corresponded to an isolated muscular enlargement seen with CT and MRI and representing active endocrine orbitopathy at this single location.