Friday, November 23, 2012
Graves ophthalmopathy is the most common cause of exophthalmos in adults. The classic imaging finding is enlargement of the extraocular muscles with sparing of their tendinous insertions. These findings tend to be bilateral and symmetric. The above image demonstrates bilateral orbital proptosis and subtle enlargement of the medial and lateral recti muscles bilaterally with sparing of their tendons.
The can be differentiated from orbital pseudotumor which is a cause of unilateral orbital proptosis. In orbital pseudotumor, the extraocular muscles and their tendons are enlarged.
LeBedis CA and Sakai O. Nontraumatic orbital conditions: diagnosis with CT and MR imaging in the emergent setting. Radiographics 2008;28:1741-53.