EOM enlargement in carotid cavernous fistulas
Reviewed by Hetvi Bhatt

This study evaluates the radiological patterns of extraocular muscle enlargement and proptosis in carotid cavernous fistulas (CCF). At least one muscle was enlarged in 27.5% of cases. The inferior rectus was most commonly enlarged, followed by the medial rectus. Proptosis was present in 43% of cases, and although most common in ipsilateral eyes there were cases of both proptosis and muscle enlargement in contralateral eyes. The radiological appearance of muscles can be confused with thyroid eye disease (TED) and other inflammatory conditions; however, this study found that in CCF the muscles tend to have cylindrical enlargement compared to fusiform in TED. The authors did not find a difference in incidence of muscle enlargement in direct compared to indirect fistulas. This is an interesting study and may help differentiate between diagnoses when there is uncertainty.

Extraocular muscle enlargement and proptosis in carotid cavernous fistulas.
Rana K, Lim WY, Caltabiano C, et al.
ORBIT
2024;43(2):203–7.