Endocrine Abstracts

Objective: CT findings indicating that a patient is at risk for developing optic neuropathy are worth- while observations.

Aim: The aim of our study was to determine the utility of CT imaging in identifying patients at risk for optic neuropathy and to compare quantifiable nonvolumetric CT data from a large series of orbits with Graves ophthalmopathy.

Method: A total of 226 patients (452 orbits), 175 women (350 orbits) and 51 men (102 orbits) with Graves ophthalmopathy were enrolled. These patients were referred to National Institute of Endocrinology C. I. Parhon between 2002 and 2008. All subjects were scanned in both axial and direct coronal planes with a high- resolution CT scanner and normal criteria from literature were used. Maximum diameters of orbital muscles, muscle diameter index, muscle enlargement index, optic nerve sheath retrobulbar and waist, maximum superior ophthalmic vein diameter and proptosis have been calculated for all patients. The patients were subgrouped into those with optic nerve involvement and those without optic nerve involvement based on CT findings.

Results: The mean age was 48 years, no statistical differences between women and men. The most prevalent pattern of muscle involvement was enlargement of a solitary muscle, the superior muscle group (60 patients). Optic nerve involvement was seen in 142 patients, with mean diameter of the retrobulbar optic nerve sheath at axial CT increased. The muscle diameter index was statistical correlated with optic nerve involvement (P<0.01). Mean superior ophthalmic vein diameter and proptosis were significantly increased (P=0.0082 and 0.001)) in the subgroup with optic nerve involvement.

Conclusions: One hundred and forty-two patients were seen with optic nerve involvement as an increase in the retrobulbar portion of optic nerve sheath. The optic nerve involvement subgroup was characterized most often by solitary muscle involvement (superior muscle group). The muscle diameter index was statistical correlated with optic nerve involvement. Superior ophthalmic vein diameter and proptosis significantly increased in the group with optic nerve involvement and may indicate that a patient is at risk for developing optic neuropathy.involvement and may indicate that a patient is at risk for developing optic neuropathy.

Muscle diameter index was statistical correlated with optic nerve involvement. Superior ophthalmic vein diameter and proptosis significantly increased in the group with optic nerve involvement and may indicate that a patient is at risk for developing optic neuropathy.