TY - JOUR T1 - Graves Ophthalmopathy: The Bony Orbit in Optic Neuropathy, Its Apical Angular Capacity, and Impact on Prediction of Risk JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 597 LP - 602 DO - 10.3174/ajnr.A1413 VL - 30 IS - 3 AU - L.-L. Chan AU - H.-E. Tan AU - S. Fook-Chong AU - T.-H. Teo AU - L.-H. Lim AU - L.-L. Seah Y1 - 2009/03/01 UR - http://www.ajnr.org/content/30/3/597.abstract N2 - BACKGROUND AND PURPOSE: Optic neuropathy (ON), a serious complication of Graves ophthalmopathy, is often subclinical and masked by symptoms of orbitopathy. We examined herein bony and soft-tissue CT features associated with ON, including an angular assessment of orbital apex capacity, and their usefulness in the risk prediction of ON.MATERIALS AND METHODS: The CT scans of 41 patients with Graves ophthalmopathy (17 men, 24 women; mean age, 49.1 years) clinically diagnosed with (19 patients, 32 orbits) or without ON were evaluated by 2 independent raters. Quantitative linear and angular measurements of the orbital structures and bony walls and categoric scores of apical crowding and intracranial fat prolapse were assessed on a clinical workstation. Inter- and intrarater variability of these features was determined. The CT features of the 2 patient groups were compared, and multivariate logistic regression analysis was performed to evaluate the predictive features of ON.RESULTS: Bony orbital angles (P < .005), length of the lateral orbital wall (P < .05), muscular diameters (P < .0005), muscular bulk of the medial rectus muscle relative to the bony orbit (P < .05), and apical crowding (P < .0005) were associated with clinical ON. Stepwise multivariate logistic regression analysis revealed the muscle diameter index and medial and lateral wall angles to be independent predictors. Combining these in a single multivariate equation yielded sensitivity, specificity, and positive and negative predictive values of 73%, 90%, 82%, and 85%, respectively.CONCLUSIONS: Orbital wall angles, especially the medial wall, and muscular enlargement are independent risk predictors. ER -