Diagnostic Significance of Computed Tomography in Unilateral Exophthalmos

Abstract

CT is very useful for differential diagnosis of unilateral exophthalmos. Lesions extending from the cranial cavity or the paranasal sinus into the orbit can be diagnosed easily by this method. About two thirds of patients with dysthyroid ophthalmopathy have enlargement of the extraocular muscles, and the remaining one third have increase in fatty tissues. Inflammation in the orbit and malignant tumor usually show a diffuse high density which cannot be differentiated from normal intraorbital structures. Benign intraorbital tumor has a localized high density mass and shows definite demarcation. Histological diagnosis frequently cannot be made from absorption density value and contrast enhancement. Therefore, the patient′s age, clinical symptoms, site of lesion and angiographic findings should be considered.