Orbital computed tomography for exophthalmos

Since exophthalmos is caused by any decrease in the size of bony orbit or occurrence of mass within the rigidorbit, the accurate diagnosis of its causes are essential in determining the therapeutic aims, Exophthalmos is oneof the important signs being the indication for orbital CT along with periobital swelling, visual loss, orbitaltrauma and diplopia. CT as the diagnostic tool for the cause of exophthalmos not only displys a superb role withuncomparable quality in comparison to any conventional diagnostic methods but also has a decisive role indetermining the therapeutic aims and the appropriate operative method when the operation is indicated. The orbital CT was performed from May in 1983 to May in 1985 whose with chief complaints were exophthalmos and 23 cases wereconfirmed by operation, biopsy, clinical progression or other diagnostic procedures. Here was report throughlyanalysized 23 cases. The results were as follows: 1. The etiologic disease of exophthalmos were 6 cases ofpseudotumor, 4 cases of thyrodid ophthalmopathy, 4 cases of maxill ary sinus and nasal cavity Ca., 3 cases ofmucocele and 1 case of alveolar soft part sarcoma, osteoma, dermoid cyst, pleomorphic adenoma, meningioma, and C.C.F. each. 2. The origin of the etiologic diseases of exophthalmos were 13 cases of primary within bony orbitand 10 cases of secondary from adjacent structure. 3. The sites of lesions were 11 cases of intraconal andextraconal, 10 cases of extraconal, and 2 cases of intraconal origin. 4. The degree of exophthalmos on CT scan wasin proportion to the volume of the mass except in the case of thyroid ophthalmopathy. The upper limit of normalrange by CT scan using regression line equation was 16.2mm in approximation. 5. CT was a very useful diagnostictool in the accurate assessment of the kinds of lesion, its location, and its relationship to adjacent structuresin the diagnosis of etiologic diseases of exophthalmos.