Radiologic clinics of North America
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Complex orbital rim and fractures of the internal orbital skeleton (orbital walls) are best analyzed by high-resolution axial CT. Optic canal fractures are optimally visualized with thin 1-mm section high-resolution CT scanning. Spiral CT may be used in the acutely injured patient because of its rapid scan technique. ⋯ Another advantage of spiral CT is the capability of CT angiography. MR imaging usually is not the initial modality for the assessment of orbital trauma, but it is helpful in evaluating vascular injuries such as carotid-cavernous sinus fistulas or post-traumatic pseudoaneurysms. In general, CT with contrast injection is not necessary except when traumatic vascular anomalies, such as carotid cavernous, dural fistulas, or thrombosis of the superior ophthalmic vein, are considered in the differential diagnosis.
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Fibrous orbital tumors present clinically and radiographically in a broad spectrum ranging from a benign mass, to locally aggressive tumor, to invasive malignancy. Pathologic analysis and diagnosis are often challenging, usually based on a combination of light microscopy, immunohistochemistry, and electron microscopic findings. Some light microscopic and immunohistochemical findings, however, are relatively characteristic. ⋯ A history of prior orbital irradiation for retinoblastoma or other tumors may raise the possibility of radiation-induced secondary tumors, such as MFH, fibrosarcoma, and osteosarcoma. Determining the extent of orbital involvement remains the primary goal of the radiologist. The final diagnosis still rests with the pathologist.