RADIOLOGY OF ORBITAL MENINGIOMA

During a 5 yr period, 3 patients with primary and 14 with secondary orbital meningiomas were examined. The appearances seen on plain films, subtraction angiography, venography, scintiscan and EMI scan are described and compared. Plain films were abnormal in 13 of the 17 cases and this was the investigation which most frequently suggested the diagnosis. Arteriographic abnormalities were present within the orbit in 12 of the 16 cases so examined, an actual tumor blush occurring in 6 of 16. Venography showed evidence of the lesion in 12 of 14; in 2 cases it was the only investigation to give positive findings. Abnormality in the adjacent cavernous sinus was demonstrated in 6 of 13. Scintiscan was negative in the 1 primary case examined; it showed evidence of the intracranial lesion in the 7 secondary cases examined but could not demonstrate intraorbital extension. The orbital lesion was demonstrated in all cases without the use of computed tomography but the delineation of the lesion was seen more clearly on the EMI scan in 12 of 14 than by other methods of investigation. Neither the density of the lesion nor the increase of attenuation after contrast was helpful in suggesting the diagnosis. A combination of plain and contrast radiology with computed tomography is recommended with a view to increasing the diagnostic accuracy and determining the full extent of a lesion. Intracranial investigation is required also, where an orbital space occupying lesion is suspected, and orbital examination should be done when an intracranial peri-orbital meningioma is diagnosed. A case history is given to show how the various investigations may complement each other.