Central nervous system disorders

VII./3.5.: Differential diagnostics

Anterior scala (olphactory) meningeomas must be differentiated from esthesioneuroblastomas, meningeomas located near the pyramis (petrous bone) must be differentiated from acustic neurinomas, and the suprasellar ones from the pituitary adenomas. Misinterpretation can be caused if the dura emerges grossly, or it has a large calcification of non-meningeomatous origin (in this case calcification is usually located also elsewhere – e.g. in the ligaments).

VII./3.6.: Angiography- embolisation

Meningeomas can/must be also embolized preoperatively (from the direction of external carotid artery but never the braches of ICA! using DSA interventional radiological methods, see there) in order to avoid a heavy bleeding during surgery - its effectivity / tissue effects (hemorrhage, necrosis, decreased contast agent uptake, DWI – diffusion, decrease in perfusion) can be demonstrated/followed by MRI. Obviously, imaging is necessary in order to demonstrate the preoperative status. MR spectroscopy can follow the efficiency of embolisation which can demonstrate the increase of lactate immediately. Lipids increase only later (appr. 3 days later).

VII./3.7.: Nuclear medicine, isotope studies

The only positive news: malignant/hyperactive meningeomas demonstrate higher avid F-18 fluorodeoxyglucose uptake compared to the more peaceful, benign forms. In my opinion, having resort to this very costly and difficultly available method is not recommended, because even confusion can be generated (confusion with other, non extraaxial avid tumors).