Angiographic diagnosis of acoustic neurinomas and meningiomas in the cerebellopontine angle--a reappraisal.

Forty-two acoustic neurinomas and seven meningiomas in the cerebellopontine angle were reviewed, and the radiological differential diagnosis of these tumors is discussed. Though enlarged internal auditory meati and characteristic CT findings were reasonably reliable indicators for the diagnosis of acoustic neurinomas, it was angiography which substantiated their correct diagnosis. An arcuate vein was frequently demonstrated with acoustic neurinomas, but never with meningiomas. Visualization of tangled veins seems to favor a diagnosis of acoustic neurinomas. Contrary to earlier reports, tumor stains were most frequently visualized using selective external carotid arteriography. The degree of tumor stains did not aid in differentiating acoustic neurinomas from meningiomas. The importance of using angiotomography, especially in the anteroposterior projection, and external carotid angiography during prolonged injections of large amounts of contrast media, is emphasized.