Computed tomography of supratentorial meningioma.

The appearance on C.T. of 28 meningiomas is described. On the plain scan they presented as a rounded, well defined lesion with a high density in 18 cases and a density equal to or lower than brain tissue in 10 cases. The density could be related to certain histologic features as the amount of connective tissue and extracellular water and the presence of psammoma bodies or lipid storage cells. After administration of contrast a homogeneous, markedly increased, sharply marginated density was seen in most meningiomas. Contrast enhancement appeared to be dependent on the vascularity of the tumour. +/- 50% of the cases demonstrated edema grade II or III. On first interpretation 93% of the meningiomas were recognized as a lesion and a tumour (2 false negative) and 79% as a meningioma (2 false negative and 4 incorrect). Only one false positive C.T. scan was encountered. As a screening method R.N. scanning has about the same accuracy as C.T.; in establishing a definite diagnosis angiography equals C.T.; but C.T. is superior as it combines the diagnostic qualities of both methods.