Computerized tomography scanning appearances of intracranial meningiomas

Abstract

The computerized tomography (CT) scans of 102 patients with meningiomas confirmed at operation and histologically were reviewed and the features displayed by the tumors were correlated with their histology. There were 54 transitional, 17 fibroblastic, 13 mixed transitional and fibroblastic, 10 angioblastic and 8 syncytial meningiomas. Each of these variants exhibited common CT features that could be helpful in predicting the probable histology. These common features were: visible Ca aggregates, degree of surrounding edema, tumor density before and after contrast medium enhancement, homogeneity and definition of outline. Visible Ca aggregates pointed to a diagnosis of either transitional or fibroblastic meningioma. None of the angioblastic or syncytial variants exhibited this feature. Most tumors were surrounded by edema of varying degrees (92%) but this was not considered to be a specific feature except perhaps in the fibroblastic type where the edema was almost invariably of moderate degree. Tumor attenuation values unenhanced by contrast medium were also nonspecific but in enhanced scans a homogenerous density distribution pointed to the tumor being most probably of the transitional type. The angioblastic and syncytial variants showed a marked tendency to exhibit low-density non-enhancing cystic areas or poorly defined, irregular tumor margins or fringes. All of the fibroblastic, transitional or mixed fibroblastic and transitional variants were well defined with more or less regular shapes. The presence of marked edema, absence of visible Ca aggregates, non-homogeneous contrast enhancement with non-enhancing cystic components and poorly defined irregular borders point to aggressive or invasive characteristics more commonly found in the angioblastic and syncytial variants.