Intracranial meningiomas: high-field MR imaging.

Twenty-five newly diagnosed intracranial meningiomas were evaluated with magnetic resonance (MR) imaging at 1.5 T, and findings were correlated with those of computed tomography (CT), angiography, and tumor histology. Meningiomas were generally hypointense on T1-weighted images and hyperintense on T2-weighted images relative to cerebral white matter. In comparison with the cortex, they were hypointense or isointense on T1-weighted images and isointense or hyperintense on T2-weighted images. A heterogeneous texture produced by tumor vascularity, calcifications, cystic foci, or an intrinsic speckled or mottled pattern was observed in all but the smallest lesions. An interface between meningioma and brain was uniformly present and consisted of a cerebro-spinal fluid cleft, vascular rim, or dural margin. Large meningiomas were associated with arcuate displacement and compression of adjacent gyri. MR imaging was superior to CT in defining extracerebral tumor location, tumor vascularity, arterial encasement, and venous sinus invasion. No correlation was found between the appearance on MR images and the pathologic classification.