Differentiation of Typical and Atypical Meningiomas Using Magnetic Resonance Imaging

Background: Meningiomas are the most common intracranial neoplasms. They are usually homogeneously enhancing extraaxial masses. However, 10% of meningiomas are atypical with different imaging appearance. Distinguishing typical from atypical meningiomas on imaging is highly important in surgical and treatment planning. Materials and Methods: Our study was a retrospective one comprising twenty cases each of pathologically proven typical and atypical meningiomas excluding enplaque lesions. Magnetic resonance images were reviewed with each of the lesions showed as dural-based enhancing mass. Individual features analyzed were age, gender, maximum size, location, signal characteristics on T1, T2 weighted, susceptibility weighted imaging, diffusion-weighted, apparent diffusion coefficient, contrast-enhanced T1, interface with adjacent brain tissue, signal changes in adjacent brain tissue, and changes in overlying bone. Aim: The aim of the study is to retrospectively assess the magnetic resonance imaging (MRI) features of pathologically proven typical and atypical meningiomas. Results: Magnetic resonance features such as diffusion restriction, bony changes in form of destruction, indistinct interface with brain parenchyma, heterogeneous postcontrast enhancement, and edematous changes >6 mm thick in adjacent brain parenchyma were in favor of atypical meningioma. Conclusion: MRI has the ability to differentiate typical and atypical meningiomas based on imaging appearance which is important in surgical and treatment planning.