Magnetic resonance imaging spectrum of intracranial meningiomas: An institutional review of common and uncommon imaging appearances

Objectives: Meningiomas are the most common non-glial central nervous system (CNS) tumors, typically presenting as well-defined extra-axial masses with distinct computed tomography (CT) and magnetic resonance imaging (MRI) features. Despite their characteristic appearance, some meningiomas exhibit atypical features that can be diagnostically challenging. This study aims to analyze the imaging findings of meningiomas in a series of 82 cases, covering both common and uncommon locations, and exploring their typical as well as atypical/malignant features. Material and Methods: A retrospective review was conducted on 82 patients with pathologically confirmed meningiomas who underwent both CT and diffusion-weighted MRI (1.5 T) at our institution. The imaging data were analyzed to assess various parameters, including age incidence, sex distribution, tumor location, T1- and T2-weighted sequences, contrast enhancement patterns, and the presence of calcifications, cysts, peritumoral edema, hemorrhage, and magnetic resonance spectroscopy findings. Results: The analysis revealed a spectrum of imaging characteristics across the 82 meningioma cases. While many tumors exhibited typical imaging features, such as well-circumscribed margins and homogeneous contrast enhancement, others presented with atypical or malignant features, including heterogeneous signal intensity, irregular borders, and evidence of invasion into adjacent structures. The study also identified a range of tumor locations, with both common (e.g., convexity and parasagittal) and uncommon (e.g., intraventricular and skull base) sites represented. Peritumoral edema, calcifications, cystic changes, and hemorrhage were noted in varying frequencies across the cases, providing insights into the diverse radiological presentations of meningiomas. Conclusion: Meningiomas are the most common non-glial primary neoplasms of the CNS, and their diagnosis is generally straightforward when located in typical regions with characteristic imaging features. However, it is crucial for radiologists to recognize that meningiomas can present in atypical locations and with misleading or atypical imaging characteristics. A broad understanding of these variations is essential for accurate diagnosis and appropriate management of meningiomas, especially in cases where the imaging findings are not straightforward.