Radiographic predictors of peritumoral brain edema in intracranial meningiomas: a review of current controversies and illustrative cases.

Meningiomas are among the most common primary tumors of the central nervous system. In the past several decades, many researchers have emphasized the importance of radiographic findings and their possible role in predicting the various aspects of the meningioma biology. One of the factors most commonly analyzed with respect to the lesions' clinical behavior is peritumoral brain edema (PTBE), not only one of the most common signs associated with meningiomas, but also a significant clinical problem. Radiographic predictors of PTBE are usually noted as being the size of the tumor, its location, irregular margins, heterogeneity, and the peritumoral arachnoid plane with its pial vascular recruitment. Here, we review the available literature on the topic of these radiographic predictors of PTBE formation, we analyze the methodology of the research conducted, and we highlight the many controversies still present. Indeed, the evidence about PTBE pathogenesis, predictive factors, and clinical significance still seems to be mostly inconclusive, despite intense research in the area. We believe that by highlighting the many inconsistencies in the methodology used, we can showcase how little is actually known about the pathogenesis of PTBE, which in turn has important clinical implications. Additionally, we provide several MR images of intracranial meningiomas from our own practice which, we believe, showcase the unpredictable nature of PTBE, and demonstrate vividly the topics we discuss.