Solitary cerebral metastases vs. High-grade Gliomas: Usefulness of two MRI signs in the differential diagnosis

Background/Aim: The differentiation between cerebral metastases (CM) and high-grade gliomas (HGG) can be difficult on magnetic resonance imaging (MRI). The aim of this study was to evaluate the usefulness of searching two MRI signs (signal alteration in the adjacent cortex, SAAC, and peripheral rim sign, PRS), in order to distinguish between these entities. Patients and Methods: A total of 61 patients were retrospectively enrolled (28 HGG, 33 CM). Fluid Attenuated Inversion Recovery (FLAIR) sequences were used to assess SAAC and contrast-enhanced T1-weighted sequences for PRS. Results: A positive SAAC sign was present in 61% of HGG, and 12% of CM. Conversely, in SAAC-negative lesions, PRS was observed in 78% of CM and in 32% of HGG. Their association had a higher frequency in HGG than in the CM group (21 vs. 3%). Conclusion: While SAAC is specific for HGG and PRS, in the absence of SAAC, is relatively specific for CMs, their combined presence is highly suggestive of HGG.