Consequences of inflammation for imaging diagnosis: differentiating between tumors and inflammatory lesions
Conventional neuroradiological techniques do not always allow a differentiation between radiation necrosis and GBM recurrence, given that both recurrent tumors and necrosis (pseudoprogressions) may appear as similar lesions in MRI protocols such as T2- and gadolinium-enhanced T1-weighted imaging, with an increase in contrast enhancement and the image of a mass [31, 37-42]. PET imaging using18F-Fluorodeoxyglucose (FDG-PET), in turn, can be useful in differentiating radiation-induced lesions from recurrent GBM [31, 43]. However, with this method false-positive and false-negative PET scan results can lead to low sensitivity and pose a severe limitation [44].