Magnetic resonance imaging (MRI) is believed to be the best method to examine intracranial tumors. The conventional MRI is not always sufficient to determine if the discovered lesion is radiation injury or tumor recurrence. Perfusion-MRI can be an alternative for examining the relative cerebral blood volume (rCBV) within the lesions active area. The purpose of this literature review was to investigate if a perfusion MRI examination can distinguish a tumor recurrence from a radiation injury. The literature review consists of 13 scientific articles. The result shows that a tumor recurrence in general has a higher rCBV than a radiation injury when examined with perfusion-MRI. It also appears that a tumor recurrence can have a lower rCBV, which usually is associated with a radiation injury. Because of this some of the articles have identified thresholds for the two groups, these thresholds differ slightly among the articles. Perfusion-MRI can be a good alternative to distinguish a tumor recurrence from a radiation injury. More research in this area is needed to establish the thresholds for these two groups.