Glioma brain tumour. Sequence of magnetic resonance imaging (MRI) axial (horizontal) scans showing the internal structure of the head of a patient with a glioblastoma multiforme (GMB). GMBs are malignant (cancerous) tumours of the glial cells of the central nervous system. In this case, the tumour is located posteriorly in the patient's left frontal lobe. It becomes visible in the second half of the sequence as a rim enhancing lesion with central necrosis (cell death). Oedema (build up of excess fluid) can also be seen surrounding the tumour. This scan is indicative of a high grade primary tumour (this means the tissue has abnormal cells and structure, and the tumour is likely to spread quickly). The pathology identified in this scan was later confirmed through biopsy.