Acoustic neuroma: false-colour magnetic resonance image (MRI) scan of an axial section of the head of someone suffering from an acoustic neurofibroma (neuroma), a benign (non-cancerous) tumour of the internal auditory meatus (IAM) that results in progressive deafness. Here, the tumour appears as a circular lesion, coloured green. Its appearance on the original black & white MRI image was enhanced by the intravenous injection of a Gadolinium-based contrast agent. Such a tumour may grow to compress the brain stem; surgical removal is the only cure & this is likely to result in a loss of hearing on the affected side. T1-weighted MRI scan: Gd contrast enhancement. Green tumour: purple, pink & blue head & brain.