Coloured composite magnetic resonance imaging (MRI) of a brain and 3D computed tomography (CT) scan of a 28-year-old female patient. The patient was admitted to emergency room with suspicion of subarachnoid haemorrhage (SAH) or arteriovenous malformation (AVM). The scan shows an arteriovenous malformation (purple) supplied by the distal branches of the right posterior cerebral artery (PCA) giving rise to a nidus (tangle of blood vessels) surrounded by a magma of draining veins flowing into the superior longitudinal sinus.