Head injury: CT scan of a human brain showing bitemporal haemorrhage resulting from a violent head injury. The bilateral nature of the haemorrhage is clearly visible, appearing as white patches in the left & right temporal lobes of the brain. Recent intracranial haematomata, the presence of blood within the brain, has a high density because of the presence of haemoglobin. This accounts for its white appearance on CT scans. Conversely, infarcted (oxygen-deprived) brain tissue has a low density and appears as a dark shade on CT images.