Healthy brain. Colored computed topography (CT or CAT) scan of an axial section through a healthy brain from a 70-year-old man. The front of the brain is at bottom frame. Colored orange are the cerebral hemispheres. Colored black are the ventricles. Blue colored circles on the ventricles either side of the brain's mid line represent the choroid plexi of blood vessels. Irregularly shaped (blue) at upper center is the pineal gland. CT scanning combines the use of a computer and fine X-ray beams to produce images of 'slices' through body parts. The scans produce good contrast between soft tissues and bone and are useful in diagnosing tumors and blood clots.