How does CT machine work?
A CT scanner uses a precisely directed X ray beam that is focused on a specific part of the body. This beam passes through the body, and the pattern of shadows created by the body is recorded by a detector, which feeds the information it receives into a computer. The computer then analyzes the information on the basis of tissue density. Bone (being very dense) is depicted in white; air in black; and water and soft tissue in varying shades of gray depending on its density. The IV contrast makes the blood temporarily very dense, so blood vessels are depicted in light gray to white.
