What is Intravenous Contrast?
Intravenous contrast is used in CT to help highlight blood vessels and to enhance the tissue structure of various organs such as the brain, spine, liver and kidneys. “Intravenous” means that the contrast is injected into a vein using a small needle. Typically the contrast is loaded into a power injector, which injects the CT contrast using tubing through the needle into the body during a specific period in the CT exam. The injection is completely under the control of the technologist or radiologist. Once the contrast has been injected into the blood stream, it circulates through the heart and passes into the arteries, through the body’s capillaries and then into the veins and back to the heart. As CT images are being acquired, the CT’s x-ray beam is attenuated (weakened) as they pass through the blood vessels and organs flush with the contrast. This causes the blood vessels and organs filled with the contrast to “enhance” and show up as white areas on the x-ray or CT images.
