A non-contrast CT scan is a computed tomography scan performed without the use of a special dye intended to make organs show up more visibly, according to Johns Hopkins Medicine. CT scans can be performed with and without contrast, depending on the medical circumstances of each unique case.
Contrast is a special dye used to target specific organs and tissue prior to undergoing CT scans. When doctors order a CT scan during a diagnosis or when examining specific parts of the body, contrast can be very valuable in increasing visibility. Contrast can be taken orally, rectally or injected intravenously, according to Imaginis. In rare cases, contrast can also be administered as a gas, similar to anesthesia. How and when contrast is provided depends on what organs or conditions a doctor needs to examine.
CT scans work through a combination of X-ray technology and computer imaging to produce horizontal images of the body, referred to as slices, according to Johns Hopkins Medicine. CTs can show images of organs, tissue, bones and muscle to give a clear snapshot of the body's interior. A CT is a commonly used medical tool due to its ability to show evidence of lesions, internal bleeding, infection, tumors and numerous other common health complaints. CT scans can be taken during a hospital stay or on an outpatient basis and are most commonly performed on the chest and abdomen.