In addition to having multiple compounds to make the contrast, you also have several choices when it comes to how the contrast enters the body. Once again, these methods will differ based upon the particular type of test being done. Most contrasts will be injected into the patient’s bloodstream via the veins. This is known as the intravenous method, and is often used to enhance images of the internal organs, GI tract, arteries, soft tissues, brain, and breast. Contrast materials can also be given orally, allowing the patient to swallow the substance. As you can imagine, the oral method is best to examine the esophagus, pharynx, stomach, or upper gastrointestinal tract. Another route of contrast administration would be through a catheter placed inside the bladder, Cystogram (CT or X-ray). If your physician is more interested in assessing your lower gastrointestinal tract, they may recommend a rectally administered contrast by way of an enema.