What are diagnostic imaging tests?

Diagnostic imaging tests are tests that allow doctors to see what’s going on inside your body. Doing this may help them diagnose a medical problem. The diagnostic imaging test or tests your doctor uses will depend on what your symptoms are, and what body part it affects. Below is an overview of the most common types of imaging tests.


An x-ray is a quick, painless imaging test that uses electromagnetic waves to produce images of your body’s internal structures, especially your bones.

How X-ray tests work:

X-ray beams are directed at you via an x-ray machine. As these beams travel through your body, they’re absorbed in differing amounts, depending on how dense the material they’re passing through is. The whitest images on an X-ray film are the densest parts of your body, such as your bones. Fat and muscle are less dense and show up as gray, while the air inside your lungs produces a black image. When a certain area needs to be seen in more detail, you may be given iodine or barium. These substances are called “contrast mediums,” because as they circulate in the body, they provide better detail on the images. X-Rays are used to see details on many body parts. These include:

  • Dental x-rays: Dentists may take X-rays of your teeth in order to check for cavities.
  • Bone x-rays: X-rays can reveal a variety of bone problems, including fractures, arthritis, infections, and tumors. Special types of X-rays can also measure bone density.
  • Chest x-rays: X-rays focused on the chest can be used to diagnose lung conditions such as cancer, tuberculosis, or pneumonia. An X-ray can also help doctors see if a person’s heart is enlarged, which is a symptom of heart failure. If you’re given a contrast material that contains iodine before the x-ray, certain parts of your circulatory system may show up in vivid detail, allowing your physician to see if any of your blood vessels are blocked.
  • Abdominal X-rays: These x-rays can help doctors pinpoint the location of an object a patient has swallowed, or diagnose the source of a digestive problem. Patients may first be given a contrast medium containing barium, to make certain features of the abdomen show up in greater detail on the X-ray film.

Possible complications from X-rays:

  • Radiation exposure: X-rays expose your body to radiation, which can cause cell changes, which can slightly increase risk of developing cancer. The level of radiation X-rays deliver, however, is very low; the risks are generally far outweighed by the benefits. If you are pregnant, do tell your physician—although the risk to your unborn child is low, your doctor may opt for other diagnostic imaging tests instead.

Contrast mediums used in x-rays, and their possible complications:

Patients are sometimes given a substance called a contrast medium before an X-ray is taken, in order for certain parts of the film to show up in greater detail. Contrast mediums may result in the following:

  • A metallic taste in your mouth
  • Flushing and/or a feeling of sudden warmth
  • Nausea
  • Hives
  • Itching
  • Lightheadedness

In rare instances, people may have a severe reaction to the contrast medium. Symptoms can include:

  • Extreme low blood pressure
  • Anaphylaxis (a severe, life-threatening allergic reaction)
  • Cardiac arrest