Imaging tests provide a picture of the body’s interior—of the whole body or part of it. Imaging helps doctors diagnose a disorder, determine how severe the disorder is, and monitor people after the disorder is diagnosed. Most imaging tests are painless, relatively safe, and noninvasive (that is, they do not require an incision in the skin or the insertion of an instrument into the body).
Imaging tests may use the following:
Radiation, as in x-rays, angiography, computed tomography (CT), and radionuclide scanning including positron emission tomography (PET)
Sound waves, as in ultrasound
Magnetic fields, as in magnetic resonance imaging (MRI)
Substances that are swallowed, injected, or inserted to highlight or outline the tissue or organ to be examined (called contrast agents)
There are some risks of using radiation in medical imaging.
For information regarding imaging tests common for specific diagnoses and screenings, see the following:
