Imaging tests are procedures that produce images of internal body organs, tissues, structures and pathways. They may be used to diagnose health conditions and manage diseases. Imaging tests may also be used to assist certain procedures and surgeries.

The most commonly used imaging tests for diagnosing neurological conditions include:

• Angiography. Uses a dye that shows up well on x-rays (radiopaque) and travels through the bloodstream. It is used to identify blood vessel obstructions throughout the body, including in the brain, head or neck.
  
  
• Brain scan. Imaging techniques used to reveal tumors, blood vessel malformations or hemorrhages in the brain. Various technologies can be used to create brain scans.
  
  
• Computed axial tomography. Also known as a CAT scan or CT scan. It uses a rotating x-ray device to create detailed cross-sectional images (or slices) of different body parts.
  
  
• Magnetic resonance imaging (MRI). Test that uses computer-generated radio waves to produce clear, cross-sectional or three-dimensional images of the body’s tissues, even through bone and other obstructions.

• Myelography. Procedure in which a dye is injected into the spinal canal to help highlight abnormalities in the spine during x-rays.
  
  
• Positron emission tomography (PET) scans. Radioactive isotopes are injected into the bloodstream to provide two- and three-dimensional images of brain activity.
  
  
• Single photon emission computed tomography (SPECT) scan. Radionuclide imaging test that evaluates brain function by highlighting blood flow to brain tissue.
  
  
• Thermography. Infrared sensing devices are used to detect changes in temperature between the two sides of the body or within a single organ.
  
  
• Ultrasound. Test that uses high frequency sound waves rather than radiation to create images of internal organs or tissues.
  
  
• X-ray. Creates an image of part of the body using low doses of electromagnetic radiation that are reflected on film or fluorescent screens.

A radiology technician in a hospital or outpatient clinic generally performs imaging tests. Patient preparation differs depending on the nature of the test to be performed. In some instances, the patient may need to drink or be injected with a dye known as a contrast medium. This solution makes certain organs and tissues in the body more visible.

The imaging test procedures are different depending on which test is performed. Generally, patients are able to return home the same day of the test. Imaging tests carry very few risks.