Imaging tests are procedures that produce images of internal body organs, tissues, structures and pathways. They may be used in the diagnosis of health conditions and the management of disease. Imaging tests may also be used to assist certain procedures and surgeries. Patients with emotional health disorders may have imaging tests to help identify the source of a problem or to rule out other conditions that might be responsible for their symptoms.

Some mental health conditions that affect the brain may be diagnosed with an imaging test. These include disorders that may cause psychosis and cognitive disorders. Imaging tests can also be helpful in diagnosing damage caused by eating disorders such as anorexia nervosa, bulimia nervosa and pica.

The most commonly used imaging tests for diagnosing emotional disorders include:

• Computed axial tomography (CAT) scan. Also known as a CT scan, it is a noninvasive or minimally invasive test that uses a rotating x-ray device to create detailed cross-sectional images (or slices) of different body parts.
  
  
• Magnetic resonance imaging (MRI). A safe and noninvasive or minimally invasive test that produces clear, cross-sectional or three-dimensional images of the body’s tissues, even through bone and other obstructions.
  
  
• Ultrasound. Uses high-frequency sound waves to create images of internal organs or tissues.
  
  
• X-ray. A test in which an image is created of part of the body by using low doses of electromagnetic radiation that are reflected on film or fluorescent screens.

Imaging tests are generally performed by a radiology technician in a hospital or outpatient clinic. Patient preparation differs depending on the nature of the test to be performed, but may include modifications to a patient’s diet or medication regimen. In some instances, a patient may 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 generally carry very few risks to the patient. However, some tests such as x-rays and CAT scans that use radiation should not be performed on pregnant women unless the potential benefits of these tests outweigh their risks.

Imaging tests produce pictures of internal body organs, tissues, structures and pathways. Some tests can be performed with external devices, including magnetic resonance imaging (MRI), computed axial tomography (CAT) scan and ultrasound. Other tests require that a device be inserted into a body opening, such as endoscopy.

Imaging tests are used in the diagnosis of conditions and the management of disease. They may also be used to assist certain procedures and surgeries, or to rule out conditions (e.g., a brain tumor) that may cause similar symptoms to a mental health disorder (e.g., schizophrenia). In some cases, a dye known as a contrast medium will be used as part of an imaging test. This solution contains an iodine liquid that makes certain organs and tissues in the body more visible by highlighting their structure. This helps reveal the presence of disease or injury.

Imaging tests are sometimes used to help diagnose physical and mental disorders that may affect a person’s psychological state. In other cases, these tests may be used to diagnose complications related to mental health conditions. Examples of conditions or complications diagnosed with imaging tests include:

• Anorexia nervosa or bulimia nervosa. Imaging tests are useful in detecting the presence of any damage in the chest, digestive tract, organs and/or brain caused by the eating disorders anorexia nervosa or bulimia nervosa. For example, a chest x-ray may reveal whether anorexia has damaged the heart muscles by reducing the size of the heart. Or, an abdominal x-ray may reveal whether bulimia has caused a tear in the esophagus, a rare complication of bulimia that requires emergency surgery.
  
  
• Pica. Imaging tests are useful in detecting the presence of any damage and/or blockages in the stomach, digestive tract and organs caused by eating nonfood substances.
  
  
• Cognitive disorders. Imaging tests such as CAT scans and MRIs may help a physician to find brain abnormalities that may be responsible for certain cases of delirium and dementia, and some types of memory loss associated with amnestic disorder.
  
  
• Psychosis. Imaging tests such as MRIs can help physicians diagnose diseases of numerous organs and vessels, including brain abnormalities that may be producing various symptoms.

Imaging tests are also used in research studies that examine brain structure or chemistry abnormalities. These tests may help devise new patient treatment methods for some mental illnesses. This research may also assist in revealing any physical causes of certain mental health disorders (e.g., obsessive-compulsive disorder [OCD], attention deficit hyperactivity disorder [ADHD]) in the future.

There are several types of imaging tests that can be used to view internal structures of the body. The tests most widely used in diagnosing mental health conditions include:

• Computed axial tomography (CAT) scan. Also known as a CT scan, it is a noninvasive or minimally invasive test that uses a rotating x-ray device to create detailed, cross-sectional images (or slices) of different body parts. It may be performed alone or with the use of a special dye (contrast medium).
  
  
• Magnetic resonance imaging (MRI). A minimally invasive test that produces clear, cross-sectional or three-dimensional images of the body’s tissues, even through bone and other obstructions. Because of its safety and clarity, the MRI is a valuable tool that can aid in the diagnosis of a wide range of conditions in nearly every part of the body.
  
  
• Ultrasound. Uses high-frequency sound waves to create images of internal organs or tissues. It works by sending low-energy sound waves against tissue. Some waves pass through the tissue and others bounce back. As sound waves bounce back, they are recorded and displayed on a computer screen or television-type monitor. The image created by an ultrasound is considered to be less clear than those from CAT scans and MRIs. However, it is often used for a wide array of procedures because it is fast, painless, generally noninvasive and relatively inexpensive.
  
  
• X-ray. A painless test in which an image is created of part of the body by using low doses of electromagnetic radiation that are reflected on film or fluorescent screens. X-rays can be used in diagnosis of a wide range of conditions including bone chips and fractures; sprains and strains; and tooth or jaw pain.
  
  
• Radionuclide imaging.  A type of imaging technique that allows physicians to obtain clear images of various parts of the body. To obtain the images generated by this technique, tiny amounts of radioactive materials (called “tracers”) are introduced into the patient’s body. The tracers emit a type of energy called gamma rays, which are detected by special devices. Examples of radionuclide imaging include PET scans (positron emission tomography scan) and the SPECT (single-photon emission computed tomography) scan. Research indicates that PET scans may be useful in identifying abnormal deposits that form in the brains of people with Alzheimer’s disease.  However, it is not a diagnostic test to determine if some suffers from Alzheimer’s.

Patients are urged follow all preparatory steps recommended by their physician prior to the imaging test. Both the physician and the technician should be informed about any implanted metal or electronic devices, such as prostheses and pacemakers. Immediately before the test, patients may be asked to change into a hospital gown. All metallic objects, such as watches and jewelry, should be removed so they do not interfere with test results. In fact, patients may want to leave these objects at home on the day of the test. Infants or children receiving the test may be given a sedative to ensure they are relaxed and remain still during the test.

If a dye known as a contrast medium is to be used, the patient may be instructed not to eat or drink for several hours before the test. Patients may also be instructed to refrain from taking certain medications prior to the test.

Contrast mediums may be administered orally (by mouth), through an enema or injected into a vein. Injection of the dye may produce a warm, flushed feeling for several minutes or a metallic taste in the mouth. Both sensations are normal and typically disappear quickly.

Imaging tests are generally performed by a radiology technician in a hospital or outpatient clinic. The manner in which the test unfolds will depend upon the imaging procedure being used. For example, patients receiving a computed axial tomography (CAT) scan will lie down and remain still on a scanning table, which slides slowly into a short, open-ended tunnel. The x-ray sensing unit and detectors then rotate around the body as images are captured.

During magnetic resonance imaging (MRI), the patient is placed on a long bed that slides into the MRI chamber. Once inside the chamber, the patient should relax and lie still for the duration of the procedure. Patients may be instructed to hold their breath at times. The MRI equipment will make many different types of noises during the scan as it takes multiple views of the target site. These noises are a normal part of the MRI procedure.

During an ultrasound, a small amount of water-soluble gel (to help transmit the sound waves) is placed on the part of the body to be tested. The technician places a wand-like instrument called a transducer on the part of the body to be scanned. In some tests, a probe transducer may be placed within an opening, such as the vagina or anus. The sound waves sent from the transducer bounce off the structures within the body and the information is deciphered by the computer to create the ultrasound images. The ultrasound images then appear on the television monitor and the moving pictures can be recorded on videotape.

During an x-ray, the patient will sit, stand or lie down between the x-ray machine and x-ray film. The x-ray machine is then pointed at the area being examined. While exposed to x-rays, the patient may be encouraged to hold the breath to help remain still. Movement during an x-ray test can cause images to blur on film. Multiple x-rays may be taken from different angles if necessary.

Imaging tests can take anywhere from a few minutes to several hours to complete, depending on the nature of the test and the part of the body to be examined. Most imaging tests are painless.

In many cases, patients undergoing imaging tests should be able to leave the facility immediately following the imaging test with no side effects. However, if a sedative is administered, patients will be monitored until the effects of the sedative have passed. They will then need a friend or relative to drive them home from the test site.

Imaging tests are generally safe and present few risks to the patient. However, there are some factors that should be kept in mind before having one of these tests.

In general, pregnant women are advised to avoid imaging tests such as x-rays, computed axial tomography (CAT) scans and magnetic resonance imaging (MRI) tests unless absolutely necessary. This is because these tests involve low levels of radiation (x-rays and CAT scans) or exposure to powerful agents (MRIs), and the effect on an fetus is not always known.

Radiation levels used with CAT scans are higher than those used with x-rays. Although some patients are concerned about radiation exposure from a CAT scan, the tests are safe and it is important to weigh the potential risks against the potentially life-saving benefits of the information obtained from the test.

In rare cases, the special dye (contrast medium) used during a CAT scan, MRI or other imaging test may cause an allergic reaction in the form of mild itching or hives (small, raised, reddened areas of skin). In more severe reactions, shortness of breath and swelling of the throat or other body areas may occur. Patients who notice any of these symptoms developing during the procedure should immediately alert the technician performing the test.

Patients should also inform the physician of the following before the test:

• Asthma or allergies. Contrast mediums can produce allergic reactions in some people, especially those with a history of asthma or allergies.
  
  
• Other medical conditions. Certain medical conditions may also increase the likelihood of an allergic reaction to contrast mediums. These include diabetes, heart disease, kidney problems and thyroid conditions.

MRI tests are not performed on patients with pacemakers or individuals with certain implants, such as some artificial joints or those used in some forms of back surgery.

Patients with tattoos or permanent makeup are encouraged to consult with their physician before an MRI is performed. These patients might experience some mild discomfort or a burning feeling on their skin due to a reaction between iron oxide or other metallic substances commonly found in the darker inks of the tattoo and the magnetic field generated during the test. Furthermore, large or very dark tattoos can also cause “artifacts,” or false shadows to appear on the film produced from the test.

If the MRI involves injection of a contrast medium, there is the possibility of a reaction. An individual may experience nausea, headache or pain at the site of injection.

Ultrasounds are considered to be extremely safe and have no significant side effects when performed properly. In extensive studies, no risks associated with properly conducted medical ultrasound have been documented. Unlike x-rays, there is no exposure to radiation during an ultrasound. This test is a noninvasive procedure that is widely available, easy to use and causes little patient discomfort.

In recent years, a trend of nonmedical ultrasound has arisen. Many facilities offer portraits or videos of fetuses as mementos for expectant parents. The U.S. Food and Drug Administration (FDA) has advised against these nonmedical ultrasounds. They are often performed by untrained individuals who may use a sound frequency that is too high or a duration that is too long to be safe.

The levels of radiation used in x-ray procedures are so low that they pose only minimal risk to patients. As a precaution, some patients may be asked to wear a lead apron to shield sex organs from exposure to radiation. At very high doses, radiation can damage a woman’s eggs or a man’s sperm.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions related to imaging tests:

1. Why do you recommend that I have an imaging test?
   
   
2. Which type of imaging test is best to diagnose my condition? Why?
   
   
3. Can you explain the procedure to me in detail?
   
   
4. What information will my imaging test provide?
   
   
5. How should I prepare for my imaging test?
   
   
6. Will a contrast medium be used during my imaging test?
   
   
7. Will my imaging test cause me any pain or discomfort?
   
   
8. Will I need to take a sedative for the discomfort?
   
   
9. Should I plan to have someone drive me home after the test?
   
   
10. When will I know my results?