Magnetic Resonance Imaging (MRI) of the Body

Test Overview

Magnetic resonance imaging (MRI) is a test that provides pictures of organs and structures inside the body. It does this by using a magnetic field and pulses of radio wave energy. In many cases, MRI provides information that cannot be obtained from X-ray tests.

For an MRI test, the area of the body being studied is positioned inside a strong magnetic field. The MRI can detect changes in the normal structure and characteristics of organs or other tissues. It can also help diagnose conditions that affect blood flow. Tissues and organs that contain water and fat provide the most detailed pictures. This makes MRI most useful for detecting conditions that replace normal fat or increase the amount of fluid in a tissue, such as inflammation, infection, tumors, and injury. Information from an MRI scan can be saved and stored on a computer for further study. Photographs or films of selected views can also be made.

In some cases a contrast material may be used during the MRI scan to enhance the images of certain structures. The contrast material may help evaluate blood flow, detect some types of tumors, and locate areas of inflammation.

Why It Is Done?

Magnetic resonance imaging (MRI) is used to detect problems of the:

• Head and brain (including the ears). MRI can help detect brain tumors, an aneurysm, bleeding in the brain, nerve injury caused by multiple sclerosis (MS), and other types of brain damage (such as damage caused by a stroke). MRI can also reveal problems of the eyes, the optic nerves, the ears, and the auditory nerves. For more information, see the medical test Magnetic Resonance Imaging (MRI) of the Head.
  
  
• Chest (including the heart). MRI can be used to look at structures of the heart, such as the valves and coronary blood vessels. It can detect damage to the heart or lungs (such as from tumors). MRI of the chest also can be used to help diagnose early breast cancer.
  
  
• Blood vessels. The use of MRI to look at blood vessels and the flow of blood through them is called magnetic resonance angiography (MRA). It can help detect problems of the arteries and veins, such as an aneurysm, blockage of a blood vessel (by fatty deposits or a blood clot), or a torn inner lining of a blood vessel (dissection). For more information, see the medical test Magnetic Resonance Angiography.
  
  
• Abdomen. MRI can detect problems of the organs and structures in the abdomen, such as tumors, bleeding, infection, and blockage. For more information, see the medical test Magnetic Resonance Imaging (MRI) of the Abdomen.
  
  
• Bones and joints. MRI can help detect some problems of the bones, joints, and soft tissues of a joint,
  such as cartilage, ligaments, and tendons. Conditions that can be evaluated include arthritis, problems with the temporomandibular joint, bone marrow disorders, bone tumors, cartilage tears, worn-out cartilage, torn ligaments, or infection. MRI may also help diagnosis a bone fracture when X-ray results are inconclusive. MRI is done more commonly than other tests (such as arthrography) to evaluate certain bone and joint problems. For more information, see the medical tests Magnetic Resonance Imaging (MRI) of the Shoulder and Magnetic Resonance Imaging (MRI) of the Knee.
  
  
• Spine. MRI can be used to help diagnose conditions such as spinal stenosis, disc bulges, and spinal tumors. For more information, see the medical test Magnetic Resonance Imaging (MRI) of the Spine.