Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging (MRI) is a
test that uses a magnetic field and pulses of radio wave energy to make
pictures of organs and structures inside the body. In many cases MRI gives
different information about structures in the body than can be seen with an
computed tomography (CT) scan. MRI also may show
problems that cannot be seen with other imaging methods.
MRI test, the area of the body being studied is placed inside a special machine
that contains a strong magnet. Pictures from an MRI scan are digital images
that can be saved and stored on a computer for more study. The images also can
be reviewed remotely, such as in a clinic or an operating room. In some cases,
contrast material may be used during the MRI scan to
show certain structures more clearly.
See pictures of a
standard MRI machine and an
open MRI machine .
Why It Is Done
Magnetic resonance imaging (MRI) is
done for many reasons. It is used to find problems such as tumors, bleeding,
injury, blood vessel diseases, or infection. MRI also may be done to provide
more information about a problem seen on an X-ray, ultrasound scan, or CT scan.
Contrast material may be used during MRI to show abnormal tissue more clearly.
An MRI scan can be done for the:
- Head. MRI can look at the brain for tumors, an
aneurysm, bleeding in the brain, nerve injury, and
other problems, such as damage caused by a
stroke. MRI can also find problems of the eyes and
optic nerves, and the ears and
- Chest. MRI of the chest can look at the heart, the
coronary blood vessels. It can show if the heart or
lungs are damaged. MRI of the chest may also be used to look for
- Blood vessels. Using MRI to look at blood vessels
and the flow of blood through them is called
magnetic resonance angiography (MRA). It can find
problems of the arteries and veins, such as an aneurysm, a blocked blood
vessel, or the torn lining of a blood vessel (dissection). Sometimes contrast
material is used to see the blood vessels more clearly.
- Abdomen and pelvis. MRI can find problems in the
organs and structures in the belly, such as the liver, gallbladder, pancreas,
kidneys, and bladder. It is used to find tumors, bleeding, infection, and
blockage. In women, it can look at the uterus and ovaries. In men, it looks at
- Bones and joints. MRI can check for problems of the
bones and joints, such as
arthritis, problems with the
bone marrow problems, bone tumors,
cartilage problems, torn
tendons, or infection. MRI may also be used to tell if
a bone is broken when X-ray results are not clear. MRI is done more commonly
than other tests to check for some bone and joint problems.
- Spine. MRI can check the discs and nerves of the
spine for conditions such as
disc bulges, and