Reasons you may not be able to
have the test or why the results may not be helpful include:
Pregnancy. An MRI test usually is not done
Medical devices that use electronics, such as a
pacemaker or medicine infusion pump. The MRI magnet may cause problems with
these devices, and that may keep you from having an MRI.
Medical devices that have metal in them. The metal might make
some of the detailed MRI pictures blurry. This may prevent your doctor from
seeing the organ that is being looked at. For example, any metal in your spine
may prevent your doctor from seeing it clearly.
Inability to remain
still during the test.
person who is very overweight may not fit into standard MRI machines.
Many modern medical devices that do not use
electronics-such as heart valves, stents, or clips-can be safely placed in most
MRI machines. But some newer MRI machines have stronger magnets. The safety of
MRI scans with these stronger MRI magnets in people with medical devices is not
What To Think About
Sometimes your MRI test results may be
different from the results of CT, ultrasound, or X-ray tests, because the MRI
scan shows tissue differently.
MRI is a safe test for
looking at structures and organs inside the body. It costs more than other
methods and may not be available in your area.
Open MRI machines
are now made so that the magnet does not completely surround you. But these
machines may not be available in all medical centers. Open MRI is useful for
people who are claustrophobic or obese.
Contrast material that contains gadolinium may cause a serious skin problem
(called nephrogenic fibrosing dermopathy) in people with
kidney failure. Before having an MRI scan, tell your
doctor if you have serious kidney disease or if you have had a kidney
Other Works Consulted
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
Fischbach FT, Dunning MB III, eds. (2009).
Manual of Laboratory and Diagnostic Tests, 8th ed.
Philadelphia: Lippincott Williams and Wilkins.