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MRI: Frequently Asked Questions

Thursday, April 19, 2012 - 13:54

Contributing Author: Guy Slowik FRCS

Here are some frequently asked questions related to MRI.

Q: Are the "radio waves" used in MRI like regular radio waves?

A: No. While the MRI does use a radio wave antenna to send signals to the body and receive signals back during the procedure, the "radio wave signals" are actually a changing magnetic field that is much weaker than the strong magnetic field of the main magnet in the machine.

Q: Why not just get an x-ray?

A: MRIs are particularly useful for looking at the non-bony parts or "soft tissues" of the body-the same types of body parts and tissues that x-ray machines are not designed to pick up

Q: Are there any disadvantages to MRI?

A: Aside from those who suffer from claustrophobia, or who have implanted medical devices that prohibit the use of MRI, there are no known medical disadvantages. One financial disadvantage is that the MRI costs more than a regular x-ray or CT scan.

Q: Why are "stress tests" ordered?

A: Standard stress tests such as treadmill exercise tests, in which the patient walks on a treadmill while being "hooked up" to an electrocardiogram machine, can indicate how well the heart handles increased physical exertion. Stress tests also help physicians to find a blockage or other problem in the blood vessels of the heart.

Q: What is the main difference between x-ray and MRI?

A: Aside from the fact that MRI does not use radiation to obtain images, the biggest difference is that MRI can "see through" bone and define fluid-filled soft-tissue, while x-rays can only define bone.