What the risks are:

There is no radiation involved in MRI. The magnetic fields and radio waves used during the same have not been shown to cause any significant side effects.

Allergic reactions to the dye used during the exam are rare. The most common type of contrast (dye) used is gadolinium. It is very safe. The person operating the machine will monitor your heart rate and breathing as needed.

People have been harmed in MRI machines when they did not remove metal objects from their clothes or when metal objects were left in the room by others.

MRI is usually not recommended for traumatic injuries, because traction and life-support equipment cannot safely enter the scanner area, and scans can take a long time.

Special considerations:

MRI is more accurate than CT scan or other tests for certain conditions, but less accurate for others. MRIs can be costly, take a long time to perform, and are sensitive to movement. Persons with claustrophobia or who are anxious may have difficulty lying still for the scans.