FAQ MRI
- What is high field MRI? How big / long is the tube (length) and bore (opening)?
- Are there any reasons I can't have an MRI exam?
- How long will I be in the magnet? Do I have to hold still?
- Is there any radiation involved in MRI?
- If I have to have a contrast injection, where will it be injected?
1. What is high field MRI? How big / long is the tube (length) and bore (opening)?
High field MRI is a term to describe the comparative magnetic field strength of a MRI magnet. High field magnets
range in strength from 1 to 1.5 tesla as opposed to low field magnets (open MRI), which range in strength from
.2 to .3 tesla. High field magnets are known for high resolution images and faster times. Today, high field
magnets linear in dimension vary between 5 and 8 feet. Both ends of high field magnet's are open and range
between 20" to 22" in diameter.
2. Are there any reasons I can't have an MRI exam?
The magnetic strength and narrow configuration of MRI magnets can prevent examination of some patients. Patients
with metal in their body from pacemakers, brain aneurysm clips, neuro or bone stimulators, BBs or metal fragments
in the eye are not safe candidates for MRI exam. Large patients with body weight near 300 pounds may not be
accommodated by the limitations of a conventional MRI unit. Short Bore or open MRI may provide examination alternatives
for such patients to include those with special needs and/or severe anxiety / claustrophobia.
3. How long will I be in the magnet? Do I have to hold still?
Motion can distort images, so you will be asked to lie still for periods (sequences) of 5 to 15 minutes. Total
examination times vary from 30 minutes to 1 hour or more, depending on the information needed.
4. Is there any radiation involved in MRI?
MRI uses a combination of radio frequencies and magnetic field to produce images. It does not involve radiation.
5. If I have to have a contrast injection, where will it be injected?
Intravenous (IV) contrast injections are administered by a technologist or a nurse and placed in a vein in
your hand or arm to enhance the results. Contrast reactions / allergies to the contrast agent (Gadolinium) are
rare.
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