What is an MRI?
Apr 9, 2015 | 8:00 am
What is Magnetic Resonance Imaging?
Magnetic Resonance Imaging (MRI) is a diagnostic procedure that uses a combination of a large magnet, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. MRI does not use ionizing radiation, unlike x-rays or computed tomography (CT scans).
How does MRI work?
MRI machines have a large coil in the cylinder where the magnet is. When the MRI takes place, the patient is laid flat on a long bed that slides in and out of the cylinder. The radiology technician slides the bed to the region of the body where the MRI will be needed. The coil receives the image of the MRI. As the magnetic force is created, other coils bounce the radio waves inside the tube. The body’s protons align themselves in reaction to this action. Once the molecules are excited, the information is sent to a computer, which records the images that occur as a result of this procedure. The strength of the magnetic field can be altered electronically from head to toe using a series of gradient electric coils, and, by altering the local magnetic field by these small increments; different slices of the body will resonate as different frequencies are applied.
How long does the MRI take?
Depending on the region of the body being studied, the MRI will take anywhere from 30 minutes to an hour. If many levels of the spine or multiple organs are being examined, it may take longer.
Is there pain involved with the MRI?
The MRI is absolutely painless. However, many people may experience a bit of claustrophobia once they enter the tube, which seems to be right in front of the eyes once inside. It can be challenging even to people who do not have claustrophobic issues. The best thing to do is keep the eyes shut and concentrate on something besides being in such a tight space. There is a nice updated version of the MRI machine called the open MRI. These are wonderful for patients who have issues with tight spots and when scheduling these procedures, one may ask to be sent to a facility that has an open MRI.
The sound of the magnets can be very noisy and quite annoying. Even though the procedure is painless, being closed in and having the loud noise can make some people very uncomfortable. Some facilities may offer music as a method to relax the patient during the procedure.
How can I prepare for MRI?
If claustrophobia is a known issue, it may help to ask the doctor if a small amount of anti-anxiety medication may be prescribed before the procedure. This will help insure the patient is still and relaxed. Complete stillness is necessary in order to get clear imaging during this procedure.
It is best to make sure that all jewelry is removed before the procedure since a magnet is involved. All magnetic objects like cards with magnetic strips, underwear clasps and hair ornaments should also be removed.