MRI (Magnetic Resonance Imaging)
WHAT IS MRI?
MRI is a painless, non-invasive way to take detailed pictures of internal
organs and tissues using a powerful magnet and radio waves to produce
a series of cross-sectional images of the body. MRI provides high-quality
images with a greater level of detail compared to other imaging modalities.
It gives the best soft tissue contrast and has great benefit in imaging
the brain, spine and musculoskeletal system. Using MRI, doctors can detect
many conditions in earlier stages.
CAN I HAVE AN MRI? WHAT ARE THE RISKS?
MRI examinations are very safe for most people; however, because of the
very strong magnet used, some people cannot enter the MRI machine for
their own safety. MRI should NOT be used for patients with: pacemakers,
cochlear implants, indwelling medication pumps, certain types of cerebral
aneurysm clips, metal fragments in the eyes and some metallic hardware.
For your safety, the presence of certain metallic objects must be determined
before entering the exam room and may need to be removed (e.g., jewelry,
eyeglasses, or hairpins). Inside the bore of the MRI, the space is small
so if you are claustrophobic or think you may be, you may need pre-medication,
an â€œopenâ€ MRI, or MRI may not be for you.
If you are, or may be, pregnant, please discuss this with your doctor
before booking an MRI. There is no evidence that MRI can harm a developing
fetus, but the risk must be evaluated.
Contrast may need to be injected for certain MRI exams. Please see the
If Contrast is Used section for further information regarding the use
of IV contrast.
HOW DOES MRI WORK?
There is a horizontal tube called the â€œbore,â€
which runs through the magnet from front to back. You will lie on your
back and slide into the bore on the table. Once the body part being scanned
is in the center of the magnetic field, the MRI exam begins. You may enter
head first or feet first, and may not be entirely inside the machine depending
on what type of MRI exam is being performed.
Once in the MRI scanner, the magnetic force combines with radio wave pulses
to view various tissues in the body. The power of the magnetic field causes
hydrogen atoms in the body to organize themselves in a certain way. The
radio waves bounce off these hydrogen atoms and the computer records the
signal. Different types of tissues send back different signals. From these
signals, the scanner builds single images called slices and integrates
all of this information to create 2-D images or 3-D models. MRI imaging
is extremely detailed and is often the choice of doctors to diagnose many
conditions because the exam can be tailored to cause tissues in the body
to take on different appearances and to help find abnormalities.
PREPARATION FOR YOUR MRI EXAM
- Most MRI exams do not require any preparation. If you are having an MRCP
(a special MRI of the abdomen), you will need to fast for four to six
hours prior to the exam.
- It is suggested that you do not wear anything metallic, if possible.
- If you are having a scan of your brain, you should not wear make-up, as
some brands contain metal.
- You may take all medications on your usual schedule, as directed by your doctor.
- If you are claustrophobic and are taking any medication to relax you for
the MRI, please take it as directed and bring someone with you to drive
you home after the MRI.
WHEN TO ARRIVE/WHAT TO EXPECT WHEN YOU DO
You should arrive a half hour before your appointment time and report
to Landmark Medical Center's registration area to register and update
your information. You will be sent to MRI where you will change your clothes
and fill out the patient screening form (and possibly a patient questionnaire
for more information about why you are having the MRI). The MRI technologist
will review your answers with you, make sure that you are cleared to enter
the machine, explain the scanning process to you, and answer any questions
you may have prior to performing the scan.
WHAT TO EXPECT DURING THE MRI EXAM
- It is noisy inside the machine, but you may listen to a CD during the exam
or use earplugs to lessen the noise.
- The technologist will position you on the table and may place small â€œcoilsâ€
around the head, arm, leg or other areas to be studied to help send and
receive radio waves for the best quality images.
- The technologist will watch you from the room next door and will communicate
with you via intercom. You and the technologist will be able to see each
other through the windows at all times.
- At any point in time if you feel uncomfortable or need assistance, press
the call button and the technologist will assist you right away.
- You will have to lie flat and very still for the entire exam as movement
reduces the quality of the images.
- You may be asked to hold your breath briefly as pictures are taken during the scan.
- If Gadolinium contrast is used, you will be injected and returned to the
scanner for pictures to be taken with contrast.
- Depending on the type of machine and the area(s) of interest, the exam
may take up to one hour or longer.
IF CONTRAST IS USED
Contrast may sometimes be needed to highlight your organs and/or blood
vessels to help the radiologist to see them better. The contrast used
for MRI exams is called Gadolinium. It does not contain iodine and is
very safe. Reaction is extremely rare. Most patients will feel nothing
at all during or after the injection. The technologist will answer any
questions you may have about the use of Gadolinium prior to injection.
Our equipment is serviced regularly to ensure your safety, and our technologists
are highly skilled and extremely knowledgeable. Also, the MRI patient
screening form is filled out by each patient and will be thoroughly reviewed
with you by the technologist prior to the exam. If there are any contraindications,
the scan will not be performed.
WHAT TO EXPECT AFTER THE MRI EXAM
There are no side effects, after-effects or restrictions after the MRI
exam. You may take all medications and perform all regular activities.
WHAT ABOUT MY RESULTS
Our radiologists will read the exam within 24 hours. If your physician
requests a STAT reading, it will be provided to them via phone call and/or
fax immediately following your exam. The results will also be available
via internet as soon as the final report is dictated by the radiologist.
A copy of the final report will be forwarded to the ordering physician
and/or primary care physician who will discuss the results with you.