Magnetic resonance imaging (MRI) is a non-invasive medical test that helps
physicians diagnose and treat medical conditions.
The MRI uses a powerful magnetic field, radio frequency pulses and a computer
to produce detailed pictures of organs, soft tissues, bone and virtually
all other internal body structures. The images can then be examined on
a computer monitor, transmitted electronically, printed or copied to a
CD. MRI does not use ionizing radiation (x-rays).
Detailed Magnetic Resonance images allow physicians to evaluate various
parts of the body and determine the presence of certain diseases.
What are Some Common Uses of the Procedure?
Cardiac MRI imaging is performed to help your physician detect or monitor
cardiac disease by:
- Evaluating the anatomy and function of the heart chambers, valves, size
and blood flow through major vessels, and surrounding structures such
as the pericardium (the fluid-filled sac that surrounds the heart).
- Diagnosing a variety of cardiovascular (heart and/or blood vessel) disorders
such as tumors, infections, and inflammatory conditions.
Evaluating the effects of
coronary artery disease such as limited blood flow to the heart muscle and scarring within the
heart muscle after a heart attack.
- Planning a patient's treatment for cardiovascular disorders.
- Monitoring the progression of certain disorders over time.
Before your test
- MRI uses strong magnets, so you'll be asked to remove your watch, jewelry
and other metal objects.
- Most MRI tests take 30 to 60 minutes. Allow yourself extra time to check in.
In most cases, an MRI exam is safe for patients with metal implants, with
only a few exceptions. People with the following implants cannot be scanned
and should not enter the MRI scanning area unless explicitly instructed
to do so by a radiologist or technologist who is aware of the presence
of any of the following:
- Artificial heart valves
- Implanted drug infusion ports
- Implanted electronic device, including a cardiac defibrillator, pacemaker
or retained leads
- Artificial limbs or metallic joint prostheses
- Implanted nerve stimulators
- Metal pins, screws, plates, stents or surgical staples
In general, metal objects used in orthopedic surgery pose no risk during
MRI. If there is any question of their presence, an x-ray may be taken
to detect and identify any metal objects.
Patients who might have metal objects in certain parts of their bodies
may also require an x-ray prior to an MRI. You should notify the technologist
or radiologist of any shrapnel, bullets, or other pieces of metal which
may be present in your body due to accidents. Foreign bodies near the
eyes are particularly important. Dyes used in tattoos may contain iron
and could heat up during an MRI, but this is rarely a problem.
You will know when images are being recorded because you will hear an feel
loud tapping or thumping sounds when the coils that generate the radio
frequency pulses are activated. Some centers provide earplugs, while others
use headphones to reduce the intensity of the sounds made by the MRI machine.
You will be able to relax between imaging sequences, but will be asked
to maintain your position without movement, as much as possible.
Who interprets the results and how do I get them?
A radiologist, who is a physician specifically trained to supervise and
interpret radiology examinations, will analyze the images and send a signed
report to primary care provider or referring physician, who will share
the results with you.