MRI Scan (Magnetic Resonance Imaging)
What is an MRI?
A Magnetic resonance imaging (MRI) scan is a radiological technique that uses strong magnetic forces and radio waves to produce detailed and clear images of organs and tissues within the body. An MRI scanner is a large tube containing a large circular magnet with whose forces images of the inside of the body are produced.
An MRI scanner can be used to produce images of almost all organs in the body including the bones, joints, breasts, heart, blood vessels, brain, spinal cord, and organs in the abdomen. The findings from an MRI scan are used to make or confirm diagnoses, determine and monitor treatment, and evaluate a patient’s condition.
How is an MRI scanning is performed?
During an MRI scanning procedure, you would be told to lie flat on a bed which is inserted into the large MRI tube scanner. You may be moved into scanner head first or feet first depending on what area of the body is to be scanned.
The procedure is done by a radiographer or a radiologist. These are medical personnel trained in carrying out radiologic investigations. They control the MRI with a computer in a different room from where the MRI machine is, however, communication with you is ensured via an intercom.
When the scanning is begun, you would hear loud repetitive noises within the MRI machine. The noises are due to turning on and off of electric current in the MRI machine’s scanner coils.
MRI scanning usually lasts 15 to 90 minutes depending on which area of your body is being scanned and you are told to hold as still as you can while it lasts.
How an MRI works
Much of the human body is made up of water molecules which comprise of hydrogen and oxygen atoms. At the centre of each hydrogen atom is a smaller particle called the proton. Protons are charged particles which act like tiny magnets.
When you lie inside the MRI scanner, the protons in your body are pulled in the same direction as the magnetic forces from the scanner. Then short pulses of radio waves are sent through your body knocking the protons out of their alignment. When the radio waves are turned off, the protons re-align and this sends signals to a receiver.
The radio signals sent by the re-alignment of the protons give information about the location of the protons in the body and the structure of the organs they are contained in. Different organs and tissues in the body give off these radio signals at different speeds and intensities, this information is also captured by the receiver which is used to produce detailed image on the part of the body being visualized.
Why is an MRI done?
An MRI produces images which show more details and clarity about the structure of an organ than other imaging techniques. It is usually done when other imaging techniques have not provided adequate information needed to confirm a patient’s diagnosis.
What are the risks involved with MRI
An MRI is a painless radiological procedure with an advantage of not using radiation. There are no known adverse effects with the use of MRI, however, patients with metallic implants, heart pacemakers, bullet fragments, and metallic clips in their eyeballs should not be scanned with an MRI because of a risk of moving the metal off its position by the MRI’s strong magnetism, causing internal injury.