What is an MRI scan? How does it work?
Magnetic Resonance Imaging (MRI) is a type of non-invasive diagnostic scan that allows the capture and production of detailed, cross-sectional images of your organs and structures in your body.
Unlike CT scans and X-rays, MRI scans do not make use of potentially harmful ionizing radiation. During an MRI scan, a constant magnetic field is applied to the molecules in your body and radio waves are sent to certain parts of your body. The radio waves which bounce off the fats and water molecules in your body will be transmitted to a receiver in the MRI machine. They are then translated into a detailed image of your body that can then be used to diagnose diseases.
When is an MRI scan needed?
An MRI scan can be used to examine almost every part of the body, including the brain and spinal cord, bones and joints, the breasts, heart and blood vessels, as well as internal organs like the liver, womb, and prostate gland.
Hence, an MRI scan could help to diagnose:
- Abnormalities of the brain or spinal cord
- Abnormalities of the joints, back, and knee
- Tumors or cysts in any part of the body
- Breast cancer
- Some heart problems
- Liver diseases
- Uterine or womb problems in women, including fibroids
- Pain in the pelvis due to pelvic congestion syndrome or endometriosis
What happens during an MRI scan?
There are few dietary restrictions before you go for an MRI scan. You may need to wear a hospital gown and remove any metal objects or jewelry.
During an MRI scan, you will lie on your back on a flat bed that passes into the MRI scanner, which is shaped like a long tunnel. The MRI scanner will be operated by a radiographer and you will be able to communicate with him through an intercom. It is important to lie still during the CT scan as movements can lead to blur images. You may be asked to hold your breath for a short period.
During the scan, it is normal to hear loud banging noises from the machine. You may be provided with earplugs or headphones to minimise the noise. Should you feel uncomfortable at any time during the scan, talk to your radiographer if you need to stop the procedure.
How long does it take?
An MRI scan typically lasts around 15 to 90 minutes depending on the size of the body area that is being scanned. The average duration of an MRI scan is about 45 minutes.
What to expect after an MRI scan?
In most cases, you will be able to go home on the same day after an MRI scan. After the MRI scan, the images are sent to a radiologist for examination. Your doctor will follow-up with you on the results after a few days or a week.
Are there any risks involved in MRI scans?
MRI scans are generally safe and painless. You may find it uncomfortable if you have claustrophobia or a fear of tight spaces. Talk to your doctor about your concern and he may prescribe you with medication to make the procedure more comfortable.
There are generally very low risks involved with the use of magnetic fields and radio waves in MRI scans. Let your doctor know if you have any metal implants such as a pacemaker or artificial joints in your body, as you may be unsuitable for an MRI scan. Your doctor may advise for you to undergo a different diagnostic scan, depending on the situation.