What is MRI and How Does It Work?
Magnetic resonance imaging (MRI) obtains detailed images of organs and tissues throughout the body without using X-rays or other ionizing radiation. Instead, MRI uses a powerful magnetic field, radio waves, changing magnetic fields, and a computer to create images that show potential injuries, diseases, or abnormal conditions.
During the exam, you will typically lie on a table that slides into a large donut-shaped scanner, open on both ends. A receiving device (similar to an aerial) is placed around the area being examined. There is no pain, and electromagnetic fields cause no known tissue damage. However, the MRI system often makes loud tapping or knocking noises. Earplugs are provided to reduce these sounds, and you can communicate with the technologist at all times through an intercom system.
MRI exam times vary from 10 to 60 minutes.
How to Prepare for the MRI Examination
Most patients do not need special preparation for an MRI. Unless otherwise instructed by your doctor, you can eat and drink normally and continue taking any prescribed medications.
You will not be allowed to wear anything metallic during the exam. It is best to leave metallic items—such as jewelry or watches—at home. Some cosmetics also contain trace metals, so you may wish to avoid wearing makeup. Typically, you will receive a gown to wear during your scan to prevent any metal objects from entering the MRI scanner’s powerful magnetic field.
Items to Remove Before the Scan
- Purse, wallet, money clip, credit cards, and any magnetic strip cards
- Electronic devices (mobile phones, pagers)
- Hearing aids
- Metal jewelry and watches
- Pens, paper clips, keys, coins
- Hair accessories with metal (barrettes, hairpins)
- Clothing with metal zippers, buttons, snaps, hooks, underwire, or metal threads
- Shoes, belt buckles, safety pins
Before the MRI Procedure
Before your scan, you will fill out a safety questionnaire about your medical history and any implants that might pose a risk or affect the imaging process. You will also have a brief interview with a member of the MRI facility. Even if you have had an MRI before, you will still be required to complete this questionnaire.
Examples of items or conditions that can create a health risk or interfere with imaging include:
- Pacemakers
- Implantable cardioverter defibrillators (ICD)
- Neurostimulators
- Aneurysm clips
- Metal implants
- Implanted drug infusion devices
- Foreign metal objects, especially in or near the eye
- Shrapnel or bullet wounds
- Permanent cosmetics or tattoos
- Dentures or teeth with magnetic keepers
- Any implants that involve magnets
- Medication patches containing metal foil
Contact Us
Diagnostic Healthcare Limited
The Royals, 353 Altrincham Road
Manchester, M22 4BJ
Tel: 0161 929 5679
Email: info@dhc.uk.com