MRI scans

Written by: 
Dr Kieran Walsh

Learn what an MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scan is and what to expect when going to have one.

A magnetic resonance imagingA technique for imaging the body that uses electromagnetic waves and a strong magnetic field. (MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field.) scan is a special form of scan that provides detailed images of organs inside the body.

An MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scanner uses a powerful magnetic field together with radio waves aimed at the body. The waves are deflected by the body's organs and the signal from the waves is picked up by the computer in the scanner. Different organs and tissues produce different signals, from which the computer creates a 3-D image of the body's internal organs that is inspected on a screen.

MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scans are extremely accurate. They provide detailed images of organs such as the brain and the spinal cord.

The scanner can be noisy and the person operating the scanner (the radiographer) may give you earplugs or earphones

Depending on the type of symptoms, your doctor may order an MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scan to find out what could be causing symptoms that you report. If you have severe and persistent back pain or weakness in your legs, for example, an MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scan might show an underlying cause such as a disc problem or a tumour.

MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scans can show changes that are not visible with other forms of scanning. For example, changes caused by multiple sclerosis are visible on MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scans but are not visible on computer tomography (CTA scan that generates a series of cross-sectional X-ray images.) scans.

If you are having or may be having an MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scan, points of interest include:

How is an MRI scan performed?

The main part of an MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scanner is a long tube surrounded by a large magnet. You lie down on a couch that is slowly moved into the tube. You need to lie as still as possible in the tube while the scan is taking place.

The scan may last a few minutes or up to an hour and a half, depending on the type and purpose of the scan.

The scanner can be noisy and the person operating the scanner (the radiographer) may give you earplugs or earphones. The radiographer will sit in a room next door to you during the scan and will be able to communicate with you via an intercom.

How do I prepare for the procedure?

Patients are usually able to eat whatever they want and take their normal medications before the scan. If you are having a scan of your abdomenThe part of the body that contains the stomach, intestines, liver, gallbladder and other organs., however, you might be told to fast beforehand because food in your stomach could interfere with the scan.

Because the magnet in the scan is so powerful, any metal objects could move very fast when the scan starts and potentially cause injury. You will not be able to wear anything with metal in it, therefore, or take any metallic objects into the scanning room. You will not be able to have an MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scan if you have a metallic implant such as some types of artificial heart valveA structure that allows fluid to flow in one direction only, preventing backflow., cochlear implants or artificial joints.

Before the scan, you may be asked to have an injection of a dye into your hand or arm that makes it easier to see particular organs or other internal areas.

Are there any risks or other concerns?

Having an MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. scan is painless.

You have to lie very still in the tube-shaped opening within the scanner. Some people with claustrophobia may find it difficult to stay within the tube for the required time. It may be possible for you to have a sedative to help you cope with this. In a few places, 'open' MRIAn abbreviation for magnetic resonance imaging, a technique for imaging the body that uses electromagnetic waves and a strong magnetic field. machines are available that can scan without completely enclosing the person.

Some people can have a reaction to the dye that can be used during the procedure - but this is rare.

What happens after the scan?

You can go home or go back to work immediately after the scan. There should be no after-effects following the scan.

The scans are read and interpreted by a radiologist, who will send a report to your own doctor.

You should get the report within weeks - depending on how fast your local service is.