Magnetic Resonance Imaging (MRI)

The  Way  Ahead

What is MRI?
How does an MRI Scanner work?
How do I prepare for my scan?
What will happen during my examination?

What is MRI?

Magnetic Resonance Imaging is the most advanced technique currently available for imaging the human body. It uses a magnetic field and radio waves which when processed through a powerful computer produce images of the internal structure of the body.

How Does an MRI Scanner Work?

The human body is made up of primarily of water and fat. Water and fat have many hydrogen atoms which make the human body approximately 60% hydrogen atoms. When placed in a strong magnetic field (a typical MRI scanner has a magnetic field 10,000 times as strong as the Earth's) the hydrogen nuclei line up with the field and spin. As they spin, these nuclei wobble on their axes, or precess. An analogy often used is to imagine a spinning top wobbling before it comes to rest. Whereas a spinning top,  precesses only once or twice each second, the hydrogen nuclei, however, precess at a rate within the radio frequency range. They are thus both receptive to and emit radio waves. The radio waves so emitted, when analysed by a powerful computer, allow the creation of an image of the internal structure of the body. Any internal injuries to soft tissues, muscle, bone, ligament or cartilage are well depicted on these images and allow a diagnosis to be made.

How do I prepare for my scan?

No specific preparation is necessary. You may eat and drink as normal and continue with any prescribed medications. It is important that there is no metal on your clothing, so if possible please try to come for your examination wearing leisure clothes, e.g. tracksuit, leggings, etc. If this is not possible, changing facilities are available.

What will happen during my examination?

On Arrival
We will check your details and go over a safety screening checklist with you. You will be asked to remove all loose metallic objects, watches, jewellery and credit cards.

During Your Scan
We will ask you to lie on the scan table and position you so that you are comfortable. If you wish, you may ask a friend or relative to accompany you, and they can remain with you throughout the examination, (in this case, they must also fill in the safety screening checklist and remove all loose metallic objects). The scanner has an open design and is quiet, a combination which greatly enhances patient comfort, reduces anxiety and eliminates claustrophobic effects. For a picture of the scanner with a patient positioned for a scan of the wrist click here.

During your scan you will not feel anything and you will not be subjected to any injections. The examination will take approximately 45 minutes, but we would ask that you allow 1 hour at the centre. There is ample free on site car parking.

After Your Scan
There are no known side effects from MR scanning. Once you have had your scan it is quite safe to drive, and you can eat and drink normally.

Directions
For directions on how to get to the imaging centre and a map click here.