What is an MRI Scan?
Magnetic Resonance Imaging (MRI) is a method of imaging which utilises a strong magnetic field to generate images of any region of the human body.
How does MRI work?
A signal is detected by an antenna or small coil which is placed around the body part being scanned. This signal is encoded by magnetic field gradients which are responsible for the loud noise associated with MRI. Finally, the signal is mathematically processed by powerful computers to form an image.
Pre-scan procedure
On arrival for your appointment, you will be given a safety questionnaire to complete. This is to ensure it is safe for you to have the scan. People with cardiac pacemakers cannot have an MRI due to the strong magnetic field. Other exclusions include some ear implants, certain brain aneurysm clips and various other medically implanted devices. We have a detailed database of various medically implanted devices which we refer to when checking a patient’s compatibility with MRI.
Patients with metallic foreign bodies in their eyes, through grinding/welding, are excluded from MRI. You may be required to have a screening x-ray to exclude metal in your eyes.
What will happen during the scan?
Due to the safety aspects involved with strong magnetic fields and the sensitive nature of the technology, you will be asked to change into a gown and remove your watch and certain jewellery. Underpants and socks may be worn. Gold jewellery may be worn if it is not located near or in the area being scanned. All valuables may be safely stored in a locker which is provided to you.
The examination will be performed by a qualified and accredited MRI radiographer.
The MRI radiographer will position you on the MRI table. Various foam pads are available for support/comfort. Often, a separate receiver coil or antenna which detects the MRI signal is placed on or around the region being imaged.
Due to the noise of the MRI scanner during the imaging process, you will be given headphones to wear during the scan. You may bring a CD or alternatively you may listen to a radio station of your choice. You will also be given a call buzzer which may be used to gain the attention of the MRI radiographer at any time during the scan.
Other considerations
InSight Clinical Imaging invests in the latest MRI technology including wide bore, short bore magnets,. The roominess of our 70cm wide scanners, together with the ultra-short bore length of just 1.5m means that our scanners can accommodate patients of all sizes. These scanners also significantly improve patient anxiety and claustrophobia.
MRI is very sensitive to motion. You will be asked to remain as still as possible during the scan.
Some MRI examinations require an injection of a contrast medium into an arm vein to allow imaging of blood vessels/vascular tissues. If required, this will be discussed prior to the injection. Reactions to MRI contrast are very rare.
Are there any risks?
MRI does not utilise ionising radiation which is used in x-ray and CT scanning. The magnetic field and radio frequency (RF) pulses used in clinical MRI are believed not to produce any long term ill effects. However, due to limited research in the area of pregnancy and MRI exposure, it may be inadvisable to undergo MRI during pregnancy. Please advise the MRI staff if you are, or suspect you are, pregnant.
After the examination
The scan processing and reporting may take up to eight hours. For your convenience we can generally deliver the imaging and report to your doctor within 2 working days. If you require the results for a follow up appointment on the day of the scan, you will be required to wait for the results. Please note that some referring doctors require their patients to wait for their imaging and report after the scan. If this is not possible, you may arrange to collect the films at an alternative time.
