MRI – Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) uses an exceptionally strong magnet, radio frequency waves and a sophisticated computer to generate detailed grayscale images. No x-rays or ionising radiation is used.
The body or body part is placed within a magnet coil that detects shifting signals, which are encoded by the magnetic field gradients. Finally, powerful computers process the signal to form an image of the area of interest. The magnetic field and radiofrequency waves have not been shown to cause any long-term effects, but please advise our staff before your MRI if you know you are, or could possibly be, pregnant.
Before your MRI
Because a strong magnet is used, patients with certain ferromagnetic implanted devices or prostheses should not have MRI scans. When you arrive, you will be asked to answer a series of safety questions. Patients with cardiac pacemakers, metal heart valves, some ear implants, certain brain aneurysm clips and various other medically implanted devices should not have MRI because the metal will respond to the strong magnetic field. Also, people with metallic foreign bodies in their eyes, through grinding or welding, are excluded from MRI.
If you are having a scan of the abdomen or pelvis, you might need to fast before the appointment, in order to avoid bowel and stomach movement. Our staff will advise you if you need to fast, and for how long, when you make your booking. Otherwise, you may eat and drink as normal before and after the scan.
Patient's who suffer from claustrophobia might not feel comfortable within the magnet for the required time. Please advise our staff prior to your appointment if you are claustrophobic, so that we can discuss your options.
Because of the strong magnetic field you must store any coins, keys, phones, mechanical watches, credit cards, metal objects or magnetic storage media in a locker outside the scan room. The radiographer will ask you to change into a gown, and to remove extraneous metal, including piercings and jewellery.
If you need someone to be with you during the scan, he or she must also remove all extraneous metal, and any electronic devices, but may be allowed to remain in street clothes after careful checking of these.
During your MRI
The MRI machine combines a doughnut-shaped magnet with a padded couch, which moves through the centre. Throughout the scan, the radiographer will maintain visual and voice contact with you. The switching of the magnet creates a muffled thumping sound, so you will be given hearing protection, which you must wear during the scan.
The scan can take from 20 to 60 minutes depending on how many areas your doctor wants scanned. During that time you must remain relaxed and very still, to avoid a blurred image.
Sometimes, a small dose of gadolinium is injected through the arm vein to temporarily alter the magnetic properties of the body tissue and enhance anatomical detail. Our radiologist will determine whether an injection is needed, at the time of your scan.
MRI is painless and you will not feel any after effects, so you can resume normal activity straight away.
At Mackay Radiology, we accept MRI referrals from medical specialists, GPs and physiotherapists. Only specialist referred Medicare eligible examinations will attract a Medicare rebate. If referred by a non-specialist (i.e. general practitioner) most patients will not be eligible for a Medicare rebate for their scan. Our friendly staff can discuss the cost and Medicare eligibility at the time of your booking with you.
Please bring any previous relevant x-rays, CT, MRI or ultrasound films, as the radiologist reporting your MRI can review these and possibly improve the quality of your report.
After your MRI
One of our radiologists will interpret your MRI and provide your doctor with a comprehensive report about the findings. You will need to return to the health practitioner who referred you to discuss your MRI results. Processing and reporting of your MRI could take up to two hours. For your convenience we can generally deliver the images and report to your doctor, by lunchtime on the next working day.
If you require the results for a follow up appointment on the day of the scan, you can wait for the films and we will fax or email the results to your doctor. Some of our referring doctors prefer that their patients wait for their films after the scan. You may arrange to collect the films at an alternative time, if you prefer that option.
As of 1 November 2013, General Practitioners are able to refer patients over the age of 16 for MRI investigations for a small range of clinically appropriate indications. This is in addition to the GP access to paediatric MRI introduced in November 2012....Find out more
Patients under 16 years of age are now eligible for Medicare benefits when a general practitioners orders an MRI for: Scan of head for any of the following - unexplained seizure(s), unexplained headache where significant pathology is suspected, and...Find out more