Magnetic Resonance Imaging (MRI) is one of the methods we use for looking inside the body. Instead of x-rays, the scanner works with magnetic fields and radio-waves to produce clear pictures of the head, spine, joints or almost all other parts of the body. The scanner consists of a very strong magnet with a radio transmitter and receiver. These instruments gather information which produce images that are used to distinguish normal healthy tissue from diseased or damaged tissue.
At SRG, Magnetic Resonance Imaging is used to evaluate:
- Musculoskeletal system which includes the pelvis, hip, knee, ankle and foot, shoulder, elbow, wrist, hand and fingers.
- Neurological system which includes the brain, internal ear and blood vessels (MR Angiography).
- The spine, which includes the cervical, thoracic and lumbar regions.
- The shoulder and hip (following an arthrogram injection).
The MRI scan may require the use of a contrast agent depending on the information required. The Radiographer will inform you if your scan requires the use of contrast. The contrast agent fluid is injected into a vein. This fluid shows up on the image and helps us better visualize structures within the body.
Preparation for your MRI scan
Unless you have been given specific instructions by our MRI staff, no special preparation is required prior to the exam. However, because you will be close to the magnet, please do not wear eye makeup, glitter or jewellery.
Please bring any old x-rays or scans related to your injury, as these may be relevant to our doctors when they are interpreting your scan.
On arrival, a questionnaire will be completed and questions relating to your medical history will be asked. If you wish, you can download and complete the questionnaire before you arrive.
All patients are required to change into a gown which will be provided, and remove all:
- Jewellery (including body piercings)
- Watches
- Hairclips
- Glasses
- Wallets/purses
- Hearing aids
- Any other metallic objects
Safety considerations
Prior to MRI scans, we require all patients to complete a safety screening form. Should you wish to complete this prior to your appointment, a copy is available for download »
Following your scan, you will require a driver as the effects of the sedative will last some time, and as such, you must refrain from any significant activity for the rest of the day. You should neither drive a car nor operate any machinery.
In most cases, an MRI exam is safe for patients with metal implants, except for a few types. People with the following implants cannot be scanned and should not enter the MRI area:
- Cardiac pacemaker
- Internal (implanted) defibrillator
- Cochlear (ear) implant
You should tell the MRI technologist if you have medical or electronic devices in your body, because they may interfere with the exam or potentially pose a risk.
The following items can also pose a risk and should be discussed with our staff prior to your scan:
- Clips used on brain aneurysms
- Cardiac or carotid shunts
- Artificial heart valves
- Implanted drug infusion ports
- Infusion catheter
- Implanted electronic device, including a cardiac pacemaker
- Artificial limbs or metallic joint prostheses
- Implanted nerve stimulators
- Metal pins, screws, plates or surgical staples
In general, metal objects used in orthopaedic surgery and abdominal surgeries pose you no risk during an MRI. However, if there is any question of their presence, an x-ray may be taken to detect the presence of any metal objects.
Those people who have had metal in their eyes from grinding metal should contact us before their scan. In some cases an x-ray will need to be taken to ensure that all the metal has been removed.
Other metallic foreign bodies such as shrapnel may also require an x-ray prior to an MRI.
Dyes used in tattoos may contain iron and could heat up during MRI, but this is rarely a problem.
Dental fillings and braces usually are not affected by the magnetic field but they may distort images of the facial area or brain, so the radiologist should be aware of them. Please advise our staff prior to your scan.
Women should always inform the MRI technologist if there is any possibility that they are pregnant.
Because the risks of an MRI exam to the unborn foetus are unknown, pregnant women should not have this exam unless the potential benefit from the MRI is assumed to outweigh the potential risks.
Some MRI examinations may require that the patient receive an injection of gadolinium based contrast into the bloodstream. You will be asked if you have allergies, however Gadolinium based contrast agents used in MRI are very safe and do not contain iodine, making it less likely to cause an allergic reaction.
You must advise us if you have kidney disease or diabetes and especially if you are undergoing renal dialysis. These conditions may prevent you from having the contrast agent.
Should you have any queries or concerns, please contact our staff prior to your scan. MRI reception can be reached at (09) 523 7054 extension 2 or by emailing mri@srgmri.co.nz.
During the procedure
The Radiographer, one of our staff trained in operating the MRI, will position you on a special bed. Your head will be placed in a padded headrest or on a pillow. The bed will then slide into the scanner. You will be able to communicate with the Radiographer throughout the examination via a two-way intercom.
While the machine is taking the pictures you will hear loud thumping noises coming from the scanner. Earplugs or headphones will be provided to reduce any discomfort. You are welcome to bring your own music CD with you should you wish to.
During this time you need to stay quite still and breathe normally. If you do feel the need to move or cough, let the Radiographer know. Following these directions will produce the best possible images.
The whole procedure will usually be repeated several times, and the actual exam usually takes 30-45 minutes. Please note that these are lengthy procedures and you could be in the department for longer than expected.
After the procedure
If you have been given a sedation by our staff prior to your scan, you will require a driver to take you home.
The images from your scan will be electronically sent to one of our doctors for interpretation. Your doctor will also be able to view these images from their clinic online.
If your doctor has specified it on your referral, you may be given your films or a CD to take away with you. Our Radiologist’s report will be sent to your doctor electronically. To learn how to open the images on the CD, visit our Images on Disc page.
- Previous films and CDs may be of use to our Radiologists when they are interpreting images from your MRI scan. Please bring these with you to your appointment.
- Please complete our safety questionnaire and bring it with you to your appointment. You can download a copy here.
- Park in the basement car parks marked ‘Medical Centre‘, otherwise you may be towed. Read our Parking and Transportation page for more information.
- We are located in Building C of Ascot Office Park. Take the lift to level 3 for MRI examinations.