How MRI Scans Work
An MRI (Magnetic Resonance Imaging) scan is a type of scan using changing magnetic fields to produce a 3D picture inside your body.
The scanner is linked to a computer that takes information from the scanner and creates this image which is then analyzed by one of our radiologists.
Prior to your scan you make be asked to fast for 2-6 hours depending on your procedure. At the time of your appointment you will be asked to complete an extensive safety consent form. It is very important that this is answered correctly. If you need assistance please ask our friendly staff to help you fill this in.
On the day of the exam, you will be require to get changed into a gown and remove all metal items from your person prior to entering the MRI room.
During the scan the technician will place a device called a coil around the anatomy to be imaged. The scan is painless and you may feel a slight warm sensation in the area being imaged.
You will be given a communication button to alert the technician. An MRI scan is very noisy while taking the pictures. Hearing protection is compulsory for all patients. Often music can be played through these headphones so feel free to bring your favourite CD to help you thought the test.
An MRI scan typically takes between 10-60mins to perform with most examination in the 15-20min range.
On completion of the procedure the pictures are processed and transmitted to the Radiologist, who will then examine the films and send a report to your referring doctor.
MRI scans use radio waves to produce the image. The waves are similar to normal radio station waves in the environment. They have no ionising radiation component and are very safe.
An MRI scanner is a very strong magnet ranging from 15000 – 30000 gauss. A fridge magnet is approximately 5 gauss. For this reason extreme care must be taken by the radiology staff to ensure that no magnetic items including implanted items enter the MRI room.
Some devices such as Pacemakers cannot enter a MRI room and as such you may be ruled out from having your procedure.
The safety questions asked by MRI staff are very important and for your safety must be answered correctly to avoid major injury or death.
No. The magnetic field only affects ferrous magnetic metal. The MRI technician will advise you if there is any concerns regarding your implanted devices.
1 in 10 people are naturally claustrophobic. MRI technicians are well trained to look after you and have multiple ways of assisting you throughout the test. The current MRI machines are much better suited to claustrophobic patients then machines of yesteryear. They are all well-lit and have their own air-conditioning supply.
Our system is 70cm wide and patients can be potentially scanned up to 200KG so there is significant room inside the machine. The tunnel is much shorter allowing in some cases your head not to be in the machine and scans can be performed very quickly if need be (less than 10min).
If you have significant concerns please discuss with your doctor prior to attending your MRI as they may be able to prescribe medication to assist your scan.
Some procedures require an injection of Gadolinium to help delineate some structures or diseases within the body.
Gadolinium is very safe and has no correlation to iodine used in CT scans. In very rare cases it is possible to have an allergic reaction to this contrast. Radiology staff are well trained in dealing with these reaction and you must inform them of any possible issues after your injection including nausea, itchiness or tightness in your chest.
It is also important to inform the staff prior to your injection if you have diabetes, heart, kidney or thyroid problems as well as if you have had issues with contrast before.
MRI imaging produces small amounts of heat within the body while generating your pictures. For this reason we typically don’t perform MRI scan within the first trimester of pregnancy.
In the 2nd or 3rd trimester it is perfectly safe to have a MRI procedure. if you feel you may be pregnant or are actively trying to conceive, please discuss this with our MRI department at the time of booking.
The contrast given within MRI is a very safe and only a small amount is required. For this reason there are no problems with breastfeeding after your MRI contrast examination.
If you are concerned, however, you may express for 24hours to ensure that there is no gadolinium within the breast milk.
After the scan, a radiologist will perform a written report for your referring doctor. The reception staff will be able to inform you when this report will be ready so you can make an appropriate appointment.