What is MRI and how does it work?
Magnetic resonance imaging (MRI) is useful means of creating detailed images of organs and tissues without the need for ionising radiation (X-rays). It utilises powerful magnetic fields and radio waves to create images of the body.
MRI works on the premise that all body tissues contain atomic particles called protons. When a strong magnetic field and radio-waves are applied to these tissues, the protons release signals which are recognised by the MRI scanner. A computer then processes these images creating thin slices for better detailed imaging of the body part of interest.
You will be placed on a table which slides into a tunnel that is open at both ends. Here at Harbour Radiology North Sydney our MRI is a leading Siemens wide bore MRI, meaning the tunnel is much broader than normal. The MRI machine will sound noisy as it is acquiring images but this is intermittent and not continuous. Our friendly staff will provide you with ear plugs and will be contactable via an intercom system at all times. The duration of your MRI will vary depending on the nature of the scan, but in general it will take anywhere from 30 minutes to 2 hours.
How safe is MRI?
MRI is painless and no known side effects have been documented, it is important however to fill out the safety questionnaire. Strong magnetic fields such as those produced by MRI attract iron containing metals (ferromagnetic), if a person was to be lying in the same path as the objects trajectory could lead to injury. For this reason Harbour Radiology has a stringent and comprehensive screening protocols.
In some cases Gadolinium a contrast agent is injected into a vein for better clarity of images. Unlike CT contrast, gadolinium does not contain iodine and has a reduced adverse reaction profile. If you suffer from kidney disease, liver disease or have had a kidney transplant you must inform Harbour Radiology and they will advise the best course of action. If you experience any side effect from the gadolinium injection please inform the staff immediately.
How should I prepare for my MRI?
In general there is no preparation for an MRI. In some cases you may be required to fast, but this will be explained to you by our reception staff at the time of booking. It is advisable to leave excess jewellery at home and leave makeup to a minimum.
Before entering the MRI room you will be asked to change into a gown and to fill out a safety questionnaire. The magnetic field can interfere with any metal objects in or within your body and as such a screening protocol is in place.