MAGNETIC RESONANCE IMAGING
Our MRI scanner is a Siemens 1.5T (high field) Sonata Magnetom.
MRI is the fastest and safest, non-interventional way to get the clearest pictures of your internal body structure. This technology enables physicians to detect developing diseases or abnormalities earlier than before and better helps them to treat any problems that may be found.
Basically, MRI involves a powerful but harmless magnetic field and radio waves. It does not use x-rays. These radio waves are just like the kind that transmit FM music on your radio. The combination of radio waves and a magnetic field produces very clear images of the body structures such as the brain, spine and other vital organs. Rather than relying on a patientís symptoms, the radiologist can detect the specific source of a physical problem and your doctor can move quickly and precisely with appropriate, early treatment. In some instances, this can reduce the need for exploratory surgery or other diagnostic studies which may present more risk.
Magnetic Resonance Imaging is at the forefront of todayís diagnostic tools.
Benefits of MRI
- Accuracy: The detail or clarity of the image obtained by an MRI scan is outstanding
- Improved diagnosis: The clear images obtained with MRI make it easier for doctors to see the physical characteristics of the body and have a better idea of how to treat the illness
- Safety: MRI uses radio waves similar to those of your FM radio station rather than radiation to obtain images
Reduced surgery: Because the MRI images are so good, MRI can reduce the need for exploratory surgery reducing risk, inconvenience, discomfort or pain and hospitalization.
- Exquisite Detail: MRI can detect differences between normal and diseased tissue in images showing exquisite detail. One of the important advantages of the MRI method is that it is possible to vary the contrast in the images in a controlled manner. MRIís ability to provide information about the state of health of organs and tissues in addition to details of their shape and appearance offers huge advantages over other imaging techniques.
- Fast imaging: MRIís fast imaging speed not only means safety, comfort and convenience for the patient because of shorter examination times, but has opened up exciting new applications involving heart, abdomen, chest and brain imaging.
In some cases you will not be able to have an MRI scan, and an alternative type of procedure will be ordered. The main contraindications for not having an MRI scan are:
- If you have or have ever had, a heart pacemaker it is not safe for you to have scanned.
- If you have had any metal in your eye in the past (even if it has been removed), you will need to have an x-ray to ensure that there is no sliver remaining. You will then be clear to have your MRI.
- If you have metallic or electronic devices in your body - depending on what type you may still be able to have a scan but we will need details. If the device is in the part of the body you are having scanned this may affect the quality of the images.
- MRI is not routinely performed during the first trimester of pregnancy.
Preparing For Your Scan
When you arrive at Manukau Radiology, the receptionist will check to see that you have answered the questionnaire to ensure that there is nothing to prevent you from proceeding with your scan/procedure. You will have a private changing room and will be asked to change into a gown .
You will also remove all metal objects including your watch, jewellery, coins, keys, pens, eyeglasses, dentures, and hairpins or hair clips. Since the MRI will erase information on bank cards and credit cards you should put them into your locker as well. The MRT will recheck your questionnaire, answer any queries you may have and explain the procedure. You will then have your scan.
Having Your Scan
Scan times differ for various investigations but usually take between 20 and 30 minutes. During the investigation you lie flat and comfortably on the padded patient table which slides you smoothly into the scanner. A lightweight device called a receiver call is placed around the area you are having scanned. The technologist will explain the procedure to you and make sure you are correctly positioned and comfortable before leaving the room.
During the MRI procedure the machine can make a strange "knocking" or "thumping" noise. This is perfectly normal and should not alarm you. Many people find it soothing to listen to music which we can provide or you are welcome to bring along your favourite CD or cassette tape to listen to during the investigation.
You can see a video of a brain MRI scan and hear this sound by following the link www.mayoclinic.com/health/mri/MM00395 .This video shows a brain scan so the receiver coil is around the head.
There may also be the need to use a contrast agent which is an injection used to get a better image of some parts of the body. The injection will be given to you by the Radiologist or MRT
It is very important not to move while you are in the MRI as this will assist in providing the best image results possible. The technologist will direct the testing from a separate room where there is a monitor which instantaneously shows the precise areas your physician has requested to know more about. An intercom system is built into the magnet for two-way communication between yourself and the technician. When the scan is complete, the technologist will assist you from the table and back to the changing area.
There are some procedures that require preparation. You will be advised of these at the time of making your appointment.
MRI Arthrogram scan
The procedure will involve a small injection of local anaesthetic, followed by an injection of contrast called into your joint. You will then have your MRI scan which will require you to lie still for approximately 30 minutes. You will need to be at Manukau Radiology for an estimated 1 Ĺ hours
MRI with Sedation (for Claustrophobia)
You will need to let us know if you are Claustrophobic prior to us making your appointment. You must not have anything to drink or eat (NIL by mouth) for 4 hours before your appointment and you should arrange for a driver to take you home after your scan.
MRI of the Abdomen
It is necessary to prepare your bowel for your MRI scan. We will send you the preparation and instructions prior to your appointment.