MRI is a non-invasive imaging technology that can produce three dimensional detailed anatomical images without the use of radiation. It is often used for disease detection, diagnosis, and treatment monitoring. It is based on sophisticated technology that excites and detects change of direction on the rotational axis of protons found in the water that makes up living tissues.
How the procedure is performed
The patient will be placed onto a padded table and depending on the body part being scanned, a device known as a coil will be placed upon or around that part, to improve the detail shown on the scan. The table will then moved into the centre of the magnet. During the scan you will be given earplugs and an alarm button to alert the staff to any discomfort you may experience at any point during the MRI exam. Once you are comfortable, the radiographer will start the scan.
You may be administered an injection of a contrast agent, or “dye” if necessary this helps to light up certain parts of the anatomy and some abnormalities, allowing for greater diagnostic accuracy. Side effects are uncommon, but may include nausea and vomiting. Serious allergic reactions are rare. The contrast agent is rapidly removed from the body by the kidneys.
How Long Will It Take?
That depends on what part of the body is to be scanned and whether or not your doctor has ordered any special or extra scans. Normally, a single part scan takes between 30 and 45 minutes.
How safe is an MRI?
An MRI is one of the safest medical procedures available and it is painless. It does not expose you to any form of radiation. Although MRI does not emit the damaging ionizing radiation that is can be found in X-rays and CT imaging, it does however employ a strong magnetic field that extends beyond the machine and exerts very powerful forces on objects of iron, certain steels, and other magnetisable objects. Because of this patients should notify their physicians of any form of medical implant prior to an MRI scan.
What preparation do i need to do before my MRI?
Usually very little preparation is needed although because the MRI machine uses a magnetic field certain people with medical implants can’t be scan.
Therefore, before you enter the scanning area you should be asked if you have any medical devices or implants are safe to enter the MRI. The following is not a definitive list but may help to remind you of the type of things radiographers need to know about:
- Internal (implanted) defibrillator or pacemaker.
- Ear (cochlear) implant.
- Surgical clips such as those used on brain aneurysms.
- Artificial heart valves.
- Implanted medicine infusion ports.
- Artificial limbs or metallic joints.
- Implanted nerve stimulators.
- Pins, screws, plates, stents or surgical staples.
Will I feel claustrophobic?
To some degree 20% of patients do experience some form of claustrophobia. If necessary, a sedative agent may be given prior to the scan if you think you will be claustrophobic, it is a good idea to advise the booking staff of this when making your appointment. Our Radiographers are highly trained and skilled at calming patients. They will make sure you are relaxed and will communicate with you throughout the scan.
When Will I Get My Results?
The radiologist will examine the images and will write a signed report to your referring doctor who will then discuss the results with you.