Patient Information
Procedures: MRI Scan
An MRI (magnetic resonance imaging) scan is a sophisticated form of imaging that produces a cross sectional view of the internal structure of the body. The test does not involve X-rays, but instead, consists of a circular scanner shaped much like a tunnel through which the patient passes on a table. The scanner sends in radio frequency pulses to the patient where it is absorbed by various tissues within the body. 
The radio frequency pulse is then returned back to the scanner allowing the MRI computer to reconstruct an image which is representative of the internal architecture of the body.
There are a variety of disorders which are amenable to investigation with MRI such as disorders of the liver, pancreas, spleen, gallbladder, and biliary tract. The findings of an MRI scan often complement those identified by other imaging studies such as ultrasound or CT (computed tomography) scan. The precise role for MRI scanning for patients with various gastrointestinal tract disorders is continuing to develop.
A more recent advance in MRI scanning is magnetic resonance cholangiopancreatography (MRCP). As far as the patient is concerned this is a straightforward MRI scan but it is performed in such a way that the gallbladder, bile ducts and pancreatic duct are well visualized without the need of any intravenous contrast or endoscopic evaluation.
How do I prepare for my MRI scan?
For the most part, no preparation is required. It is not necessary to drink any form of contrast.
There are some absolute contra-indications for an MRI scan. Patients with permanent pace makers, intraocular foreign bodies, or cerebral aneurysm clips can not undergo MRI scans. And it is felt that an MRI should be avoided if possible in the first three months of pregnancy (although no complications have yet been reported).
Prior to entering the MRI scanner the technologist will discuss in detail the possible contra-indications as outlined, as well as advise the patient not to take any metal objects into the MRI scanner suite such as wrist watches or credit cards or sharp objects such as scissors. These may become highly dangerous when placed in close proximity to the powerful magnet within the scanner. At most institutions the MRI scanner is in the form of a tunnel; some patients do find the procedure rather claustrophobic and require some form of oral or intravenous sedation prior to entering the MRI scanner.
In some instances it may be necessary for the patient to receive an intravenous injection of contrast which will highlight certain organs and/or diseases during the scan. This contrast will be administered slowly via an IV placed in the patients hand or arm and is itself associated with an extremely low incidence of adverse reaction.
What will happen during my MRI scan?
The scan itself consists of the patient lying on the MRI scan table for between 40 minutes and one hour. The patient will be asked by the technologist to hold their breath at certain points during the scan. One of the most obvious things that patients note is a loud banging noise from the scanner. The patient will be offered earplugs in order to minimize the effects of this noise or be allowed to listen to music by headphones. At all times the patients will be in direct radio communication with the technologist who will be in the adjacent room.
What will happen after my MRI scan?
Most patients leave the department and resume normal activities. Patients who receive sedation will be monitored in the adjacent observation area until they are deemed fit to leave the department.
What are the risks of a MRI scan?
Assuming appropriate measures have been taken prior to the patients entering the MRI scan suite, there are no risks or complications. The intravenous contrast agent used is different from that used during the CT examination and has an extremely low incidence of adverse reaction.