You are required to complete an MRI safety questionnaire before scanning. You may be asked to wear a gown during the exam or you may be allowed to wear your own clothing if it is loose-fitting and has no metal fasteners. You can eat and drink normally on the day of the scan except for some specific procedures that you may be asked not to eat or drink for a period of time before scanning.
For some MRI scans, you will be given an injection of a special dye, known as a contrast agent. Some conditions, such as severe kidney disease, hypertension or diabetes may prevent you from being given a contrast agent. It may be necessary to perform a blood test to determine whether the kidneys are functioning adequately. However, the contrast material used for an MRI exam, called gadolinium, does not contain iodine and is less likely to cause side effects or an allergic reaction. Women should always inform their physician or staff if there is any possibility that they are pregnant. To date, there are no reports of any ill effects on pregnant women or their babies from MRI. However, because the baby will be in a strong magnetic field, pregnant women should not have this exam unless the potential benefit from the MRI is assumed to outweigh the potential risks. If you have claustrophobia or anxiety, you may ask your physician or MRI staff for a prescription for a mild sedative prior to the scheduled examination.
Due to the strong magnetic fields that are used by the MRI scanner, it is important to remove any metal objects from your body, including:
- Watches, jewelry, credit cards and hearing aids, all of which can be damaged
- Piercings, such as ear, nipple and nose rings
- Dentures (false teeth)
- Wigs (as some wigs contain traces of metal)
In most cases, an MRI exam is safe for patients with metal implants, except for a few types of the following:
- Artificial heart valves
- Implanted electronic device, including a cardiac pacemaker
- Electronic inner ear implants (bionic ears)
- Implanted nerve stimulators
If you have any of these, experienced MRI staff will have to discuss the exact implant or metal with you to decide if it is safe to perform the scan. Deciding which implants cannot be scanned takes special knowledge and experience. Please do not try to guess, and do not just rely on your doctor to determine if we can scan you. Some people with tattoos have reported a burning sensation during an MRI scan. This is because some tattoo ink contains traces of metal. If, during the scan, you experience any pain related to your tattoo, tell the technologists immediately.