Magnetic Resonance Imaging (MRI) Scan

The following information has been specially prepared to help you understand the procedure and to make your visit to the Department of Diagnostic and Interventional Imaging a pleasant one.

Where are we?
The entrance to the Department of Diagnostic and Interventional Imaging is located within the Admissions at Level 1.

What is Magnetic Resonance Imaging (MRI) Scan
MRI scan is a specialised examination using a strong magnet and radio waves (similar to VHF or UHF) to produce medical images for diagnostic purposes.

What to expect during the examination?
During the MRI examination, you will be comfortably positioned on a special cushioned table. You will not feel anything except table movement between scans.

You will hear loud humming and thumping noises due to gradient switching and radio tuning.

Do not be alarmed.

Earplugs or headphone with music will be provided for your comfort. We will remain in contact with you through a video camera and speakerphone. In certain cases, the MRI radiographer may instruct you to hold your breath for 10 to 15 seconds while the scans are being taken.

In some instances, you will be given an injection of contrast medium (colourless dye), usually in the arm. This contrast medium goes into your blood system and outlines your blood vessels, helping to show up certain structures clearly. The contrast may make you feel cool for a few seconds. It will be passed out in your urine in about two hours.

If you feel any discomfort or pain during the injection, please inform the doctor.

You may resume normal activities after the scan.

Radiation dose/Biological effect
As there is NO X-ray used in this specialised examination, NO radiation dose is involved.

Please also note that no known biological effect will be caused by the magnetic field strength.

Will I need to be admitted?
The examination does not require hospital admission (except for pre-arranged sedation/GA cases). It can be performed on an outpatient basis.

Can pregnant patient do MRI Scan?
Yes. MRI combines strong magnetic field and radio frequency waves to generate signals from the body for the purpose of creating images.
Currently, there are no known adverse effects to the pregnant woman and the fetus due to exposure to magnetic fields and radiofrequency pulses used in diagnostic MRI.

Important points to note:

1. For safety reasons, all patients must complete the MRI Safety Screening Questionnaire. They must clear all relevant questions within this form before an MRI appointment is given.
2. The examination time may vary from 45 to 90 minutes. It could take up to a few hours for MRI of multiple body regions.
3. Please inform us if you are allergic to any MRI contrast media (dye) or suffering from any heart problem.
4. If you are pregnant or suspect that you are pregnant, please inform your doctor or the MRI radiographer.
5. Please do not carry any valuables or excessive cash with you during your appointment.
   

Preparation for MRI scan
For some MRI studies, fasting is required for at least four to six hours before the scan.

All makeup, hairspray and any metallic objects should be removed.

You will be asked to change to our hospital gown and to remove all personal belongings (eg. dentures, handphone, magnetic cards and spectacles) before the scan.

MRI scan requiring sedation or general anaesthesia
You may need to be admitted in the ward one day before examination.

If you are under 21 years old, written consent shall be taken from your parent or guardian.

Food and drinks are not allowed for about six hours before the anaesthesia*.

Before the MRI scan, the doctor will insert a needle into your vein for the administration of MRI dye or the medication for anaesthesia/sedation.

* For young infants or children, further instructions will be advised by the anaesthetist-in-charge or MRI nurse.

*Do note that an Excuse Sheet will be given upon request. Medical Certificate (MC) will only be issued for this procedure that is performed under General Anaesthesia.