Magnetic Resonance Imaging (MRI)

What is a MRI Scan?

Magnetic Resonance Imaging (MRI) is designed to produce detailed images of internal organ using magnet, radio waves and computer program.

MRI is useful to discover the minor changes of inside body which is important for early diagnosis. It is suitable for any part of the body (such as bones and soft tissue) without involving X-rays.

1.5T Magnetic Resonance Imaging (MRI) – Philips Ingenia

In Hong Kong, there are 5 machines only. Philips Ingenia its 70 cm large bore design enhances comfort and workflow for challenging patients. With MultiVane technology, we get excellent motion-corrected images with high spatial resolution. Combined MultiVane with dStream technology, it shortens the scan time remarkably. Whole-body MRI scan requires around 20-30 minutes only.

Advantage of 1.5T MRI Philips Ingenia

  • Wide bore (70cm) provides more space and helps to reduce anxiety.
  • Smart softwares such as mDIXON and MultiVane reduce retakes increase consistency and exam speed.
  • Patient-perceived gradient acoustic noise is reduced by more than 80%
  • Metal Artifact Reduction technology (MAR) can effectively eliminate the metal artifacts within the the MRI images
  • Advanced Imaging Techniques with Whole body DWI & MR angiography

 

What to expect

Usually, MRI will not make you feel uncomfortable or painful. However, some patients with anxiety or claustrophobia may not feel very well. In these cases, you are responsible to tell technician in advance.

Once you have registered at the reception, you will be guided to a private changing room in which you can get a specific exam gown. The personal belongings are not appropriate to be used during the examination. You can keep them in a secure locker. When you have changed the clothes, the radiographer will bring you to a private room to have a discussion about the relevant questions.

It will take you around 30 minutes during the whole procedure which depends on the different parts of body.

How is a MRI done?

The MRI scanner is a cabin comprising of a large coil of magnet with a moveable table which glides inside the magnet.
The radiographer will require you to lie the table with the gesture which makes you comfortable. The inner table will  gently slide till the examined body is staying in the middle of the ring-shaped scanner. One of the cabin ends is usually opened so that you will not feel uncomfortable during the examination.

The apparatus noises may annoy you. So it is useful to bring ear defenders or earplugs provided by us.

Several scans may be needed and a short breaking time will be given in between. Lying still and breathe easily are very important during the whole procedure. Otherwise, any movement will make the images blurring and may need to repeat once again. The radiographer will tell you which gesture you need to pose. He/she can see and hear you clearly during the scan. The alarm button is touchable which is useful to get attention from radiographer at any time.

Contrast agents

In any cases, we need to view some tissues and blood vessels clearly by using a contrast agent.

The contrast agent is made by gadolinium, which is less likely to produce an allergic reaction compared with the iodine-based materials used for X-rays and CT scan. However, it is very rare that some patients will experience an allergic reaction. Medication can control mild symptoms. Serious reactions are very less likely to happen.

Nephrogenic systemic fibrosis (NSF), a rare complication, occurs when gadolinium-based contrast agents are provided to patients with severe kidney disease. Therefore, this contrast is prohibited in these cases. Please inform radiographer if you are suffering from this type of kidney disease.

When you are injected with gadolinium in your hand or arm, you may feel cold at the beginning but this feeling may disappear within a few seconds.

If you have already known that you are allergic to any contrast agents, please tell radiographer before the procedure starts.

What to notice afterwards

In many cases, you are able to go home by your own after completing the scan. But if you have taken sedative, you better not to drive, drink alcohol, or sign any formal document within 24 hours. Under this situation, you may ask a friend’s accompany.

Your radiographer will send a wet film and written report after finishing the scan procedure.

What to let us know?

MRI scans are not suitable for pregnant women. However, it can be done at the first three months of pregnancy under extreme cases. If you are in this period, or you are ready to give birth of a baby. Please tell your radiographer before MRI appointment.

Preparing for your MRI

Most MRI scans cannot be applied in some conditions. For instances:

  • Eye make-up should be avoided on the day of examination
  • If it is whole abdomen and whole body, it is necessary to fast 2-4 hours and drink water as usual.
  • Please bring any previous wet films, discs or reports (if any) for reference.
MRI Abdomen or MRCP Scans
  • No food or drinks for 4 hours before the examination. Regular medications can still be taken with small amounts of plain water.
MRI Cardiac (Function/Perfusion/Viability) 
MRI Cardiac
  • Do not drink coffee, tea, or caffeinated products for 12 hours before the examination. 
  • No food or drinks for 4 hours before the examination. Regular medications can still be taken with small amounts of plain water 
    but you are under this medication:

1. Please bring any sprays or inhalers that you are taking to the scan appointment. If you are on any medication from your doctor 
please continue to take it as normal.

2. If you are taking medication known as dipyridamole/Persantin or Nicorandil/Ikorel, please stop this for 24 Hours prior to the scan appointment.

MRI Cardiac Perfusion
  • No food or drinks for 4 hours before the examination. Regular medications can still be taken with small amounts of plain water.
  • Do not drink coffee, tea, or caffeinated products for 12 hours before the examination. 

MRI Cardiac of Function, or Function and Viability 

  • Food or drinks are allowed before the examination.  Regular medications can still be taken with small amounts of plain water.

Due to the strong magnetic field produced by MRI, it is crucial to take off any metal objects with you, such as:

  • Piercings, such as ear, nose rings and tummy.
  • Audiphones
  • Watches
  • Jewelry, including earrings and necklaces
  • Hairpieces (some of them contain metal device)
  • Underwire bras
  • Glasses

For safety reason, it is necessary to inform us before the scan if you:

  • Have had any dental implants or have braces
  • Have any metal implant in your body
  • Have a heart pacemaker or an artificial heart valve
  • Have any electro-mechanical devices used for drug delivery
  • Have any surgical clips
  • Be pregnant
  • Tattoos
  • Have a cochlear implant, a neurostimulator or a programmable hydrocephalus shunt.
  • Have had any operations
  • Have had any injury to your eyes involving metal or metal fragments
  • Intrauterine Contraceptive Devices(IUCD)

If your scan is involving Abdomen, Pelvis or MRCP, please do not eat or drink for 4 hours before the examination. Regular medications can still be taken with small amounts of plain water.