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PET-MR - Procedures & Preparations


As a hybrid imaging modality, a person undergoing a FDG PET-MR exam should be prepared to meet requirement and safety precautions for both PET and MR.

The PET-MR scan time may last from 30 minutes to 2 hours, depending on exam regions. The whole procedure will last for about 4 hours.

Patient Preparations

PET Patient Preparations

Fasting over-night before examination.

  1. Female patients should not be pregnant.
  2. Keep fast for 6 hours and refrain from dextrose drip for 6 hours before scan..
  3. Bring along relevant X-ray, CT or MR films.
  4. Patient should keep well hydrated with plain water.
  5. No vigorous exercise the day before examination.
  6. Patients with diabetes should inform our staff before the examination. Out-Patient should stop their diabetes medications in the morning of examination and bring their medications; while in-patients should have the blood glucose level controlled within normal range. The optimal blood glucose level for this examination should be 8 mmol/l or below.
  7. Please stop taking chinese medicine (e.g. Lingzhi, Yunzhi) for at least 3 days before the exam.

MR Patient Preparations

  1. In general, minimum preparations are required for an MR examination. However, precautions should be observed for general safety of MR environment, as well as Gadolinium contrast media safety when required.
  2. Please inform the duty radiographer if you have any metallic implant or prosthesis such as
    • cardiac pace-maker / implantable cardiac defibrillator.
    • artificial cardiac valves.
    • orthopedic prosthesis.
    • cerebral aneurysm clip.
    • neurostimulator.
    If you have any previous surgery with metallic implant, please be sure to inform the duty radiographer. Certain models of the medical devices are vulnerable to malfunction or damage in the MR environment and may cause hazards to you.
  3. For female patients, please inform the duty radiographer if you think you are/may be pregnant, or if you are breast feeding, before the examination.
  4. Do not wear make-up. Do not wear colored contact lenses or cosmetic contact lenses. If you have tattoo, please inform the duty radiographer because any metallic particles in the make-up or tattoo may cause local heating effect under the influence of strong and varying magnetic field during the MR procedure.
  5. Remove personal possession such as hearing aid, spectacles, removable dentures, hair pins, jewellery, watch, wallet and keys before entering the scan room because these metallic objects can be dangerous under the magnetic field or they can affect the image quality. Credit cards or magnetic tickets must be kept outside the scan room as the magnetic field can erase the card information.
  6. You may be asked to get changed and keep your personal belongings in lockers provided.
  7. Please bring relevant MR films (whether it is done in our department or not) and all related diagnostic tests records (e.g. x-rays, CT scans, etc.).
  8. You are required to keep still during the examination which may last for 30 minutes to up to 2 hours. Therefore, children and infants or claustrophobic patients may have to be sedated. If you suffer from anxiety or claustrophobia, please discuss your worries with our nurses or radiographers. If sedation is anticipated, you should keep fast 4 hours prior to the examination. Children below 8 should refrain from eating or drinking (skip one meal for infants), prior to the examination. You should also prevent the infant / child from sleeping 3-4 hours before the examination.
  9. Patients with / at risk of renal impairment should obtain a renal function test within 2 weeks to 1 month prior to the contrast MR examination for contrast safety considerations. Risk factors impaired renal functions includes over 60 years old, diabetes, previous renal disease, cirrhosis, etc. consult your physician if needed.