The First Private Teaching Hospital in South Africa, Johannesburg

Patient Guide

Advice for patients having a CT scan:

What should I eat or drink

Please do not eat solid foods for 6 hours prior to your CT appointment. You may drink clear liquids (black tea/coffee, water or juice) prior to your scan. Please notify the radiographer if you are diabetic.

What medication should I take?

Please take all regular medication that your doctor has prescribed for you.

What if I am allergic to intravenous (IV) contrast materials?

We use iodine containing contrast media as a “dye” to light up areas of increased blood supply. If you have significant allergies, or have experienced a prior reaction to IV contrast material, please notify the x-ray department prior to your appointment as we may need to provide you with a prescription for cortisone/steroids to counteract an allergic reaction.

Might the IV contrast harm my kidneys?

If you have a history of kidney disease or are at risk for kidney disease please notify your referring physician prior to your CT scan appointment. You can have a blood test (urea and creatinine) to determine your kidney function prior to your scan.

What should I wear?

We encourage our patients to wear loose, comfortable clothing that does not have any metal buttons or zippers. Otherwise you may be asked to change your clothes and wear a hospital gown. We have private dressing rooms but it is best to leave your valuables at home or with a family member. We may ask you to remove any jewellery, dentures, glasses or any metal objects which may interfere with the CT scan.

Additional Information

  • Please arrive 15 minutes prior to your scheduled appointment time to complete paperwork at our reception desk. We try to keep arranged times but emergencies may delay appointment times.
  • Upon arrival you will be given additional contrast to drink.
  • You will also need to sign a consent form for administration of IV contrast (iodine).
  • The scan will take approximately 30-45 minutes.

Purpose of contrast

  • When colon or small bowel needs to be visualised, you would need to drink oral contrast in order to see the loops of small intestine & large bowel loops more distinctly. It creates a white coating and allows the bowel to stand out against the other abdominal structures when loops of bowel are filled with it.
  • CT scan preparation takes much longer than the scan itself. CT scan preparation can take 4-6 hours before you have the scan if your doctor orders it with oral and IV contrast. This is because oral contrast has to travel through the entire length of the intestinal tract after you start drinking it.