The following CT scans require NO preparation:
- Spine (cervical, thoracic, lumbosacral)
- Extremity (hand, wrist, elbow, shoulder, hip, knee, ankle, foot)
- Kidneys-Ureter-Bladder – “KUB” (looking for kidney stones)
- Sinus/Facial Bones
- Most brain scans
- HRCT Chest (note: If a standard CT chest or CTPA is also requested, these latter two require X-ray dye and hence the need to fast for 4 hours)
Unless otherwise specified at the time of booking, the following scans need X-ray dye (also known as contrast – see below) and therefore require fasting for 3 hours prior to the examination:
- Abdomen and Pelvis (also must arrive 30 minutes before appointment to drink 1L of water).
- This include CT examinations dedicated to liver (“triphasic liver”), pancreas and kidneys scans
- All Angiograms
If you are to undergo an examination that requires X-ray dye in conjunction with another that does not (for example, a CT of the lumbar spine and CT of the abdomen and pelvis), then you must also fast for three hours.
Patients who have poor kidney function (renal impairment) will often not be given contrast so as not to worsen the condition. Diabetic patients who are to undergo a CT with contrast must let the clinic know if they are taking medications for their diabetes eg. Metformin. If this is the case, you will be given special instructions.