Here are some precautions for certain groups of patients:

• Referring clinician has responsibility of identifying patients who may be at risk.
• Radiology staff will check menstrual history of patient of child-bearing age.
• Radiologist may consider postponing the examination if there is likelihood
  of pregnancy.

• IV contrast may exacerbate asthma inpatients with clinically active disease.
• For asthmatic patients requiring IV contrast, the radiologist will consider a short course of oral steroids prior to the examination or modify the type of investigation based on his assessment of the severity of their asthma.
  

• Metformin should be stopped two days before and resumed two days following
  the investigation requiring IV contrast.
• Alternative means of diabetic control should be used during this period.

We strongly recommend that the referring clinician ensure patient compliance with special instructions given.