Contraindications
There are few contraindications for patients undergoing CT evaluation. The most important concerns prior allergeric / anaphylactic reactions to iodinated contrast. Risk factors for contrast reactions include a history of prior contrast reactions and asthma.
Severe reactions include laryngospasm, anaphylaxis shock, and cardiopulmonary arrest. In these patients, contrast exposure should be avoided, yet if the exam is necessary, these patients may be pre-medicated with the following prescriptions:
- Medrol 32mg PO 12 and two hours prior to receiving contrast
- Benedryl 50mg PO one hour prior to receiving contrast
Contrast nephropathy is another possible complication associated with the administration of iodinated contrast. Pre-disposing factors include: preexisting renal disease, diabetes mellitus, multiple myeloma, and dehydration. These patients are best managed with aggressive hydration prior to contrast, the use of low osmolar contrast with a limited dose, and Mucormist.
Contraindications for contrast enhanced CT
- Iodinated contrast allergy
- Renal insufficiency / failure
Contraindications for Cardiac Imaging
- Active asthma (requiring steroids)/ COPD
- Vasodialator usage within 48 hours of scan
- Hypotension (systolic b.p. < 100)
- Severe cardiac arrythmia (atrial fibrilation)
- AV block II,III