Locations & Hours | Radiology Services & Procedures | Insurance Info | Policies & Payments Intravenous Contrast by Scott A. Montesi, M.D. Frequently Asked Questions: What is IV contrast? IV contrast is a commercially made, readily available substance used to enhance structures in your body, usually for CT, MR, or some ultrasound (US) studies. These substances are generally referred to as “dye” or “x-ray dye”; some specific names are Isovue, Omnipaque, Gadolinium, Magnevist, though others do exist. These are neither the agents used in nuclear medicine, which are radioactive, nor are they the “oral” contrast you may drink for many imaging studies. Why do I need IV contrast? The use of intravenous (IV) contrast consistently gives a radiologist more and better information to evaluate from your imaging study, increasing the ability to make a specific and confident diagnosis. While it is not necessary for all imaging studies, you will receive it for most CT (CAT) scans, MR and some ultrasound studies, unless your doctor feels it is not necessary. How is it given to me? A nurse or technologist will place a small catheter (tube) in a vein in your arm. Occasionally they will use a preexisting catheter tube you may have in your chest/neck, placed by another doctor. Contrast is either injected by hand or using an injector machine. What will I feel? The majority of patients feel nothing other than the sensation of an injection in their arm. Some patients experience a metallic flavor or warm sensation, which is usually gone by the end of the exam. Rarely, a patient will feel sick or vomit. Can the dye be dangerous? Radiology Alliance (RA) insists on the use of the safest types of contrast agents available. Serious, life-threatening reactions are rare and occur approximately 1 out of 10,000 – 20,000 injections. RA facilities have nurses and doctors available to treat these if they occur. There is no test to determine the rare person who will react other than a history of reaction in the past. If you have received IV contrast in the past and experienced shortness of breath or lost consciousness or if you have a severe allergy to shellfish, inform the technologist. Either your test will be performed without contrast or, if it is absolutely necessary, your test will be performed with contrast after you have received medication to help prevent a reaction to contrast. Other more minor side effects can occur such as hives or itching. Benadryl or other similar medication can be given if these do not go away in a short time.