Radiologists use contrast material such as dyes in order to better see the details in advanced medical scans such as computerized tomography (CT) or magnetic resonance imaging (MRI). These also help images to be more clearly seen in medical picture archiving and communication systems, which make it easier for doctors, surgeons and specialists to transfer and access patient data. One such system is Dell PACS, which can store images of X-rays or scans and magnify them in extraordinary detail.

    But patients need to take blood tests in order to determine that they are not allergic to this contrasting material. Despite popular belief, having an allergy to shellfish does not automatically make a person allergic to contrast dyes. This is why allergy testing is done whenever possible.

    Radiocontrast Media Allergy

    To help doctors read CT scans more quickly, it is common practice for the patient to receive an IV of radiocontrast media or a type of iodine dye. Although shellfish is an ingredient in this dye, shellfish proteins are not included, and it’s the proteins that trigger allergic reactions in people with shellfish food allergies.

    Symptoms of radiocontrast media allergy include vomiting, sudden skin swelling, reddening of the skin, and hives. Those patients that had a previous allergic reaction may still get the radiocontrast media IV if a doctor is sure that symptoms can be prevented with antihistamines or epinephrine injections.

    MRIs

    Not all MRIs will need contrast media, made from gadolinium rather than iodine. This depends on what body part is being scanned for what purpose. For example, if the blood vessels need to be scrutinized, then contrast makes it easier to spot any abnormalities. The decision whether an MRI needs contrast depends upon the prescribing physician. Less people are allergic to gadolinium-based contrast dyes than iodine contrast dyes.