<prompt> Allergic reactions to radiological contrast agents are:Anaphylactic reactionsIgE mediated reactionsUicariaEdema  <response>: In radiological imaging it is usually believed that the adverse effects of contrast media are non-IgE mediated anaphylactoid reactions, as a result of released vasoactive amines histamine, serotonin, etc which trigger the mast cells directly. Since anaphylactoid reaction is not given in the choice, anaphylactic reaction may be the right choice. Ref: Encyclopedia of Diagnostic Imaging By Albe L Bae Pages 44-46 