title: What is the risk of reaction on repeat exposure to contrast material, and how should the patients be premedicated?
mesh_terms: D003287:Contrast Media / Q000009:adverse effects*; D006801:Humans; D011292:Premedication; D012008:Recurrence; D013256:Steroids / Q000008:administration & dosage*
chemical_list: D003287:Contrast Media; D013256:Steroids