Pain and aortofemoral arteriography: the importance of chemical structure and osmolality of contrast agents.

A total of 216 aortofemoral angiograms were performed on 72 patients being triple-injected with different contrast media. The characteristics of the contrast media being studied with relation to injection pain included the anionic component, the cationic component, and osmolality. A double-blind study was carried out with neither the examiner nor the patient being aware of the specific contrast medium being injected. The patients were then questioned as to which contrast agent was most painful. There was a significantly lower incidence of severe injection pain with pure meglumines and contrast media with low osmolality. Variation of the anionic component did not improve injection pain.