Heating contrast media: role in contemporary angiography. 
While constant injection pressure was maintained, in vitro flow rates of contemporary contrast media through selected, typical, contemporary angiographic catheters were measured at room and body temperatures.  Heating the contrast media increased the flow rate by greater than 8% only when high-viscosity (ionic monomeric 76% and ionic dimeric 58.9%) contrast material was used in small (4- and 5-F) catheters.  Although flow rates with other combinations of catheter length, contrast material, and injection pressure cannot be predicted from these results, heating of contrast material is probably most useful when a high-viscosity contrast medium is used in a small catheter.