[Pharmacologic effects of contrast media in angio-densitometry]

Angio-densitometry is a very sensitive method in the evaluation of vascular effects of a contrast medium. For that purpose the renal circulation is especially suitable. The method is based on the zero or subtraction method. Thus, the majority of the well known interference sources will not be recorded. Only changes of density caused by the passing blood are measured. Four different contrast media are compared. Their effects on the circulation cannot be predicted from a single measurement. The mean value of several measurements limits the scattering range and allows comparisons to be made. Accordingly there are some differences between the examined conventional contrast media and their influence upon the kidney circulation. They all slow down the blood velocity in the renal artery, but the extent is different. The causes responsible for the circulatory effects of the contrast media are discussed on the basis of current scientific knowledge. In addition the results of 144 angio-densitometric studies are reported. The analysis of the pharmacological effect of meglumine iothalamate (Conray 60) revealed only an unimportant influence upon the renal circulation.