[Haemodynamic effects of intraarterial contrast injections (author's transl)].

Intra-arterial contrast injections have well known systemic and pulmonary vascular effects; in addition there are local haemodynamic changes which begin immediately after the injection and last for several seconds. Three phases can be recognised: Phase 1 Increased flow, pressure and turbulence due to transmission of kinetic energy from the contrast medium to the vessel contents. Phase 2 Reduced flow due to the high viscosity of the contrast medium. Phase 3 Increased flow, probably a pharmacological results produced by contrast (osmolarity). The effects of contrast injection can be altered by changes to the catheter or to the properties of the contrast medium. This has practical consequences for injection techniques and for flow measurements. While assessing the clinical usefulness of the "spill over" flow measurements described by Olin and Redman in 1966, we concluded that the haemodynamic effects of the contrast lead to significant falsification of the measurements, and this also has some significance for the performance of angiography. We have therefore studied this phenomenon, its causes and the factors which influence it, on a model and in animal experiments. In order to quantify changes in flow caused by the injection during animal experiments, a study was carried out on the effects of contrast media on electromagnetic measurements.