Iodine delivery rate in catheter angiography under pressure conditions in manual injection

PURPOSE: The aim of this study was to record the flow-rate and to calculate the "iodine delivery rate" (IDR) of contrast media of various viscosities when the contrast media are injected by hand. METHODS: Five different catheters for coronary angiography were tested with the injection system Medrad Mark V Plus. Injections were performed with pressures of 100, 200 and 400 PSI. The contrast media examined were Imeron 350, Imeron 400, Omnipaque 350 and Ultravist 370. The IDR was calculated on the basis of the measured flow rate and the Iodine content of the contrast medium. RESULTS: As was expected, the IDR was higher as the pressure increased. In addition to the Iodine content the viscosity of the contrast medium is a very important factor for the IDR. At both 100 PSI and 200 PSI the increase of the IDR was higher with Imeron 350 than with Imeron 400. The comparison of contrast media with identical Iodine contents but differing viscosities (Imeron 350, Omnipaque 350) clearly showed that the IDR depended on viscosity. CONCLUSION: The "iodine delivery rate" is a decisive factor in the opacification of arterial vessels. Both Iodine content and viscosity of a contrast medium are important for the IDR. Because of the low pressure at manual injection, contrast media with low viscosities should be used. A further possibility to increase the IDR is warming-up the contrast medium to body temperature.