AbstractID: 7688 Title: Difference in Flow Characteristics between Contrast Media and Blood during Xray Angiography
X-ray angiography is used to evaluate blood flow by observing the flow of contrast media. A limitation of this approach is that the
density and the viscosity of the iodinated contrast media are substantially greater than that of blood. During our angiographic studies
of the modification of blood flow in cerebrovascular aneurysms by stents using silicone aneurysm phantoms, we observed different
flow patterns when the aneurysms were placed at different orientations with respect to gravity. To further investigate this effect, we
performed an experiment to track the flow in an aneurysm phantom using optical dye. We used 40% aqueous glycerin fluid to match
the viscosity and density of blood, and the refractive index of silicone. Pulsatile flow with an average rate of 178 ml/min was used.
Two runs were recorded at 10 frames/sec using a video camera to compare differences in flow with injection of optical dye only and
with injection of the mixture of contrast media and optical dye. We did a polynomial fit of the time-density curves obtained from a
region-of-interest inside the aneurysm. The mixture with contrast media was delayed as expected compared to that with only optical
dye by 1.2 sec in time-to-peak optical density and 1.8 sec in time-to-half-peak washout. These results indicate that the flow properties
demonstrated by contrast media in x-ray angiograms are not that of blood and must be interpreted by taking the density and viscosity
differences into consideration. (Partial support: NIH Grant 1R01NS38746 and the Oishei Foundation)