Abstract
The distribution of contrast media injected from catheters into vessels has been studied experimentally, using ultra-short radiographic exposures which prevent any motion blurring. This enabled observations to be made about the effect of direction and rate of injection, presence or absence of the side holes in the catheter, and the effect of flow-pattern in the main stream upon the distribution and degree of mixing of the injected medium, immediately after injection. One of the striking findings is the readiness with which contrast media enter the stagnant boundary layer at the periphery of the flow, which counters rapid mixing; the presence of side holes in the catheter encourages boundary layer penetration, and it is suggested that the use of side holes be avoided unless selective filling of branch vessels is desired. Retrograde injections also tend to produce boundary layer filling. Thorough mixing is most likely to be achieved if the rate of injection is equated with the flow-volume locally, and rapid injections of less concentrated media may be necessary for this. Complete mixing of contrast media, by avoiding unnecessarily high local concentrations, should tend to reduce the incidence of toxic complications in angiography.
Published Version
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