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Influence of the contrast medium iodine concentration on quality of the CT examination
RANŠOVÁ, Pavlína
Our work focused on determining absolute and relative density of various contrast agents in relation to iodine contents using in vitro and in vivo methods. It was documented that the relative density of contrast agents increases with the decreasing contents of iodine, i.e. density absolute values vary inversely as iodine content in these substances. Four various agents, bearing commercial names Visipaque 270, Visipaque 320, Ultravist 370 and Iomeron 400, in their original glass packing were used for our in vitro measurements. The measurements were carried out using CT equipment Emotion Duo (Siemens, Forchheim, Germany). Individual packing of the contrast agents were scanned by means of a standard protocol and under standard conditions. The obtained data were entered into tables. A retrospectively selected array of patients with standard scan of their stomachs was used for our in vivo measurements with a defined standard protocol using the same CT equipment and pressure injector CT 9000 Advantage (Liebel-Flarsheim, Mallinckrodt, the U.S.A.). The following data from 258 patients were recorded: age, sex, blood density after administering contrast agent in vitro on the level of diaphragm hiatus and on the bifurcation level, AP dimension of the patients on the hiatus level. Mean densities of the individual kinds of contrast agents were compared and a good correlation with the in vitro measurements was found out. The measured values were then analysed. The interdependence was studied in the measured densities and age, density changes measured on the hiatus level and on the bifurcation level for the individual contrast agents. The interdependence of the blood density on the AP dimension of the patients was also studied due to its practical use and it was documented that there is a good correlation of the decreasing density with the AP dimension as a simple parameter used instead of finding out patients{\crq} weights.
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