Prostacyclin (PGI2) and thromboxane (TXA2) levels during intravenous contrast medium administration in CT.

Meglumine/sodium diatrizoate was administered as a one minute bolus of 60 ml. (60%) and subsequent 5 minute infusion of 250 ml. (24%) into antecubital veins during pelvic CT Scanning of 15 patients. Blood samples were taken from the opposite arm before and at 1 and 5 minutes after starting the contrast medium injection. The average plasma concentrations of diatrizoate were 2.2 +/- 0.5 and 3.8 +/- 0.8 mg./ml. in the 1 and 5 minute blood samples, respectively. The systemic levels of thromboxane A2 (TXA2) increased in 10 patient's plasma during contrast medium infusion while the level of prostacyclin (PGI2) remained unchanged. One patient had immediate adverse reaction due to contrast without any changes in PGI2 of TXA2 levels. Contrast medium infusion increased the systemic ratio of TXA2/PGI2 which may predispose to hemostatic disorders.