Contrast media extravasation during dynamic CT: detection with an extravasation detection accessory.

To detect extravasation of contrast media during mechanical power injection at dynamic computed tomography, a 5 x 8-cm pliable adhesive patch was applied to the skin over the intravenous cannula and connected to the power injector with a cable to monitor electrical skin impedance. If the rate of change or the slope of impedance over time indicated an extravasation event, the power injector was set into a pause mode. In animal and human studies, monitoring with the device was successful. Extravasation of ionic contrast agents decreased impedance and that of nonionic agents increased impedance.