Radiology, Vol 184, 141-144, Copyright © 1992 by Radiological Society of North America
Early detection of extravasation of radiographic contrast medium. Work in progress
J Shaeffer, SV Sigfred, MA Sevcik, RS Grabowy, LA Gemmell and AD Hirschman
Department of Radiation Oncology, Eastern Virginia Medical School, Norfolk 23507.
Microwave radiometry is a passive and noninvasive technique that allows
quick detection of subcutaneous temperature changes. The feasibility of
this technique for differentiating normal intravenous infusions of
radiographic contrast medium from extravasations of contrast medium was
tested in anesthetized dogs. Room-temperature and heated ionic and nonionic
contrast media were administered at flow rates ranging from 0.2 to 9.9
mL/sec by means of a power injector. On the basis of these experiments, an
algorithm to adjust for extravasation detection thresholds as a function of
injection flow rates was developed. With this algorithm, results showed a
false-positive rate of 0% at all infusion rates and false-negative rates of
2%, 2%, and 4% at pump speeds of 0.2, 1.0, and 9.9 mL/sec, respectively.
The times of these extravasation "alarms" corresponded to maximum
extravasated volumes, respectively, of 4, 6.5, and 8 mL. Microwave
radiometry has clinical potential for early detection of extravasation of
contrast medium administered with power injectors.
