Intravascular contrast agent in the ultrasonography of ectopic pregnancy

The aim of this study was to characterize the effect of an intravascular ultrasound contrast agent in the adnexal circulation and to evaluate the applicability of the contrast agent in imaging ectopic trophoblastic blood flow.

Thirty-three color Doppler and 13 power Doppler examinations were performed among 30 patients with ectopic pregnancy, first without and then with galactose-based contrast agent enhancement. The effect of the contrast agent was evaluated both visually (color Doppler) and with computerized power Doppler signal intensity measurements.

The Doppler signal intensity from the adnexal blood circulation increased within 30 s after antebrachial injection, yielding an effect that was recognizable up to 2-4 min later. There was a clear enhancement of trophoblastic flow after addition of the contrast agent in all except one of the ectopic pregnancies. In 12% of the cases, trophoblastic flow could be imaged only by using the contrast agent. The contrast agent increased the amount of recognizable vascular areas around the trophoblastic mass in 91% of the examinations, resulting in a more complete peritrophoblastic ring. The increase in the mean intensity of the power Doppler signal was 7.8% (p < 0.01).

The intravascular ultrasound contrast agent has a recognizable effect on Doppler ultrasonographic examination of the adnexal circulation. It appears to be of help when examining ectopic pregnancies where the finding in color flow imaging is ambiguous. The use of a contrast agent may also facilitate localization of trophoblastic tissue in a hemorrhagic adnexal mass.