Journal of Ultrasound in Medicine, Vol 20, Issue 4 335-342, Copyright © 2001 by American Institute of Ultrasound in Medicine
Low-resistance endometrial arterial flow in the exclusion of ectopic pregnancy revisited
K. L. Wherry, T. J. Dubinsky, G. M. Waitches, M. L. Richardson and S. Reed
Department of Radiology, The University of Washington Medical Center, Seattle 98195, USA.
The objective of this study was to evaluate the efficacy of endometrial
arterial flow in the exclusion of ectopic pregnancy. From October 1997 to
June 1999, 66 women with elevated beta-human chorionic gonadotropin titers
and clinical indications of ectopic pregnancy were evaluated by endovaginal
sonography. Women with a gestational sac containing an embryo, a yolk sac,
or both were excluded from the study. Doppler ultrasonography was performed
in the remaining cases when a definite intrauterine pregnancy could not be
visualized. In all cases the thermal index was kept to less than 1.0,
consistent with as-low-as-reasonably-achievable principles. Trophoblastic
flow was defined as a resistive index of less than 0.6 within the
endometrium. Statistical analysis was performed using a 2-tailed t test.
Twenty women had ectopic pregnancies; 33 had spontaneous pregnancy losses;
and 13 had normal intrauterine pregnancies. A total of 29 women had
endometrial trophoblastic flow: 11 of 13 with intrauterine pregnancies, 1
of 20 with ectopic pregnancies, and 17 of 33 with spontaneous pregnancy
losses. The negative predictive value for the presence of endometrial
low-resistance flow for excluding ectopic pregnancy was 97%. The presence
of low-resistance arterial endometrial flow can be a useful sign in
diagnosing an early intrauterine pregnancy and decreasing the probability
that an ectopic pregnancy is present, particularly in patients with
otherwise normal ultrasonographic findings.
