The chorionic rim and low-impedance intrauterine arterial flow in the diagnosis of early intrauterine pregnancy: Evaluation of efficacy

OBJECTIVE. We undertook this study to evaluate whether sonographic imaging of an intrauterine chorionic rim or arterial flow can help diagnose an early intrauterine pregnancy. MATERIALS AND METHODS. One hundred sixty-nine women with early intrauterine pregnancies and 69 women with ectopic pregnancies underwent pelvic sonography. All sonograms were examined for a chorionic rim (an echogenic rim bordering an intrauterine fluid collection) or a double decidual sac. Of these 238 patients, 126 also underwent Doppler examination for endometrial arterial flow. RESULTS. The chorionic rim and double decidual sac had sensitivities for intrauterine pregnancy of 80% and 64%, respectively, and specificities of 97% and 100%, respectively. Intrauterine arterial flow with either peak systolic velocity greater than or equal to 15 cm/sec or resistive index less than or equal to 0.55 had a sensitivity of 70% and a specificity of 95%. Combining these two signs led to sensitivities and specificities of approximately 90%. Similar test performance was observed in patients having intrauterine pregnancies that lacked an embryo, yolk sac, or amniotic remnant. CONCLUSION. The chorionic rim and low-impedance endometrial arterial flow can indicate an intrauterine pregnancy even when the double decidual sac is not seen. These two signs are particularly useful for patients with intrauterine pregnancies that show no other sonographic findings.