The sonographic appearance of placenta accreta

Abstract

Placenta accreta is an uncommon entity in which the placental villi invade the myometrium. The classic sonographic findings include the absence of a hypoechoic retroplacental zone, the presence of dilated vessels extending from the placenta through the myometrium, irregular cystic spaces in the placenta, and pulsatile maternal blood flow within these hypoechoic spaces. It is often accompanied by placenta previa. In this study, the authors report findings in six cases, four of which were accurately diagnosed sonographically as placenta accreta, one which resulted in a false-positive diagnosis, and one which resulted in a false-negative diagnosis. We review the roles of two-dimensional imaging color-flow Doppler, and power Doppler in assessing this condition. Because of the associated high risk of maternal exsanguination, ultrasonography is an important and reliable tool in diagnosing accreta.