Question

What does placenta accreta look like on an ultrasound?

Answer 1

According to one study 9, ultrasoundhas a sensitivity of 89.5%, the positive predictive value of 68% and negative predictive value of 98% for the diagnosis of placenta accreta. When aplacenta accreta occurs on the posterior or lateral walls of the uterus, it may be difficult to detect byultrasound.

Answer 2

• Placenta accreta is both the general term applied to abnormal placental adherence and also the condition seen at the milder end of the spectrum of abnormal placental adherence. This article focuses on the second, more specific definition.
• In a placenta accreta, the placental villi extend beyond the confines of the endometrium and attach to the superficial aspect of the myometrium but without deep invasion.
• According to one study 9, ultrasound has a sensitivity of 89.5%, the positive predictive value of 68% and negative predictive value of 98% for the diagnosis of placenta accreta.
• Several sonographic criteria for the diagnosis of placenta accreta have been reported:marked thinning or loss of the retroplacental hypoechoic zoneinterruption of the hyperechoic border between the uterine serosa and bladderpresence of mass-like tissue with echogenicity similar to that of the placentavisualization of prominent vessels or lakes within the placenta or myometriumvisualization of lacunae has the highest sensitivity in the diagnosis of PA, allowing identification in 78%-93% of cases after 15 weeks gestation, with a specificity of 78.6%10
• When a placenta accreta occurs on the posterior or lateral walls of the uterus, it may be difficult to detect by ultrasound..