Objectives: To assess the ultrasound (US) impact in diagnosing placenta accreta (PA) in patients with anterior placenta praevia localization, overlying a Caesarean scar.
Patients, materials and methods: This is a prospective study between January 2016 and December 2017 that included patients with Caesarean scar and placenta praevia in the third trimester of pregnancy. By means of two-dimensional (2D) grayscale and color Doppler, we investigated the presence of the following US markers for placental invasion: intraplacental lacunae, abnormal blood vessels at the myometrium-bladder interface, thinning of the hyperechogenic uterine serosa-bladder wall interface, loss of normal hypoechoic retroplacental myometrial space. Definitive diagnosis was made at delivery. The US findings were correlated with intraoperative and histopathological (HP) evaluations.
Results: We found 46 cases with anterior placenta praevia overlying a Caesarean scar. Twelve patients presented US criteria for PA. The confirmation was obtained (by means of intraoperative and/or HP features) in 11 of them. The US evaluation with all markers yields a sensitivity of 100% for PA detection. Among the US markers, the association of abnormal blood vessels at the myometrium-bladder interface and the intraplacental lacunae had the highest statistical correlation in the antenatal diagnosis of PA.
Conclusions: Our study suggests that the antenatal US is a useful tool in predicting PA in high-risk patients. Special attention should be given to the presence of intraplacental lacunae and abnormal myometrial vessels in cases where the placental insertion overlaps a uterine scar for best identification of PA high-risk cases.