OC09.05: MRI findings in placenta accreta spectrum disorders: correlation with ultrasound and anatomopathological findings

Abstract

The role of prenatal diagnosis in placenta accreta spectrum (PAS) disorders is to reduce the risk of maternal complications by allowing a preplanned management. Although ultrasound (US) is the first diagnostic tool of choice, Magnetic Resonance Images (MRI) contributes in assessing the location, extension and depth of the invasion. Our objective is to describe the most characteristic features of PAS by MRI and correlate them with US, surgical and anatomopathological findings. Methods: We retrospectively reviewed prenatal MRI of patients with suspected diagnosis of PAS treated at our institution from 2015 to 2017. MRI were performed with standardised protocols to evaluate placenta. Localisation and extension of the abnormality was identified and correlated with US, macroscopic and histopathological findings. Results: During this period 41 patients with PAS were studied. All cases had heterogeneous placental showed as irregular venous lakes in US which by MRI corresponded to abnormal intraplacental blood vessels and thick dark bands on T2 weighted images (T2WI). These latter were correlated with fibrin deposits in the histopathologic evaluation. Conclusions: In our experience, abnormal intraplacental vascularisation together with thick hypointense bands on T2WI constitute the most frequent MRI findings to determine the presence, location and extension of PAS disorders. Therefore, MRI is currently considered a highly useful diagnostic tool for surgical planning of these patients.