Placental evaluation with magnetic resonance.

Because of the high maternal morbidity and mortality of undiagnosed placental abnormalities, there is a need for accurate antenatal diagnosis. Important placental features amenable to investigation with magnetic resonance (MR) imaging include variant placental location and morphology, and abnormal implantation or invasion of placenta into the myometrium. MR imaging features permit the diagnosis of abnormal placentation include placental lobulation with uterine contour deformity, interruption of the inner low signal-intensity myometrial layer, and placental heterogeneity resulting from dark intraplacental bands and abnormal vascularity.