Imaging Modalities for the Diagnosis of Placenta Accreta Spectrum.

Placenta accreta spectrum (PAS) is the result of the invasion of the placental trophoblasts into the myometrium. The rate of PAS continues to increase due to the increased number of cesarean sections. Other risk factors include increasing maternal age, multiparity, uterine surgeries, and placenta previa. Due to the high risk of maternal morbidity and mortality, prenatal diagnosis is essential to ensure proper resources and surgical planning before delivery. Ultrasound is considered the gold standard for diagnosis of PAS. Ultrasound findings include placental lacuna, loss of placental clear space, lower uterine segment thickness, and increased vascularity between the placenta and bladder.