MR Imaging of Abnormal Placentation.

Morbidly adherent placenta (MAP) encompasses a spectrum of conditions characterized by abnormal adherence of the placenta to the implantation site. Classification of MAP is based on the degree of trophoblastic invasion through myometrium and uterine serosa and includes accrete, when the villi are attached to the myometrium but do not invade the muscle; increta, when the placenta invades partially through the myometrium; and percreta, when it invades up to and beyond the uterine serosa. Knowledge of the common findings of MAP on MR imaging is important to be able to provide an accurate diagnosis.