Postpartum MRI appearance of placental implantation abnormality / 第二军医大学学报

ABSTRACT

Objective: To explore postpartum MRI appearance and diagnostic value of MRI for placental implantation abnormality (PIA). Methods: Postpartum MRI findings of 11 PIA patients (mean age28?4.5 years; range 23-25) were analyzed retrospectively. All patients underwent hysterectomy because their placentae were not discharged spontaneously, the postpartum hemorrhage added up to 800-4 500 ml and PIA was diagnosed by MRI 2-6 d after delivery. Results:Compared with the signal of the outer layer of the myometrium on the same scanning sequence, the placental signals appeared isointense or slightly hyperintense and the dividing line between the placenta and uterine wall was indistinct on T_1WI. On T_2WI the placental signal intensity was higher than that of the uterine wall. Placenta accreta showed that the placenta was confluent with the uterine wall and the junctional zone continued and the thickness of junctional zone was normal or slightly thinning. Placenta increta showed that the placental tissue invaded the myometrium in the shape of “triangle”, “nodule” or “mushroom”, and the junctional zone became thinner locally or discontinued. On Gadolinium-enhanced T_1WI, the intensity of placental enhancement was higher than that of uterine wall and the placental tissue was confluent with the uterine wall. The surgico-pathologic examination found 7 cases of placenta accrete and 4 cases of placenta increta. MRI diagnosis showed 8 cases of placenta accreta and 3 cases of placenta increta. There was one misdiagnosis by MRI. Conclusion: MRI is an ideal tool for postpartum diagnosis of PIA and can accurately evaluate placental configuration, the extent of placental accreta and the location and deepness of placental invasion.