Clinical Radiology Exhibits

Learning Objectives: To describe a case report of an advanced case of placenta percreta. To illustrate the MR sequence protocol and imaging findings of placenta percreta.Background: Placenta percreta is the more severe form of the placenta accreta spectrum (PAS) (1,2).The incidence of PAS in Australia and New Zealand is estimated to be 44.2 per 100,000 women (0.044%) (3).The prevalence of placenta percreta is approximately 22% of PAS cases (4).Multiparity, older maternal age, an increased number of prior caesarean deliveries, and presence of placenta previa are well-known risk factors for PAS (3,5).In the setting of high prevalence risk factors, the diagnostic accuracy of US and MR for PAS is similar (6), however the high sensitivity and specificity of MR for depth of invasion and topographic spread to adjacent structures is likely to assist in surgical planning (7).Case Report: A 35-year-old Aboriginal patient presented with frank hematuria and suspected placenta previa at the end of second trimester with an acute reduction in hemoglobin.Imaging Findings or Procedure Details: US followed by MR were performed.An MR placenta protocol utilizing a series of T1/T2 weighted ultrafast gradient and spin echo sequences were obtained.MR findings demonstrated extensive placenta previa, intra-placental bands, and extension of placenta through the bladder wall.There was placental invasion through the myometrium with direct contact apparent between the placenta and the rectus sheath at the umbilical level, superior to the bladder.There was no invasion into pelvic side wall structures.After establishment of a multidisciplinary team protocol, the patient proceeded to elective caesarean section delivery of a healthy fetus after insertion of bilateral internal iliac balloons.The patient then underwent coil embolization of both uterine arteries prior to bilateral salpingectomy and hysterectomy.Intra-operative findings included a morbidly adherent utero-vesical plane.Placenta percreta was confirmed on histology.The patient was discharged in the following days with no immediate complications.Conclusion: Placenta percreta is a rare potential life-threatening obstetric complication requiring multidisciplinary team involvement.In this advanced case of placenta percreta MR played a significant role in surgical planning.The background, case history, MRI protocol and imaging findings have been described in this report.