The Role of MRI in the Assessment of Placenta Previa and Abnormal Placental Invasion

Abstract Background: Placenta accreta is a serious condition that may threaten life with increasing incidence in the past years. Placenta accreta denotes abnormal placentation including placenta accrete (direct myometrial placental abnormal attach-ment), placenta increta (myometrial placental invasion) and placenta percreta (complete placental invasion within the uterine walls with or without extra-uterine extension). Lower anterior uterine segment is the commonest site for placenta accreta. Multiple cesarean section with presence of placenta previa are considered the commonest risk factors for placenta accreta. The percent of developing placenta accreta is 24% in females having placenta previa and previous one cesarean section and rises with increased number of previous to cesarean sections. Aim of Study: This study was done aiming at the clarifi-cation of the role of MRI in the assessment of the uterine walls' invasion by the placenta in cases with placenta previa. Patients and Methods: Prospective study of 50 pregnant women with age range between 35 and 45 years old. They were all referred form the Gynecology and Obstetric Depart-ment with clinical and ultra-sonographic criteria of placenta previa with suspected abnormal placental invasion. The clinical and sonographic data were assessed followed by MRI study of the abdomen and pelvis for placental assessment. Results: This study diagnosed placenta previa accompanied by accreta in 18/50 cases & placenta previa with no abnormal placental uterine walls' invasion in 32/50 cases. After corre-lation with surgical and histo-pathological reports, 100% of the cases showed true positive results regarding the MRI detection of placenta accreta as well as true negative results occurred in 81% of cases and false negative in 19% of cases. Conclusion: MRI study offers a superior choice for as-sessment of placenta previa and detection of placental invasion of the uterine walls (accreta type).