Placenta previa - accreta: Do we need MR imaging?

Objective: To determine whether magnetic resonance imaging has a considerable impact in the assessment of antenatal suspicion of placenta accreta. Subjects and methods: Ultrasound and magnetic resonance imaging was performed for 35 gravid females with placenta previa prior to delivery. Delivery plan was made according to the imaging suggestion of the degree of placenta previa and the presence/absence of placenta accreta. Findings at cesarean section were considered the gold standard of reference. Results: Ultrasound had suggested true-positive diagnosis of accreta in 86.6% (n = 13/15) and MRI in 93.3% (n = 14/15). Matching between US and MRI findings took place in 75% (n = 15/20) of the negative cases and in 80% (n = 12/15) of the positive cases of placenta accreta in the studied cohort. Sensitivity, specificity, positive predictive value and negative predictive value of Ultrasound and MRI were 86.6%, 80%, 89%, 76.5% and 93.3%, 85%, 94.4%, 82.3% respectively regarding their ability to predict placenta accreta within high risk patients with placenta previa. Conclusion: Magnetic resonance imaging hand in hand with Ultrasound is important for the accurate diagnosis of placenta previa and the seriously co-existing placenta accreta. (C) 2011 Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier B.V. All rights reserved.