Placenta previa; MRI as an adjunct to ultrasound in assessment of suspected placental invasion

Objective: Evaluate adding MRI to ultrasound in imaging of placenta previa with suspected placenta accreta. Patients and methods: evaluation of 23 pregnant females presenting with placenta previa was done. The age ranged from 20 to 39 years (mean = 30.9). All of the patients were subjected to ultrasonography (US) and magnetic resonance imaging (MRI) of the pelvis at gestational age of 25–37 weeks prior to elective delivery. Results: 11 out of 23 patients were proved placenta accreta based on surgical and pathological reports. US suggested diagnosis of placenta previa/accreta in 8 patients and placenta previa without accreta in 15 cases. 7/8 was true positive (87.5%) & one was false positive (12.5%) with sensitivity 63.64%, accuracy 78.26%, and specificity 91.67%. MRI has suggested diagnosis of placenta previa/accreta in 8/23 & placenta previa with no accreta in 15/23 patients. MRI was found to give true positive results in 8/8 patients proved to be accreta. MRI gave true negative in 12 patients (80%) & false negative in 3 (20%) with sensitivity 72.73%, accuracy 86.96%, and specificity 100%. Conclusion: Combining MRI and ultra sound provide more diagnostic information and may reduce unnecessary interventions with favorable outcome. Keywords: Ultra sound, MRI, Placenta previa, Placenta accret