The Role of Ultrasonography and Magnetic Resonance Imaging in the Diagnosis of the Adherent Placenta: An Observational Study.

Introduction Placenta accreta is an important factor responsible for maternal morbidity and mortality and is commonly associated with emergent postpartum hysterectomy. The precise prenatal diagnosis of affected pregnancies allows optimal obstetric management. Ultrasonography (USG) and magnetic resonance imaging (MRI) are the only diagnostic modalities available for the prenatal diagnosis of placenta accreta. Objective This study aims to evaluate the accuracy of USG and MRI in diagnosing adherent placenta. Methods Thirty females with placenta previa or a history of previous cesarean sections were evaluated with USG at 28-30 weeks, followed by MRI. The findings of USG and MRI were compared with the intra-operative findings (gold standard) as determined at surgery and by pathological examination. Results Abnormal bridging vessel (n = 24; 80%) was the most common finding seen on USG, whereas abnormal bulge (n = 22; 73.3%) and heterogenous placenta (n = 21; 70%) were the most common findings seen on MRI. The sensitivity of USG and MRI was in the range of 86.7%-92.9% and 92.9%-100%, respectively, in diagnosing three types of adherent placenta. The positive predictive values (PPV) of USG and MRI were in the range of 86.7%-86.7% and 93.8%-100%, respectively, in diagnosing three types of adherent placenta. The accuracy of USG and MRI was in the range of 86.7%-96.7% and 96.7%-100%, respectively, in diagnosing three types of adherent placenta. Conclusion MRI helps to accurately classify placental invasion according to depth, as can be seen from the results of the present study, where the MRI technique was more accurate in diagnosing three types of adherent placenta.