[Application of magnetic resonance imaging to predict the type and severity of placenta accreta]

Objective: To investigate the value of magnetic resonance imaging (MRI) in predicting the type and severity of placenta accreta (PA). Methods: The clinical data of 67 PA cases in Peking University Third Hospital from January, 2015 to November, 2016 were analyzed retrospectively.Cases were classified according to the direct and indirect MRI signs.Chi-square test was applied to disclose the difference between different PA types and MRI signs.MRI signs with statistical significance were further calculated by the area under ROC curve (AUC) value analysis to reveal the correlation between specific signs and the type/severity of PA. Results: Among the 67 cases, 24 cases were of mild PA and 43 cases were of severe PA.Statistical difference was found between the two PA groups in some signs such as placenta tissues invading the uterus myometrium, placenta tissues extending beyond the uterus outline, the uniformity of placental signal, abnormal vessel imaging in the placenta basilar part, Bladder Tent Sign and the discontinuity of low signal zone in the gap between bladder and placenta.AUC analysis showed that the above MRI signs had the stronger correlations between the type/severity of PA, compared with other signs. Conclusion: Not only can MRI be used to predict the type of PA, but also it can be used to predict the location and severity of PA, which has an important reference value for clinical works.