Abstract: ［Abstract］ Objective〖HTSS〗To explore the clinical value of ultrasound scoring combined with magnetic resonance imaging（MRI）magnetic resonance imaging in the diagnosis of dangerous placenta previa and predicting the degree of risk.
〖HTH〗〖WTHZ〗Methods〖HTSS〗Retrospective analysis of clinical data of 71 patients with suspected placenta implanted in the third trimester of pregnancy who were hospitalized and terminated. Preoperative evaluation of the risk of placenta previa and placenta implantation were performed according to the ultrasound score combined with MRI. The diagnostic sensitivity, specificity, positive predictive value and negative predictive value were evaluated postoperatively.
〖HTH〗〖WTHZ〗Results〖HTSS〗All patients were considered as sinister placenta preoperatively. The postoperative pathology confirmed the sensitivity of the ultrasound score combined with MRI for the risky placenta previa with placenta implantation was 95.65%, the positive predictive value was 80.00%, and the negative predictive value was 87.50%. Both were higher than singleuse ultrasound scoring or MRI.The specificity is 56.00%, which is lower than a single inspection method.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗For pregnant women who are suspected to be sinister placenta previa in late pregnancy, feasible ultrasound scoring combined with MRI to predict the degree of risk, with high diagnostic accuracy, improve maternal and child postpartum quality of life and other advantages, it is worth promoting in clinical applications.

Key words: placenta previa, placenta implantation； ultrasonography； magnetic resonance inaging