目的 本研究旨在评价MRI和超声检查对产前胎盘植入的诊断效能。方法 从2017年1月至2019年12月连续随机纳入临床疑似诊断胎盘植入的112例患者的临床及影像学资料。根据术中所见或术后病理作为诊断的“金标准”，绘制受试者工作特性（Receiver operating characteristic，ROC）曲线并计算曲线下面积（The area under the curve, AUC）、敏感性、特异性、阳性预测值(Positive predictive value, PPV)和阴性预测值（Negative predictive value, NPV），以对比MRI和超声检查对诊断产前胎盘植入的差异性。结果 临床诊断疑似胎盘植入的112例患者，有85例纳入本研究（75.9%，85/112）。MRI和超声检查诊断产前胎盘植入的敏感性、特异性、PPV和NPV分别为96.5%、74.1%、92.1%、7.0%和68.2% 、59.3%、84.1%和37.2%。两种检查方法的AUC值分别为AUCMRI=0.926和AUCUS=0.906。胎盘植入MRI直接征象：85例MRI均显示子宫底蜕膜连续性中断，胎盘组织侵入子宫肌层。8例胎盘穿透示局部胎盘组织突出子宫浆膜层，子宫肌层信号中断，胎盘与膀胱分界欠清楚，膀胱后壁局部呈结节样改变。间接征象：96.5%的病例显示胎盘信号不均质，92.9%显示胎盘内流空血管影，88.2%显示胎盘附着处子宫肌层变薄、模糊，81.2%显示T2WI上胎盘内低信号带，68.2%显示胎盘局部增厚、21.2%显示胎盘局部凹陷。 结论 MRI和超声检查是产前诊断胎盘植入的主要手段，但MRI对胎盘植入的诊断效能优于超声。

Objective The purpose of this study was to evaluate the diagnostic efficacy of MRI and ultrasonography in prenatal placenta implantation. Methods From January 2017 to December 2019, the clinical and imaging data of 112 patients with suspected placental implantation were randomly included. According to the intraoperative or postoperative pathology as the "gold standard" of diagnosis, The area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated, To compare the difference between MRI and ultrasonography in the diagnosis of prenatal placental implantation. Results Direct signs of placental implantation on MRI: 85 cases of MRI all showed interruption of the continuity of decidual fundus of uterus and invasion of placental tissue into myometrium. 8 cases of placental penetration showed that the local placental tissue protruded from the uterine serosa layer, the signal of uterine muscular layer was interrupted, the boundary between placenta and bladder was not clear, and the local posterior wall of bladder showed nodular changes.In 8 cases of placenta penetration, local placental tissues protruded the uterine serous layer, the signal of myometrium was interrupted, the boundary between placenta and bladder was not clear, and the posterior wall of bladder presentednodular changes locally. Indirect signs: Placental signal heterogeneity was observed in 96.5% of cases, intraplacental flow empty vascular shadow at 92.9%, thinning and blurriness of myometrium at placental attachment at 88.2%, low signal bands within the placenta on T2WI at 81.2%, local thickening of placenta at 68.2%, and local depression at 21.2%.