MRI对胎盘植入的诊断价值

T he diagnostic value of MRI in placenta accreta

目的:探讨胎盘植入(placental adhesive disorders,PADs)MRI表现的特点及诊断价值。方法:回顾性分析我院2014年1月至2015年3月45例因经超声检查怀疑胎儿或胎盘异常行盆腔MRI检查患者的影像学及临床资料,其中30例经手术或病理证实为PADs。45例均行常规MRI扫描,2例行动态增强扫描。结果:MRI诊断PADs的灵敏度为87.1%(27/31),特异度为73.3%(11/15)。MRI检出PADs与手术及病理检查一致性分析结果显示,K=0.644,U=4.33,P=0.000,诊断符合率为84.4%(38/45),即一致性良好。MRI对PADs的检出率(90%)与超声(76.7%)比较差异无统计学意义(χ2=1.92,P=0.166)。胎盘粘连8例,PADs 20例,胎盘穿透肌层侵及膀胱后壁2例,其中,13例可见子宫肌层内或肌层与胎盘底蜕膜之间T2WI信号极低的增粗血管影。21例PADs患者合并完全前置胎盘。结论:MRI能明确诊断PADs、判断肌层侵入深度及范围,为临床产前诊断及治疗提供可靠依据。

Objective：To explore the placental imaging sign and diagnostic value of placenta invasion by MRI. Method：From January 2014 through March 2015,we made a retrospective analysis that 45 pregnant women who suspected abnormal placenta or fetus by ultrasound at our hospital,and then underwent prenatal MRI examination. 30 patients were confirmed with placental invasion at delivery or pathology. All the patients had routine non-contrast MRI examination,and only 2 MRI scans were done after intravenous injection of gadolinium. Results：Diagnostic sensitivity and specificities for placenta accreta was 87.1%（27/31） and 73.3%（11/15） for MRI. The diagnosis had good consistency between MRI and pathology （K=0.644,U=4.33,P=0.000）. Of the confirmed 30 cases,the frequency of placenta accrete detected by MRI and uhrasonography had no significant difference （90.0%＆76.7%,x2=1.92,P=0.166）. There were 8 cases that placenta attached to the myometrium but did not invade the myometrium. 20 cases showed irregular and heterogeneous placenta,thinner and discontinuous of uterine walls. Another 2 cases showed that bladder was involved,irregular appearance of the bladder wall. Furthermore,13 cases showed low-signal-intensity bands on T2-weighted imaging between the myometrium and decidua basalis. The uterine cervical orifices were completely covered by placenta （21 cases）. Conclusion：MRI,which can definitively diagnose placenta accreta and show the depth and extent of invading the myometrium,provide reliable basis for clinical prenatal diagnosis and treatment.