产后胎盘植入的MRI表现及诊断价值

Postpartum MRI Appearance and Diagnostic Value of Placental Accrete

目的探讨胎盘植入的MRI表现特征及诊断价值。方法回顾性分析10例经病理或临床证实的产后植入性胎盘患者资料(年龄20～33岁,平均27.6岁)。10例均行常规MRI,7例行增强扫描。总结其MRI特点及诊断价值。结果 10例中,MRI确诊9例,误诊1例。MRI表现为:子宫体积不同程度增大;子宫肌层内层结合带完整性破坏,局部模糊甚至中断。子宫内见混杂信号团块影,孕龄短的胎盘表现为单纯的团块状结构,孕龄长的胎盘具有特征性的叶状、结节状结构。以子宫肌层为对照,T1WI病灶表现为等低信号,与宫壁分界欠清,T2WI表现为混杂的明显高信号,内可见条状及点状低信号,病灶突入肌层,肌层局部明显变薄,其中接近浆膜层者7例,基本在肌层内3例。增强扫描病灶呈不均匀明显强化,类似"花瓣"样,边缘呈较高信号而中央呈稍低信号,其强化程度基本等同于子宫肌层,坏死区无强化,有时表现为"裂隙"状。结论 MRI能明确诊断胎盘植入及判断肌层侵入的大致程度,是显示胎盘植入的辅助诊断工具之一。

Objective To investigate the features and diagnostic value of MRI in placenta accreta（PA）.Methods 10 cases PA comfirmed clinically or pathologically were retrospectively analyzed（aged 20-33 years old,with an average of 27.6 years old）.All cases were examined by conventional MRI scans,7 cases by contrast-enhanced MRI scans.Results 9 patients were correctly diagnosed with MRI,and 1 patients misdiagnosed.Uterus enlarged in various degrees.The integrity of junctional zone（JZ） of myometrium was destructed,with local fuzzy even discontinued.The mixed signal intensity mass was showed in the uterus.Placentas of shorter gestational age appeared to be a mixed simple mass,the longer ones to be lobulated structure distinctively.Compared with the signal intensity of the outer layer of the myometrium,the placental signal intensity appeared isointense or hyperintense and the boundary of it and uterus was not clear on T1WI.On T2WI,the placenta appeared significantly mixed heperintense with a few dark intraplacental spotted or linear bands.The lesion invaded myometrium,the myometrium appeared to be thinner locally.Lesions invaded close to perimetrium in 7 cases and were located within muscular layer basically in 3 cases.By contrast enhanced,placentas were heterogeneous enhancement significantly,appeared to be ＂rosette or petal-like＂,similar to enhancement degree of myometrium.The necrotic area was not enhanced,sometimes depicted as ＂aperture shape＂.Conclusion MRI can make correctly diagnosis of PA and judge the general degree of placental invasion.It is a kind of auxiliary diagnostic tool ideally.