晚孕期胎盘植入的MRI诊断及分型

MRI diagnosis and classification of placenta increta in the third trimester of pregnancy

目的:探讨晚孕期各型胎盘植入MRI征象及其诊断价值。方法:回顾性分析2010年7月-2013年12月期间经手术及病理证实27例胎盘植入孕妇的临床资料。所有孕妇均行MRI检查。结果:粘连型3例,植入型15例,穿透型9例,均为前置胎盘。三型胎盘厚度及胎盘内流空血管数目分别为4.87cm/5.0;5.31cm/5.7;6.51cm/6.8。3例粘连型2例胎盘附着面呈弧形,1例呈结节状膨出,肌层连续;15例植入型11例胎盘结节状膨出,11例肌层渐进性消失,10例肌层异常信号;9例穿透型4例胎盘结节状膨出,5例块状突出,超过肌层轮廓,2例肌层渐进性消失,7例肌层中断,肌层信号均见异常,4例膀胱肌层信号异常。结论:常规MRI序列对胎盘植入的诊断与分型具有较高的应用价值,部分病例存在征象重叠。

Objective：To assess the MRI manifestations and diagnostic value of different types of placenta increta in the third trimester of pregnancy.Methods：The clinical materials of 27 patients with placenta increta confirmed by surgery and pathology from Jul 2010 to Dec 2013 were retrospectively analyzed.All cases performed MR scanning before delivery.Results：Among the 27 pregnant women,3,15 and 9cases were classified as placenta accreta,placenta increta and placenta percreta respectively All cases had placenta previa.The thickness of placenta and number of flow-void blood vessels within the placenta were 4.87 cm and 5.0in placenta accreta,5.31 cm and 5.7in placenta increta,6.51 cm and 6.8in placenta percreta respectively.In the 3patients with placenta accreta,the placental myometrial apposition interface was arc shape in 2cases,and nodular protrusion with continuous myometrium in one case.Among the 15 cases of placenta increta,abnormal MR findings included nodular protrusion of placenta（n=11）,progressive obliteration of normal myometrium（n=11）and abnormal signal intensity of myometrium（n=10）.Among 9cases of placenta percreta,there were 4cases with nodular protrusion of placenta and 5cases with massive placenta penetrating the full thickness of the myometrium.All 9cases showed abnormal signal intensity of myometrium,2cases with disappearance of the normal myometrium and 7cases with interruption of the normal myometrium.4cases showed abnormal signal in the normal bladder wall.Conclusion：Conventional MRI plays a significant role in the diagnosis and classification of placenta increta,but overlapping features were still existed.