胎盘形态异常的MRI表现及其临床应用

The MRI Manifestation and Clinical Significances of Variant Placental Shapes

目的探讨胎盘形态异常的MRI表现及其对临床治疗的指导作用。方法对19例经手术或病理证实胎盘形态异常患者的MRI影像表现进行回顾性研究,并与产前超声诊断相比较。结果19例胎盘形态异常的患者中,副胎盘8例,MRI表现为一个或多个附属胎盘小叶与主胎盘相连,脐带插入口位于主胎盘;双叶胎盘4例,表现为相连的两个胎盘小叶体积相近,脐带插入口位于两叶之间;轮状胎盘1例,表现为胎盘边缘呈环状的膜性带状结构,向羊膜面弯曲卷入;胎盘部分附着于宫腔粘连带3例,胎盘部分附着于子宫纵隔1例,均表现为宫腔内带状低信号分隔,其中子宫纵隔为一纵行分隔,顶端与宫底相连,分隔两侧宫腔内膜光滑且厚度多大于1 cm;而宫腔粘连带可发生于宫腔内任何位置,厚度不均且多小于1 cm,两端均与子宫肌壁相连;双子宫畸形左侧子宫单胎妊娠1例,表现为左侧妊娠子宫腔内胎盘部分覆盖于子宫纵行分隔上,右侧非妊娠子宫体积增大并出现明显蜕膜反应;胎盘间叶发育不良1例,表现为胎盘体积增大,病变胎盘内有弥漫分布的长T、长T囊性信号区。结论MRI对于胎盘形态异常具有良好的诊断效能,能为产前超声补充更全面的诊断信息,特别是对于胎盘前置合并形态异常患者的临床治疗具有重要指导价值。

Objective To investigate the MRI features and their clinical significances of variant placental shapes.Methods The MRI findings of 19 cases with abnormal placental morphology confirmed by surgery or pathology were reviewed and compared with prenatal ultrasound diagnosis.Results Among the 19 cases with variant placental shapes,8 were succenturiate placenta,which could have one or more accessory lobules that were not congiguous with the main placental lobe,and the insertion of umbilical cord was located in main lobe.Four cases were bilobed placenta,which presented as two fairly equal size lobes with the umbilical cord located between the lobules.One case was circumvallate placenta,in which the amniotic covering inserted at an area more medial than the junction of the chorion and placenta and folds upon itself.Three cases of intrauterine adhering zone,and 1 case of placenta was adhering to uterus septus.They might be identified as hypointense linear images that cross the endometrial cavity.Uterus septus was a longitudinal septum and usually starts from the uterine fundus,the septus was smooth and the thickness was more than 1 cm.While intrauterine adhesions could be seen in anywhere in the uterine cavity,the septus was uneven and the thickness was less than 1 cm.One case was uterus didelphys having single pregnancy in her left horn,and the placenta in the left horn was partially covered the vaginal septa.The right horn was also enlarged and the decidua reaction was obvious.Placental mesenchymal dysplasia was reported in 1 case,it was characterized by enlarged and cystic placenta with long Tand long Tsignal.Conclusion MRI has an important role in diagnosing variant placental shapes.It is also a valuable complement to ultrasound,especially in cases combined with placenta previa.