羊水过少胎儿结构和相关畸形的MRI诊断价值

摘要

Purpose: To evaluate the value of MRI on normal structures and abnormalities of fetuses with oligohydramnios. Methods: Thirty - four pregnant women, aged from 20 to 35 years were studied with a 1.5 T superconductive MR unit within 24 to 48 hours after ultrasound studies. The imaging protocol included fast - imaging employing steady - state acquisition (FIESTA), single - shot fast spin echo (SSFSE)sequences in the axial, coronal, and sagittal planes relative to the fetal brain, thorax, abdomen, especially bilateral kidneys and lungs. Prenatal US and MR imaging findings were compared with postnatal diagnoses or autopsy. Postnatal evaluation included US, MR imaging, computed tomography. Calculation of the ratio of lung signal intensity to liver signal intensity (LLSIR) was performed on MR images by using region -of- interest analysis. Results: MRI displayed all normal structures and abnormalities of 34 fetuses with oligohydramnios. The abnormalities of 18 fetuses with oligohydramnios included genitourinary anomaly (n = 20, 12 cases with pulmonary hypoplasia ), bilateral pulmonary hypoplasia(n = 3), idiopathic oligohydramnios(n = 11) . Eighteen cases were born, 16 cases were induced. Except 4 cases induced abortion without autopsy, the others were confirmed by birth imaging or autopsy after abortion. Conclusion:Prenatal MRI is effective in the assessment of normal structures and anomalies of of fetuses with oligohydramnios, it can clearly show the normal structures and associated fetal abnormalities without the impact of oligohydramnios.%目的:评价磁共振成像(MRI)对羊水过少胎儿结构及相关畸形的诊断价值.方法:34例孕妇,孕龄20～35周.产前常规行超声(US)检查后24～48h内行MR检查,采用二维快速平衡稳态采集(2D FIESTA)序列、单次激发快速自旋回波(SSFSE)序列,行胎儿颅脑胸腹部常规及双肺、双肾重点冠状面、矢状面及横断面扫描,将产前MRI、US表现与出生后影像或引产后尸解对照.通过MRI采用感兴趣区工具(ROI)测量胎儿肺肝信号强度比(LLSIR).结果:34例羊水过少胎儿MRI均能清晰显示其结构,20例存在泌尿系统畸形(其中12例合并肺发育不良),3例只合并双肺发育不良,特发性羊水过少11例.合并肺发育不良共计15例.18例出生,16例引产.除4例引产未尸检外,其余均由出生影像学或引产后尸解证实.结论:MRI是显示羊水过少胎儿结构及相关异常最有效的诊断方法,它能不受羊水过少的影响,清晰显示胎儿结构及相关异常.