胎儿胼胝体发育不良的MRI与超声诊断对比研究

Diagnostic Value of Fetal MRI in the Evaluation of Anomalies of the Corpus Callosum

目的:探讨MRI相对超声在胎儿胼胝体发育不良(ACC)中的诊断价值。方法:回顾性分析胎儿MRI资料共296例,总结胎儿ACC的MRI特征,并以MRI诊断结果为“金标准”,对超声诊断结果进行评价,研究MRI的附加诊断价值。结果:MRI共诊断胎儿ACC23例,其中完全性ACC17例、部分性ACC6例;胎儿ACC的MRI直接征象包括胼胝体完全或部分性缺失,间接征象包括侧脑室扩张、侧脑室“泪滴”样改变、半球间裂增宽、第三脑室上移、透明隔缺失;ACC伴发畸形包括无脑回畸形1例(4.35%)、DandyWalker畸形2例(8.70%)、脑穿通畸形2例(8.70%)、室管膜下囊肿1例(4.35%)。超声共诊断胎儿ACC8例,均为完全性ACC;对6例部分性ACC全部漏诊;对MRI发现的伴发脑穿通畸形2例、无脑回畸形1例均未诊断出。超声诊断胎儿ACC的灵敏度为34.78%、特异度为99.64%、阳性预测值为88.89%、阴性预测值为94.79%。结论:胎儿ACC有较典型的MRI特征,MRI对胎儿ACC的诊断较超声精确,且可以发现更多的伴发畸形。

Purpose:To investigate the diagnostic value of fetal MRI compared to ultrasound in the evaluation of anomalies of the corpus callosum(ACC).Methods:The fetal MRI and US data in 296 pregnant women were reviewed retrospectively.The MRI findings of the fetal ACC detected in these women studied were summarized,and the diagnostic accuracy of ultrasound was evaluated using MRI as the reference test.Results:A total of 23 cases of fetal ACC were diagnosed by MRI,including 17 cases of complete ACC and 6 cases of partial ACC.The direct signs of ACC characterized by the partial or complete absence of the corpus callosum.The indirect signs include the dilation of the lateral ventricles as tear-drop sign,widening of the distance between the two cerebral hemispheres,absence of septum pellucidum,and upward displacement of the third ventricle.All the 8 cases of ACC diagnosed by ultrasound were complete ACC.Six cases of partial ACC were all missed by ultrasound.The sensitivity and specificity of ultrasound for the diagnosis of ACC were 34.78%and 99.64%,and the positive and negative predictive value were 80.2%and 84.2%,respectively.Conclusion:Fetal ACC has typical features on MRI.MRI is more accurate in the evaluation of ACC when compared to ultrasound.