产前多序列MRI诊断胎儿先天性马蹄内翻足

Prenatal multi-sequence MRI diagnosis of fetal congenital talipes equinovarus

目的观察产前多序列MRI诊断胎儿先天性马蹄内翻足(CTEV)的价值,并与超声诊断结果对比。方法纳入26胎经出生后证实的CTEV胎儿。A组孕周≤28周,B组孕周>28周,各13胎,均于产前超声检查后3天内接受单次激发快速自旋回波(SSFSE)、稳态采集快速成像(FIESTA)、弥散加权成像(DWI)及快速反转恢复运动抑制(FIRM)序列胎儿足部MR扫描。观察CTEV胎儿足部信号特点,比较MRI与超声诊断CTEV的准确率。结果MR SSFSE、FIESTA及FIRM序列图像中,CTEV胎儿足部骨组织均呈低信号、皮肤肌肉均呈等信号;DWI图像中,长骨骨干及皮肤肌肉均呈低信号,骨骺端呈高信号。产前MRI共误诊1胎CTEV为多趾畸形,漏诊2胎及1胎双侧病变中的1侧CTEV,诊断CTEV的准确率为88.46%(23/26);超声共漏诊5胎,诊断准确率为80.77%(21/26)。A组产前超声诊断CTEV准确率(100.00%)高于MRI(76.92%),但差异无统计学意义(P>0.05);B组产前MRI诊断CTEV准确率(100.00%)明显高于超声(61.54%),差异有统计学意义(P<0.05)。结论多序列MRI可用于产前诊断胎儿CTEV。采用快速扫描技术、反复采集胎儿足部位置变化后冠状位图像有利于明确诊断。

Objective To observe the value of prenatal multi-sequence MRI in diagnosis of fetal congenital talipes equinovarus(CTEV)compared with ultrasound.Methods A total of 26 fetuses with CTEV confirmed by following-up after birth were enrolled,including 13 with gestational age(GA)≤28 weeks(group A)and 13 GA>28 weeks(group B).Within 3 days after prenatal ultrasound examination,MR scanning of fetal foot were performed using single-shot fast spin echo(SSFSE),fast imaging employing steady-state acquisition(FIESTA),diffusion weighted imaging(DWI)and fast inversion recovery motion insensitive(FIRM)sequence.MRI characteristics of fetal CTEV were analyzed,and the accuracies of MRI and ultrasound for diagnosing fatal CTEV were compared.Results The bone tissue of CTEV foot showed low signals,while the skin and muscles showed isointense signals on SSFSE,FIESTA and FIRM images.On DWI images,the long bone shaft,skin and muscles showed low signals,while the metaphysis showed high signals.Prenatal MRI misdiagnosed 1 fetus of CTEV as polydactylia,missed diagnosed 2 fetuses and one of bilateral CTEV of 1 fetus,the diagnostic accuracy of prenatal MRI for fetal CTEV was 88.46%(23/26).Prenatal ultrasound missed diagnosed CTEV in 5 fetuses,and the diagnostic accuracy was 80.77%(21/26).The accuracy of prenatal ultrasound was 100%(13/13),of prenatal MRI was 76.92%in group A(P>0.05),while in group B,the accuracy of prenatal MRI was 100%,obviously higher than that of prenatal ultrasound(61.54%,P<0.05).Conclusion Prenatal MRI could be used to diagnose fetal CTEV,especially for screening fetal limb malformations after 28 weeks of gestation.Rapid MR sequences and acquisition of coronal images repeatedly with the changes of fetal foot position might help to diagnosis of fetal CTEV.