胎兒磁共振成像-胎兒頭顱MRI檢查

1、胎兒磁共振成像,MR Imaging of the Fetus,超聲Ultrasound -母體肥胖 -羊水過少 -妊娠中晚期胎頭增大 -胎兒顱骨骨化 MRIUltrafast MRI -單次激發(fā)快速序列 -大FOV -安全性？ MRI僅適用于當(dāng)產(chǎn)前超聲不足以解決臨床問題時(shí),MRI檢查技術(shù),1.5T及以下MR機(jī) 體部相共振線圈 序列：單次激發(fā)FSE(0.5NEX） FIASTA序列 常規(guī)軸、冠、矢掃描,胎兒頭顱MRI檢查,胎兒頭顱MR檢查主要觀察 -腦室擴(kuò)大 -可疑后顱窩異常 -胼胝體發(fā)育不良,Limperopoulos C, et al. AJR Am J Roentgenol 2008;

2、190:16371643.,Total fetuses MRI abnormal,90 60 (67%),Comparison of antenatal and postnatal MR findings in 39 of 42 live born infants,Complete agreement 23 (59%) Disagreement 16 (41%) Excluded fetal MRI 6 (15%) Revealed additional abnormalities 10 (26%),枕大池(cisterna magna)正常值211mm 側(cè)腦室體部10mm 異常表現(xiàn)：Dand

3、y-Walker 畸形，小腦蚓部發(fā)育不良，大枕大池，蛛網(wǎng)膜囊腫,小腦蚓部的發(fā)育,1112W，小腦及原始蚓部從第四腦室嘴側(cè)發(fā)生 1314W，原始頂點(diǎn)可見（第四腦室頂部裂縫） 1416W，小腦蚓部原裂出現(xiàn) 16W，小腦蚓部向尾側(cè)發(fā)育，于頂點(diǎn)處“折疊”覆蓋四腦室頂，第四腦室“閉合” 1617W，錐前裂、頂前裂等可見 1819W，蚓部顱尾方向長度與小腦半球相等,1112W 1314W 16W 18W,17.5w 21w 22w 24w 27w,Assessment of Vermian Maturity,小腦原裂 primary fissure 頂點(diǎn) fastigial point 頂蚓角tengme

4、nto-vermian angle，TVA 顱尾徑 craniocaudal diameter，CCD,Normal Abnormal,Tengmento-vermian angle,22week fetus,A. axial sonography showed a large cystic posterior fossa with small cerebellar hemispheres. B. the tegmento-vermian angle is increased with the fourth ventricle uncovered . The vermis is very sm

5、all; there is no primary fissure or fastigial point. C. Diagrammatic representation of DWC. D. the cerebellar hemispheres are small.The ventricular system is dilated, resulting in large temporal horns,22week fetus,Sonography and MRI findings are similar to the previous case except that the cerebella

6、r hemispheres seems larger and vermian tisse can be seen in the midline.,Craniocaudal diameter,Craniocaudal diameter (perpendicular to fastigial point-declive line),28-week fetus,The craniocaudal diameter of vermis measures 10.9mm (equivalent of 22 weeks). The expected measurement is 14.8mm. The transcerebellar diameter is also small.,孕283周，B超提示胎兒腦室擴(kuò)張,14.9mm,12.3mm,9.8mm,上下蚓比,小腦蚓部胚胎期呈線性協(xié)調(diào)發(fā)育 以頂點(diǎn)為分界上下蚓比例為47和53，不隨生長發(fā)育變化,23-week fetus,36-week fe