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1、胎儿磁共振成像,MR Imaging of the Fetus,超声Ultrasound-母体肥胖-羊水过少-妊娠中晚期胎头增大-胎儿颅骨骨化MRIUltrafast MRI-单次激发快速序列-大FOV-安全性？MRI仅适用于当产前超声不足以解决临床问题时,MRI检查技术,1.5T及以下MR机体部相共振线圈序列：单次激发FSE(0.5NEX）FIASTA序列常规轴、冠、矢扫描,胎儿头颅MRI检查,胎儿头颅MR检查主要观察-脑室扩大-可疑后颅窝异常-胼胝体发育不良,Limperopoulos C,et al.AJR Am J Roentgenol 2008;190:16371643.,Total
2、 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侧脑室体部10mm异常表现：Dandy-Walker 畸形，小脑蚓部发育不良，大枕大池，蛛网膜
3、囊肿,小脑蚓部的发育,1112W，小脑及原始蚓部从第四脑室嘴侧发生1314W，原始顶点可见（第四脑室顶部裂缝）1416W，小脑蚓部原裂出现16W，小脑蚓部向尾侧发育，于顶点处“折叠”覆盖四脑室顶，第四脑室“闭合”1617W，锥前裂、顶前裂等可见1819W，蚓部颅尾方向长度与小脑半球相等,1112W 1314W 16W 18W,17.5w 21w 22w 24w 27w,Assessment of Vermian Maturity,小脑原裂 primary fissure顶点 fastigial point顶蚓角tengmento-vermian angle，TVA颅尾径 craniocauda
4、l 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 small;there is no primary fissure or fastigi
5、al 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 cerebellar hemispheres seems larger and vermian tisse can
6、 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超提示胎儿脑室扩张,14.9mm,12.3mm,9.8mm,上下蚓比,小脑蚓部胚胎期呈线性协调发育以顶点为分界上下蚓比例为47和53，不随生长发育变化,23-week fetus,36-week fetus,大枕大池,枕大池蛛网膜囊肿,29-week fetus,5-month,孕32周，外院超声提示左脑室扩张、枕大池积水,孕31周，超声提示：可疑侧脑室增宽,知识回顾Knowledge Review,
