胎儿磁共振成像_胎儿头颅MRI检查ppt课件

.,1,胎儿磁共振成像,MRImagingoftheFetus,.,2,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MRIUltrafastMRI-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,.,3,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,.,4,胎儿头颅MRI检查,.,5,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,.,6,LimperopoulosC,etal.AJRAmJRoentgenol2008;190:16371643.,TotalfetusesMRIabnormal,9060(67%),ComparisonofantenatalandpostnatalMRfindingsin39of42liveborninfants,Completeagreement23(59%)Disagreement16(41%)ExcludedfetalMRI6(15%)Revealedadditionalabnormalities10(26%),.,7,枕大池(cisternamagna)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，蛛网膜囊肿,.,8,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,.,9,1112W1314W16W18W,.,10,17.5w21w22w24w27w,.,11,AssessmentofVermianMaturity,小脑原裂primaryfissure顶点fastigialpoint顶蚓角tengmento-vermianangle，TVA颅尾径craniocaudaldiameter，CCD,.,12,NormalAbnormal,Tengmento-vermianangle,.,13,22weekfetus,A.axialsonographyshowedalargecysticposteriorfossawithsmallcerebellarhemispheres.B.thetegmento-vermianangleisincreasedwiththefourthventricleuncovered.Thevermisisverysmall;thereisnoprimaryfissureorfastigialpoint.C.DiagrammaticrepresentationofDWC.D.thecerebellarhemispheresaresmall.Theventricularsystemisdilated,resultinginlargetemporalhorns,.,14,22weekfetus,SonographyandMRIfindingsaresimilartothepreviouscaseexceptthatthecerebellarhemispheresseemslargerandvermiantissecanbeseeninthemidline.,.,15,Craniocaudaldiameter,Craniocaudaldiameter(perpendiculartofastigialpoint-decliveline),.,16,.,17,28-weekfetus,Thecraniocaudaldiameterofvermismeasures10.9mm(equivalentof22weeks).Theexpectedmeasurementis14.8mm.Thetranscerebellardiameterisalsosmall.,.,18,孕283周，B超提示胎儿脑室扩张,14.9mm,12.3mm,9.8mm,.,19,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,.,20,23-weekfetus,.,21,36-weekfetus,大枕大池,.,22,枕大池蛛