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1、胎兒磁共振成像MRImagingoftheFetus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MRI－UltrafastMRI--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LimperopoulosC,etal.AJRAmJRoentgenol2008;190:1
2、637–1643.TotalfetusesMRIabnormal9060(67%)ComparisonofantenatalandpostnatalMRfindingsin39of42liveborninfantsCompleteagreement23(59%)Disagreement16(41%)ExcludedfetalMRI6(15%)Revealedadditionalabnormalities10(26%)枕大池(cisternamagna)正常值2－11mm側(cè)腦室體部<10mm異常表現(xiàn)：Dandy-Walker畸形，小腦蚓部發(fā)育不良，大枕大池
3、，蛛網(wǎng)膜囊腫小腦蚓部的發(fā)育11－12W，小腦及原始蚓部從第四腦室嘴側(cè)發(fā)生13－14W，原始頂點(diǎn)可見（第四腦室頂部裂縫）14－16W，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”16－17W，錐前裂、頂前裂等可見18－19W，蚓部顱尾方向長度與小腦半球相等11－12W13－14W16W18W17.5w21w22w24w27wAssessmentofVermianMaturity小腦原裂primaryfissure頂點(diǎn)fastigialpoint頂－蚓角tengmento-vermianangle，TVA顱尾徑c
4、raniocaudaldiameter，CCDNormalAbnormalTengmento-vermianangle22－weekfetusA.axialsonographyshowedalargecysticposteriorfossawithsmallcerebellarhemispheres.B.thetegmento-vermianangleisincreasedwiththefourthventricleuncovered.Thevermisisverysmall;thereisnoprimaryfissureorfastigialpoint
5、.C.DiagrammaticrepresentationofDWC.D.thecerebellarhemispheresaresmall.Theventricularsystemisdilated,resultinginlargetemporalhorns22－weekfetusSonographyandMRIfindingsaresimilartothepreviouscaseexceptthatthecerebellarhemispheresseemslargerandvermiantissecanbeseeninthemidline.Cranio
6、caudaldiameterCraniocaudaldiameter(perpendiculartofastigialpoint-decliveline)28-weekfetusThecraniocaudaldiameterofvermismeasures10.9mm(equivalentof22weeks).Theexpectedmeasurementis14.8mm.Thetranscerebellardiameterisalsosmall.孕28＋3周，B超提示胎兒腦室擴(kuò)張14.9mm12.3mm9.8mm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)
7、為分界上下蚓比例為47％和53％，不隨生長發(fā)育變化23-weekfetus36-weekfetus大枕大池枕大池蛛網(wǎng)膜囊腫29-weekfetus5-month孕32周，外院超聲提示左腦室擴(kuò)張、枕大池積水孕31周，超聲提示：可疑側(cè)腦室增寬知識回顧KnowledgeReview
