脑室周围白质软化早产儿出生早期MRI表现及其演变

目的 探讨最终发展为脑室周围白质软化（periventricular leucomalacia,PVL）的早产儿出生早期头部MRI表现及其演变.方法 选取2010年1月至2013年12月中国医科大学附属盛京医院新生儿科住院经MRI确诊为PVL的患儿12例,所有病例均在生后2～7d（平均5.5d）及17～23 d（平均20.3 d）完成2次常规MRI及弥散加权成像（diffusion-weighted imaging,DWI）扫描.结果 最终被确诊的12例PVL患儿,初次扫描结果：全部病例DWI显示脑室周围白质高信号,其中6例弥漫、对称性高信号,3例线状高信号,3例簇状高信号,而常规MRI仅有5例显示T1加权像稍高信号,T2加权像稍低信号,余7例无改变;再次扫描结果：全部患儿脑室周围白质出现大小不等、数量不一的病灶,常规MRI显示T1加权像低信号,T2加权像高信号,相应病变部位DWI呈低信号.结论 早产儿出生早期,DWI对发现和预测PVL优于常规MRI;弥漫性脑白质损伤易发展为PVL,较严重的局灶性脑白质损伤,如多簇状、线状损伤也有发展成PVL的可能.     

早产儿脑白质损伤早期磁共振成像改变及其高危因素分析

目的以磁共振成像(MRI)提供的影像学资料为依据,评价早产儿脑白质损伤的早期MRI变化及其临床意义,并探讨其高危因素。方法选取2007年9月至2009年9月中国医科大学附属盛京医院儿科收治的262例早产儿,全部在7d内完成磁共振检查,根据MRI诊断早产儿脑白质损伤,分为病例组134例,对照组128例。并对病例组29例患儿进行二次复查。结果 (1)早产儿脑白质损伤早期,局灶性病变表现弥散加权成像(DWI)高信号,T1加权(T1WI)信号正常或稍高信号,伴有或不伴有T2加权(T2WI)低信号;弥漫性脑白质损伤仅能看到DWI弥漫性高信号,常规MRI无信号改变。复查结果,局灶性病变有两种情况:一是病灶消失,二是DWI高信号消失或稍高信号,T1WI高信号,伴或不伴有T2WI低信号;弥漫性病变,发生脑室周围白质软化,表现为T2WI高信号或高低混杂信号,DWI异常信号消失或高低混杂信号,T1WI高低混杂信号。(2)病例组与对照组在胎龄,出生体重差异无统计学意义。单因素分析:母孕期感染、双胎、代谢性酸中毒、低钙、低氧、机械通气和感染与早产儿早期脑白质损伤有统计学意义。Logistic模型多因素分析,母孕期感染、低氧和胎儿宫内窘迫是早产儿早期脑白质损伤的危险因素。结论 (1)DWI能发现早期脑白质损伤病变。(2)早产儿脑白质损伤是多种因素相互作用的结果:母孕期感染、胎儿宫内窘迫及出生后低氧与早产儿早期脑白质损伤有密切关系。(3)早产儿脑白质损伤早期临床表现缺乏特异性,建议常规行头MRI检查,且脑白质信号异常均需要动态随访观察。     

弥散加权成像在新生儿重度缺氧缺血性脑病早期评价中的意义

目的探索新生儿重度缺氧缺血性脑病（HIE）早期弥散加权成像（DWI）动态演变规律及其意义。方法对2006年1月至2007年2月收住我院14例重度HIE患儿,分别于生后72h。7、14、21d及8个月行DWI及常规MRI扫描。结果72h内,常规MRI的T1加权（T1WI）和T2加权（T2WI）均未见异常,DWI表现为双侧腹外侧丘脑对称性的高信号;7d常规MRI表现双侧腹外侧丘脑对称性T1WI高信号,T2WI稍低信号,DWI表现为双侧基底节高信号,而初期腹外侧丘脑高信号消失;14d常规MRI双侧丘脑、基底节对称性T1WI高信号,T2WI低信号;21d常规MRI双侧丘脑及基底节T1WI高信号,T2WI高信号,DWI则未见明显异常;8个月常规MRI脑沟变深、脑室扩大及脑外间隙增宽,基底节T2WI不规则的高信号。结论重度HIE（主要因急性的完全性窒息所致）生后初期DWI显示相同的病变部位（腹外侧丘脑和基底节）和相似的病变程度,但其异常信号很快消失,而常规MRI可继之弥补DWI的不足。     

早产儿脑室周围-脑室内出血与脑室周围白质软化的诊断建议

早产儿常见脑损伤主要为脑室周围．脑室内出血（PVH-IVH）和脑室周围白质软化（PVL）,与早产儿中枢神经系统的解剖生理学和神经生物学发育不成熟密切相关。前者为出血性病变,常导致脑室内出血后脑积水和脑室周围出血性髓静脉梗死等严重并发症。后者为缺血性病变,也与官内感染有关。其中局部PVL的病理特征是白质少突胶质细胞前体的急性坏死,在后期可形成多发小囊腔。弥漫性PVL又称为弥漫性白质损伤,其病理特征是白质少突胶质细胞前体的凋亡性死亡,少见出现囊腔改变。局部和弥漫性PVL最终均导致脑白质容量减小和髓鞘化受损。PVH-IVH和PVL是引起早产儿早期死亡、脑瘫、视、听和认知障碍的主要原因。     

晚期早产儿脑白质损伤临床特点及磁共振影像学发现

目的：探讨晚期早产儿脑白质损伤的临床特点及常规磁共振成像（MRI）和弥散加权成像（DWI）影像学特征。方法：总结2005年1月至2008年5月中国医科大学盛京医院收治的519例早产儿资料（277例晚期早产儿,242例早期早产儿）,对其头部常规MRI和DWI特征进行分析。结果：晚期早产儿中,脑白质损伤118例,占脑损伤的71.9%（118/164）,占全部晚期早产儿的42.6%（118/277）。早期早产儿脑白质损伤占脑损伤的69.2%（92/133）,占全部早期早产儿的38.0%（92/242）,晚期早产儿脑白质损伤发生率与早期早产儿相比无明显差异。晚期早产儿脑白质损伤中无明显临床症状者占61.9%（73/118）,重症脑损伤（广泛性及弥漫性脑损伤）早期有明显临床症状者占75%（15/20）。损伤1周内,DWI表现为高信号,T1WI信号正常或稍高信号,伴或不伴T2WI高信号;弥漫性损伤者呈DWI高信号,常规MRI无明显信号改变。结论：脑白质损伤在晚期早产儿亦较常见。重症脑白质损伤患儿早期多有明显的临床表现。DWI在损伤早期的敏感度高于常规MRI。［中国当代儿科杂志,2010,12（5）：321-326］     

磁共振成像在早产儿白色念珠菌感染脑脓肿诊断中的意义

目的：探讨磁共振成像在中枢神经系统侵袭性真菌感染（IFI）致脑脓肿中的诊断价值。方法：回顾性分析8例中枢神经系统IFI早产儿临床资料,8例患儿于住院期间和出院后接受了MRI T1WI、T2WI和DWI 3种序列头部检查。结果：8例IFI早产儿均为白色念珠菌感染。其中7例表现为脑脓肿,4例伴有脑膜炎。7例脑脓肿患儿MRI提示侵袭范围广泛,皮层下白质、深部脑室周围及半卵圆中心白质受累。其中4例MRI检查在感染后11 d内完成,表现为弥漫或多发粟粒样结节,DWI呈高信号,而T1WI和T2WI改变不明显,DWI信号3周后近消失;在感染的2~4周T1WI/T2WI信号改变最明显,结节可呈环形,T1WI周边为高信号,中央低信号,T2WI信号与之相反,严重者表现不同程度的融合,在T1WI可见明显强化效应。4周后病灶在T1WI也逐渐变少和变小,转为点或线样的高信号,T2WI明显低信号。2例MRI动态随访表现有髓鞘发育延迟,胼胝体变薄。结论：MRI-DWI和动态的MRI改变可为早产儿白色念珠菌感染脑脓肿的早期诊断及治疗转归评估提供客观依据。     

早产儿脑室周围白质软化的相关因素研究

目的分析导致早产儿脑损伤的相关危险因素。方法以2006年1月至2009年6月入住安徽省立儿童医院新生儿科的443例早产儿为研究对象,分为脑室周围白质软化(PVL)组(125例)与无PVL组(318例),按PVL级别分为非囊性PVL组(116例)和囊性PVL组(9例),采用头颅超声诊断技术早期诊断早产儿PVL,用多因素分析影响PVL及其不同级别的高危因素。结果单因素分析显示:胎龄、出生体重、分娩方式、低体温、生后感染、呼吸暂停、血糖、心肌酶谱、C-反应蛋白(CRP)和血清白蛋白在PVL组和无PVL组之间差异有统计学意义(P0.05或P0.01)。多因素Logistic回归分析显示:出生体重低、母亲低剖宫产率、生后感染及血清白蛋白和心肌酶谱水平高是早产儿发生PVL的危险因素,另外,生后感染是发生囊性PVL的危险因素。结论出生体重低、母亲低剖宫产率、生后感染及血清白蛋白和心肌酶谱高是早产儿发生PVL的危险因素,另外,生后感染的早产儿发生囊性PVL的风险较高。     

早产儿脑室周围白质软化的影像学研究进展

脑室周围白质软化(PVL)是早产儿脑损伤的主要形式,包括囊性和弥漫性PVL.近年来其发病率有逐渐增高趋势,已成为影响早产儿生存质量及导致小儿脑瘫的主要疾病.因早产儿PVL缺乏特异的临床表现,故其诊断必须依赖于影像学检查.B超是目前确诊PVL最常用的检测手段,但其漏诊率较高;常规磁共振成像对评价PVL的脑损伤程度及预后判定具有重要意义,但在早期,特别是对弥漫性PVL也有其局限性;而弥散加权成像作为一种新型的检测技术,弥补了B型超声及常规磁共振成像的不足,为弥漫性PVL早期诊断提供了有价值的影像学信息.     

早产儿脑室周围白质软化20例B超表现及分析

目的　分析早产儿脑室周围白质软化 (PVL)的超声表现以及预后。方法　对入住福建省妇幼保健院新生儿科所有早产儿进行常规床边头颅B超检查,对确诊为PVL的早产儿进行PVL超声图像分析并定期随访。结果　1996年底至 2004年 7月间经常规床边B超检查确诊为PVL的早产儿共 20例,其中 19例初次B超检查时间为(4 20±0 85)d,均在超声中表现为双侧脑室前角、体部或三角部外上方对称性强回声区。1例因故迟至 29日龄进行初次B超检查,显示双侧侧脑室三角部外上方已呈多发小囊腔改变。10例于 (23 6±6 1)d在原回声增强区呈现多个低回声或无回声囊腔,直径范围在 2~19 5mm,其中 2例显示囊腔分别于 41日龄和 67日龄消失。除早期死亡、自动出院及失访 12例外,余 8例患儿中,发生脑瘫 4例,疑似脑瘫 1例,其中 2例伴有智测评分低下;仅 3例 3~7个月龄随访时暂未发现异常。结论　PVL的超声表现十分典型。由于PVL患儿预后不良,对早产儿在生后早期进行常规床边头颅B超检查很有必要。     

早产儿脑室周围出血性梗塞的发病机制和临床特征

在过去的2 0年中,随着围生期护理的明显改善,尽管脑室周围脑室内出血(PV IVH)的发生率正在减少,重度IVH或伴有脑实质累及的IVH仍然是极低出生体重儿(特别是<1 0 0 0 g的超低出生体重儿)的常见问题,脑室周围出血性梗塞(PHI)是继发于早产儿PV IVH所致的脑室周围白质损伤,与早产儿脑室周围白质软化(PVL)一样,是引起早产儿新生儿期死亡和远期神经发育缺陷(包括运动和认知)的主要原因。但是,这二种脑白质损伤有本质上的区别,PHI是脑室周围白质的出血性坏死,而PVL则是脑室周围白质的缺血性损害。本文将重点讨论PHI的神经病理学、发病…     

磁共振弥散加权成像在新生儿脑梗死早期诊断中的意义及其变化规律

目的探讨弥散加权成像（DWI）对新生儿脑梗死（NCI）早期的诊断价值。方法收集2004年6月至2005年10月,在我院新生儿科住院的6例NCI患儿的临床资料。全部病例完成了血常规、血糖、血清总钙及离子钙、C-反应蛋白、凝血酶原时间及部分凝血活酶时间、心脏彩色多普勒及头部MRI检查。并对其中4例进行MRI动态观察。结果（1）全部病例为足月儿,1例有重度窒息史,其余5例无明显宫内窘迫及出生窒息史。（2）5例以全身惊厥为首发症状。（3）全部病例无红细胞增多症,无出血及凝血机制障碍,心内结构正常。（4）MRI检查时间：发病后18h至4d。常规MRI4例异常（T1WI低信号,T2WI高信号）,2例正常;DWI6例异常（全部高信号）,随访（2周至15个月）：常规MRI6例异常（T1WI低信号,T2WI高信号）;DWI6例异常（低信号）。梗死部位：4例左侧颞叶、顶叶和枕叶,1例左侧额叶和顶叶,1例左侧基底节。结论NCI早期,常规MRI尚未出现明显异常,DWI即显示明显高信号,从而证实DWI对NCI早期诊断的价值。     

新生儿脑梗死早期的临床表现与磁共振成像特点

目的：磁共振成像（MRI）是目前诊断新生儿脑梗死的金标准,然而常规MRI对于2 d内的新生儿脑梗死的早期显像并不敏感。为了早期诊断新生儿脑梗死,该研究探讨了新生儿脑梗死患儿的早期临床表现及头部MRI成像学特征,包括常规MRI及弥散加权成像（DWI）,并为早期诊断提供依据。方法：回顾分析该院新生儿病房收治的16例新生儿脑梗死患儿临床资料、头部MRI检查(所有病例均于生后5 d内行常规序列扫描后接受弥散加权序列扫描),其中5例于新生儿期（生后11~18 d）进行了第2次头部MRI检查。结果：①高危因素：产前8例（50%）,产时9例（56%）,产后0例（0%）;临床表现：11例以惊厥发作为首发症状,患儿每次抽搐持续时间较短（平均为2~3 min）,9例于24 h内停止抽搐;②MRI扫描结果：初期（5 d内）病灶部位T1稍低信号,T2加权稍高信号,相同部位弥散加权影像均表现为高亮信号,且病灶边界清晰;再次扫描时（生后11~18 d）病灶部位T1低信号、T2高信号较前明显,相同部位弥散加权均表现为低信号。结论：惊厥多为新生儿脑梗死的首发表现,发作次数少且程度轻;梗死早期DWI表现为高亮信号,继之常规MRI出现T1低信号、T2高信号,并随时间逐渐明显,尤以T2表现更为敏感。［中国当代儿科杂志,2009,11（2）：96-99］     

Magnetic resonance imaging of the brain in a cohort of extremely preterm infants.

To define magnetic resonance imaging (MRI) appearances of the brain in extremely preterm infants between birth and term, a sequential cohort of infants born at a gestational age <30 weeks was studied with a dedicated neonatal magnetic resonance scanner. Images of infants (n = 41) with a median gestational age of 27 weeks (range 23 to 29 weeks) were initially obtained at a median age of 2 days (range 1 to 20 days) and then repeatedly studied; 29 (71%) infants had MRI at a median gestational age of 43 weeks (range 38 to 52 weeks) (term MRI). On the initial MRI scan 28 of 41 infants had abnormalities: either intraventricular hemorrhage, germinal layer hemorrhage, ventricular dilatation, or diffuse and excessive high signal intensity in the white matter on T(2)-weighted images. When magnetic resonance images for preterm infants at term gestation were compared with those of infants in the control group born at term, 22 of 29 infants had dilatation of the lateral ventricles, 24 of 29 had squaring of the anterior or posterior horns of the lateral ventricles, 11 of 29 had a widened interhemispheric fissure or extracerebral space, and 22 of 29 had diffuse and excessive high signal intensity in the white matter. There were no cases of cystic periventricular leukomalacia. We conclude that MRI abnormalities are commonly seen in the brain of preterm infants on whom images are obtained within 48 hours of birth and that further abnormalities develop between birth and term. A characteristic appearance of diffuse and excessive high signal intensity in the white matter on T(2)-weighted images is associated with the development of cerebral atrophy and may be a sign of white matter disease. These MRI appearances may help account for the high incidence of neurodevelopmental impairment in extremely preterm infants.     

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??Abstract?? Objective??To assess the early changes of MRI and its clinical significance in the preterm infants with the cerebral white matter damage??CWMD????based on the data offered by MRI?? and to investigate the related factors. Methods??The research was prospectively performed on 262 preterm infants from September 2007 to September 2009 at the neonatal ward of the Shengjing Hospital of China Medical University. All were performed MRI examination in 7 days??subjects were classified into two groups according to MRI diagnostic criteria?? case group and control group. Of case group??29 were followed up. Results????1??Focal injury??high signal appeared on DWI??with normal or slightly high signal on T1WI??accompanying low or normal signal on T2WI.The diffuse injury??diffusive high signal only on DWI?? no abnormal signal on regular MRI. After about two weeks??focal lesions have been shown in two ways???? lesion vanished ?? normal or slightly high signal on DWI?? while on T1WI high signal and low or normal signal on T2WI??diffuse injury have been change into periventricular leukomalacia??PVL????High signal or miscellaneous ??high and low??signal on T2WI??while on T1WI and DWI?? miscellaneous signal .??2??Related factors were analyzed.Univariate analysis?? perinatal infection?? twins?? hypocalcaemia?? metabolic acidosis?? hypoxia??mechanical ventilation and infants infection for preterm CWMD were considered statistically significant. Logistic Regression analysis showed that perinatal infection?? hypoxia and intrauteral embarrassment were risk factors for preterm infants with CWMD. Conclusion????1??DWI can detect the lesions in early stage of CWMD.??2??The interaction of multiple factors??includly the premature infant CWMD?? perinatal infection??hypoxia and intrauteral embarrassment has close relationship with the CWMD.??3??There are no specific clinical manifestations of CWMD??so it is suggested MRI should be performed as a routine in preterm infants??and follow up is necessary if abnormal signal appears.     

高危晚期早产儿脑损伤病因学及其磁共振发现

目的 探讨以弥散加权成像(DWI)结合常规磁共振成像(T1WI-T2WI)诊断的高危晚期早产儿脑损伤的相关危险因素及临床特点,并分析不同时间MRI序列的信号特点及DWI的早期诊断价值。方法 首先对符合纳入标准的649例晚期早产儿的MRI片重新阅片,按照脑损伤评估标准得出诊断,其次收集相关的临床资料,分析不同类型脑损伤的危险因素和临床特点,并对其中271例确诊脑白质损伤（CWMD）的MRI序列进行分析,探讨不同类型CWMD的信号特点、损伤部位及结局。结果 ①晚期早产儿发生脑损伤332例（51.2%）,其中CWMD 271例（41.8%）,以局灶性CWMD为主（62.7％,170例）;颅内出血112例（17.3%）,主要为蛛网膜下腔出血55.4%（62/112）。②非出血性脑损伤的危险因素是男性（OR=1.510,95％CI：1.067～2.136,P=0.020）、阴道分娩（OR=2.367,95％CI：0.251～22.294 ,P=0.000）、早发型败血症（OR=2.194,95％CI：1.159～4.155,P=0.016）及抢救复苏史（OR=3.784,95％CI：1.908～7.506,P=0.000）。出血性脑损伤的危险因素是阴道分娩（OR=7.195,95％CI：4.249～12.184 ,P=0.000）和早发型败血症（OR=2.692,95％CI：1.185～6.117,P=0.018）。低钙血症（OR=2.593,95％CI：1.343～5.005,P=0.005）、晚发型败血症（OR=1.533,95％CI：1.012～2.323,P=0.044）和抽搐（OR=4.006,95％CI：1.790～8.970,P=0.001）是非出血性脑损伤组的主要临床特点。出血性脑损伤组主要表现为高血糖和抽搐。③局灶性CWMD 65.3％仅累及一处损伤,主要集中在侧脑室后脚（53.5%）,有97.1%病灶消失或病灶范围减少;广泛性CWMD 79.2%累及胼胝体和内囊;弥漫性CWMD 50％合并灰质损伤,全部发生软化。④生后2周内,DWI具有较高的敏感性,98.0%表现为高信号,T1WI信号无变化或稍高信号,伴或不伴T2WI低信号。局灶性CWMD DWI高信号持续时间长达3周以上,弥漫性CWMD DWI高信号持续时间2周以内。结论 晚期早产儿仍然容易受产前产时因素影响而发生不同类型的脑损伤。对有高危因素,或早期出现临床表现或电解质紊乱的患儿应选择生后2周内（1周内最佳）进行DWI和常规MRI检查,以早期发现病变。局灶性CWMD预后较好,合并有灰质损伤或弥漫性CWMD预后极差,需要动态随访,并进行早期康复训练。     

Early detection of periventricular leukomalacia by diffusion-weighted magnetic resonance imaging techniques

Periventricular leukomalacia (PVL), the principal form of brain injury in the premature infant, is characterized by overt focal necrotic lesions in periventricular white matter and less prominent, more diffuse cerebral white matter injury. The early detection of the latter, diffuse component of PVL is not consistently possible with conventional brain imaging techniques. We demonstrate the early detection of the diffuse component of PVL by diffusion-weighted magnetic resonance imaging (DWI). In a premature infant with no definite cerebral abnormality detectable by cranial ultrasonography or conventional magnetic resonance imaging, DWI showed a striking bilateral decrease in water diffusion in cerebral white matter. The DWI abnormality (ie, decreased apparent diffusion coefficient) was similar to that observed with acute cerebral ischemic lesions in adults. At 10 weeks of age, conventional magnetic resonance imaging and ultrasonography showed striking changes consistent with PVL, including the presence of small cysts. The observations indicate the importance of DWI in the early identification of the diffuse component of PVL and also perhaps the role of ischemia in the pathogenesis of the lesion.     

Magnetic resonance imaging of the brain in very preterm infants: visualization of the germinal matrix, early myelination, and cortical folding

OBJECTIVE: To investigate preterm infants, we have installed in our neonatal intensive care unit a dedicated magnetic resonance (MR) imaging system which was specifically designed for neonatal use. The aim of this study was to describe the MR appearances of the brain in preterm infants who were first scanned between 25 and 32 weeks gestational age (GA) and to outline changes to the brains of these infants between their first scan and term. METHODS: Preterm infants of 25 to 32 weeks GA were imaged using the 1T neonatal MR system (Oxford Magnet Technology, Eyensham, Oxfordshire, England/Picker International, Cleveland, OH). The scanning protocol included T1-weighted conventional spin echo (repetition time [TR], 600; echo time, 20 ms), inversion recovery fast spin echo (TR, 3530; effective echo time, 30; inversion time, 950 ms), and T2-weighted fast spin echo (TR, 3500; effective echo time, 208 ms) sequences. RESULTS: Seventeen infants of median 28 weeks GA (range, 24 to 31 weeks) at birth were imaged a total of 53 times between birth and term. The median number of images per infant was two (range, 1 to 9). In infants of < 30 weeks GA, the germinal matrix was visualized at the margins of the lateral ventricles. It had a short T1 and short T2 and the bulk of it involuted at between 30 and 32 weeks GA. The white matter had a relatively homogeneous low signal except for bands of altered signal (probably originating from regions containing radial glia and migrating cells) which were most apparent anterolateral and posterolateral to the lateral ventricles. Myelination was seen in the posterior brainstem, cerebellum, and region of the ventrolateral nuclei of the thalamus. Infants had very little cortical folding at 25 weeks GA but this developed later in an orderly fashion. CONCLUSION: The neonatal MR system allowed extremely preterm infants to be studied safely with MR imaging. The images acquired demonstrated the germinal matrix, early myelination, and early cortical folding. Evolution of these features was demonstrated with serial studies.