Developmental neuropathology of the second half of gestation

In this review we focus primarily on the events taking place in the second half of gestation. At second trimester end, human brain weight gain accelerates rapidly. Germinal matrix attains maximal absolute volume, only to ablate 50% over two gestational weeks. At 10 weeks of gestation interhemispheric, choroidal, and transverse fissures exist. Germinal matrix hemorrhages peak during its devolution and some of these rupture into the lateral ventricle. By 28 weeks homologous primary sulci are present, having appeared in both hemispheres at slightly different gestational ages. Secondary sulcation, during the third trimester, is hemispherically unique. Despite emphasis on neuronal vulnerability, prevalence of lesions in white matter exceeds that of gray matter and, within white matter, diffuse white matter astrocytosis prevalence exceeds that of focal necroses. Gray matter hypotensive lesions most commonly occur in the upper brainstem and thalami followed by convexity borderzone lesions causing sclerotic microgyria. White matter hypoplasia with normal gray matter volume is sometimes associated with hypomyelination.     

MRI of a family with leukoencephalypathy with vanishing white matter

Leukoencephalopathy with vanishing white matter (VWM) is a newly described entity with characteristic MRI features. We report the cranial MRI findings in three sisters with slowly progressive neurological deterioration. The MRI showed symmetrical diffuse abnormalities of cerebral white matter with hypointensity on FLAIR images. The diagnosis of leukoencephalopathy with VWM was made on the basis of genetic analysis.     

MRI changes in the central nervous system in a child with lupus erythematosus

We report on a 10-year-old girl with systemic lupus erythematosus who presented in status epilepticus as the only manifestation of central nervous system involvement. MRI of the brain showed diffuse gray and white matter lesions which almost completely resolved after treatment with methylprednisolone. MRI findings in this child are similar to those in adults with diffuse clinical manifestations. The study is essential in the initial evaluation of patients suspected of central nervous system lupus.     

Brain White Matter Abnormality in a Newborn Infant with Congenital Adrenal Hyperplasia

Several studies have described brain white matter abnormalities on magnetic resonance imaging (MRI) in children and adults with congenital adrenal hyperplasia (CAH), while the brain MRI findings of newborn infants with CAH have not been clarified. We report a newborn boy with CAH who presented brain white matter abnormality on MRI. He was diagnosed as having salt-wasting CAH with a high 17-OHP level at neonatal screening and was initially treated with hydrocortisone at 8 days of age. On day 11 after birth, he had a generalized tonic seizure. No evidence of serum electrolyte abnormalities was observed. Brain MRI revealed white matter abnormalities that consisted of bilateral small diffuse hyperintensities on T1-weighted images with slightly low intensity on T2-weighted images in the watershed area. Several factors associated with brain white matter abnormalities in adults with CAH, such as increasing age, hypertension, diabetes and corticosteroid replacement, were not applicable. Although the cause of the phenomenon in this case is unclear, brain white matter abnormality could be observed in newborn infants with CAH as well as in adult patients.     

Hypomyelination and congenital cataract: Identification of novel mutations in two unrelated families

BackgroundHypomyelination and congenital cataract (HCC) is a rare autosomal recessive white matter disorder characterized by congenital cataract, progressive neurologic impairment, and myelin deficiency in the central and peripheral nervous system, caused by mutations in the FAM126A gene.AimsTo report three patients of two unrelated families segregating novel mutations.Methodsclinical, neurophysiological, neuroradiologic and molecular investigations were carried out.ResultsAll patients show bilateral congenital cataract and progressive neurological impairment with peripheral neuropathy. The clinical phenotype is consistent with the severe form of HCC. Brain magnetic resonance imaging show the combination of a diffuse hypomyelination with superimposed periventricular white matter signal abnormalities.Conclusionsthis study describes three additional HCC patients indicating that this recently defined leukoencephalopathy should be included in the differential diagnosis of hypomyelination in childhood. The peculiar clinical and neuroradiologic findings are useful to properly address molecular investigations and allow the differential diagnosis between HCC and other hypomyelinating forms.     

Leukoencephalopathy with swelling, megalencephalopathy and surprisingly mild course. A case report

Leukoencephalopathy with swelling and a discrepantly mild clinical course is a recently identified syndrome described by van der Knaap et al. It is characterised by macrocephaly occurring during the first year of life, initially normal or nearly normal development, slowly progressive ataxia and spasticity with initial preservation of intellectual functions. MRI shows diffuse abnormality of signal intensity in the hemisphere white matter with subcortical cyst-like spaces in the fronto-parietal and anterior temporal areas. The case of a 5-year-old boy whose clinical and neuroimaging findings are consistent with this syndrome is reported. The clinical and neuroimaging findings of this case may provide further information about this new syndrome which could possibly be useful also for genetic counselling.     

Very-low-birth-weight, preterm infants with or without intracranial hemorrhage. Neurologic, cognitive and cranial MRI correlations at 4-8-year follow-up

Fourteen very-low-birth-weight (VLBW) preterm infants with and without intracranial hemorrhage (ICH) were prospectively followed from birth to 4 to 8 years for the purpose of determining neurologic and cognitive sequelae associated with ICH severity and to correlate outcomes with brain morphology as determined by Magnetic Resonance Imaging (MRI). Intracranial hemorrhage was documented by cranial ultrasonography performed in early life. Follow-up assessments included neurologic and psychometric examinations and cranial MRI scans. Of six children with no ICH, five had normal results on all three follow-up measures. Three children with Grade I-II ICH had mild to moderate neurologic and cognitive sequelae with focal white matter MRI abnormalities. Five children with Grade III-IV ICH had severe neurologic, cognitive, and MRI deficits, including MRI regional and diffuse white matter abnormalities and/or cortical atrophy. Focal and diffuse neurologic deficits correlated with the extent of MRI morphologic abnormalities. Results of this study indicate that ICH severity correlated with outcomes in children at follow-up; the more severe the ICH, the more adverse the neurologic, cognitive, and MRI results. MRI white matter abnormalities were present in all children with any degree ICH, while ventriculomegaly was seen only in severe ICH (Grade III-IV ICH). Neurologic deficits correlated with MRI structural abnormalities.     

Disturbed myelination in patients with treated hyperphenylalaninaemia: evaluation with magnetic resonance imaging

Cranial magnetic resonance imaging (MRI) was performed in nine treated adolescents with hyperphenylalaninaemia (HPA) in order to analyse possible changes in myelination. Three patients suffered from type I HPA, four from type II and two from type III (persistent HPA). Images were obtained with a 1.5T unit using spin-echo-sequences. In all patients with type I or type II HPA, abnormal findings in the cerebral white matter were demonstrated including band-like and/or confluent patchy areas of high signal intensity predominantly in the peritrigonal region, with anterior and posterior periventricular extension and/or involvement of the subcortical white matter. The extent of MRI changes did not correlate with the initiation, duration or quality of dietary treatment. There was also no consistent relationship between electrophysiological changes and white matter abnormalities on MRI. Our findings suggest a disturbance of myelination in patients with treated HPA. These results correspond well with earlier neuropathological and biochemical studies in untreated patients.     

Cerebral white matter disease in children may be caused by mitochondrial respiratory chain deficiency

Several mitochondrial diseases are known to occasionally involve the cerebral white matter, namely Leigh syndrome, Kearns-Sayre syndrome, and MELAS syndrome, but in these cases the major finding is alteration in the basal ganglia and brainstem. Here we report on severe diffuse white matter involvement and respiratory chain enzyme deficiency or mitochondrial DNA rearrangement in 5 unrelated families. It is interesting that white matter lesions were the only abnormal neuroradiologic feature in 3 of the 5 families, and multiple small cyst-like white matter lesions were found in 2 of 5 probands. Respiratory chain deficiency should be considered in the diagnosis of severe white matter involvement in childhood.     

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.     

Diffusion-weighted MRI in shaken baby syndrome

We present the characteristic CT and MRI findings of a 2-month-old girl with shaken baby syndrome. Diffusion-weighted MR imaging performed 8 days after the insult established the presence of injury to the white matter in the corpus callosum and subcortical white matter in the temporo-occipito-parietal region. Diffusion-weighted MR imaging is valuable in the diagnostic work-up of suspected shaken baby syndrome, as injury to the white matter can be demonstrated days after the injury.     

Neuroimaging findings (ultrasonography,CT, MRI) in 3 infants with congenital rubella syndrome

Neuroimaging observations of three infants with congenital rubella syndrome are reported. We have observed congenital rubella syndrome lesions in the subependymal area, the basal ganglia and the deep white matter. Cranial ultrasonography defines subependymal cysts, calcification and possible vascular changes in the basal ganglia while MRI is the most sensitive to minor atrophic changes and white matter lesions. Although CT defines calcification, it is less sensitive than MRI to white matter changes and does not demonstrate subependymal cysts.     

Brain imaging findings in very preterm infants throughout the neonatal period: Part II. Relation with perinatal clinical data

This study describes the relation between frequent and clinically relevant brain imaging findings in very preterm infants (GA < 32 weeks), assessed with sequential cranial ultrasonography throughout the neonatal period and MRI around term age, and several potential perinatal risk factors.For ultrasound findings during admission the following independent risk factors were identified: male gender for periventricular echodensities and intraventricular haemorrhage, postnatal corticosteroid treatment for cystic white matter lesions, and lower gestational age for post-haemorrhagic ventricular dilatation. For MRI findings around term age, including punctate white matter lesions, ventricular dilatation, decreased cortical complexity, and diffuse and excessive high signal intensity, no independent risk factors were found.In very preterm infants, the risk factors for frequently found changes on cranial ultrasound have largely remained unchanged over the last decades, while no risk factors could be identified for subtle and diffuse white matter injury as seen on MRI around term age.     

白质消融性白质脑病临床分析

目的分析白质消融性白质脑病的临床特点及诊断方法。方法对9例临床诊断为该病的患儿的临床及头颅影像学特点、实验室检查等进行分析,结合病例对该病进行综述介绍。结果（1）临床表现：9例中8例出现神经系统症状和体征,1例仅有MRI异常。发病时间为生后6个月-3岁;5例家族史阳性,病前智力运动发育多正常;多以运动症状起病,下肢为著。6例发病前或每遇病情加重前有呼吸道感染史,3例病前有轻微头部外伤史;到目前为止,有症状的7例呈进行性加重病程,其中4例同时有发作性加重现象。所有病例智力受损相对轻。7例头围正常,8例有上运动单元病变体征,4例有共济失调体征。3例双侧视神经萎缩。（2）头颅MRI：表现为双侧对称弥漫性深部白质长T1长T2信号,可累及皮层下白质,额、顶叶为主,Flair像为对称性白质高信号伴部分白质低信号甚至囊性变或大部分白质低信号仅存少量线状稍高信号,为此症特征性改变。（3）其他遗传性白质脑病相关酶学或生化检查均正常。结论以运动障碍起病、运动障碍重于智力障碍、神经影像学改变显著重于临床表现、MRI表现为双侧对称弥漫性深部白质长T1长T2病变伴早期出现白质消融征象是本症的临床特点,临床诊断还需除外其他遗传性及获得性脑白质病。找到相应基因的致病突变可最终确诊。     

Hypoxic-ischaemic encephalopathy: early and late magnetic resonance imaging findings in relation to outcome.

Sixteen infants with hypoxic-ischaemic encephalopathy (HIE) were studied using serial magnetic resonance imaging (MRI) up to the age of 2 years. The infants had regular neurological and developmental assessments. An nuclear magnetic resonance (NMR) score was devised to quantify the early and late MRI findings and a neurological optimality score was used to quantify abnormal neurological signs at the time of the final examination. The follow up MRI score was compared with the neonatal MRI score and the outcome of the child. There was a strong positive correlation between the neonatal and follow up MRI scores and between MRI scores and optimality score. All infants with a normal outcome had patchy white matter abnormalities. All infants with an abnormal outcome had extensive white matter abnormalities. The outcome was most severe in those infants with additional basal ganglia atrophy with or without cyst formation. Infants with mild HIE who are developmentally normal at the age of 2 years do not have normal MRI scans and may be at risk of minor neurological problems by school age. Bilateral basal ganglia abnormalities are associated with severe developmental delay, but infants with mainly white matter and cortical abnormalities have less severe problems despite extensive tissue loss.     

Tetrasomie 18p

Tetrasomy 18p is a rare chromosomal disorder. The phenotype results from the presence of a small extra metacentric marker chromosome, an isochromosome 18p. The syndrome is characterized by mild to moderate mental retardation, microcephaly, minor dysmorphic features and spasticity of the lower limbs. Here we report on a 2-year-old girl, who was referred because of developmental delay and minor dysmorphic signs. Cytogenetic investigations revealed a small supernumerary marker chromosome. Further analysis using spectral karyotyping (SKY?) and fluorescence in situ hybridization (FISH) identified the marker chromosome fragment as an isochromosome 18p.     

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.     

An unexpected finding in a child with neurological problems: mosaic ring chromosome 18

Major neurological disorders may accompany rare chromosomal abnormalities. As an example of this rare condition, we present a case with microcephaly, mental retardation, developmental delay, hyperactivity, stereotypic movements, seizures and dysmorphic facial appearance in whom a mosaic ring chromosome 18 was found [45,XX,-18/46,XX,r(18)/46,XX,dicr(18)]. Although ring chromosome 18 phenotype has been known for a long time, this is the third reported patient with a dicentric ring chromosome 18 mosaicism. The presented case will contribute to the identification of the genotype-phenotype correlation in chromosome 18 anomalies.     

Defining the nature of the cerebral abnormalities in the premature infant: a qualitative magnetic resonance imaging study

OBJECTIVES: The aim of this study was to define qualitatively the nature and extent of white and gray matter abnormalities in a longitudinal population-based study of infants with very low birth weight. Perinatal factors were then related to the presence and severity of magnetic resonance imaging (MRI) abnormalities. METHODS: From November 1998 to December 2000, 100 consecutive premature infants admitted to the neonatal intensive care unit at Christchurch Women's Hospital were recruited (98% eligible) after informed parental consent to undergo an MRI scan at term equivalent. The scans were analyzed by a single neuroradiologist experienced in pediatric MRI, with a second independent scoring of the MRI using a combination of criteria for white matter (cysts, signal abnormality, loss of volume, ventriculomegaly, corpus callosal thinning, myelination) and gray matter (gray matter signal abnormality, gyration, subarachnoid space). Results were analyzed against individual item scores as well as the presence of moderate-severe white matter score, total gray matter score, and total brain score. RESULTS: The mean gestational age was 27.9+/-2.4 weeks (range, 23-32 weeks), and mean birth weight was 1063+/-292 g. The greatest univariate predictors for moderate-severe white matter abnormality were lower gestational age (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.1-1.7; P<.01), maternal fever (OR, 2.2; 95% CI, 1.1-4.6; P<.04), proven sepsis in the infant at delivery (OR, 1.8; 95% CI, 1.1-3.6; P=0.03), inotropic support (OR, 2.7; 95% CI, 1.5-4.5; P<.001), patent ductus arteriosus (OR, 2.2; 95% CI, 1.2-3.8; P=.01), grade III/IV intraventricular hemorrhage (P=.015), and the occurrence of a pneumothorax (P=.05). There was a significant protective effect of intrauterine growth restriction (OR, 0.51; 95% CI, 0.23-0.99; P=.04). Gray matter abnormality was highly related to the presence and severity of white matter abnormality. A unique pattern of cerebral abnormality consisting of significant diffuse white matter atrophy, ventriculomegaly, immature gyral development, and enlarged subarachnoid space was found in 10 of 11 infants with birth gestation <26 weeks. Given the later outcome of these infants, this pattern may have very high risk for later global neurodevelopmental disability. CONCLUSIONS: This MRI study confirms a high incidence of cerebral white matter abnormality at term in an unselected population of premature infants, which is predominantly a result of noncystic injury in the extremely immature infant. We confirm that the major perinatal risk factors for white matter abnormality are related to perinatal infection, particularly maternal fever and infant sepsis, and hypotension with inotrope use. We have defined a distinct pattern of diffuse white and gray matter abnormality in the extremely immature infant.