Fetal arachnoid cyst of the quadrigeminal cistern in MRI and ultrasound

Case The authors report a fetus with an arachnoid cyst of the quadrigeminal cistern without hydrocephalus at 30 gestational weeks.Discussion and conclusion We reviewed the literature and could find only 62 reported cases of arachnoid cyst of the quadrigeminal cistern. We present a case without hydrocephalus diagnosed by combining ultrasound (US) and magnetic resonance imaging (MRI). The fetus, born by normal delivery, was followed up and did not show hydrocephalus for 1 year. This combined prenatal study, which uses US and MRI, helps in dispensing proper counseling to parents and assists the gynecologist and the neurosurgeon in the pre- and postnatal management of this condition.     

Prenatal diagnosis of periventricular hemorrhage by fetal brain magnetic resonance imaging

Following the incidental diagnosis of triventricular hydrocephalus in a fetus 34 weeks after the mother's last menstrual period, during an uneventful pregnancy, 1.5-T brain magnetic resonance (MR) was carried out. A subependymal hemorrhage, which had not been revealed by transabdominal ultrasound, was found; this finding was confirmed by neonatal brain ultrasound and MR. Fetal MR allowed identification of the hemorrhage as the cause of the hydro-cephalus and also established its time of occurrence. Unexplained hydrocephalus should be included among the indications for fetal MR. Received: 15 June 1998     

Diagnosis of congenital hydrocephalus and delivery of its patients in Japan

The study population included 193 patients with prenatally diagnosed (fetal) hydrocephalus and 181 with postnatally (12 or less than 12 months after birth) diagnosed (infantile) hydrocephalus identified by a nationwide questionnaire survey of congenital hydrocephalus performed in 2000. Of 180 patients with fetal, 101 (56.1%) were diagnosed before week 32 of gestation and 18 (10%) were diagnosed week 37 and later of gestation. In patients with fetal hydrocephalus, US was used in more than 80% of the cases, whereas in patients with infantile hydrocephalus, CT was used in more than half of the cases. For diagnosis of fetal hydrocephalus, either US or MRI had become dominantly utilized and CT had gone out of use in 1996–2000. The adoption ratio of cesarean delivery to transvaginal delivery was around 7 to 3 in patients with fetal hydrocephalus, and 2 to 7 in patients with infantile hydrocephalus, respectively, with significant difference between fetal hydrocephalus and infantile hydrocephalus groups (p < 0.001). Clinical outcomes in patients with fetal hydrocephalus was better in those delivered transvaginally than in those by cesarean delivery, although without no statistical significance (p = 0.124) and those in patients with infantile hydrocephalus showed almost no difference between transvaginal and cesarean delivery groups. There was a tendency for the Apgar score at 5 min to be lower in smaller birth weight infants with a body weight of less than 2000 g. This score could be useful as an index for predicting immediate postnatal death in patients with fetal hydrocephalus.     

Imaging diagnosis of periventricular leukomalacia

The neurodevelopmental prognosis of periventricular leukomalacia (PVL) has been predicted effectively by ultrasonography (US). US is the best imaging modality to identify both the early changes of PVL (echogenic phase) and the late changes (cystic phase). In cases with intraventricular hemorrhage, however, it was difficult to differentiate from periventricular hemorrhage in the echogenic phase by US. The PVL resolved to a discrete cyst separate from the ventricle, but periventricular hemorrhage developed a porencephalic cyst. Computed tomography is useful for distinguishing periventricular hemorrhage from PVL in the early changes. However, it is not particularly useful in the late changes, as only extensive cystic lesions can be seen. Magnetic resonance imaging is useful for following the progress in myelination.     

Annual incidence of first silent stroke in the United States: a preliminary estimate

BACKGROUND: Recent estimates of stroke incidence in the US range from 760,000 to 780,000 annually, however these estimates do not reflect the incidence of silent infarcts and hemorrhages. Since population-based studies indicate the prevalence of silent stroke is substantially higher than that of symptomatic stroke, estimates of stroke incidence based solely on symptomatic events may substantially underestimate the annual stroke burden. METHODS: The prevalence of silent infarcts for different age strata were abstracted from two US population-based MRI studies, the Atherosclerosis Risk in Communities Study and the Cardiovascular Health Study. Similarly, first silent cerebral hemorrhage incidence rates were derived from population-based MRI prevalence observations in the Austrian Stroke Prevention Study. Prevalence observations in these studies and death rates from the US Census were inputted to calculate age-specific first silent MRI infarct and hemorrhage incidence. Age- specific incidence rates were projected onto 1998 US population age cohorts to calculate the annual burden of first silent MRI ischemic stroke and first silent MRI cerebral hemorrhage. RESULTS: Estimated age-specific annual incidence rates (per 100,000) of persons experiencing first silent MRI infarct ranged from 1,600 in the age 30-39 stratum to 16,400 at ages 75-79. Estimated incidence rates of first silent MRI cerebral hemorrhage ranged from 180 in the ages 30-39 to 6,900 at age >85. Overall, the projected annual incidence in 1998 of US individuals experiencing first silent MRI infarct was 9,040,000, and first silent MRI hemorrhage 1,940,000. CONCLUSIONS: In 1998, more than 11 million persons experienced stroke in the US, in whom approximately 770,000 were symptomatic and 11 million were first-ever silent MRI infarcts or hemorrhages. These findings demonstrate the incidence of stroke is substantially higher than suggested by estimates based solely on clinically manifest events.     

Subarachnoid hemosiderin deposition after subarachnoid hemorrhage on T2*-weighted MRI correlates with the location of disturbed cerebrospinal fluid flow on computed tomography cisternography

A 72-year-old male was admitted with subarachnoid hemorrhage associated with a ruptured cerebral aneurysm. The aneurysm was treated with clipping soon after radiological examination. Eight weeks after the treatment, the patient suffered from secondary hydrocephalus resulting from blockage of the subarachnoid space due to subarachnoid granulation. Previous pathological examination revealed the granulation was associated with hemosiderin deposition. We investigated subarachnoid hemosiderin deposition in this patient using T2FNx01-weighted (T2FNx01-w) magnetic resonance image (MRI), a sensitive method for hemosiderin detection. computed tomography (CT) cisternography demonstrated that cerebrospinal fluid (CSF) flow was disturbed adjacent to sites of subarachnoid hemosiderin deposition on T2FNx01-w MRI. Placement of a ventriculo-peritoneal shunt contributed to neurological improvement. In this case, T2FNx01-w MRI was an effective means of diagnosing the location of disturbed CSF flow associated with subarachnoid hemosiderin deposition.     

Glial reaction in periventricular areas of the brainstem in fetal and neonatal posthemorrhagic hydrocephalus and congenital hydrocephalus

This immunohistochemical, neuropathological study was performed on the ventricular wall of the brainstem in children with fetal and neonatal posthemorrhagic and congenital hydrocephalus. In posthemorrhagic hydrocephalus (PHH), hemosiderin deposits, nodular gliosis, ependymal cell loss and subsependymal rosette formation developed subventricularly after 2 weeks of age. Ferritin-positive reactive microglia were well stained until about 2 weeks of age and thereafter diminished as reactive astrocytosis occurred. In congenital hydrocephalus (CH), the damage to the ventricular wall was less than in PHH at all ages and was associated with only mild astrogliosis. These differences in the neuropathological findings of periventricular regions, consisting mainly of glial reactions between PHH and CH, are due to differences in pathophysiology, and the timing of the insult in both conditions. The differences may be due to the effects of intraventricular hemorrhage and/or rapidly increased intracranial pressure in PHH. These results may have implications for the neurological prognosis in children with PHH.     

Prenatal diagnosis and postnatal outcome of fetal intracranial hemorrhage

Background

The aim of this study was to present our experience with six cases of fetal intracranial hemorrhage (ICH) in terms of prenatal diagnostic features, and postnatal outcome.

Methods

The database of prenatal diagnosis unit was searched for antenatally diagnosed ICH cases. Maternal characteristics, ultrasound (US), and magnetic resonance imaging (MRI) findings, clinical course, and postnatal outcome were noted.

Results

We evaluated six consecutive cases of fetal ICH. One case was terminated at 24 weeks, and remaining five cases were delivered between 34 and 38 weeks. Five cases (5/6) had intraventricular, and one (1/6) had intraparenchymal hemorrhage. Hemorrhages were right sided in five cases (5/6), left sided in one case (1/6). Dilated and echogenic ventricular wall were the common US findings. No predisposing factor was detected in four of the cases, and intrauterine growth restriction was an underlying factor in two fetuses. Intrauterine progression of the hydrocephaly, and parenchymal thinning was seen in four cases (4/6). In three of four cases (3/4) with progressive grade 3–4 hemorrhage and hydrocephaly, postnatal outcome were dismal, and one case had mild neurological impairment at three months. In one case which had non-progressive mild ventriculomegaly, the lesion regressed after 4 weeks, and had normal short-term outcome

Conclusion

Fetal ICH can be accurately identified and categorized by antenatal sonography, and fetal MRI. Although intrauterine regression or normal short-term postnatal outcome is possible, the outcome is usually poor for fetuses with high grade and/or progressive lesions. Therefore, further studies assessing long-term postnatal outcome are needed     

Prenatal screening: invasive diagnostic approaches

INTRODUCTION: Fetal invasive procedures provide ovular samples that are helpful in establishing diagnosis, etiology, and prognosis when ultrasonography and MRI show a central nervous system (CNS) anomaly or when the fetus is at high risk of such pathology. PROCEDURES: Invasive procedure techniques are amniocentesis, fetal blood sampling (FBS), and chorionic villous sampling (CVS). They provide material for fetal DNA, biochemical analysis, or identification of various infectious agents. COMPLICATIONS: The main complications are miscarriage and premature delivery. Counseling the parents about the risks and benefits of these procedures is therefore mandatory. DISCUSSION: Amniocentesis may be performed as early as 15 weeks' gestation and is the most widely used invasive technique. FBS is performed after 18 to 20 weeks of pregnancy and CVS may be carried out after 11 weeks. Indications for invasive techniques include DNA and cytogenetic analysis, diagnosis of neural tube defects, identification of infectious agents (toxoplasmosis, cytomegalovirus, rubella, and varicella), and etiology of intracerebral hemorrhage (fetal platelets and coagulation factors).     

Congenital glioblastoma multiforme with abnormal vascularity presenting as intracranial hemorrhage in prenatal ultrasound

Background A rare case of a congenital brain neoplasm with intratumoral massive hemorrhage suggested by prenatal ultrasound examination in a 32-week gestational age male fetus is reported. The child died shortly after birth due to cardiorespiratory insufficiency.Methods Autopsy disclosed a large well-delimited tumor with a sponge-like appearance due to high vascularization, which involved nearly the whole left cerebral hemisphere and led to marked hydrocephalus by secondary aqueductal stenosis. Histological and immunohistochemical examination confirmed the diagnosis of a malignant glioma with features of a glioblastoma multiforme (GBM) matching well with previous findings in primary pediatric GBMs.Findings The present case demonstrates that malignant congenital neoplasms should be considered in the differential diagnosis of fetal intracranial hemorrhage.     

Brain macrophages and microglia in human fetal hydrocephalus

Whereas several studies have addressed the activation of microglia (the resident mononuclear phagocytes of the brain) and macrophages within the nervous system in experimental animal models of congenital and induced hydrocephalus, little is known of their state of activation or regional distribution in human fetal hydrocephalus. This investigation aimed to address such questions. Ten human fetal cases [20-36 gestational weeks (GW) at postmortem] previously diagnosed with hydrocephalus on ultrasound examination in utero, and 10 non-hydrocephalic controls (22-38 GW at postmortem) were assessed immufcnohistochemically with antibodies directed against MHC class II and CD68 antigens, and lectin histochemistry with Lycopersicon esculentum (tomato lectin). Adjacent sections were also immunoreacted with an antiserum to laminin to detect cerebral blood vessels. Eight out of the 10 hydrocephalus cases showed numerous CD68 and tomato lectin-positive macrophages located at focal regions along the ependymal lining of the lateral ventricles (particularly within the occipital horn). However, only five of these cases demonstrated MHC class II positive macrophages associated with the ventricular lining. Microglial reactivity within periventricular regions could also be identified using the lectin in four cases, two of which were also immunoreactive with CD68 (but not with MHC class II). By comparison, in control cases five out of 10 fetal brains (aged between 20 and 24 GW) showed few or no ependymal or supraependymal macrophages. One case at 28 GW, and cases at 32 and 38 GW (two of which were diagnosed with intrauterine hypoxic-ischemia) did, however, show some MHC class II (CD68 negative) cells located at the ependymal surface. Nevertheless, these were not as numerous or intensely immunoreactive as in the hydrocephalus cases. Microglia interspersed throughout the intermediate zone and circumscribing the basal ganglia were within normal confines in all cases examined. Hydrocephalic cases additionally showed focal regions of hypovascularization or alterations in the structure and orientation of capillaries within periventricular areas, compared to controls. The macrophage response detected at the ependymal lining of the ventricles and within the periventricular area in hydrocephalus may be related both to the severity of hydrocephalus and the age of the fetus.     

Development of microglia in the cerebral white matter of the human fetus and infant

Although microglial activation may be an initial beneficial response to a variety of insults, prolonged activation can release toxic substances and lead to cell death. Microglial activation secondary to hypoxia-ischemia and/or infection in immature cerebral white matter is important in the pathogenesis of periventricular leukomalacia (PVL), the major pathological substrate of cerebral palsy in the premature infant. We hypothesize that a transient overexpression in activated microglial density occurs normally in the cerebral white matter of the human fetus during the peak window of vulnerability for PVL. Such an increase could render this region susceptible to insults that cause prolonged microglial activation, as conceptualized in PVL. To examine the developmental profile of microglia in the human fetus and infant brain, immunocytochemistry with microglial specific markers were used in 23 control (non-PVL) cases ranging from 20 to 183 postconceptional (PC) weeks. Tomato lectin, used to identify microglial morphology, revealed that the cerebral white matter of the human fetus and infant is densely populated with intermediate and amoeboid microglia; the latter is indicative of an activated state. Quantitative analysis with CD68 showed increased density of activated microglia in the cerebral white matter of the fetus (<37 PC weeks) relative to the neonate/infant (> or =37 PC weeks) and to the overlying cortex of either age group (P = 0.01). The primary finding of a transient, developmental-dependent overabundance of CD68-activated microglia in the cerebral white matter of the fetus suggests a potential "priming" of this area for diverse brain insults characterized by activation of microglia, particularly PVL. J.     

A case of Walker-Warburg syndrome

Walker-Warburg syndrome (WWS) is an autosomal recessive disorder characterized by type II lissencephaly, cerebellar and retinal anomalies, and congenital muscular dystrophy. We report a female diagnosed with WWS based on clinical criteria. This patient was found to have fetal hydrocephalus on ultrasonography at 29 weeks of gestation, and exhibited severe hypotonia, ocular malformations, and hydrocephalus at birth. MRI revealed type II lissencephaly, hydrocephalus, and other severe brain malformations. Genetic analysis was performed to distinguish WWS from severe Fukuyama-type congenital muscular dystrophy (FCMD), which has numerous findings in common. This revealed no expression of the founder haplotype or single-stranded conformation polymorphism (SSCP) abnormalities. Since the life expectancy of patients with FCMD is longer, differential diagnosis should be performed precisely.     

Ependymal denudation and alterations of the subventricular zone occur in human fetuses with a moderate communicating hydrocephalus

In mutant rodents, ependymal denudation occurs early in fetal life, preceding the onset of a communicating hydrocephalus, and is a key event in the etiology of this disease. The present investigation was designed to obtain evidence whether or not ependymal denudation occurs in 16- to 40-week-old human fetuses developing a communicating hydrocephalus (n = 8) as compared to fetuses of similar ages with no neuropathologic alterations (n = 15). Sections through the walls of the cerebral aqueduct and lateral ventricles were processed for lectin binding and immunocytochemistry using antibodies against ependyma, astroglia, neuroblasts, and macrophages markers. Anticaveolin was used as a functional marker of the fetal ependyma. The structural and functional molecular markers are differentially expressed throughout the differentiation of the human fetal ependyma. Denudation of the ependyma of the aqueduct and lateral ventricles occurred in all fetuses developing a communicating hydrocephalus, including the youngest ones studied. The denuded surface area increased in parallel with the fetus age. The possibility is advanced that in many or most cases of human fetal hydrocephalus there is a common defect at the ependymal cell lineage leading to ependymal detachment. Evidence was obtained that in hydrocephalic human fetuses a process to repair the denuded areas takes place during the fetal life. In hydrocephalic fetuses, detachment of the ependyma of the lateral ventricles resulted in the (i) loss of the germinal ependymal zone, (ii) disorganization of the subventricular zone and, (iii) abnormal migration of neuroblasts into the ventricular cavity. Thus, detachment of the ependymal layer in hydrocephalic fetuses would not only be associated with the pathogenesis of hydrocephalus but also to abnormal neurogenesis.     

Correlative value of magnetic resonance imaging for neurodevelopmental outcome in periventricular leukomalacia

The aim of this study was to evaluate the correlative value of magnetic resonance imaging (MRI) in children with periventricular leukomalacia (PVL) for neurodevelopmental outcome. MRI examinations of 89 children (46 males, 43 females) with PVL (median age 4y, range 1 to 14y) were reevaluated. PVL was graded as follows: grade I, unilateral or bilateral areas of periventricular hyperintensity (1-3); grade II, hyperintensity more than 3; grade III, hyperintense lesions more than 3 and ventricular wall irregularity; grade IV, diffuse PVL and ventricular dilatation. Localizations of PVL and brain abnormalities associated with PVL were also noted. Assignment to PVL grades on MRI was as follows: PVL I (n=22), PVL II (n=18), PVL III (n=30), and PVL IV (n=19). Cerebral palsy was slightly less common in children with PVL I and II compared with PVL III to IV. Motor function was normal in 50% of children with PVL grade I, but severely impaired in 73.7% of children with PVL grade IV. Results of visual function were normal in all with PVL I, but pathological in 42.1% of patients with PVL IV. Developmental tests were appropriate for age in 75% of patients with PVL I, but significantly delayed in all patients with PVL IV. Thinning of the corpus callosum and presence of cortical atrophy were also correlated with neurological outcome. Significant risk factors associated with developmental delay were asphyxia at birth (odds ratio [OR] 4.3), PVL localization numbers over 3 (OR 4.4), PVL III to IV (OR 15), thinning of corpus callosum, and cortical atrophy.     

Arthrogryposis and multicystic encephalopathy after acute fetal distress in the end stage of gestation

The natural history of the rare association "multicystic encephalopathy-arthrogryposis" was traced in a fetus carefully followed after artificial insemination. The fetus exhibited normal viability and brain morphology up to the 32nd week. At 36 weeks, active movements diminished and at 37 weeks, hydramnios and signs of fetal distress led to cesarean section. The infant presented with severe arthrogryposis of the limbs and spine, but not with the other elements of a long-lasting akinesia. US showed multicystic encephalopathy. Both the clinical and the neuropathological findings established that multicystic encephalopathy was neither the cause nor the sequential consequence of the fetal akinesia, but the result of a recent diffuse, acute malacic process that also involved the anterior horn cells. Acute fetal distress, responsible for major ischemic damage to CNS but compatible with fetal survival, remains an obscure condition which allows for the development of severe arthrogryposis in a few weeks.     

Developmental lag in superoxide dismutases relative to other antioxidant enzymes in premyelinated human telencephalic white matter

Periventricular leukomalacia (PVL) involves free radical injury to developing oligodendrocytes (OLs), resulting from ischemia/reperfusion, particularly between 24 and 32 gestational weeks. Using immunocytochemistry and Western blots, we tested the hypothesis that this vulnerability to free radical toxicity results, in part, from developmental lack of superoxide dismutases (SOD)-1 and -2, catalase, and glutathione peroxidase (GPx) in the telencephalic white matter of the human fetus. During the period of greatest PVL risk and through term (> or = 37 weeks), expression of both SODs (for conversion of O2- to H2O2) significantly lagged behind that of catalase and GPx (for breakdown of H2O2), which, in contrast, superseded adult levels by 30 gestational weeks. Our data indicate that a developmental "mismatch" in the sequential antioxidant enzyme cascade likely contributes to the vulnerability to free radical toxicity of the immature cerebral white matter, which is "unprepared" for the transition from a hypoxic intrauterine to an oxygen-rich postnatal environment. All enzymes, localized to astrocytes and OLs, had higher-than-adult expression at 2 to 5 postnatal months (peak of myelin sheath synthesis), suggesting an adaptive mechanism to protect against lipid peroxidation during myelin sheath (lipid) synthesis. The previously unrecognized dissociation between the expression of the SODs and that of catalase and GPx in the fetal period has potential implications for future antioxidant therapy in PVL.     

The use of magnetic resonance imaging for the diagnosis of fetal intracranial anomalies

While fetal cranial sonography has been used for the sensitive detection of ventriculomegaly, ancillary imaging techniques may be needed for precise delineation of structural abnormalities. This report outlines the radiologic and clinical results using maternal magnetic resonance imaging (MRI) in ten patients with suspected fetal intracranial anomalies. Imaging was accomplished at 17–39 weeks gestational age, using spin-echo, a multislice technique with intramuscular morphine sulfate for sedation. In four cases, MRI significantly clarified the sonographic diagnosis, while in two cases the scan agreed with the sonographic findings. In one patient, MRI failed to image a lumbar meningomyelocele associated with the Chiari II malformation. In two patients with the Chiari II malformation, both sonography and MRI failed to delineate the anatomic pathology completely. Optimal imaging resolution was achieved in the third trimester. Four patients died in the perinatal period. All the surviving patients required shunting to treat intracranial hypertension; only two patients were meeting cognitive milestones. We conclude that due to the high incidence of multiple anomalies in the fetus with ventriculomegaly, precision in neuroradiological diagnosis is essential. MRI can be a useful adjunct to cranial sonography for the specific delineation of abnormalities of the fetal central nervous system.     

MRI findings in patients with spastic cerebral palsy. I: correlation with gestational age at birth

The authors studied MR images of the brain in 152 patients, aged 1 to 19 years (mean 3.3), who had spastic cerebral palsy (CP) and were attending two hospitals in Japan in 1993 and 1994. The relation was studied between the patients' gestational age at birth and their MRI findings, including the severity of periventricular leukomalacia (PVL) seen on MRI. In 119 of these patients, the CP was thought to be due to acquired, destructive brain injury. PVL was seen in 90 and posthemorrhagic porencephaly in 11. These preterm-type brain injuries were observed often in patients who had been born preterm but were also seen in those born at term. Full-term-type border-zone infarct, bilateral basal ganglia-thalamic lesion, subcortical leukomalacia, and multicystic encephalomalacia were seen in 9,14,7, and 3 patients, respectively; these term-type brain injuries were observed only in patients born at or near term. Of the patients with PVL, 90% had been born preterm. Severe PVL was common in the patients whose gestational ages at birth were between 25 and 32 weeks; all patients with PVL who had been born at term had only mild PVL. The authors concluded that MRI findings for patients with spastic CP are closely correlated with gestational age.     

术中终板造瘘治疗动脉瘤性蛛网膜下腔出血后脑积水

目的对动脉瘤性蛛网膜下腔出血(SAH)患者进行出血后脑积水测查,同时评价动脉瘤夹闭术中行终板造瘘在脑积水治疗中的作用.方法应用出血后2周的CT或MRI评价SAH后脑积水的发生,18例脑积水患者中7例行动脉瘤夹闭术中终板造瘘,术后随访观察疗效.结果脑积水的总体发生率为13.6% (18/132),7例终板造瘘患者6例术后脑积水得到明显缓解,随访未见相应并发症出现,1例无效.结论动脉瘤夹闭术中行终板造瘘技术相对简单,不会加重患者的经济负担和神经系统损害,对大部分SAH后脑积水疗效肯定.