Neonatal Magnetic Resonance Imaging Research Articles

Prothrombotic disorders and abnormal neurodevelopmental outcome in infants with neonatal cerebral infarction.

The aim of this study was to evaluate the occurrence of prothrombotic disorders in a well-characterized cohort of infants with neonatal stroke and to document any association of prothrombotic disorders with the type of infarct seen on magnetic resonance imaging (MRI) and clinical outcome. Twenty-four infants with perinatal cerebral infarction confirmed by neonatal MRI were enrolled in the study. All the infants and, when possible, both parents were tested to identify inherited and acquired prothrombotic disorders. None of the infants had a significant bleeding diathesis, but 10 (42%) had at least 1 prothrombotic risk factor. Five children showed heterozygosity for factor V Leiden, and 6 had high factor VIIIc concentrations. There was a striking association between the occurrence of these abnormalities and both the presence of cerebral hemorrhage on MRI and poor neurologic outcome. Eight of the 11 patients (73%) with hemiplegia or global developmental delay had factor V Leiden and/or raised factor VIIIc, whereas only 1 of the 13 patients (8%) with normal outcome had any prothrombotic risk factors. In particular, all 5 infants with factor V Leiden had hemiplegia, compared with only 4 of the 19 infants without factor V Leiden (21%). These data suggest that the presence of prothrombotic risk factors and, in particular, of the factor V Leiden mutation, is significantly associated with poor outcome after perinatal cerebral infarction.

Combined use of electroencephalogram and magnetic resonance imaging in full-term neonates with acute encephalopathy.

The electroencephalogram (EEG) is widely used in full-term infants with acute neonatal encephalopathy, and its prognostic value has been confirmed by several studies. Magnetic resonance imaging (MRI) of the brain has also been applied in these patients, and increasing numbers of reports affirm its prognostic reliability. The aim of this study has been to investigate the correlation between an early EEG and MRI findings in infants with acute neonatal encephalopathy and to assess the prognostic value of a combination of EEG and MRI findings. Twenty-five full-term infants had an EEG recorded within the first 72 hours after birth and a neonatal brain MRI scan after the end of the first week. Both EEG and MRI were predictive of outcome. A normal MRI was always associated with normal EEG background activity and normal outcome and severe abnormalities on MRI with marked EEG abnormalities and an abnormal outcome. When the MRI showed moderate abnormalities, the EEG in all cases but one identified patients with normal and abnormal outcome.EEG, MRI, HIE, neurodevelopment.

Microstructural brain development after perinatal cerebral white matter injury assessed by diffusion tensor magnetic resonance imaging.

Brain injury in premature infants is characterized predominantly by perinatally acquired lesions in the cerebral white matter (WM). The impact of such injury on the subsequent development of cerebral WM is not clear. This study uses diffusion tensor magnetic resonance imaging (MRI) to evaluate the effects of cerebral WM injury on subsequent microstructural brain development in different WM areas of the brain. Twenty premature infants (gestational age: 29.1 +/- 1.9 weeks) were studied by conventional MRI within the first 3 weeks of life and again at term, with the addition at the latter time of diffusion tensor MRI. Ten of the preterm infants had cerebral WM injury identified by the early MRI and were matched with 10 premature infants of similar gestational age and neonatal course but with normal neonatal MRI scans. Diffusion tensor MRI at term was acquired in coronal and axial planes and used to determine the apparent diffusion coefficient, a measure of overall restriction to water diffusion, and the relative anisotropy (RA), a measure of preferred directionality of diffusion, in central WM, anterior frontal WM, occipital WM, temporal WM, and the posterior limb of the internal capsule. Diffusion vector maps were generated from the diffusion tensor analysis to define the microstructural architecture of the cerebral WM regions. At term, the diffusion tensor MRI revealed no difference in apparent diffusion coefficient among preterm infants with or without perinatal WM lesions. By contrast, RA, the measure of preferred directionality of diffusion and thereby dependent on development of axonal fibers and oligodendroglia, was 25% lower in central WM, the principal site of the original WM injury. However, RA was unaffected in relatively uninjured WM areas, such as temporal, anterior frontal, and occipital regions. Notably, RA values in the internal capsule, which contains fibers that descend from the injured cerebral WM, were 20% lower in the infants with WM injury versus those without. Diffusion vector maps showed striking alterations in the size, orientation, and organization of fiber tracts in central WM and in those descending to the internal capsule. Perinatal cerebral WM injury seems to have major deleterious effects on subsequent development of fiber tracts both in the cerebral WM and more distally. The ultimate impact of brain injury in the newborn should be considered as a function not only of tissue destruction, but also of impaired subsequent brain development.

Neurologic examination in infants with hypoxic-ischemic encephalopathy at age 9 to 14 months: Use of optimality scores and correlation with magnetic resonance imaging findings

Objectives: To evaluate whether a structured and scorable neurologic examination (The Hammersmith Infant Neurological Examination) correlates with early magnetic resonance imaging findings in a group of infants with hypoxic-ischemic encephalopathy (HIE) and whether the scores of this assessment can predict the locomotor function in these children. Study design: A total of 53 term infants fulfilling the criteria for HIE underwent scanning within 4 weeks from delivery with a 1 Tesla HPQ magnet. The scores from the neurologic examination performed between 9 to 14 months were correlated to the neonatal magnetic resonance imaging findings and to the maximal locomotor function defined at the ages of 2 and 4 years. Results: The scores were always optimal in the infants with normal or minor neonatal magnetic resonance imaging findings. The lowest scores were associated with severe basal ganglia and white matter lesions. All the infants who had a global score between 67 and 78 at 1 year were able to walk independently at 2 years and without restrictions at 4 years. Scores between 40 and 67 were associated with restricted mobility and scores <40 with severely limited self-mobility at 2 and 4 years. Conclusions: The use of a standardized neurologic optimality scoring system gives additional prognostic information, easily available in the clinic, on the severity of the functional motor outcome in infants with HIE. (J Pediatr 2001;138:332-7)

Head growth in infants with hypoxic-ischemic encephalopathy: Correlation with neonatal magnetic resonance imaging

Head growth in infants with hypoxic-ischemic encephalopathy: Correlation with neonatal magnetic resonance imaging

Head growth in infants with hypoxic-ischemic encephalopathy: correlation with neonatal magnetic resonance imaging.

The aims of the study were to establish the relationship between head growth in the first year of life with the pattern on injury on neonatal magnetic resonance imaging (MRI) in infants with hypoxic-ischemic encephalopathy (HIE) and to relate these to the neurodevelopmental outcome. Fifty-two term infants who presented at birth with a neonatal encephalopathy consistent with HIE and who had neonatal brain MRI were entered into the study. Head circumference charts were evaluated retrospectively and the head growth over the first year of life compared with the pattern of brain lesions on MRI and with the neurodevelopmental outcome at 1 year of age. Suboptimal head growth was classified as a drop of >2 standard deviations across the percentiles with or without the development of microcephaly, which was classified as a head circumference below the third percentile. There was no statistical difference between the neonatal head circumferences of the infants presenting with HIE and control infants. At 12 months, microcephaly was present in 48% of the infants with HIE, compared with 3% of the controls. Suboptimal head growth was documented in 53% of the infants with HIE, compared with 3% of the controls. Suboptimal head growth was significantly associated with the pattern of brain lesions, in particular to involvement of severe white matter and to severe basal ganglia and thalamic lesions. Suboptimal head growth predicted abnormal neurodevelopmental outcome with a sensitivity of 79% and a specificity of 78%, compared with the presence of microcephaly at 1 year of age, which had a sensitivity of only 65% and a specificity of 73%. The exceptions were explained by infants with only moderate white matter abnormalities who had suboptimal head growth but normal outcome at 1 year of age and by infants with moderate basal ganglia and thalamic lesions only who had normal head growth but significant motor abnormality.

Preserving Plasticity: New Directions in Research for the Developing Brain

After completing this article, readers should be able to: 1. Characterize the process of corticogenesis. 2. Describe findings of magnetic resonance imaging of the developing brain. Cerebral development of the fetus is under genetic control, and during the third trimester of gestation, synapse development, dendritic spine elaboration, and cortical-cortical connections proceed as the period of developmental plasticity begins. In contrast to infants born at term, those who are born preterm can suffer significant developmental disability; many reports have shown that the neurodevelopmental outcome of very low-birthweight preterm infants is related directly to gestational age at birth. Infants weighing less than 1,000 g at birth now represent almost 1% of all live births in the United States, and the survival rate for this population approaches 85%. In stark contrast to the improved survival, however, are the emerging reports of neurodevelopmental disability in these very tiny and frequently critically ill infants. The incidence of cerebral palsy is increasing as the survival rate increases, and the incidence of cognitive deficits in this population has not changed during the past decade. The incidence of major neurodevelopmental handicaps in very preterm infants ranges from 12% to 32%, and even “healthy” preterm infants experience a high degree of educational difficulties. When we examined 200 very low-birthweight survivors of the Randomized Indomethacin Intraventricular Hemorrhage Prevention Trial who had reached 8 years of age, more than 50% required special assistance in school or were educated in full-time special education classrooms, and 25% already had repeated at least one grade in school. These data are consistent with those of other observers and indicate that preterm birth disrupts the normal genetically programmed series of events regulating corticogenesis in the developing brain. Intracranial hemorrhage (ICH), or hemorrhage into the germinal matrix tissues of the developing brain, is a major cause of neurodevelopmental handicap …

Visual function in term infants with hypoxic-ischaemic insults: correlation with neurodevelopment at 2 years of age

AIMSTo determine if there is any association between the findings of visual assessment performed at the age of 5 months and neurodevelopmental outcome at the age of 2 years in...

Early prognostic indicators of outcome in infants with neonatal cerebral infarction: a clinical, electroencephalogram, and magnetic resonance imaging study.

The aim of this study was to identify prognostic factors in newborns with cerebral infarction. Antenatal and perinatal factors and early clinical, electroencephalogram (EEG), and magnetic resonance imaging (MRI) findings were compared with neurodevelopmental outcome in 24 children with evidence of cerebral infarction on neonatal MRI. Out of 24 infants, 19 had an infarction in the territory of a major cerebral vessel and 5 in the borderzone between cerebral arteries. Neuromotor outcome was normal in 17 and abnormal in 7 infants. Of these 7 infants, 5 infants showed a definite hemiplegia, whereas the other 2 showed some asymmetry of tone or function but no definite hemiplegia. None of the adverse antenatal or perinatal factors was significantly associated with abnormal outcome. Neonatal clinical examination was also not always predictive of the outcome. The extent of the lesion on MRI was a better predictor. In particular, it was the concomitant involvement of hemisphere, internal capsule and basal ganglia that was always associated with an abnormal outcome whereas the involvement of only one or two of the three tended to be associated with a normal outcome. EEG was also very helpful. Abnormal background activity either unilateral or bilateral was found in 6 infants and 5 out of 6 developed hemiplegia. In contrast, the presence of seizure activity in presence of a normal background was not related to abnormal outcome. Early MRI and EEG can help to identify the infants with cerebral infarction who are likely to develop hemiplegia.

Correlation between neonatal cranial ultrasound, MRI in infancy and neurodevelopmental outcome in infants with a large intraventricular haemorrhage with or without unilateral parenchymal involvement.

During a 7-year-period, 1625 infants of 34 weeks gestation or less were enrolled in a prospective ultrasound (US) study. One hundred and eleven (6.8%) infants developed a large intraventricular haemorrhage (IVH) with or without unilateral parenchymal involvement (PI). Fifty-six of these 111 infants survived (50.4%) and in 23 (41%) of them a magnetic resonance imaging (MRI) study was performed beyond 12 months corrected age. There appeared to be a good agreement between neonatal ultrasound findings and MRI changes noted in infancy. Of the 10 cases with a large IVH without PI (group A), seven had a VP shunt with complete decompression of previously enlarged ventricles. Six of these seven infants had periventricular hyperintensity (PVHI) but none developed cerebral palsy (CP). Two of the ten cases without a VP shunt had irregular ventricular enlargement (VE) with PVHI in one. Both developed CP. Seven cases showed thinning of the corpus callosum. Of the 13 cases with a large IVH associated with PI (group B), the site of the PI could still be recognised on MRI and the degree of communication of the porencephalic cyst (PC) with the lateral ventricles correlated well with neonatal US findings. On MRI, VE was present in only 6 cases. Wallerian degeneration was present in 9/13 infants and all but one developed a hemiplegia. In 12/13 cases there was thinning of the corpus callosum, either focal or diffuse. PVHI was present in all infants. In 6/13 PVHI was only present around the PC. Neurodevelopmental outcome differed for both groups. CP was only present in 2/10 infants in group A, compared to 11/ 13 in group B. Global delay, in the absence of CP, was more common in infants with a large IVH than in those with associated PI. Combining neonatal US with MRI in infancy enhances our understanding of the long-term effects of severe haemorrhagic brain lesions, occurring in preterm infants.

PRENATAL SONOGRAPHIC FINDINGS ASSOCIATED WITH SPORADIC SUBCORTICAL NODULAR HETEROTOPIA

In Brief Background Subcortical nodular heterotopia is a neuronal migration disorder of uncertain etiology. This disorder occurs primarily in females and has a familial X-linked dominant inheritance pattern. The predominant symptom associated with heterotopia is seizures. Case At 23 weeks' gestation, prenatal sonography disclosed an isoechoic supratentorial intracranial mass causing right-sided shift of midline structures and compression of the contralateral cerebral ventricle. Serial ultrasound examinations of this mass were significant for the absence of invasion into surrounding structures, gross enlargement of cranial biometric parameters, and hydrocephalus and hydrops fetalis. Neonatal magnetic resonance imaging findings were consistent with gray matter heterotopia and were confirmed as such by brain biopsy. Conclusion Subcortical nodular heterotopia manifested unique prenatal sonographic findings. This case suggests the possibility of prenatal diagnosis in families at risk for this lesion. Prenatal ultrasonography at 23 weeks' gestation revealed subcortical nodular heterotopia that presented as an isoechoic intracranial mass displacing midline structures.

Prenatal Sonographic Findings Associated with Sporadic Subcortical Nodular Heterotopia

Background: Subcortical nodular heterotopia is a neuronal migration disorder of uncertain etiology. This disorder occurs primarily in females and has a familial X-linked dominant inheritance pattern. The predominant symptom associated with heterotopia is seizures.Case: At 23 weeks’ gestation, prenatal sonography disclosed an isoechoic supratentorial intracranial mass causing right-sided shift of midline structures and compression of the contralateral cerebral ventricle. Serial ultrasound examinations of this mass were significant for the absence of invasion into surrounding structures, gross enlargement of cranial biometric parameters, and hydrocephalus and hydrops fetalis. Neonatal magnetic resonance imaging findings were consistent with gray matter heterotopia and were confirmed as such by brain biopsy.Conclusion: Subcortical nodular heterotopia manifested unique prenatal sonographic findings. This case suggests the possibility of prenatal diagnosis in families at risk for this lesion.

Combined application of MR imaging and spectroscopy in neonates and children: installation and operation of a 2.35-T system in a clinical setting.

Published pediatric magnetic resonance (MR) imaging results are usually obtained with medium-field-strength whole-body systems, while MR spectroscopy is done on a different high-field-strength/small-bore laboratory system. The authors investigated metabolism and structural development of the brain in over 100 neonates and children with combined MR imaging and spectroscopy at 2.35 T. With a 40-cm-bore magnet, MR imaging and spectroscopy data are obtained in the same session with use of the same system. The approach demands modified technical devices and elaborate patient handling. Concepts for sedation in different age groups and for patient monitoring, as well as protocols for the combined use of imaging and spectroscopy, have been worked out. The data prove high quality of imaging and spectroscopy at 2.35 T.