Periventricular leukomalacia: relationship between lateral ventricular volume on brain MR images and severity of cognitive and motor impairment

Two-point discrimination responses in children with idiopathic toe walking: A feasibility fMRI study

Idiopathic toe walking (ITW) is a diagnosis given to children who walk with an absence or limitation of heel strike in the contact phase of the gait cycle, that are otherwise typically developing. There is emerging evidence that this gait pattern may occur in children who experience tactile sensory processing challenges. This feasibility study aimed to determine if children were able to respond to a sensory stimulus during a fMRI. Children aged between 8-16 years of age, with and without idiopathic toe walking were recruited from general public advertising. Participants were required to perform a two-point discrimination test (task block) and press a button without being tested (control block) during an fMRI using a standard block design. Activation differences were examined in the left frontal pole, left supramarginal gyrus, left parahippocampal gyrus, left paracingulate gyrus and the right superior temporal. Five children were in the typically developing (TD) group and three were in the ITW group. There were between-group activation differences in the decision-making block compared to the control block in the left frontal lobe, parahippocampal gyrus and the right superior temporal gyrus. There was greater variation in activation in the left supramarginal gyrus and the left paracingulate gyrus in the ITW group compared to the typically developing group. Based on this study a future sample size of 15 children per group will be required to detect an adequate effect across chosen regions of interest Conducting fMRI using two-point discrimination testing on this population is feasible. Further research is required with larger population sizes to determine if brain activation patterns during the sensory input decision-making process are different in this population.

A brain extraction algorithm for infant T2 weighted magnetic resonance images based on fuzzy c-means thresholding

It is challenging to extract the brain region from T2-weighted magnetic resonance infant brain images because conventional brain segmentation algorithms are generally optimized for adult brain images, which have different spatial resolution, dynamic changes of imaging intensity, brain size and shape from infant brain images. In this study, we propose a brain extraction algorithm for infant T2-weighted images. The proposed method utilizes histogram partitioning to separate brain regions from the background image. Then, fuzzy c-means thresholding is performed to obtain a rough brain mask for each image slice, followed by refinement steps. For slices that contain eye regions, an additional eye removal algorithm is proposed to eliminate eyes from the brain mask. By using the proposed method, accurate masks for infant T2-weighted brain images can be generated. For validation, we applied the proposed algorithm and conventional methods to T2 infant images (0–24 months of age) acquired with 2D and 3D sequences at 3T MRI. The Dice coefficients and Precision scores, which were calculated as quantitative measures, showed the highest values for the proposed method as follows: For images acquired with a 2D imaging sequence, the average Dice coefficients were 0.9650 ± 0.006 for the proposed method, 0.9262 ± 0.006 for iBEAT, and 0.9490 ± 0.006 for BET. For the data acquired with a 3D imaging sequence, the average Dice coefficient was 0.9746 ± 0.008 for the proposed method, 0.9448 ± 0.004 for iBEAT, and 0.9622 ± 0.01 for BET. The average Precision was 0.9638 ± 0.009 and 0.9565 ± 0.016 for the proposed method, 0.8981 ± 0.01 and 0.8968 ± 0.008 for iBEAT, and 0.9346 ± 0.014 and 0.9282 ± 0.019 for BET for images acquired with 2D and 3D imaging sequences, respectively, demonstrating that the proposed method could be efficiently used for brain extraction in T2-weighted infant images.

Automatic segmentation and location learning of neonatal cerebral ventricles in 3D ultrasound data combining CNN and CPPN

Preterm neonates are highly likely to suffer from ventriculomegaly, a dilation of the Cerebral Ventricular System (CVS). This condition can develop into life-threatening hydrocephalus and is correlated with future neuro-developmental impairments. Consequently, it must be detected and monitored by physicians. In clinical routing, manual 2D measurements are performed on 2D ultrasound (US) images to estimate the CVS volume but this practice is imprecise due to the unavailability of 3D information. A way to tackle this problem would be to develop automatic CVS segmentation algorithms for 3D US data. In this paper, we investigate the potential of 2D and 3D Convolutional Neural Networks (CNN) to solve this complex task and propose to use Compositional Pattern Producing Network (CPPN) to enable Fully Convolutional Networks (FCN) to learn CVS location. Our database was composed of 25 3D US volumes collected on 21 preterm nenonates at the age of 35.8±1.6 gestational weeks. We found that the CPPN enables to encode CVS location, which increases the accuracy of the CNNs when they have few layers. Accuracy of the 2D and 3D FCNs reached intraobserver variability (IOV) in the case of dilated ventricles with Dice of 0.893±0.008 and 0.886±0.004 respectively (IOV = 0.898±0.008) and with volume errors of 0.45±0.42 cm³ and 0.36±0.24 cm³ respectively (IOV = 0.41±0.05 cm³). 3D FCNs were more accurate than 2D FCNs in the case of normal ventricles with Dice of 0.797±0.041 against 0.776±0.038 (IOV = 0.816±0.009) and volume errors of 0.35±0.29 cm³ against 0.35±0.24 cm³ (IOV = 0.2±0.11 cm³). The best segmentation time of volumes of size 320×320×320 was obtained by a 2D FCN in 3.5±0.2 s.

Prophylactic inhibition of NF-κB expression in microglia leads to attenuation of hypoxic ischemic injury of the immature brain

Background

Periventricular leukomalacia (PVL), a devastating brain injury affecting premature infants, is the most common cause of cerebral palsy. PVL is caused by hypoxia ischemia (HI) and is characterized by white matter necrotic lesions, microglial activation, upregulation of NF-κB, and neuronal death. The microglia is the main cell involved in PVL pathogenesis. The goal of this study was to investigate the role of microglial NF-κB activity and its prophylactic inhibition in a neonate mouse model of HI.

Methods

Transgenic mice with specific knockout NF-κB in microglia and colony stimulating factor 1 receptor Cre with floxed IKKβ (CSF-1R Cre + IKKβ^flox/wt ) were used. Postnatal day 5 (P5) mice underwent sham or bilateral temporary carotid artery ligation followed by hypoxia. After HI insult, inflammatory cytokines, volumetric MRI, histopathology, and immunohistochemistry for oligodendroglia and microglial activation markers were analyzed. Long-term neurobehavioral assessment, including grip strength, rotarod, and open field testing, was performed at P60.

Results

We demonstrate that selective inhibition of NF-κB in microglia decreases HI-induced brain injury by decreasing microglial activation, proinflammatory cytokines, and nitrative stress. Rescue of oligodendroglia is evidenced by immunohistochemistry, decreased ventriculomegaly on MRI, and histopathology. This selective inhibition leads to attenuation of paresis, incoordination, and improved grip strength, gait, and locomotion.

Conclusion

We conclude that NF-κb activation in microglia plays a major role in the pathogenesis of hypoxic ischemic injury of the immature brain, and its prophylactic inhibition offers significant neuroprotection. Using a specific inhibitor of microglial NF-κB may offer a new prophylactic or therapeutic alternative in preterm infants affected by HI and possibly other neurological diseases in which microglial activation plays a role.

Early Diagnosis of Spastic Cerebral Palsy in Infants with Periventricular White Matter Injury Using Diffusion Tensor Imaging

BACKGROUND AND PURPOSE

Periventricular white matter injury is the common cause of spastic cerebral palsy. However, the early diagnosis of spastic cerebral palsy still remains a challenge. Our aim was to investigate whether infants with periventricular white matter injury with bilateral spastic cerebral palsy have unique lesions different from those in infants without cerebral palsy and to evaluate the efficiency of DTI in the early diagnosis of spastic cerebral palsy.

MATERIALS AND METHODS

Infants with periventricular white matter injury and controls underwent MR imaging at 6-18 months of age. Fractional anisotropy was calculated from DTI. Cerebral palsy was diagnosed by 24-30 months of age. Subjects were divided into 3 groups: infants with periventricular white matter injury with bilateral spastic cerebral palsy, infants with periventricular white matter injury without cerebral palsy, and controls. Tract-Based Spatial Statistics and Automated Fiber Quantification were used to investigate intergroup differences. Receiver operating characteristic curves were used to assess the diagnostic accuracy of spastic cerebral palsy. Correlations between motor function scores and fractional anisotropy were evaluated along white matter tracts.

RESULTS

There were 20, 19, and 33 subjects in periventricular white matter injury with spastic cerebral palsy, periventricular white matter injury without cerebral palsy, and control groups, respectively. Decreased fractional anisotropy in the corticospinal tract was only observed in infants with periventricular white matter injury with spastic cerebral palsy, whereas decreased fractional anisotropy in the posterior thalamic radiation and genu and splenium of the corpus callosum was seen in both periventricular white matter injury subgroups. Fractional anisotropy in the corticospinal tract at the internal capsule level was effective in differentiating infants with periventricular white matter injury with spastic cerebral palsy from those without cerebral palsy by a threshold of 0.53, and it had strong correlations with motor function scores.

CONCLUSIONS

Corticospinal tract lesions play a crucial role in motor impairment related to spastic cerebral palsy in infants with periventricular white matter injury. Fractional anisotropy in the corticospinal tract at the internal capsule level could aid in the early diagnosis of spastic cerebral palsy with high diagnostic accuracy.

Three-dimensional ultrasound cranial imaging and early neurodevelopment in preterm growth-restricted infants

AIM

Fetal growth restriction (FGR) is associated with increased perinatal morbidity, mortality and long-term neurodevelopmental sequelae. The objective of this study was to examine whether information about early neurodevelopmental deficits was evident using three-dimensional head ultrasound and developmental assessments in preterm infants with FGR, compared with appropriate for gestational age (AGA) infants in the early post-natal period.

METHODS

Twenty preterm FGR infants weighing <10th centile and born between 28 and 32 weeks were compared with age-matched AGA infants. In the second post-natal week after birth, we used three-dimensional ultrasound to assess cerebral ventricular volumes. Prechtl General Movement Assessments were performed at 4-6 weeks after birth. Test of Infant Motor Performance (TIMP) to measure functional motor behaviour was performed at 4-6 and 12-14 weeks corrected age.

RESULTS

There was no statistically significant difference in the combined cerebral ventricular volume between the two groups (FGR, 0.81 ± 0.42 vs. AGA 0.72 ± 0.38 cm³ , P = 0.4). The TIMP assessment at 12-14 week term corrected demonstrated lower scores (worse performance) in FGR infants compared with the AGA cohort (regression coefficient: -7.74 (95% CI -16.06, 0.57); P = 0.07). We observed a significant correlation between greater ventricular volume and lower TIMP scores in the cohorts separately and also overall (FGR, r = -0.5, P = 0.06 vs. AGA, r = -0.62, P = 0.007 and overall, r = -0.53, P = 0.001).

CONCLUSION

Ultrasound in the early weeks may be useful to detect the neuropathology which could then mediate functional consequences.

Susceptibility-weighted and diffusion kurtosis imaging to evaluate encephalomalacia with epilepsy after traumatic brain injury

Objective

Encephalomalacia after traumatic brain injury (TBI) is one of the factors leading to epilepsy. In this study, magnetic resonance imaging (MRI) was used to explore the brain image features of epilepsy after traumatic encephalomalacia, and to provide objective evidence for predicting the possible occurrence of epilepsy after traumatic encephalomalacia.

Methods

Two‐hundred‐fifty‐two patients with traumatic encephalomalacia were prospectively enrolled in the study. All patients underwent MRI after discharge from the hospital. At the 1‐year follow‐up, participants were divided into epilepsy and nonepilepsy groups. All participants underwent MRI including conventional imaging, susceptibility‐weighted imaging (SWI), and diffusion kurtosis imaging (DKI). The lesion volume, iron deposition, mean diffusion (MD), and mean kurtosis (MK) around the lesions were calculated for each group and compared using t‐tests. P values < 0.05 were considered statistically significant.

Results

Sixty patients with epilepsy and 91 without epilepsy were reported. There were no significant differences in Glasgow Coma Scale (GCS), lesion volume, encephalomalacia, or MD values between the two groups. Iron deposition was significantly higher in the epilepsy group (P < 0.05). The MK values were significantly different (P < 0.05).

Interpretation

Advanced MRI is an important means of evaluating risk of developing epilepsy at 1 year due to encephalomalacia in patients with TBI. SWI and DKI could be used to assess the microstructural changes around the encephalomalacia, and therefore be used to evaluate risk of developing epilepsy at 1 year.

Identifying relevant biomarkers of brain injury from structural MRI: Validation using automated approaches in children with unilateral cerebral palsy

Previous studies have proposed that the early elucidation of brain injury from structural Magnetic Resonance Images (sMRI) is critical for the clinical assessment of children with cerebral palsy (CP). Although distinct aetiologies, including cortical maldevelopments, white and grey matter lesions and ventricular enlargement, have been categorised, these injuries are commonly only assessed in a qualitative fashion. As a result, sMRI remains relatively underexploited for clinical assessments, despite its widespread use. In this study, several automated and validated techniques to automatically quantify these three classes of injury were generated in a large cohort of children (n = 139) aged 5–17, including 95 children diagnosed with unilateral CP. Using a feature selection approach on a training data set (n = 97) to find severity of injury biomarkers predictive of clinical function (motor, cognitive, communicative and visual function), cortical shape and regional lesion burden were most often chosen associated with clinical function. Validating the best models on the unseen test data (n = 42), correlation values ranged between 0.545 and 0.795 (p<0.008), indicating significant associations with clinical function. The measured prevalence of injury, including ventricular enlargement (70%), white and grey matter lesions (55%) and cortical malformations (30%), were similar to the prevalence observed in other cohorts of children with unilateral CP. These findings support the early characterisation of injury from sMRI into previously defined aetiologies as part of standard clinical assessment. Furthermore, the strong and significant association between quantifications of injury observed on structural MRI and multiple clinical scores accord with empirically established structure-function relationships.

Volumetric Magnetic Resonance Imaging Study of Brain and Cerebellum in Children with Cerebral Palsy

Introduction. Quantitative magnetic resonance imaging (MRI) studies are rarely used in the diagnosis of patients with cerebral palsy. The aim of present study was to assess the relationships between the volumetric MRI and clinical findings in children with cerebral palsy compared to control subjects. Materials and Methods. Eighty-two children with cerebral palsy and 90 age- and sex-matched healthy controls were collected. Results. The dominant changes identified on MRI scans in children with cerebral palsy were periventricular leukomalacia (42%) and posthemorrhagic hydrocephalus (21%). The total brain and cerebellum volumes in children with cerebral palsy were significantly reduced in comparison to controls. Significant grey matter volume reduction was found in the total brain in children with cerebral palsy compared with the control subjects. Positive correlations between the age of the children of both groups and the grey matter volumes in the total brain were found. Negative relationship between width of third ventricle and speech development was found in the patients. Positive correlations were noted between the ventricles enlargement and motor dysfunction and mental retardation in children with cerebral palsy. Conclusions. By using the voxel-based morphometry, the total brain, cerebellum, and grey matter volumes were significantly reduced in children with cerebral palsy.

Pathogenesis, neuroimaging and management in children with cerebral palsy born preterm

With advances in obstetric and perinatal management, the incidence of intraventricular hemorrhage in premature infants has declined, while periventricular leukomalacia remains a significant concern. It is now known that brain injury in children born preterm also involves neuronal-axonal disease in supratentorial and infratentorial structures. The developing brain is especially vulnerable to white matter (WM) injury from 23 to 34 weeks gestation when blood vessels serving the periventricular WM are immature. Oligodendrocyte progenitors, which are beginning to form myelin during this time, are susceptible to attack from oxygen free radicals, glutamate, and inflammatory cytokines. Advances in imaging techniques such as diffusion tensor imaging provide a more complete picture of the location and extent of injury. Effective management of children born preterm with cerebral palsy is predicated on an understanding of sequential links from etiological antecedents to brain neuropathology as revealed with neuroimaging techniques to clinical phenotypes, toward focused interventions with measurable outcomes.

Whole-Brain DTI Assessment of White Matter Damage in Children with Bilateral Cerebral Palsy: Evidence of Involvement beyond the Primary Target of the Anoxic Insult

BACKGROUND AND PURPOSE

Cerebral palsy is frequently associated with both motor and nonmotor symptoms. DTI can characterize the damage at the level of motor tracts but provides less consistent results in nonmotor areas. We used a standardized pipeline of analysis to describe and quantify the pattern of DTI white matter abnormalities of the whole brain in a group of children with chronic bilateral cerebral palsy and periventricular leukomalacia. We also explored potential correlations between DTI and clinical scale metrics.

MATERIALS AND METHODS

Twenty-five patients (mean age, 11.8 years) and 25 healthy children (mean age, 11.8 years) were studied at 3T with a 2-mm isotropic DTI sequence. Differences between patients and controls were assessed both voxelwise and in ROIs obtained from an existing DTI atlas. Clinical metrics included the Gross Motor Function Classification System, the Manual Ability Classification System, and intelligence quotient.

RESULTS

The voxel-level and ROI-level analyses demonstrated highly significant (P < .001) modifications of DTI measurements in patients at several levels: cerebellar peduncles, corticospinal tracts and posterior thalamic radiations, posterior corpus callosum, external capsule, anterior thalamic radiation, superior longitudinal fasciculi and corona radiata, optic nerves, and chiasm. The reduction of fractional anisotropy values in significant tracts was between 8% and 30%. Statistically significant correlations were found between motor impairment and fractional anisotropy in corticospinal tracts and commissural and associative tracts of the supratentorial brain.

CONCLUSIONS

We demonstrated the involvement of several motor and nonmotor areas in the chronic damage associated with periventricular leukomalacia and showed new correlations between motor skills and DTI metrics.

Using ventricular modeling to robustly probe significant deep gray matter pathologies: Application to cerebral palsy

Understanding the relationships between the structure and function of the brain largely relies on the qualitative assessment of Magnetic Resonance Images (MRIs) by expert clinicians. Automated analysis systems can support these assessments by providing quantitative measures of brain injury. However, the assessment of deep gray matter structures, which are critical to motor and executive function, remains difficult as a result of large anatomical injuries commonly observed in children with Cerebral Palsy (CP). Hence, this article proposes a robust surrogate marker of the extent of deep gray matter injury based on impingement due to local ventricular enlargement on surrounding anatomy. Local enlargement was computed using a statistical shape model of the lateral ventricles constructed from 44 healthy subjects. Measures of injury on 95 age-matched CP patients were used to train a regression model to predict six clinical measures of function. The robustness of identifying ventricular enlargement was demonstrated by an area under the curve of 0.91 when tested against a dichotomised expert clinical assessment. The measures also showed strong and significant relationships for multiple clinical scores, including: motor function (r²  = 0.62, P < 0.005), executive function (r²  = 0.55, P < 0.005), and communication (r²  = 0.50, P < 0.005), especially compared to using volumes obtained from standard anatomical segmentation approaches. The lack of reliance on accurate anatomical segmentations and its resulting robustness to large anatomical variations is a key feature of the proposed automated approach. This coupled with its strong correlation with clinically meaningful scores, signifies the potential utility to repeatedly assess MRIs for clinicians diagnosing children with CP. Hum Brain Mapp 37:3795-3809, 2016. © 2016 Wiley Periodicals, Inc.

In Vivo Validation of a 3-D Ultrasound System for Imaging the Lateral Ventricles of Neonates

Intra-ventricular hemorrhage, with the resultant cerebral ventricle dilation, is a common cause of brain injury in preterm neonates. Clinically, monitoring is performed using 2-D ultrasound (US); however, its clinical utility in dilation is limited because it cannot provide accurate measurements of irregular volumes such as those of the ventricles, and this might delay treatment until the patient's condition deteriorates severely. We have developed a 3-D US system to image the lateral ventricles of neonates within the confines of incubators. We describe an in vivo ventricle volume validation study in two parts: (i) comparisons between ventricle volumes derived from 3-D US and magnetic resonance images obtained within 24 h; and (ii) the difference between 3-D US ventricle volumes before and after clinically necessary interventions (ventricle taps), which remove cerebral spinal fluid. Magnetic resonance imaging ventricle volumes were found to be 13% greater than 3-D US ventricle volumes; however, we observed high correlations (R(2) = 0.99) when comparing the two modalities. Differences in ventricle volume pre- and post-intervention compared with the reported volume of cerebrospinal fluid removed also were highly correlated (R(2) = 0.93); the slope was not found to be statistically significantly different from 1 (p < 0.05), and the y-intercept was not found to be statistically different from 0 (p < 0.05). Comparison between 3-D US images can detect the volume change after neonatal intra-ventricular hemorrhage. This could be used to determine which patients will have progressive ventricle dilation and allow for more timely surgical interventions. However, 3-D US ventricle volumes should not be directly compared with magnetic resonance imaging ventricle volumes.

Developmental neurotoxicity of inhaled ambient ultrafine particle air pollution: Parallels with neuropathological and behavioral features of autism and other neurodevelopmental disorders

Accumulating evidence from both human and animal studies show that brain is a target of air pollution. Multiple epidemiological studies have now linked components of air pollution to diagnosis of autism spectrum disorder (ASD), a linkage with plausibility based on the shared mechanisms of inflammation. Additional plausibility appears to be provided by findings from our studies in mice of exposures from postnatal day (PND) 4-7 and 10-13 (human 3rd trimester equivalent), to concentrated ambient ultrafine (UFP) particles, considered the most reactive component of air pollution, at levels consistent with high traffic areas of major U.S. cities and thus highly relevant to human exposures. These exposures, occurring during a period of marked neuro- and gliogenesis, unexpectedly produced a pattern of developmental neurotoxicity notably similar to multiple hypothesized mechanistic underpinnings of ASD, including its greater impact in males. UFP exposures induced inflammation/microglial activation, reductions in size of the corpus callosum (CC) and associated hypomyelination, aberrant white matter development and/or structural integrity with ventriculomegaly (VM), elevated glutamate and excitatory/inhibitory imbalance, increased amygdala astrocytic activation, and repetitive and impulsive behaviors. Collectively, these findings suggest the human 3rd trimester equivalent as a period of potential vulnerability to neurodevelopmental toxicity to UFP, particularly in males, and point to the possibility that UFP air pollution exposure during periods of rapid neuro- and gliogenesis may be a risk factor not only for ASD, but also for other neurodevelopmental disorders that share features with ASD, such as schizophrenia, attention deficit disorder, and periventricular leukomalacia.

Clinical study of cerebral palsy in 408 children with periventricular leukomalacia

This study aimed to investigate the high risk factors, cerebral palsy (CP) subtypes and comorbidities of periventricular leukomalacia (PVL). Based on treatment conditions at a specialist hospital, a cross-sectional clinical study and retrospective analysis of computed tomography and magnetic resonance imaging examinations was conducted to evaluate the risk factors, subtypes and comorbidities of CP in children with PVL. Among the 408 children with PVL, 8.58% were born with a weight of ≤1,500 g and 44.36% were born with a weight of ≥2,500 g. In addition, 36.76% of these children had a gestational age of ≤32 weeks and 37.75% had a gestational age of ≥37 weeks. The proportion of the children born with various high risk factors was 95.59%, including perinatal infections and hypoxia. Severe PVL was observed in preterm infants (63.41% with a gestational age of <28 weeks and 21.95% with a gestational age of 28-30 weeks) and low-birth weight infants, which were prone to quadriplegia (43.90%). The common comorbidities included visual and auditory disorders, epilepsy, mental retardation and language barriers. Visual and auditory disorders (26.96%) were the most common comorbidities. PVL was identified primarily in premature and low-birth weight infants. The degree of PVL was found to be negatively correlated with gestational age and birth weight. The degree of PVL in the full-term infants correlated with exposure to infections or hypoxia. Quadriplegia is common among the various subtypes of CP. Visual and hearing disorders are the most common comorbidities of CP; these comorbidities occurred most frequently with quadriplegia.

Neuroradiology Can Predict the Development of Hand Function in Children With Unilateral Cerebral Palsy

Background. Much variation is found in the development of hand function in children with unilateral cerebral palsy (CP). Objective. To explore how anatomic brain abnormalities can be used to predict the development of hand function. Methods. A total of 32 children with unilateral CP (16 boys and 16 girls) were evaluated at least once a year by the Assisting Hand Assessment (AHA). The data collection covered an age range from 18 months to 8 years (mean time in study, 4 years and 6 months). Computerized tomography or magnetic resonance imaging of the brain were assessed for patterns of brain damage, including the location of gray and extent of white-matter damage. The children were divided into groups according to lesion characteristics, and a series of univariate models were analyzed with a nonlinear mixed-effects model. The rate and maximum limit of development were calculated. Results. The highest predictive power of better development of hand function was the absence of a concurrent lesion to the basal ganglia and thalamus, independent of the basic type of brain lesion. This model predicted both the rate of increasing ability and hand function at age 8 years. Hand function was also predicted by the basic pattern of damage and by the extent of white-matter damage. The presence of unilateral or bilateral damage had no predictive value. Conclusions. Neuroradiological findings can be used to make a crude prediction of the future development of the use of the affected hand in young children with unilateral CP.

Intracerebral lipopolysaccharide induces neuroinflammatory change and augmented brain injury in growth-restricted neonatal rats

INTRODUCTION

Intrauterine growth restriction (IUGR) alters fetal development and is associated with neurodevelopmental abnormalities. We hypothesized that growth restriction from reduced intrauterine perfusion would predispose neonatal rats to subsequent inflammatory brain injury.

METHODS

In this study, IUGR was achieved by induced placental insufficiency in pregnant rats at 14 days of gestation. IUGR offspring and sham-operated control pups were subsequently injected with intracerebral lipopolysaccharide (LPS) as a model of periventricular leukomalacia (PVL).

RESULTS

LPS similarly elevates proinflammatory cytokines in the brains of both IUGR and control rat pups. However, the chemokines cytokine-induced neutrophil chemoattractant-1 (CINC-1) and macrophage chemoattractant protein-1 (MCP-1), as well as microglia activation, were significantly higher in LPS-treated IUGR rat pups as compared with LPS-treated controls. In addition to the unique brain inflammatory response, IUGR rat pups demonstrated increased brain damage with an increased number of apoptotic cells, larger lateral ventricular size, and more severe impairment of myelination.

DISCUSSION

This study provides evidence that placental insufficiency may sensitize the innate immune system in the immature brain and reveals a possible link between brain inflammation and injury.

Electrophysiological auditory responses and language development in infants with periventricular leukomalacia

This study presents evidence suggesting that electrophysiological responses to language-related auditory stimuli recorded at 46weeks postconceptional age (PCA) are associated with language development, particularly in infants with periventricular leukomalacia (PVL). In order to investigate this hypothesis, electrophysiological responses to a set of auditory stimuli consisting of series of syllables and tones were recorded from a population of infants with PVL at 46weeks PCA. A communicative development inventory (i.e., parent report) was applied to this population during a follow-up study performed at 14months of age. The results of this later test were analyzed with a statistical clustering procedure, which resulted in two well-defined groups identified as the high-score (HS) and low-score (LS) groups. The event-induced power of the EEG data recorded at 46weeks PCA was analyzed using a dimensionality reduction approach, resulting in a new set of descriptive variables. The LS and HS groups formed well-separated clusters in the space spanned by these descriptive variables, which can therefore be used to predict whether a new subject will belong to either of these groups. A predictive classification rate of 80% was obtained by using a linear classifier that was trained with a leave-one-out cross-validation technique.

Sequence learning in cerebral palsy

We investigated sequence-learning skills in 64 children with cerebral palsy (aged 4.01-14.7 years; 49 with bilateral, two with dystonic, and 13 with unilateral cerebral palsy), compared with a matched control group of typically developing children. Participants' motor and handling abilities were classified according to the Gross Motor Function Classification System and the Manual Ability Classification System. General cognitive, visuoperceptual, and constructive abilities were assessed. Participants performed an experimental computerized version of Corsi Span, followed by a normalized Supraspan sequence. Controls outperformed cerebral palsy participants in visual memory and accuracy. Participants with cerebral palsy were likelier to fail the test (cerebral palsy, 37.5%; control subjects, 5%) and obtain overall lower scores. Sequence learning skills were not related to motor and handling impairments. Failure to learn sequences resulted in an overall lower functioning profile regarding visuoperceptual, verbal, and performance abilities. The ability to fix sequences seemed to split the cerebral palsy group into an overall high-functioning group (successful in sequence learning) and low-functioning (failing) group. Results are discussed in light of a specific implicit memory impairment and the abnormal development of white matter frontostriatal and parietal connections.

Ventricular dilatation in relation to outcome at 2 years of age in very preterm infants: a prospective Finnish cohort study

AIM

The aim of this study was to analyse the relation between ventricular dilatation at term and neurodevelopmental outcome at 2 years corrected age in infants of very low birthweight (VLBW) or very low gestational age (VLGA).

METHOD

A total of 225 VLBW or VLGA infants (121 males, 104 female; mean birthweight 1133 g, SD 333 g; mean gestational age 29 wks, SD 2 wks 5d) born in Turku University Hospital were included. Ventricular-brain ratio and the widths of each lateral ventricular horn were determined using ultrasonography, and the volume of the ventricles was measured by magnetic resonance imaging at term. The 2-year outcome measures included scores for the Hammersmith Infant Neurological Examination, the presence of cerebral palsy (CP), the Mental Developmental Index (MDI) of the Bayley Scales of Infant Development (2nd edition), and the presence of severe hearing or vision impairments or any neurodevelopmental impairment (NDI).

RESULTS

CP was diagnosed in 15 participants (6.7%) and severe hearing deficit in 12 participants (5.3%). No severe vision impairment was found. Mild and severe cognitive delay was found in 24 (10.7%) and 8 (3.6%) of the VLBW or VLGA infants respectively. Isolated ventricular dilatation did not increase the risk for developmental impairments. However, ventricular dilatation with additional brain pathology was significantly associated with CP, MDI score below 70, and NDI. A ventricular-brain ratio above 0.35 was a sensitive measure of developmental impairment.

INTERPRETATION

Ventricular dilatation at term increases the risk of poor developmental outcome only when associated with other brain pathology. The ventricular-brain ratio is a useful clinical tool for determining the prognosis in VLBW and VLGA infants.

Is prematurity associated with adult cognitive outcome and brain structure?

Previous studies have indicated that preterm birth and low birth weight are associated with structural brain abnormalities and neurocognitive deficits in childhood and adolescence, although very few studies have included follow-up in adulthood. Here we assessed the effect of preterm delivery (524 subjects; mean 34.6 weeks, S.D. = 1.7) or low birth weight (366 subjects; mean 2159 g, S.D. = 303) on educational and occupational outcomes at age 31 years in the Northern Finland 1966 Birth Cohort, along with 10,132 term, normal birth weight control subjects. Cognitive tests and brain morphology using magnetic resonance imaging were assessed at age 33-35 years in a subset of the cohort (9 subjects; 95 controls). The preterm or low birth weight subjects had slightly lower school ratings and lower educational levels in adulthood, and they performed worse in verbal learning. The low birth weight subjects were less likely to be employed. There were no mean differences in the magnetic resonance imaging tissue segmentation analysis of the brain. In conclusion, although there were no overall changes in brain morphology in the preterm or low birth weight group, there was evidence for slightly poorer educational and occupational careers and cognitive capacity, which may reflect functional disruption not evident in structure.

Relationship between enlargement of the lateral ventricle and periventricular leukomalacia in infants

AIM

To examine if we could predict periventricular leukomalacia (PVL) from the area of the lateral ventricle (LV).

METHODS

Six neonates in whom cystic PVL could be detected by magnetic resonance imaging (MRI) but not by ultrasound (US) were termed the 'invisible group'. Six neonates in whom cystic PVL could be detected by MRI and US were termed the 'visible group'. Eleven neonates in whom cystic PVL could not be detected by MRI or US were termed the 'control group'. The ratio of LV to head circumference (HC) was calculated as the area of LV (cm²)/HC (cm) × 100. Receiver operating characteristic (ROC) curve analysis was carried out to find the cutoff value.

RESULT

There were no significant differences among the three groups with respect to gestational age, birthweight, postnatal age and HC. The ratio of LV to HC in the control group was a median value of 0.38, it was 0.79 in the invisible group, and 0.96 in the visible group. The ratio was significantly higher in the visible group (P < 0.001) and in the invisible group (P < 0.05) than in the control group. This ratio was low in the two infants who had PVL only in the collateral trigone. The ROC curve suggested a cutoff value of 0.6 (sensitivity 79.17%, specificity 100%) to suspect PVL.

CONCLUSION

We may need to suspect PVL in infants whose lateral ventricle is enlarged even if cystic PVL is not detected by ultrasound. PVL present only in the collateral trigone needs to be evaluated using cerebral MRI.

Neuronal damage in the preterm baboon: impact of the mode of ventilatory support

We evaluated the impact of randomized ventilatory strategies on specific neuronal populations of the cerebral cortex of preterm baboons. In the first series, baboons (n = 5) were delivered at 125 days of gestation (dg; term, 185 days) and exposed to 14 days of positive pressure ventilation (PPV) and compared with 140 dg controls (n = 6). In the second series, baboons were delivered at 125 dg and ventilated by either i) PPV for 1 day, followed by 27 days of nasal continuous positive airway pressure (early [EnCPAP]; n = 6) or ii) PPV for 5 days, followed by 23 days of CPAP (delayed [DnCPAP]; n = 4). Gestational controls were delivered at 153 dg (n = 3). The density of immunoreactive neurons for calretinin and somatostatin was assessed in the primary and secondary visual cortices, cingulate and parietal cortices, and subiculum in paraffin sections. Compared with gestational controls, PPV for 14 days resulted in a reduction in the density of calretinin-positive cells in the visual cortex (Areas 17 and 18) but not in the other cortical areas. No effect of PPV was observed on somatostatin-positive cells. DnCPAP, but not EnCPAP, was associated with a reduction in the density of calretinin and somatostatin-positive cells in the visual cortical areas but not in the other cortical areas compared with gestational controls. Taken together, these data demonstrate that ventilatory strategies involving greater than 5 days of PPV have a regionally selective impact on cortical neuronal subpopulations within the visual area but not in areas of association cortex in a nonhuman primate model of prematurity.

Understanding brain injury and neurodevelopmental disabilities in the preterm infant: the evolving role of advanced magnetic resonance imaging

The high incidence of neurodevelopmental disability in premature infants requires continued efforts at understanding the underlying microstructural changes in the brain that cause this perturbation in normal development. Magnetic resonance imaging (MRI) methods offer great potential to fulfill this need. Serial MR imaging and the application of newer analysis techniques, such as diffusion tensor imaging (DTI), volumetric MR analysis, cortical surface analysis, functional connectivity MRI (fcMRI) and diffusion tractography, provide important insights into the trajectory of brain development in the premature infant and the impact of injury on this developmental trajectory. While some of these imaging techniques are currently available in the research setting only, other measures, such as DTI and brain metric measures can be used clinically. MR imaging also has an enormous potential to be used as a surrogate, short-term outcome measure in clinical studies evaluating new therapeutic interventions of neuroprotection of the developing brain. In this article, we review the current status of these advanced MR imaging techniques.

Preoperative MRI findings and functional outcome after selective dorsal rhizotomy in children with bilateral spasticity

PURPOSE

To identify MRI characteristics that may predict the functional effect of selective dorsal rhizotomy (SDR) in children with bilateral spastic paresis.

METHODS

We performed SDR in a group of 36 patients. The gross motor functioning measure-66 (GMFM-66) was applied before and after SDR. Available cerebral MRIs were retrospectively classified into three diagnostic groups: periventricular leucomalacia (PVL; n = 10), hydrocephalus (n = 2), and normal (n = 6). In patients with PVL, we scored the severity of the MR abnormalities. We compared the changes in the GMFM-66 after SDR in the diagnostic groups. In patients with PVL, we correlated the severity of the MR abnormalities with the changes in the GMFM-66.

RESULTS

The mean follow-up period was 5 years and 4 months (range, 1 year and 1 month to 9 years). The best improvement in gross motor function was observed in patients with normal MRI, and the slightest improvement was observed in patients with hydrocephalus. The severity of the PVL did correlate with the GMFM-66 score before SDR but not with the functional effect of SDR.

CONCLUSION

We conclude that with respect to gross motor skills, the improvements after SDR are good in patients with no MRI abnormalities. In the patients with hydrocephalus, the improvements after SDR were insignificant. In patients with PVL, the improvements were intermediate and did not correlate with the degree of PVL.

Motor mapping in cerebral palsy

The measurement of motor deficits in individuals with cerebral palsy (CP) has been largely based on clinical criteria. Yet functional imaging and non-invasive stimulation methods provide a means to measure directly abnormalities of the motor system. The size and location of muscles and movement representations can be determined with transcranial magnetic stimulation (TMS) and functional magnetics resonance imaging. Thus the homunculus can be individually mapped in children with CP. Because size of representation within the homunculus relates to quality of motor control, measurement of the distance between body parts provides a metric that may be useful in classifying deficits. Bilateral motor control in one hemisphere, while normal in neonates, persists variably in CP, providing another physiological metric. In this study, we used TMS to measure hand and ankle representations in a convenience sample of children with spastic CP. Overlapping thumb and ankle maps were found in children with both hemiplegia and diplegia, and these maps may be from either side of the body. While more participants are required to make conclusions about disability and compression/bilaterality of the homunculus, it appears as if TMS-derived metrics relate to motor abnormalities. These abnormal motor maps also are a therapeutic target, as stimulation methods are being developed as adjuncts to physical means of rehabilitation.

Somatosensory and visual evoked potentials in children with cerebral palsy: Correlations and discrepancies with MRI findings and clinical picture

PURPOSE

To determine if there is any association between the findings of visual evoked potentials (VEPs), somatosensory evoked potentials (SEPs), and magnetic resonance imaging (MRI) findings with the neurodevelopment and severity in children with cerebral palsy (CP).

METHODS

The present study included 15 children with spastic diplegic CP and five children with spastic hemiplegic CP and 42 healthy children as controls. The number of the controls was two-times greater than the study group to increase statistical power of this study. VEPs and SEPs were recorded in the CP children and compared with healthy controls. All MR scans were obtained using a 1.5 T MR scanner.

RESULTS

A significant difference was found in the latencies P100 (VEP) between the CP and controls. No correlations between increased P100 latencies and asphyxia, prematurity, the CP severity, MRI findings and mental retardation were noted. A significant difference in N13-N20 conductions (SEPs) between the subjects with CP and the control group was found. SEPs were positively correlated with mental retardation in CP children. The brain lesions in MRI showed a significant correlation with the CP severity scores and mental retardation.

CONCLUSION

The differences in VEPs and SEPs were determined between CP children and healthy children. The MRI findings were positively correlated with the CP severity and mental retardation.

3D reconstructions of the cerebral ventricles and volume quantification in children with brain malformations

RATIONALE AND OBJECTIVES

The aim of this study was to assess the ability of a semiautomated process to produce three-dimensional reconstructions of the ventricles and calculate ventricular volumes from magnetic resonance (MR) imaging data in children with structural brain abnormalities.

MATERIALS AND METHODS

Fourteen children referred for MR imaging of the brain for neurologic symptoms were selected. Seven participants had structural brain abnormalities on MR imaging; seven further participants were age-matched controls with normal brain morphology. MR imaging included T1-weighted volumetric images in all cases. Semiautomated postprocessing techniques were performed on the MR imaging data to generate three-dimensional reconstructions of the ventricles. These were analyzed for morphologic changes, and volumes were calculated. Inter- and intrarater agreement of ventricular volumes were calculated.

RESULTS

This technique produced detailed three-dimensional reconstructions of the ventricles, even in children with grossly abnormal ventricular morphology. All MR imaging data were successfully postprocessed in <5 minutes. Inter- and intrarater reliability was excellent, with correlation coefficients of 0.99 and 0.92, respectively.

CONCLUSION

This methodology can create detailed three-dimensional visualizations and volumetric measurements of morphologically abnormal ventricles. This technique could help physicians and parents comprehend abnormal ventricular anatomy better and may have future clinical uses in monitoring disease progression or neurosurgical planning.

Brain and ventricles in very low birth weight infants at term: a comparison among head circumference, ultrasound, and magnetic resonance imaging

OBJECTIVES

The aim of this study was to assess the relationship among the size of the lateral ventricles, head-circumference measure, and brain volumes. In addition, the association between ventricular dilatation and various brain lesions was defined.

PATIENTS AND METHODS

A total of 257 preterm very low birth weight (< or =1500 g) infants who met the inclusion criteria were born in Turku University Central Hospital between 2001 and 2006. A total of 209 (84.8%) of 218 survivors participated in the study. The measurements at term included the ventricular brain ratio, the widths of the frontal and occipital horns of the lateral ventricles by ultrasound, total and regional brain volumes by MRI, and head circumference. Brain lesions were defined by ultrasound at 3 to 5, 7 to 10, and 30 days of age monthly until discharge and by MRI and ultrasound at term.

RESULTS

An abnormal ventricular brain ratio (>0.35), an increasing number of dilated ventricular horns, and smaller head circumference were significantly associated with smaller total brain tissue volume. The abnormal ventricular brain ratio and the increasing number of dilated ventricular horns in ultrasound associated with larger ventricular volumes in MRI, and a smaller head circumference was associated significantly with reduced regional brain tissue volumes. Brain lesions were more common in infants with ventriculomegaly.

CONCLUSIONS

The ventricular brain ratio, widths of the lateral ventricular horns, and head circumference are appropriate measures for the estimation of both total and regional brain tissue volumes. Ventriculomegaly is strongly associated with brain lesions.

Magnetic resonance imaging and developmental outcome following preterm birth: review of current evidence

Preterm birth is associated with an increased risk of developmental difficulties. Magnetic resonance imaging (MRI) is increasingly being used to identify damage to the brain following preterm birth. It is hoped this information will aid prognostication and identify neonates who would benefit from early therapeutic intervention. Cystic periventricular white matter damage has traditionally been associated with abnormal motor developmental and cerebral palsy, but its presence on MRI does not preclude normal cognitive development. This has led to increasing interest in the identification of diffuse periventricular white matter damage with conventional and sophisticated MRI. However, the correlation between these appearances and developmental outcome remains unclear. Measurements of the size, volumes, and growth rates of many regions of the brain, such as the corpus callosum, ventricular system, cortex, deep grey matter, and cerebellum, are all also altered following preterm birth, but there is insufficient evidence to use this data in the clinical setting. This article is a review of the current evidence on MRI and developmental outcome, suggesting possible indications for the use of MRI following preterm birth.

Fiber-tracking techniques can predict the degree of neurologic impairment for periventricular leukomalacia

OBJECTIVE

Preterm or low birth weight infants display a greater propensity for white matter injury caused by hypoxic-ischemic encephalopathy in the perinatal period. Such episodes can result in periventricular leukomalacia, which may substantially influence later brain development. Noninvasive methods of assessing the severity of injury at the earliest stage of life have not yet been established.

METHODS

We used diffusion tensor imaging to evaluate sensorimotor fibers in periventricular leukomalacia. Region-of-interest measurements and tractography-based measurements were performed for 10 patients with periventricular leukomalacia. The mean age of the patients was 19 +/- 9.5 months (range: 9-41 months). Motor functions were assessed at a mean age of 28 +/- 14.5 months.

RESULTS

Measured fractional anisotropy values of the motor tract were significantly higher in all mild periventricular leukomalacia cases than in severe cases. A fractional anisotropy cutoff value of <0.5 was useful for predicting severe periventricular leukomalacia. Region-of-interest measurements were less sensitive, compared with tractography-based measurements.

CONCLUSIONS

Fiber-tracking techniques can provide information on the pathophysiologic features of motor disability in patients with periventricular leukomalacia. Early screening of patients with a history of asphyxia may facilitate early intervention (eg, rehabilitation), to achieve better motor function.

Diffuse axonal injury in periventricular leukomalacia as determined by apoptotic marker fractin

Periventricular leukomalacia (PVL), the major substrate of neurologic deficits in premature infants, is associated with reduced white matter volume. Using immunomarkers of axonal pathology [beta-amyloid precursor protein (beta-APP) and apoptotic marker fractin], we tested the hypothesis that widespread (diffuse) axonal injury occurs in the gliotic white matter beyond the foci of necrosis in PVL, thus contributing to the white matter volume reduction. In a cohort of 17 control cases and 13 PVL cases with lesions of different chronological ages, diffuse axonal damage in PVL was detected by fractin in white matter sites surrounding and distant from acute and organizing foci of necrosis. Using beta-APP, axonal spheroids were detected within necrotic foci in the acute and organizing (subacute) stages, a finding consistent with others. Interestingly, GAP-43 expression was also detected in spheroids in the necrotic foci, suggesting attempts at axonal regeneration. Thirty-one percent of the PVL cases had thalamic damage and 15% neuronal injury in the cerebral cortex overlying PVL. We conclude that diffuse axonal injury, as determined by apoptotic marker fractin, occurs in PVL and that its cause likely includes primary ischemia and trophic degeneration secondary to corticothalamic neuronal damage.

Cognitive profile in young Icelandic children with cerebral palsy

We describe the cognitive profile in a complete national cohort of children with cerebral palsy (CP). One hundred and twenty-seven Icelandic children (67 females, 60 males) with CP, born between 1985 and 2000 and assessed between the ages of 4 and 6 years 6 months (mean age 5y 5mo, SD 6mo), were included in the study. IQ was measured using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) and developmental quotient (DQ) was obtained using various developmental scales. Physiological classification of CP in the children was: spasticity, n=104 (82%); dyskinesia, n=14 (11%); ataxia, n=six (4.7%), and unclassified CP, n=3 (2.3%). Spastic diplegia was the most prevalent subtype (35%) followed by hemiplegia and quadriplegia. Forty-five per cent of the group were at Level I of the Gross Motor Function Classification System, 32% were at Levels II and III, and 23% were at Levels IV and V. Sixty per cent of the children had an IQ or DQ >70. Median scores on the WPPSI were Full-scale IQ 84, Verbal IQ (VIQ) 92, and Performance IQ (PIQ) 77. Children with spastic diplegia and quadriplegia had a significantly lower PIQ than VIQ. Of the children who failed to complete the WPPSI, 20% had DQ >85. Thus, cognitive skills can be masked by limitations of movement and motor control in children with CP.

Pontine hypoplasia in children with periventricular leukomalacia

BACKGROUND AND PURPOSE

The brain stem in patients with periventricular leukomalacia (PVL) appears smaller than normal on MR imaging, but few reports have described this feature, and the number of patients has been relatively small. The present study was conducted to examine the hypothesis that the pons in patients with PVL is smaller than normal.

MATERIALS AND METHODS

Using MR imaging, we examined 80 children (43 boys and 37 girls) with PVL and 80 age-matched control children (41 boys and 39 girls). The control children were diagnosed as neurologically and developmentally normal by pediatric neurologists and also showed normal MR imaging findings. MR imaging was performed at a corrected age range of 0-5 years in both groups. We measured the anteroposterior diameter of the whole pons, the tegmentum and the basis, and the corpus callosal length by using midline T1-weighted sagittal images and compared each parameter between the PVL groups and the control groups.

RESULTS

Pontine diameters in all of the regions were significantly smaller in the PVL group than in the control group (mean +/- SD, whole pontine diameters, 1.66 +/- 0.21 and 1.87 +/- 0.23 cm [P < .001]; basis diameters, 0.42 +/- 0.10 and 0.51 +/- 0.14 [P < .001]; tegmentum diameters, 1.23 +/- 0.20 and 1.36 +/- 0.19 [P < .001], respectively). The respective corpus callosal lengths were 5.02 +/- 0.90 and 5.51 +/- 0.76 (P < .001). There was no significant difference in the basis/tegmentum ratio between the PVL group and the control group. When the age-related pontine diameter differences were examined, there was already a significant difference at 0 years of age between the 2 groups. There was a significant correlation between whole pontine diameter and corpus callosal length in the PVL group (correlation coefficient, 0.52; P < .001) and the control group (correlation coefficient, 0.63; P < .001).

CONCLUSION

We have proven that pontine diameter in patients with PVL is significantly smaller than that in normal control subjects, including each diameter of basis and tegmentum.

Cerebral palsy

Cerebral palsy (CP) is a group of disorders of movement and posture resulting from nonprogressive disturbances of the fetal or neonatal brain. More than 80% of cases of CP in term infants originate in the prenatal period; in premature infants, both prenatal or postnatal causes contribute. The most prevalent pathological lesion seen in CP is periventricular white matter injury (PWMI) resulting from vulnerability of the immature oligodendrocytes (pre-OLs) before 32 wk of gestation. PWMI is responsible for the spastic diplegia form of CP and a spectrum of cognitive and behavioral disorders. Oxidative stress and excitotoxicity resulting from excessive stimulation of ionotropic glutamate receptors on preOLs are the most prominent molecular mechanisms for PWMI. Asphyxia around the time of birth in term infants accounts for less than 15% of CP in developed countries but the incidence is higher in underdeveloped areas. Asphyxia causes a different pattern of brain injury and CP than is seen after preterm injuries. This type of CP is associated with the clinical syndrome of hypoxic-ischemic encephalopathy shortly after the insult, and the cortex, basal ganglia, and brainstem are selectively vulnerable to injury. Experimental models indicate that neurons in the neonatal brain are more likely to die by delayed apoptosis extending over days to weeks than those in the adult brain. Neurons die by glutamate-mediated excitotoxicity involving downstream caspase-dependent and caspase-independent cell death pathways. Recent reports indicate that males and females preferentially utilize different pathways. Clinical trials indicate that mild hypothermia reduces death or disability in term infants following asphyxia and basic research suggests that this approach might be combined with pharmacological strategies in the future.

Motor development and sleep, play, and feeding positions in very-low-birthweight infants with and without white matter disease

We investigated the association of infants' sleep and awake positioning with motor milestone acquisition as measured by the Alberta Infant Motor Scale (AIMS). Participants were 30 very-low-birthweight (VLBW) infants with preterm white matter disease (PTWMD; 21 males, nine females; mean birthweight [BW] 1,129 g [SD 338]; mean gestational age [GA] 28 wks [SD 2.44]); 21 VLBW infants without preterm WMD (PT; 13 males, eight females; mean BW 1,107 g [SD 370]; mean GA 28.05 wks [SD 2.21]); and 17 term infants (Term; seven males, 10 females; mean BW 3,565 g [SD 382]; mean GA 40 wks [SD 1.31]). Testing occurred at 1, 5, and 9 months of age (corrected for prematurity). Preferred positions during sleeping, playing, and feeding were obtained through parent interview. These positions and group were the independent variables. Prone sleeping was significantly and positively associated with motor development at all ages (1 mo: p=0.005; 5 mo: p=0.011; 9 mo: p=0.040). At 5 months, prone sleeping and playing were significantly and positively associated with AIMS scores (prone sleeping, p=0.016; prone playing, p=0.047). However, group was negatively associated with preterm white matter disease, with the PTWMD group having significantly lower AIMS scores than the Term group (p=0.029). At 9 months, sitting playing and group membership were significantly associated with AIMS scores (sitting playing, p=0.005; group, p=0.012). Prone positioning should be encouraged for awake time, particularly for infants with preterm white matter disease.

Pediatric seizure imaging

The objective of this article was to show the spectrum of magnetic resonance and computed tomographic abnormalities in the pediatric seizure patient. Seizure is a common indication for pediatric neuroimaging. Characteristic imaging findings can lead to a specific pathologic diagnosis. Imaging findings may be subtle. Clinical correlation and optimization of magnetic resonance imaging protocols are important for seizure imaging.

Neuronal damage accompanies perinatal white-matter damage

Extremely low-gestational-age newborns have a prominently increased risk of brain dysfunctions attributed to white-matter damage, which is thought to result from the vulnerability of the oligodendrocyte. This white-matter damage now appears to be accompanied by cerebral-cortex and deep-gray-matter abnormalities, including excess apoptosis without replacement and the impairment of surviving neurons and resulting interference with synaptogenesis and connectivity. Recent advances in corticogenesis suggest that neurons migrate from the germinative zones through the white matter to the cortex when the white matter is most vulnerable and perhaps is being injured. Advances in developmental neuroscience also suggest that the excitotoxic and inflammatory processes that probably contribute to white-matter damage are also able to damage developing neurons. Together, these advances support the untested hypothesis that white-matter damage in the preterm newborn is accompanied by the death of neurons as they migrate through the dangerous minefield of white matter undergoing injury.

Brain structure in prenatal stroke: quantitative magnetic resonance imaging (MRI) analysis

Neonatal stroke outcome studies demonstrate variable findings of either relatively spared intellectual function or persistent impairments. Volumetric measurement of the brain can provide more precise data on lesion-cognition outcomes. We studied 7 children with unilateral focal lesions from prenatal stroke. Whole-brain magnetic resonance imaging scans were analyzed to produce volumes of cortical gray matter, total white matter, cerebrospinal fluid, lesion, and lesion constricted fluid, and we ascertained the relationship of morphometric variables to intellectual and clinical outcome. Children with cystic encephalomalacia plus atrophy had poorer outcomes than children with atrophy or gliosis alone. These children also demonstrated the largest lesion size, smallest gray matter volume, and greatest proportion of hyperintense white matter in the affected hemisphere. Findings suggest that the type and size of the lesion, in addition to the integrity of white matter and residual cortex, may be better predictors of intellectual functioning than either of these indices alone.

Antenatal Doppler measurements and early brain injury in very low birth weight infants

OBJECTIVE

To determine the correlation between fetoplacental blood flow and brain injury and volumes in very low birth weight (VLBW) infants.

STUDY DESIGN

Antenatal blood flow from the umbilical artery (UA), middle cerebral artery (MCA), and descending aorta was determined in 70 VLBW infants. The directions of the total diastolic flow of the aortic isthmus and the end-diastolic flow of ductus venosus also were measured. Serial brain ultrasound examinations and MRI at term were performed to assess brain abnormalities. On the basis of brain imaging findings, the newborn infants were classified as normal (n = 14), intermediate brain pathology (n = 31), and major pathology (n = 25) groups.

RESULTS

Abnormalities in fetoplacental blood flow were not related to anatomic brain lesions. However, an abnormal UA/MCA pulsatility index ratio was associated with reduced total brain volume (mean, 360 mL; SD, 32.5 mL) and reduced cerebral volume (344 mL; SD, 28.4 mL) compared with infants with normal UA/MCA pulsatility index ratio (mean, 405 mL; SD, 51.3 mL, P = .01, and mean, 368 mL; SD, 52.3 mL, P = .012), respectively.

CONCLUSIONS

Redistribution of fetal blood flow in VLBW infants is associated with reduced brain volume at term age. Neurodevelopmental follow-up of this cohort will clarify the significance of these blood flow changes on development.

MRI Findings in Patients with Hemiparetic Cerebral Palsy

Given the more severe and extensive unilateral brain abnormalities in hemiparetic cerebral palsy (HCP) patients than in other spastic cerebral palsy patients we focused exclusively on the localization of brain lesions in children with HCP. The relationship between neuroradiological findings and side of hemiparesis was investigated in a group of 30 children with HCP. Seventeen boys and 13 girls aged four to 18 years (mean age 9.7±4.2 years) were included in this study. Computed tomography and magnetic resonance imaging examinations were correlated with the birth histories, obstetrical records and clinical summaries. Of the 30 patients with HCP, 2 (6.6%) had normal neuroradiological examinations, 20 (66.6%) had unilateral and eight (26.6%) bilateral brain lesions. A brain lesion on the contralateral side of hemiparesis was found in 93.3% of the neuroradiological examinations. The commonest neuroradiological findings in our study were periventricular leukomalacia (PVL, 80%), atrophy (70%) and porencephalic cyst (50%). There was a significant relationship between the symptomatic side and contralateral PVL, atrophy and porencephalic cyst (40%). PVL, atrophy and porencephalic cyst were significantly concomitant on the same side (46.6%). We demonstrated for the first time in the literature that PVL, atrophy and porencephaly are usually observed concomitantly and contralateral to the side of motor impairement in HCP patients.

MR imaging of the neonatal brain

The advent of modern neuroimaging tools and methods has revolutionized the evaluation of the brain in neonates. The development of magnetic resonance (MR)-compatible monitoring tools and incubators has alleviated concerns regarding transportation of these unstable infants. The development of dedicated neonatal imaging coils has increased signal-to-noise ratios dramatically in images of the neonatal brain; this has made high-quality anatomic imaging, diffusion tensor imaging, and proton MR spectroscopy feasible in a normal imaging time. In centers that are equipped properly for neonatal MR imaging, MR is now unquestionably the study of choice for neonates who have encephalopathy or suspected brain injury. This article discusses the application of modern MR techniques to some of the causes of encephalopathy in neonates.

In vitro MRI of brain development

In this review, we demonstrate the developmental appearance, structural features, and reorganization of transient cerebral zones and structures in the human fetal brain using a correlative histological and MRI analysis. The analysis of postmortem aldehyde-fixed specimens (age range: 10 postovulatory weeks to term) revealed that, at 10 postovulatory weeks, the cerebral wall already has a trilaminar appearance and consists of: (1) a ventricular zone of high cell-packing density; (2) an intermediate zone; (3) the cortical plate (in a stage of primary consolidation) with high MRI signal intensity. The anlage of the hippocampus is present as a prominent bulging in the thin limbic telencephalon. The early fetal telencephalon impar also contains the first commissural fibers and fornix bundles in the septal area. The ganglionic eminence is clearly visible as an expanded continuation of the proliferative ventricular zone. The basal ganglia showed an initial aggregation of cells. The most massive fiber system is in the hemispheric stalk, which is in continuity with thalamocortical fibers. During the mid-fetal period (15-22 postovulatory weeks), the typical fetal lamination pattern develops and the cerebral wall consists of the following zones: (a) a marginal zone (visible on MRI exclusively in the hippocampus); (b) the cortical plate with high cell-packing density and high MRI signal intensity; (c) the subplate zone, which is the most prominent zone rich in extracellular matrix and with a very low MRI signal intensity; (d) the intermediate zone (fetal "white matter"); (e) the subventricular zone; (f) the periventricular fiber-rich zone; (g) the ventricular zone. The ganglionic eminence is still a very prominent structure with an intense proliferative activity. During the next period (22-26 postovulatory weeks), there is the developmental peak of transient MRI features, caused by the high content of hydrophyllic extracellular matrix in the subplate zone and the accumulation of waiting afferent axons. The period between 27 and 30 postovulatory weeks is characterized by gradual blurring of the laminar structure in parallel with the formation of cerebral convolutions. In near-term preterm infants, T2-weighted MR images showed better contrast resolution than T1-weighted images. We conclude that transient fetal zones and subcortical structures display characteristic MRI features due to the high content of extracellular matrix in the subplate zone, higher MRI signal intensity of zones with high cell-packing intensity, and the presence of growing fibers.

Quantitative analysis of the corpus callosum in children with cerebral palsy and developmental delay: correlation with cerebral white matter volume

BACKGROUND

The direct quantitative correlation between thickness of the corpus callosum and volume of cerebral white matter in children with cerebral palsy and developmental delay has not been demonstrated.

OBJECTIVE

This study was conducted to quantitatively correlate the thickness of the corpus callosum with the volume of cerebral white matter in children with cerebral palsy and developmental delay.

MATERIAL AND METHODS

A clinical database of 70 children with cerebral palsy and developmental delay was established with children between the ages of 1 and 5 years. These children also demonstrated abnormal periventricular T2 hyperintensities associated with and without ventriculomegaly. Mid-sagittal T1-weighted images were used to measure the thickness (genu, mid-body, and splenium) and length of the corpus callosum. Volumes of interest were digitized based on gray-scale densities to define the hemispheric cerebral white matter on axial T2-weighted and FLAIR images. The thickness of the mid-body of the corpus callosum was correlated with cerebral white matter volume. Subgroup analysis was also performed to examine the relationship of this correlation with both gestational age and neuromotor outcome. Statistical analysis was performed using analysis of variance and Pearson correlation coefficients.

RESULTS

There was a positive correlation between the thickness of the mid-body of the corpus callosum and the volume of cerebral white matter across all children studied (R=0.665, P=0.0001). This correlation was not dependent on gestational age. The thickness of the mid-body of the corpus callosum was decreased in the spastic diplegia group compared to the two other groups (hypotonia and developmental delay only; P<0.0001). Within each neuromotor subgroup, there was a positive correlation between thickness of the mid-body of the corpus callosum and volume of the cerebral white matter.

CONCLUSION

The thickness of the mid-body of the corpus callosum positively correlates with volume of cerebral white matter in children with cerebral palsy and developmental delay, regardless of gestational age or neuromotor outcome. Assessment of the thickness of the corpus callosum might help in estimating the extent of the loss of volume of cerebral white matter in children with a broad spectrum of periventricular white matter injury.