Interhemispheric Distance Research Articles

The prevalence of subdural blood products in extremely premature infants with no history of abusive head trauma, studied by magnetic resonance imaging around term-equivalent age.

Prematurity and enlarged subarachnoid spaces are both hypothesised to represent an increased risk of subdural haemorrhages (SDHs) in infancy, both with and without a history of abuse. To examine the prevalence of a previous haemorrhage, particularly SDHs, in infants born extremely prematurely around term-equivalent age; to examine intra- and inter-observer agreement for identification of haemorrhages; and to examine the width of the subarachnoid spaces. A total of 121 extremely premature infants had cerebral magnetic resonance imaging (MRI) performed around term-equivalent age (mean chronological age 14.7weeks, range 10.3-24.0weeks). There were no infants investigated for abuse in our cohort. Intracranial haemorrhages were classified as isolated germinal matrix-haemorrhages, parenchymal haemorrhages (cerebellar- and cerebral haemorrhages), or extra-axial haemorrhages (subarachnoid haemorrhages, SDHs, or epidural haemorrhages). Sinocortical width and interhemispheric distance were measured. No appreciable SDH was detected with the performed sequences. Haemorrhage/blood products related to prematurity were seen in 60 (49.5%) of the neonates. Agreement was good to very good for identification of haemorrhage. The mean sinocortical width was 3.5mm with a standard deviation (SD) of 1.4mm on the right side and 3.3mm (SD 1.2mm) on the left side. The mean interhemispheric distance was 3.1mm (SD 1.1mm). 61.1% of the infants had a sinocortical width > 3mm on one or both sides. Our study does not support the hypothesis that premature infants are more prone to SDH unrelated to abusive head trauma during the first 3-4months of life. A large percentage of the ex-premature infants had prominent subarachnoid spaces.

A Simple MRI Score Predicts Pathological General Movements in Very Preterm Infants with Brain Injury-Retrospective Cohort Study.

Very preterm infants are at increased risk of brain injury and impaired brain development. The Total Abnormality Score and biometric parameters, such as biparietal width, interhemispheric distance and transcerebellar diameter, are simple measures to evaluate brain injury, development and growth using cerebral magnetic resonance imaging data at term-equivalent age. The aim of this study was to evaluate the association between the Total Abnormality Score and biometric parameters with general movements in very preterm infants with brain injury. This single-center retrospective cohort study included 70 very preterm infants (≤32 weeks' gestation and/or <1500 g birth weight) born between January 2017 and June 2021 in a level-three neonatal intensive care unit with brain injury-identified using cerebral magnetic resonance imaging data at term-equivalent age. General movements analysis was carried out at corrected age of 8-16 weeks. Binary logistic regression and Spearman correlation were used to examine the associations between the Total Abnormality Score and biometric parameters with general movements. There was a significant association between the Total Abnormality Score and the absence of fidgety movements [OR: 1.19, 95% CI = 1.38-1.03] as well as a significant association between the transcerebellar diameter and fidgety movements (Spearman ρ = -0.269, p < 0.05). Among very preterm infants with brain injury, the Total Abnormality Score can be used to predict the absence of fidgety movements and may be an easily accessible tool for identifying high-risk very preterm infants and planning early interventions accordingly.

Brain Region Size Differences Associated With Dystonia in People With Cerebral Palsy Born Premature

BackgroundDystonia in cerebral palsy (CP) is classically associated with deep gray matter injury at term gestation, but the patterns of injury associated with dystonia following premature birth are unclear. We examined whether there were brain regional size differences associated with dystonia in people with CP born premature. MethodsIn this retrospective cohort study, we identified subjects with CP born premature (<37 weeks gestational age) seen at a tertiary care CP center between February 1, 2017, to February 1, 2021, who had T1-weighted brain magnetic resonance imaging (MRI) done between ages one and five years available in the clinical record. We measured the following on these brain MRI images per the 2013 Kidokoro criteria: interhemispheric distance, biparietal width, lateral ventricle diameter, transcerebellar diameter, deep gray matter area, and corpus callosum thickness. We then compared the sizes of these structures between those with and without dystonia correcting for gestational age at birth and gross motor functional ability (univariate general linear models). ResultsFifty-five subjects met the inclusion and exclusion criteria. Interhemispheric distance was significantly greater in those with dystonia, suggesting decreased cortical volume (P = 0.005). There was no significant difference in the other measured structures between those with and without dystonia, including deep gray matter area. ConclusionsIncreased interhemispheric distance, not measures of deep gray matter size, correlate with the presence of dystonia in people with CP born premature.

Brain Biometry Reveals Impaired Brain Growth in Preterm Neonates with Intraventricular Hemorrhage

Introduction: Preterm birth and cerebral hemorrhage have adverse effects on brain development. Alterations in regional brain size on magnetic resonance imaging (MRI) can be assessed using 2D biometrical analysis, an easily applicable technique showing good correlation with 3D brain volumes. Methods: This retrospective study included 74 preterm neonates with intraventricular hemorrhage (IVH) born <32+0 weeks of gestation between 2011 and 2019. Cerebral MRI was performed at term-equivalent age, and 2D measurement techniques were used for biometrical analysis and compared to normative data of two control groups. Finally, the correlation and association of brain parameters and patterns of impaired brain growth and outcome at 2 and 3 years of age were evaluated. Results: Interhemispheric distance (IHD), the 3rd ventricle, and lateral ventricles presented larger, in contrast, cerebral biparietal width (cBPW), fronto-occipital diameter (FOD), and the length of the corpus callosum were smaller in IVH patients compared to respective controls. The strongest correlations with outcome were observed for the parameters FOD, anteroposterior diameter of the vermis, transverse cerebellar diameter (tCD), corpus callosum, 3rd ventricle, and left ventricular index. Patients with the small FOD, small BPW, and increased IHD pattern reached overall lower outcome scores at follow-up. Discussion: Preterm neonates with IVH showed reduced total brain sizes and enlarged pericerebral spaces compared to neurologically healthy controls. Biometric analysis revealed that several 2D brain parameters as well as different patterns of impaired brain growth were associated with neurodevelopmental impairment in early childhood. These findings may support prediction of long-term outcome and parental counseling in patients with IVH.

Association between Fat-Free Mass and Brain Size in Extremely Preterm Infants.

Postnatal growth restriction and deficits in fat-free mass are associated with impaired neurodevelopment. The optimal body composition to support normal brain growth and development remains unclear. This study investigated the association between body composition and brain size in preterm infants. We included 118 infants born <28 weeks of gestation between 2017–2021, who underwent body composition (fat-free mass (FFM) and fat mass (FM)) and cerebral magnetic resonance imaging to quantify brain size (cerebral biparietal diameter (cBPD), bone biparietal diameter (bBPD), interhemispheric distance (IHD), transverse cerebellar diameter (tCD)) at term-equivalent age. FFM Z-Score significantly correlated with higher cBPD Z-Score (rs = 0.69; p < 0.001), bBPD Z-Score (rs = 0.48; p < 0.001) and tCD Z-Score (rs = 0.30; p = 0.002); FM Z-Score significantly correlated with lower brain size (cBPD Z-Score (rs = −0.32; p < 0.001) and bBPD Z-Score (rs = −0.42; p < 0.001). In contrast weight (rs = 0.08), length (rs = −0.01) and head circumference Z-Score (rs = 0.14) did not. Linear regression model adjusted for important neonatal variables revealed that FFM Z-Score was independently and significantly associated with higher cBPD Z-Score (median 0.50, 95% CI: 0.59, 0.43; p < 0.001) and bBPD Z-Score (median 0.31, 95% CI: 0.42, 0.19; p < 0.001); FM Z-Score was independently and significantly associated with lower cBPD Z-Score (median −0.27, 95% CI: −0.42, −0.11; p < 0.001) and bBPD Z-Score (median −0.32, 95% CI: −0.45, −0.18; p < 0.001). Higher FFM Z-Score and lower FM Z-scores were significantly associated with larger brain size at term-equivalent age. These results indicate that early body composition might be a useful tool to evaluate and eventually optimize brain growth and neurodevelopment.

Relationship between the Quantitative Indicators of Cranial MRI and the Early Neurodevelopment of Preterm Infants.

Aim To explore the relationship between the quantitative indicators (biparietal width, interhemispheric distance) of the cranial MRI for preterm infants at 37 weeks of postmenstrual age (PMA) and neurodevelopment at 6 months of corrected age. Methods A total of 113 preterm infants (gestational age < 37 weeks) delivered in the Obstetrics Department of the First People's Hospital of Lianyungang from September 2018 to February 2020 and directly transferred to the Neonatology Department for treatment were enrolled in this study. Based on their development quotient (DQ), the patients were divided into the normal (DQ ≥ 85, n = 76) group and the abnormal (DQ < 85, n = 37) group. Routine cranial MRI (cMRI) was performed at 37 weeks of PMA to measure the biparietal width (BPW) and interhemispheric distance (IHD). At the corrected age of 6 months, Development Screening Test (for children under six) was used to assess the participants' neurodevelopment. Results Univariate analysis showed statistically significant differences in BPW, IHD, and the incidence of bronchopulmonary dysplasia between the normal and the abnormal groups (P < 0.05), while no statistically significant differences were found in maternal complications and other clinical conditions between the two groups (P > 0.05). Binary logistic regression analysis demonstrated statistically significant differences in IHD and BPW between the normal and the abnormal groups (95% CI: 1.629-12.651 and 0.570-0.805, respectively; P = 0.004 and P < 0.001, respectively), while no significant differences were found in the incidence of bronchopulmonary dysplasia between the two groups (95% CI: 0.669-77.227, P = 0.104). Receiver operating characteristic curve revealed that the area under the curve of BPW, IHD, and the joint predictor (BPW + IHD) were 0.867, 0.805, and 0.881, respectively (95% CI: 0.800-0.933, 0.710-0.900, and 0.819-0.943, respectively; all P values < 0.001). Conclusion BPW and IHD, the two quantitative indicators acquired by cMRI, could predict the neurodevelopmental outcome of preterm infants at the corrected age of 6 months. The combination of the two indicators showed an even higher predictive value.

Value of amplitude-integrated electroencephalogram combined with quantitative indices of cranial magnetic resonance imaging in predicting short-term neurodevelopment in moderately and late preterm infants: a prospective study.

To study the association of amplitude-integrated electroencephalogram (aEEG) and the quantitative indices biparietal width (BPW) and interhemispheric distance (IHD) of cranial magnetic resonance imaging (cMRI) with short-term neurodevelopment in moderately and late preterm infants. A total of 104 moderately and late preterm infants who were admitted to the neonatal intensive care unit from September 2018 to April 2020 were selected as the subjects for this prospective study. The Naqeeb method and sleep-wake cycling (SWC) were used for aEEG assessment within 72 hours after birth. cMRI was performed at the corrected gestational age of 37 weeks. BPW and IHD were measured at the T2 coronal position. At the corrected age of 6 months, the Developmental Screening Test for Child Under Six (DST) was used to follow up neurodevelopment. According to developmental quotient (DQ), the infants were divided into a normal DST group (78 infants with DQ≥85) and an abnormal DST group (26 infants with DQ<85). Related indices were compared between the two groups. The association between aEEG and cMRI was evaluated. Compared with the normal DST group, the abnormal DST group had significantly lower aEEG normal rate and SWC maturation rate (P<0.05), as well as a significantly larger IHD and a significantly smaller BPW (P<0.05). Immature SWC, aEEG abnormality, and a relatively large IHD were the risk factors for abnormal DST (P<0.05), and a relatively large BPW was a protective factor against abnormal DST (P<0.05). For moderately and late preterm infants, aEEG within 72 hours after birth and the quantitative indices BPW and IHD of cMRI at the corrected gestational age of 37 weeks may affect their neurodevelopmental outcome at the corrected age of 6 months.

Automating Quantitative Measures of an Established Conventional MRI Scoring System for Preterm-Born Infants Scanned between 29 and 47 Weeks' Postmenstrual Age.

Conventional MR imaging scoring is a valuable tool for risk stratification and prognostication of outcomes, but manual scoring is time-consuming, operator-dependent, and requires high-level expertise. This study aimed to automate the regional measurements of an established brain MR imaging scoring system for preterm neonates scanned between 29 and 47 weeks' postmenstrual age. This study used T2WI from the longitudinal Prediction of PREterm Motor Outcomes cohort study and the developing Human Connectome Project. Measures of biparietal width, interhemispheric distance, callosal thickness, transcerebellar diameter, lateral ventricular diameter, and deep gray matter area were extracted manually (Prediction of PREterm Motor Outcomes study only) and automatically. Scans with poor quality, failure of automated analysis, or severe pathology were excluded. Agreement, reliability, and associations between manual and automated measures were assessed and compared against statistics for manual measures. Associations between measures with postmenstrual age, gestational age at birth, and birth weight were examined (Pearson correlation) in both cohorts. A total of 652 MRIs (86%) were suitable for analysis. Automated measures showed good-to-excellent agreement and good reliability with manual measures, except for interhemispheric distance at early MR imaging (scanned between 29 and 35 weeks, postmenstrual age; in line with poor manual reliability) and callosal thickness measures. All measures were positively associated with postmenstrual age (r = 0.11-0.94; R2 = 0.01-0.89). Negative and positive associations were found with gestational age at birth (r = -0.26-0.71; R2 = 0.05-0.52) and birth weight (r = -0.25-0.75; R2 = 0.06-0.56). Automated measures were successfully extracted for 80%-99% of suitable scans. Measures of brain injury and impaired brain growth can be automatically extracted from neonatal MR imaging, which could assist with clinical reporting.

Unsubstantiated belief in the diagnostic accuracy of the triad of abusive head trauma may lead to incorrect diagnoses of alleged abuse cases.

Unsubstantiated belief in the diagnostic accuracy of the triad of abusive head trauma may lead to incorrect diagnoses of alleged abuse cases.

Supratentorial Brain Metrics Predict Neurodevelopmental Outcome in Very Preterm Infants without Brain Injury at Age 2 Years

Introduction: Very preterm infants are at risk for adverse neurodevelopmental outcome. To better identify children without brain injury at risk for developmental sequelae, we assessed predictive values of supratentorial brain metrics in relation to outcome. Methods: Very preterm infants underwent magnetic resonance imaging (MRI) at term-equivalent age. Infants with any grade of supra- or infratentorial brain injury according to Kidokoro et al. [Pediatrics 2014;134:e444–53] were excluded. Supratentorial brain metrics (biparietal width, extracerebral space, interhemispheric distance) were measured and categorised using existing cut-off values. The Psychomotor Developmental Index (PDI) and Mental Developmental Index (MDI) were assessed using the Bayley Scales of Infant Development, second and third edition, at 2 years of age. Developmental delay was defined as a score <85. Positive and negative predictive values for developmental delay were calculated. Results: A total of 237 very preterm infants were enrolled. Of all infants, 59 (21.2%) showed developmental delay. Infants with z-scores less than –0.5 for biparietal width had significantly lower PDI (p = 0.039) and MDI (p = 0.042) than infants with normal z-scores. Enlargement of extracerebral spaces was also related to lower PDI (p = 0.047) and MDI (p = 0.036). Negative predictive value was highest when all brain metrics were within the normal range (PDI <85: 96.6%, MDI <85: 90.0%). Combining the biparietal width and the interhemispheric distance showed highest positive predictive values for developmental delay (MDI or PDI <85: 58.3%). Discussion: Supratentorial brain metrics are predictive for neurodevelopmental outcome in infants with ostensibly normal MRI. A combination of supratentorial brain metrics is most meaningful for identifying infants at risk for long-term sequelae.

Are Simple Magnetic Resonance Imaging Biomarkers Predictive of Neurodevelopmental Outcome at Two Years in Very Preterm Infants?

Background: Preterm infants are at increased risk of neurodevelopmental impairment due to the vulnerability of the immature brain. Early risk stratification is necessary for predicting outcome in the period of highest neuroplasticity. Several biomarkers in magnetic resonance imaging (MRI) at term equivalent age (TEA) have therefore been suggested. Objective: To assess the predictive value of simple brain metrics and the total abnormality score (TAS) – a modified score for brain injury and growth – in relation to neurodevelopmental outcome of very preterm infants in MRI at TEA. Methods: Single-centre cohort study including preterm infants with gestational age (GA) ≤32 weeks and birth weight ≤1,500 g. Biparietal width (BPW), interhemispheric distance, transcerebellar diameter (TCD) and TAS were assessed. To detect subtle haemorrhages, additional susceptibility-weighted imaging (SWI) was used in addition to conventional MRI to evaluate its clinical relevance. Neurodevelopment was tested by the Mental and Psychomotor Developmental Index (MDI/PDI) of the Bayley Scales of Infant Development II at a corrected age of 24 months. Results: One hundred twenty-nine children with median GA of 28.1 weeks and median birth weight of 980 g were included. BPW significantly correlated with PDI (p= 0.01, R² = 0.06) and TCD with MDI (p < 0.01, R² = 0.05) and PDI (p < 0.01, R² = 0.06) but explained variances were low. TAS was not predictive of neurodevelopmental outcome. By using SWI, additional 4 cases of low grade haemorrhages were identified compared to conventional sequences. In one case this additional information was clinically relevant (MDI/PDI below average). Conclusion: Simple brain metrics and TAS did not reliably predict neurodevelopmental outcome in a cohort with low prevalence of high grade brain injury. The additional value of SWI is yet to be determined in larger cohorts. The combination of imaging and functional biomarkers may be advisable for the prediction of neurodevelopmental outcome.

Relationship between brain function (aEEG) and brain structure (MRI) and their predictive value for neurodevelopmental outcome of preterm infants

To improve the prediction of neurodevelopmental outcome in very preterm infants, this study used the combination of amplitude-integrated electroencephalography (aEEG) within the first 72 h of life and cranial magnetic resonance imaging (MRI) at term equivalent age. A single-center cohort of 38 infants born before 32 weeks of gestation was subjected to both investigations. Structural measurements were performed on MRI. Multiple regression analysis was used to identify independent factors including functional and structural brain measurements associated with outcome at a corrected age of 24 months. aEEG parameters significantly correlated with MRI measurements. Reduced deep gray matter volume was associated with low Burdjalov Score on day 3 (p < 0.0001) and day 1–3 (p = 0.0012). The biparietal width and the transcerebellar diameter were related to Burdjalov Score on day 1 (p = 0.0111; p = 0.0002). The final multiple regression analysis revealed independent predictors of neurodevelopmental outcome: intraventricular hemorrhage (p = 0.0060) and interhemispheric distance (p = 0.0052) for mental developmental index; Burdjalov Score day 1 (p = 0.0201) and interhemispheric distance (p = 0.0142) for psychomotor developmental index.Conclusion: Functional aEEG parameters were associated with altered brain maturation on MRI. The combination of aEEG and MRI contributes to the prediction of outcome at 24 months.What is Known:• Prematurity remains a risk factor for impaired neurodevelopment.• aEEG is used to measure brain activity in preterm infants and cranial MRI is performed to identify structural gray and white matter abnormalities with impact on neurodevelopmental outcome.What is New:• aEEG parameters observed within the first 72 h of life were associated with altered deep gray matter volumes, biparietal width, and transcerebellar diameter at term equivalent age.• The combination of aEEG and MRI contributes to the prediction of neurodevelopmental outcome at 2 years of corrected age in very preterm infants.

Region-specific growth restriction of brain following preterm birth.

Regional brain sizes of very-preterm infants at term-equivalent age differ from those of term-born peers, which have been linked with later cognitive impairments. However, dependence of regional brain volume loss on gestational age has not been studied in detail. To investigate the spatial pattern of brain growth in neonates without destructive brain lesions, head MRI of 189 neonates with a wide range of gestational age (24–42 weeks gestation) was assessed using simple metrics measurements. Dependence of MRI findings on gestational age at birth (Agebirth) and the corrected age at MRI scan (AgeMRI) were assessed. The head circumference was positively correlated with AgeMRI, but not Agebirth. The bi-parietal width, deep grey matter area and the trans-cerebellar diameter were positively correlated with both Agebirth and AgeMRI. The callosal thickness (positive), atrial width of lateral ventricle (negative) and the inter-hemispheric distance (negative) were exclusively correlated with Agebirth. The callosal thickness and cerebral/cerebellar transverse diameters showed predominant dependence on Agebirth over AgeMRI, suggesting that brain growth after preterm-birth was considerably restricted or even became negligible compared with that in utero. Such growth restriction after preterm birth may extensively affect relatively more matured infants, considering the linear relationships observed between brain sizes and Agebirth.

Early general movements and brain magnetic resonance imaging at term-equivalent age in infants born < 30 weeks' gestation

BackgroundNeurodevelopmental assessments and brain magnetic resonance imaging (MRI) at term-equivalent age (TEA) predict developmental outcomes in preterm infants. However, the relationship between neurodevelopment prior to term and cerebral structure is currently unknown. AimsTo examine the relationships between General Movements (GMs) assessed from birth to TEA and brain MRI at TEA in infants born <30weeks' gestation. Study designProspective cohort study. GMs (categorised as ‘normal’ or ‘abnormal’) were recorded weekly from birth to 32weeks, and at 34 and 36weeks' postmenstrual age. At TEA, GMs were assessed concurrently with brain MRI (using a validated scoring system). Subjects149 infants born <30weeks' gestation were recruited from a tertiary hospital. Results103 infants had MRI at TEA and GMs recorded. Abnormal GMs prior to term were associated with cortical grey matter abnormality (p<0.03), deep grey matter abnormality (p=0.02) and increased interhemispheric distance (p<0.02). Abnormal GMs at TEA (n=55/90) were associated with more global brain abnormality (p<0.01) and cortical grey matter abnormality (p=0.01), and decreased transcerebellar diameter (p=0.04) on concurrent brain MRI. ConclusionsAbnormal GMs both prior to term and at TEA were associated with more marked brain abnormality, and smaller brains at TEA. Abnormal GMs are an early marker of brain abnormalities in very preterm infants.

Regional Brain Biometrics at Term-Equivalent Age and Developmental Outcome in Extremely Low-Birth-Weight Infants.

This study aims to evaluate individual regional brain biometrics and their association with developmental outcome in extremely low-birth-weight (ELBW) infants. This is a retrospective study evaluating term-equivalent magnetic resonance imaging (TE-MRI) from 27 ELBW infants with known developmental outcomes beyond 12 months corrected age. Regional biometric measurements were performed by a pediatric neuroradiologist blinded to outcome data. Measures included biparietal width, transcerebellar diameter (TCD), deep gray matter area (DGMA), ventricular dilatation, corpus callosum, and interhemispheric distance. The relationship between regional biometrics and Bayley-II developmental scores were evaluated with linear regression models. The study cohort had an average±standard deviation birth weight of 684±150 g, gestational age of 24.6±2 weeks and 48% males. DGMA was significantly associated with both cognitive and motor outcomes. Significant associations were also observed between TCD and corpus callosum splenium with cognitive and motor outcomes, respectively. Other biometric measures were not associated with outcome (p>0.05). DGMA<10.26 cm2 was highly specific for poor motor and cognitive outcome. TE-MRI biometrics reflecting impaired deep gray matter, callosal, and cerebellar size is associated with worse early childhood cognitive and motor outcomes. DGMA may be the most robust single biometric measure to predict adverse developmental outcome in preterm survivors.

Brain injury and altered brain growth in preterm infants: predictors and prognosis.

To define the nature and frequency of brain injury and brain growth impairment in very preterm (VPT) infants by using MRI at term-equivalent age and to relate these findings to perinatal risk factors and 2-year neurodevelopmental outcomes. MRI scans at term-equivalent age from 3 VPT cohorts (n = 325) were reviewed. The severity of brain injury, including periventricular leukomalacia and intraventricular and cerebellar hemorrhage, was graded. Brain growth was assessed by using measures of biparietal width (BPW) and interhemispheric distance. Neurodevelopmental outcome at age 2 years was assessed across all cohorts (n = 297) by using the Bayley Scales of Infant Development, Second Edition (BSID-II) or Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III), and evaluation for cerebral palsy. Of 325 infants, 107 (33%) had some grade of brain injury and 33 (10%) had severe injury. Severe brain injury was more common in infants with lower Apgar scores, necrotizing enterocolitis, inotropic support, and patent ductus arteriosus. Severe brain injury was associated with delayed cognitive and motor development and cerebral palsy. Decreased BPW was related to lower gestational age, inotropic support, patent ductus arteriosus, necrotizing enterocolitis, prolonged parenteral nutrition, and oxygen at 36 weeks and was associated with delayed cognitive development. In contrast, increased interhemispheric distance was related to male gender, dexamethasone use, and severe brain injury. It was also associated with reduced cognitive development, independent of BPW. At term-equivalent age, VPT infants showed both brain injury and impaired brain growth on MRI. Severe brain injury and impaired brain growth patterns were independently associated with perinatal risk factors and delayed cognitive development.

Measurements using 7.0 T post-mortem magnetic resonance imaging of the scalar dimensions of the fetal brain between 12 and 20 weeks gestational age

In this study, scalar values for the fetal brain from 12 to 20 weeks gestational age were obtained. Fifty-two fetal specimens of 12–20 weeks gestational age with an anatomically normal and developmentally appropriate central nervous system (CNS) were scanned using a 7.0 T magnetic resonance imaging (MRI) scanner. The linear biometric measurements of the brain were then determined. All the measurements (except for the interhemispheric distance) were found to increase linearly with gestational age, although each increased at a different growth rates. The 95% confidence interval for each value was obtained. These data may be considered to be a valuable reference for the assessment of normal fetal brain development in clinical settings and as a supplement to post-mortem MRI or anatomical investigations.

Reduced cerebellar diameter in very preterm infants with abnormal general movements

Background Abnormal General Movements (GMs) early in life are predictive of later neuromotor deficits and are related to white matter abnormalities on magnetic resonance imaging (MRI). However, other structural correlates of abnormal GMs have not been defined. Aims The objective of this study was to explore brain-metrics (linear brain measurements on MRI representative of 3-D brain volumes) at term as a predictor of abnormal GMs at 1 and 3 months' corrected age in preterm infants. It was hypothesized that abnormal GMs would be related to reduced brain-metrics in primary motor areas, namely the cerebellum and parietal lobes. Study design Eighty three preterm infants (< 30 weeks' gestational age) were scanned at term-equivalent age. MRI was assessed for white matter abnormality and brain-metrics in six predefined brain regions (i.e. bifrontal, biparietal, lateral ventricles and transverse cerebellar diameters, and inter-hemispheric distance). Outcome measures At 1 and 3 months' corrected age infants' GMs were assessed from video-taped footage and rated as normal or abnormal using standardized methodology. Results At 1 month, 63% ( n = 52) of infants had abnormal GMs with no association between any of the brain-metrics and abnormal GMs. At 3 months, 23% ( n = 18) of infants had abnormal GMs (absent fidgety movements n = 18; abnormal fidgety movements n = 0). Reduced bifrontal, biparietal, and cerebellar transverse diameters, along with an increase in lateral ventricle sizes were associated with an increased risk of abnormal GMs at 3 months' corrected age. After controlling for white matter abnormality and grade III/IV intraventricular haemorrhage, only the cerebellar transverse diameter was predictive of abnormal GMs at 3 months. Conclusions Reduced cerebellar diameter at term equivalent age is related to abnormal GMs at 3 months' corrected age, independent of white matter abnormality and intraventricular haemorrhage.

Magnetic resonance imaging examination of the fetal brain

Magnetic resonance imaging examination of the fetal brain

One hundred million years of interhemispheric communication: the history of the corpus callosum.

Analysis of regional corpus callosum fiber composition reveals that callosal regions connecting primary and secondary sensory areas tend to have higher proportions of coarse-diameter, highly myelinated fibers than callosal regions connecting so-called higher-order areas. This suggests that in primary/secondary sensory areas there are strong timing constraints for interhemispheric communication, which may be related to the process of midline fusion of the two sensory hemifields across the hemispheres. We postulate that the evolutionary origin of the corpus callosum in placental mammals is related to the mechanism of midline fusion in the sensory cortices, which only in mammals receive a topographically organized representation of the sensory surfaces. The early corpus callosum may have also served as a substrate for growth of fibers connecting higher-order areas, which possibly participated in the propagation of neuronal ensembles of synchronized activity between the hemispheres. However, as brains became much larger, the increasingly longer interhemispheric distance may have worked as a constraint for efficient callosal transmission. Callosal fiber composition tends to be quite uniform across species with different brain sizes, suggesting that the delay in callosal transmission is longer in bigger brains. There is only a small subset of large-diameter callosal fibers whose size increases with increasing interhemispheric distance. These limitations in interhemispheric connectivity may have favored the development of brain lateralization in some species like humans.