Dataset Information

White matter microstructural differences identified using multi-shell diffusion imaging in six-year-old children born very preterm.

ABSTRACT:

Introduction

The underlying microstructural properties of white matter differences in children born very preterm (<32?weeks gestational age) can be investigated in depth using multi-shell diffusion imaging. The present study compared white matter across the whole brain using diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) metrics in children born very preterm and full-term children at six years of age. We also investigated associations between white matter microstructure with early brain injury and developmental outcomes.

Method

Multi-shell diffusion imaging, T1-weighted anatomical MR images and developmental assessments were acquired in 23 children born very preterm (16 males; mean scan age: 6.57?±?0.34?years) and 24 full-term controls (10 males, mean scan age: 6.62?±?0.37?years). DTI metrics were obtained and neurite orientation dispersion index (ODI) and density index (NDI) were estimated using the NODDI diffusion model. FSL's tract-based spatial statistics were performed on traditional DTI metrics and NODDI metrics. Voxel-wise comparisons were performed to test between-group differences and within-group associations with developmental outcomes (intelligence and visual motor abilities) as well as early white matter injury and germinal matrix/intraventricular haemorrhage (GMH/IVH).

Results

In comparison to term-born children, the children born very preterm exhibited lower fractional anisotropy (FA) across many white matter regions as well as higher mean diffusivity (MD), radial diffusivity (RD), and ODI. Within-group analyses of the children born very preterm revealed associations between higher FA and NDI with higher IQ and VMI. Lower ODI was found within the corona radiata in those with a history of white matter injury. Within the full-term group, associations were found between higher NDI and ODI with lower IQ.

Conclusion

Children born very preterm exhibit lower FA and higher ODI than full-term children. NODDI metrics provide more biologically specific information beyond DTI metrics as well as additional information of the impact of prematurity and white matter microstructure on cognitive outcomes at six years of age.

SUBMITTER: Young JM

PROVIDER: S-EPMC6737393 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Publications

White matter microstructural differences identified using multi-shell diffusion imaging in six-year-old children born very preterm.

Young Julia M JM Vandewouw Marlee M MM Mossad Sarah I SI Morgan Benjamin R BR Lee Wayne W Smith Mary Lou ML Sled John G JG Taylor Margot J MJ

NeuroImage. Clinical 20190504

<h4>Introduction</h4>The underlying microstructural properties of white matter differences in children born very preterm (<32 weeks gestational age) can be investigated in depth using multi-shell diffusion imaging. The present study compared white matter across the whole brain using diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) metrics in children born very preterm and full-term children at six years of age. We also investigated associations betwee ...[more]

PMID: 31103872

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Project description:Very preterm birth is associated with altered white matter microstructure and language difficulties, which may compromise communication, social function and academic achievement, but the relationship between these two factors is unclear. The aim of this study was to explore associations between white matter microstructure and language domains of semantics, grammar and phonological awareness at 7-years of age on a whole-brain level and within the arcuate fasciculus, an important language pathway, in very preterm and term-born children. Language was assessed in 145 very preterm-born (<30?weeks' gestation and/or <1250?g birth weight) and 33 term-born children aged 7?years. Fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), axon orientation dispersion and axon density were estimated from diffusion magnetic resonance images also obtained at 7?years. The correlation between diffusion values and language was assessed using Tract-Based Spatial Statistics (TBSS). The arcuate fasciculus was delineated using constrained spherical deconvolution tractography and diffusion parameters from this tract were related to language measures using linear regression. While there was evidence for widespread associations between white matter microstructure and language, there was little evidence of differences in these associations between very preterm and term-born groups. TBSS analyses revealed that higher FA and lower AD, RD, and MD in major fibre tracts, including those subserving language, were associated with better semantic, grammar and phonological awareness performance. Higher axon density in widespread fibre tracts was also associated with better semantic performance. The tractography analyses of the arcuate fasciculus showed some evidence for associations between white matter microstructure and language outcomes. White matter microstructural organisation in widespread fibre tracts, including language-relevant pathways, was associated with language performance in whole-brain and tract-based analyses. The associations were similar for very preterm and term-born groups, despite very preterm children performing more poorly across language domains.

Project description:Purpose Language difficulties are prevalent among children born preterm. Existing studies have largely used standardized language tests, providing limited scope for detailed descriptive examination of preterm language. This study aimed to examine differences in conversational language between children born < 30 weeks and at term as well as correlations between language sample analysis (LSA) and a standardized language tool. Method Two hundred four 3-year-olds (103 born < 30 weeks, 101 born at term) recruited at birth provided a 10-min language sample and completed the Preschool Language Scales-Fifth Edition (I. Zimmerman, Steiner, & Pond, 2011). LSA was conducted using the Systematic Analysis of Language Transcripts and Index of Productive Syntax. Group differences were analyzed using linear regression, and Pearson correlation coefficient (coef) was used to determine correlations between measures. Results Children born < 30 weeks scored lower than term-born peers on multiple metrics when controlled for confounding factors (sex, high social risk, multilingualism, and diagnosed neurodevelopmental disorders), including mean length of utterance in morphemes (coef = -0.28, 95% confidence interval [CI] [-0.56, 0.01]) and words (coef = -0.29, 95% CI [-0.53, -0.05]), number of different word roots (coef = -10.04, 95% CI [-17.93, -2.14]), and Index of Productive Syntax sentence structures (coef = -1.81, 95% CI [-3.10, -0.52]). Other variables (e.g., number of utterances, number of nouns and adjectives) were not significantly different between groups. LSA and the Preschool Language Scales-Fifth Edition were at most moderately correlated (≤ .45). Conclusions Three-year-old children born preterm demonstrated poorer conversational language than children born at term, with some specific areas of deficit emerging. Furthermore, formal assessment and LSA appear to provide relatively distinct and yet complementary data to guide diagnostic and intervention decisions. Supplemental Material https://doi.org/10.23641/asha.11368073.

Project description:Individuals born very preterm (VPT; <32?weeks' gestational age) are at increased risk of impaired mathematics and word reading performance, as well as widespread white matter microstructural alterations compared with individuals born full term (FT; ?37?weeks' gestational age). To date, the link between academic performance and white matter microstructure is not well understood. This study aimed to investigate the associations between mathematics and reading performance with white matter microstructure in 114 VPT and 36 FT 13-year-old children. Additionally, we aimed to investigate whether the association of mathematics and reading performance with white matter microstructure in VPT children varied as a function of impairment. To do this, we used diffusion tensor imaging and advanced diffusion modelling techniques (Neurite Orientation Dispersion and Density Imaging and the Spherical Mean Technique), combined with a whole-brain analysis approach (Tract-Based Spatial Statistics). Mathematics performance across VPT and FT groups was positively associated with white matter microstructural measurements of fractional anisotropy and neurite density, and negatively associated with radial and mean diffusivities in widespread, bilateral regions. Furthermore, VPT children with a mathematics impairment (>1 standard deviation below FT mean) had significantly reduced neurite density compared with VPT children without an impairment. Reading performance was not significantly associated with any of the white matter microstructure parameters. Additionally, the associations between white matter microstructure and mathematics and reading performance did not differ significantly between VPT and FT groups. Our findings suggest that alterations in white matter microstructure, and more specifically lower neurite density, are associated with poorer mathematics performance in 13-year-old VPT and FT children. More research is required to understand the association between reading performance and white matter microstructure in 13-year-old children.

Project description:Irreversible white matter (WM) damage, including severe demyelination and axonal loss, is a main determinant of long-term disability in multiple sclerosis (MS). Non-invasive detection of changes in microstructural WM integrity in the disease is challenging since commonly used imaging metrics lack the necessary sensitivity, especially in the early phase of the disease. This study aims at assessing microstructural WM abnormalities in early-stage MS by using ultra-high gradient strength multi-shell diffusion MRI and the restricted signal fraction (FR) from the Composite Hindered and Restricted Model of Diffusion (CHARMED), a metric sensitive to the volume fraction of axons. In 22 early MS subjects (disease duration ?5?years) and 15 age-matched healthy controls, restricted fraction estimates were obtained through the CHARMED model along with conventional Diffusion Tensor Imaging (DTI) metrics. All imaging parameters were compared cross-sectionally between the MS subjects and controls both in WM lesions and normal-appearing white matter (NAWM). We found a significant reduction in FR focally in WM lesions and widespread in the NAWM in MS patients relative to controls (corrected p?<?.05). Signal fraction changes in NAWM were not driven by perilesional tissue, nor were they influenced by proximity to the ventricles, challenging the hypothesis of an outside-in pathological process driven by CSF-mediated immune cytotoxic factors. No significant differences were found in conventional DTI parameters. In a cross-validated classification task, FR showed the largest effect size and outperformed all other diffusion imaging metrics in discerning lesions from contralateral NAWM. Taken together, our data provide evidence for the presence of widespread microstructural changes in the NAWM in early MS stages that are, at least in part, unrelated to focal demyelinating lesions. Interestingly, these pathological changes were not yet detectable by conventional diffusion imaging at this early disease stage, highlighting the sensitivity and value of multi-shell diffusion imaging for better characterizing axonal microstructure in MS.

Dataset Information

White matter microstructural differences identified using multi-shell diffusion imaging in six-year-old children born very preterm.

Introduction

Method

Results

Conclusion

Publications

White matter microstructural differences identified using multi-shell diffusion imaging in six-year-old children born very preterm.

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