White matter microstructure of 6-year old children born preterm and full term

Abstract

AimWe previously observed a complex pattern of differences in white matter (WM) microstructure between preterm-born (PT) and full-term-born (FT) children and adolescents age 9–17 years. The aim of this study was to determine if the same differences exist as early as age 6 years.MethodWe obtained diffusion MRI (dMRI) scans in children born PT at age 6 years (n = 20; 11 males) and FT (n = 38; 14 males), using two scanning protocols: 30 diffusion directions (b = 1000 s/mm2) and 96 diffusion directions (b = 2500 s/mm2). We used deterministic tractography and analyzed fractional anisotropy (FA) along bilateral cerebral WM pathways that demonstrated differences in the older sample.ResultsCompared to the FT group, the PT group showed (1) significantly decreased FA in the uncinate fasciculi and forceps major and (2) significantly increased FA in the right anterior thalamic radiation, inferior fronto-occipital fasciculi, and inferior longitudinal fasciculi. This pattern of group differences resembles findings in the previous study of older PT and FT participants. Group differences were similar across dMRI acquisition protocols.InterpretationThe underlying neurobiology driving the pattern of PT-FT differences in FA is present as early as age 6 years. Generalization across dMRI acquisition protocols demonstrates the robustness of group differences in FA. Future studies will use quantitative neuroimaging techniques to understand the tissue properties that give rise to this consistent pattern of WM differences after PT birth.

Diffusion tensor imaging in frontostriatal tracts is associated with executive functioning in very preterm children at 9 years of age

“…The present study found higher fractional anisotropy and axial diffusivity values in two frontostriatal tracts bilaterally in VLGA children compared to term children. Supporting our findings, recent studies have also found higher fractional anisotropy values in certain white matter pathways among different age groups of individuals born preterm [26][27][28][29][30]. A meta-analysis, based on 13 studies and including participants from children to young adults born preterm, identified four regions of increased fractional anisotropy and 11 regions of decreased fractional anisotropy in preterm subjects compared to term controls [25].…”

White matter properties associated with pre‐reading skills in 6‐year‐old children born preterm and at term

“…One child in the term group was born at 36 weeks by parent report but was above our weight threshold (2780g). See Dodson et al for recruitment methods. Exclusion criteria for all participants included neurological factors unrelated to preterm birth that would account for white matter differences or potential reading disorders among participants, including congenital anomalies, active seizure disorder, hydrocephalus, or sensorineural hearing loss.…”

“…For each participant, we collected a high‐resolution T1‐weighted anatomical image using a 5‐minute inversion recovery‐prep three‐dimensional fast‐spoiled gradient sequence and a 30‐direction diffusion MRI with a b ‐value of 1000 seconds/mm 2 . Methods for imaging parameters, data preprocessing steps, analysis of motion, and individual native‐space tractography are described in several previous publications and are included in Appendix S1 . White matter pathways (AF‐L, SLF‐L, UF‐R) for analysis were selected a priori based on evidence for associations with pre‐reading skills in this sample of children born at term at 6 years of age …”

“…Among children and adolescents, studies have observed altered fractional anisotropy values in preterm versus term participants . Recently, in the current sample of 6‐year‐old children, we replicated a similar pattern of both increased and decreased fractional anisotropy in children born preterm versus at term that had been previously observed in a cohort of older children and adolescents …”

Neonatal white matter tract microstructure and 2-year language outcomes after preterm birth

“…The diffusion scan with the least motion was selected for analysis. Imaging parameters, data preprocessing steps, motion correction procedures, diffusion tensor estimation, and individual native space tractography are described in the Supplementary Material and previous publications (Dodson, Travis, Ben-Shachar, & Feldman, 2017;Travis, Adams, Kovachy, Ben-Shachar, & Feldman, 2017). We analyzed 2 diffusion tensor metrics: FA and MD.…”