engleski

Maturational changes of white matter segments in preterm children revealed by FA and ADC values

White matter (WM) lesions are the most important pathogenetic substrate of neurological abnormalities in prematurely born infants. WM organization into the white matter segments (WMS) is most precisely described by Constantin Von Monakow, where each segment contains different commissural, projection and association axonal patwhays. Exact location and extent of lesion is often difficult to detect by conventional magnetic resonance imaging (MRI), especially considering subtle lesions. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) are MRI diffusion parametars often used in assessment of WM abnormalities. The aim of this study was to evaluate whether diffusion parameters measured in each WMS can show maturational and eventually pathological changes in preterm children at term equivalent age (TEA) and at second year of life. Infants scanned TEA were divided in groups by birth time (22-28 postconceptional weeks-PCW, 28-32PCW, 33-36PCW + control group), and by presence or absence of visible lesions on MRI. Examinees scanned at 2nd year of life were also divided into the groups using the same criteria. Most important results show that: 1) there are significant differences in FA values between all WMS in both time points except segments III and IV at 2nd year ; 2) FA values show obvious decrease in radial direction (ventricles-> pia) ; 3) different groups divided by birth time significantly differ among each other considering FA values while those differences diminish or even dissapear in toddlers ; 4) ADC values are more sensitive to discern pathological/normotypic group compared to FA values. In conclusion, FA and ADC values expressed in relation to WMS give us insight in WM differentiation and can serve as additional criteria for both maturation level and topography of developmental lesion. In addition, we have demonstrated protracted WM maturation which seems to be one of the key features of human brain development.

white matter, FA, ADC, preterm brain, brain development

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