Changes in Brain Water Diffusion during the 1st Year of Life

Forbes, Kirsten; Pipe, James G.; Bird, C R

doi:10.1148/radiol.2222010179

Cited by 70 publications

(47 citation statements)

References 8 publications

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“…The first of these findings was that ADC and FA change at a faster rate in the first 3 months after birth at term gestation than in the rest of the year. This observation is qualitatively similar to previous findings [2,25,28,33] of an exponential decline in ADC in several peripheral WM and deep WM (and gray matter) structures, the period of greatest change occurring before the end of the first month after birth at term gestation. Our ADC (and FA) data were best fit with broken-line linear regression models with a breakpoint at 100 days, indicating that the period of rapid change in ADC and FA continues beyond the first month of life.…”

Section: Changes In Cerebral Wm Early In the First Year Of Lifesupporting

confidence: 91%

“…Both types of WM had a slowed but steady progression in maturation toward adult values throughout the rest of the first year. These findings are generally consistent with those of previous reports of ADC and FA data on infants in the first year of life [2,25,28,33,35]. However, methodologic differences and variation in the size, shape, and precise placement of ROIs make it difficult to compare ADC and FA for infants of any age and their rates of change throughout early infancy.…”

Section: Changes In Cerebral Wm Later In the First Year Of Lifesupporting

confidence: 89%

“…Results of a study by Forbes et al [25] also suggested a difference between the rate of decrease in ADC in peripheral WM and the rate in deep WM in the first few months of life, although the rates of ADC change were not quantified. In that study, graphs indicated that the greatest rate of decline in ADC was in peripheral (anterior and posterior subcortical) WM, with less-rapid change occurring in deep WM (anterior and posterior limbs of internal capsule).…”

Section: Changes In Cerebral Wm Early In the First Year Of Lifementioning

confidence: 98%

“…Deep WM structures had already achieved approximately one half of the mean adult ADC and FA at this age, and peripheral WM remained barely discernible at the thresholds of detection (Table 1). ADC and FA are thought to reflect a number of WM features, including degree of myelination and volume of the extracellular compartment, amount of extracellular water, changes in composition of the extracellular matrix, density and organization of axons in WM structures, maturation of neurofilaments and other constituents of the axonal cytoskeleton, and maturation of voltage-gated conductances along axonal membranes [9,[25][26][27][28]. At term, the deep structures we studied (portions of the corpus callosum and internal capsule) are still immature with respect to each of these cytologic and histologic features of WM [5].…”

Section: Status Of Cerebral Wm At Termmentioning

confidence: 99%

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Diffusion Tensor Imaging Assessment of Brain White Matter Maturation During the First Postnatal Year

Provenzale

Liang²,

DeLong³

et al. 2007

American Journal of Roentgenology

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OBJECTIVE. The purpose of this study was to use diffusion-weighted and diffusion tensor imaging to investigate the status of cerebral white matter (WM) at term gestation and the rate of WM maturation throughout the first year of life in healthy infants.MATERIALS AND METHODS. Fifty-three children (35 boys) ranging in age from 1.5 weeks premature to 51.5 weeks (mean age, 22.9 weeks) underwent conventional MRI, diffusion imaging in three directions (b = 1,000 s/mm 2 ), and diffusion tensor imaging with gradient encoding in six directions, all on a 1.5-T MRI system. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in three deep WM structures (posterior limb of internal capsule, genu, and splenium of corpus callosum) and two peripheral WM regions (associational WM underlying prefrontal and posterior parietal cortex) with a standard region of interest (44 ± 4 cm 2 ). ADC and FA were expressed as a percentage of corresponding values measured in a group of healthy young adults. Mean ADC and FA values for deep and peripheral WM were plotted against gestational age normalized to term. The data were fit best with a broken-line linear regression model with a breakpoint at 100 days. ADC and FA values at term were estimated according to the intercept of the initial linear period (before day 100) with day 0. The slope of the linear fits was used to determine the rate of WM maturation in both the early and the late (after day 100) periods. Multivariate analysis of variance tests were used to compare deep and peripheral WM structures at term and at representative early and late ages (days 30 and 200) and to compare rates of ADC and FA maturation in early and late periods within the first year.RESULTS. At term, peripheral WM was less mature than deep WM according to results of extrapolation of ADC and FA values in the first 100 days of life to day 0 (p < 0.01). Mean ADC and FA value (percentage of mean adult value) for peripheral WM were 1.32 × 10 −3 mm 2 /s (163%) and 0.16 (32%), respectively, and 1.09 × 10 −3 mm 2 /s (143%) and 0.36 (54%), respectively, for deep WM. On day 30 and day 200, estimated mean ADC and FA continued to show greater diffusion (higher ADC) and less anisotropy (lower FA value) in peripheral WM (p < 0.01). During the first year of postnatal life, both ADC and FA matured at higher rates before postnatal day 100 compared with a later time. Differences were observed in rates of maturation in the first 100 days when rates of decrease in ADC and increase in FA were compared between peripheral WM and deep WM; however, the maturational trends differed whether ADC or FA was examined. The early rate of ADC decrease (maturation) was twice as great for peripheral WM than for deep WM (p < 0.01) unexpectedly, but the opposite pattern was observed for FA. The early rate of FA increase (maturation) was approximately one half as great for peripheral WM as for deep WM (p = 0.01). Throughout the rest of the first year, no differences were observed in the rates of change in either index betwee...

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Section: Changes In Cerebral Wm Early In the First Year Of Lifesupporting

confidence: 91%

Section: Changes In Cerebral Wm Later In the First Year Of Lifesupporting

confidence: 89%

Section: Changes In Cerebral Wm Early In the First Year Of Lifementioning

confidence: 98%

Section: Status Of Cerebral Wm At Termmentioning

confidence: 99%

See 2 more Smart Citations

Diffusion Tensor Imaging Assessment of Brain White Matter Maturation During the First Postnatal Year

Provenzale

Liang²,

DeLong³

et al. 2007

American Journal of Roentgenology

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“…Gestational age at MR imaging plays an important role in the changes of diffusion indices, 44 especially in the first year of life. 45 In our study, there was no significant difference in the gestational age at MR imaging between groups; however, the gestational age at MR imaging was considered as a covariate when we performed the comparisons.…”

Section: Discussionmentioning

confidence: 72%

White Matter Abnormalities Are Related to Microstructural Changes in Preterm Neonates at Term-Equivalent Age: A Diffusion Tensor Imaging and Probabilistic Tractography Study

Liu¹,

Aeby²,

Balériaux³

et al. 2012

AJNR Am J Neuroradiol

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Deletion of Ac‐NMePhe¹ from [NMePhe¹]arodyn under acidic conditions, part 2: Effects of cleavage conditions and N‐terminal functionality

2011

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Peptides containing N-methylamino acids can exhibit improved pharmacodynamic and pharmacokinetic profiles compared to nonmethylated peptides, and therefore interest in these N-methylated peptides has been increasing in recent years. Arodyn (Ac[Phe1,2,3,Arg4,D-Ala8]Dyn A(1–11)-NH2) is an acetylated dynorphin A (Dyn A) analog that is a potent and selective κ opioid receptor antagonist (Bennett et al. J. Med. Chem. 2002, 45, 5617), and its analog [NMePhe1]arodyn shows even higher affinity and selectivity for κ opioid receptors (Bennett et al., J. Pep. Res. 2005, 65, 322). During the synthesis of [NMePhe1]arodyn analogs, the arodyn (2–11) derivatives were obtained as major products. Analysis indicated that Ac-NMePhe was lost from the completed peptide sequence during acidic cleavage of the peptides from the resin and that the acetyl group played an important role in this side reaction. Different cleavage conditions were evaluated to minimize this side reaction and maximize the yield of pure [NMePhe1]arodyn analogs. Modifications to the N-terminus of the peptides to prevent the side reaction were also explored. The incorporation of a heteroatom-containing group such as methoxycarbonyl as the N-terminal functionality prevented this side reaction, while the incorporation of a bulky acyl group could not. Substituting NMePhe with the conformationally constrained analog Tic (1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) also prevented the side reaction.

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Changes in Brain Water Diffusion during the 1st Year of Life

Abstract: Results suggest that in neonates and infants, water diffusion is highly dependent on both subject age and brain location.

Cited by 70 publications

References 8 publications

Diffusion Tensor Imaging Assessment of Brain White Matter Maturation During the First Postnatal Year

Diffusion Tensor Imaging Assessment of Brain White Matter Maturation During the First Postnatal Year

White Matter Abnormalities Are Related to Microstructural Changes in Preterm Neonates at Term-Equivalent Age: A Diffusion Tensor Imaging and Probabilistic Tractography Study

Deletion of Ac‐NMePhe¹ from [NMePhe¹]arodyn under acidic conditions, part 2: Effects of cleavage conditions and N‐terminal functionality

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Changes in Brain Water Diffusion during the 1st Year of Life

Abstract: Results suggest that in neonates and infants, water diffusion is highly dependent on both subject age and brain location.

Cited by 70 publications

References 8 publications

Diffusion Tensor Imaging Assessment of Brain White Matter Maturation During the First Postnatal Year

Diffusion Tensor Imaging Assessment of Brain White Matter Maturation During the First Postnatal Year

White Matter Abnormalities Are Related to Microstructural Changes in Preterm Neonates at Term-Equivalent Age: A Diffusion Tensor Imaging and Probabilistic Tractography Study

Deletion of Ac‐NMePhe1 from [NMePhe1]arodyn under acidic conditions, part 2: Effects of cleavage conditions and N‐terminal functionality

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Deletion of Ac‐NMePhe¹ from [NMePhe¹]arodyn under acidic conditions, part 2: Effects of cleavage conditions and N‐terminal functionality