Brain metabolite changes on in vivo proton magnetic resonance spectroscopy in children with congenital hypothyroidism.
ABSTRACT Localized in vivo proton magnetic resonance spectroscopy and imaging were performed in five children with untreated congenital hypothyroidism to look for biochemical markers of abnormal myelin and neuronal development. The patients had high levels of choline-containing compounds, which returned to normal with euthyroidism. These metabolic alterations may reflect blocks in myelin maturation that are reversible by thyroid hormone replacement throughout childhood.
SourceAvailable from: Isabelle RapinNeurology 11/2000; 55(10):1442-1449. DOI:10.1212/WNL.55.10.1442 · 8.30 Impact Factor
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ABSTRACT: Infants born at extreme prematurity are at a high risk of developmental disability. A major risk factor for disability is having a low level of thyroid hormone, described as hypothyroxinemia, which is recognized to be a frequent phenomenon in these infants. At present, there is uncertainty among clinicians regarding the most appropriate method of managing hypothyroxinemia of prematurity. The literature suggests that some, but not all, forms of thyroid supplementation may reduce the incidence of disability in infants born at extreme prematurity. There is a pressing need to confirm the benefit of treatment and to establish the optimal way to treat transient hypothyroxinemia in these infants.Expert Review of Endocrinology & Metabolism 01/2014; 3(4). DOI:10.1586/174466220.127.116.113
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ABSTRACT: In order to assess relationships between thyroid hormone status and findings on brain MRI, a subset of babies was recruited to a multi-centre randomised, placebo-controlled trial of levothyroxine (LT4) supplementation for babies born before 28 weeks' gestation (known as the TIPIT study, for Thyroxine supplementation In Preterm InfanTs). These infants were imaged at term-equivalence. Forty-five TIPIT participants had brain MRI using diffusion tensor imaging (DTI) to estimate white matter development by apparent diffusion coefficient (ADC), fractional anisotropy (FA) and tractography metrics of number and length of streamlines. We made comparisons between babies with the lowest and highest plasma FT4 concentrations during the initial 4 weeks after birth. There were no differences in DTI metrics between babies who had received LT4 supplementation and those who had received a placebo. Among recipients of a placebo, babies in the lowest quartile of plasma-free thyroxine (FT4) concentrations had significantly higher apparent diffusion coefficient measurements in the posterior corpus callosum and streamlines that were shorter and less numerous in the right internal capsule. Among LT4-supplemented babies, those who had plasma FT4 concentrations in the highest quartile had significantly lower apparent diffusion coefficient values in the left occipital lobe, higher fractional anisotropy in the anterior corpus callosum and longer and more numerous streamlines in the anterior corpus callosum. DTI variables were not associated with allocation of placebo or thyroid supplementation. Markers of poorly organised brain microstructure were associated with low plasma FT4 concentrations after birth. The findings suggest that plasma FT4 concentrations affect brain development in very immature infants and that the effect of LT4 supplementation for immature babies with low FT4 plasma concentrations warrants further study.Pediatric Radiology 03/2014; 44(8). DOI:10.1007/s00247-014-2911-6 · 1.65 Impact Factor