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Age‐related deep white matter changes in myelin and water content: A T 2 relaxometry study
Author(s) -
Papadaki Efrosini,
Kavroulakis Eleftherios,
Kalaitzakis Georgios,
Karageorgou Dimitra,
Makrakis Dimitrios,
Maris Thomas G.,
Simos Panagiotis G.
Publication year - 2019
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.26707
Subject(s) - white matter , myelin , fluid attenuated inversion recovery , biology , anatomy , medicine , magnetic resonance imaging , endocrinology , central nervous system , radiology
Background According to the retrogenesis hypothesis, the rate of age‐related changes in white matter (WM) myelin content varies between early myelinating (parietal, occipital) and late myelinating (prefrontal, lateral–posterior temporal) areas. The multiecho spin echo (MESE), PD‐to‐T 2 ‐weighted sequence provides an index of myelin content (myelin water fraction [MWF]) derived from measurements of myelin water (via the short T 2 component [10–50 msec]) and intra‐ and extracellular water (via the long T 2 component [>50–200 msec]). Purpose To assess the shape and regional variations in the rate of age‐related myelin and water content changes in deep WM regions using the MESE sequence. Study Type Prospective, cross‐sectional. Population In all, 90 healthy adults aged 22–81 years. Field Strength/Sequence 1.5T/ T 1 w, T 2 w, fluid attenuated inversion recovery (FLAIR), MESE sequences. Assessment Short T 2 , long T 2 , and MWF values were measured in prefrontal, parietal, lateral–posterior temporal, and occipital normal‐appearing WM (NAWM) areas. Statistical Tests Linear and quadratic effects of age on long T 2 and MWF were assessed through regression analyses. Regional variations in the effect of age on long T 2 and MWF values at both the individual and group level were examined, using regression and analysis of covariance (ANCOVA) analyses, respectively, controlling for total WM volume. Results The rate of age‐related changes in long T 2 and MWF was higher for older persons and a significant increase or decline, respectively, was first noted at 60–69 years ( P < 0.0033). MWF values peaked earlier (at 30 years of age) and displayed a steeper age‐related reduction in prefrontal and lateral–posterior temporal NAWM as compared with the occipital lobes ( P < 0.05). The opposite pattern of age‐related effect was found for long T 2 values. Data Conclusion Significant age‐related reductions in myelin content were closely followed by corresponding increases in intra‐ and extracellular water content. These changes were more pronounced among elderly people and followed an anterior–posterior pattern. Level of Evidence: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:1393–1404.