Four in vivo g‐ratio‐weighted imaging methods: Comparability and repeatability at the group level
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The data showed that repeatability and comparability depend largely on the marker for the FVF (NODDI outperformed TFD), and that they were improved by masking, and that the calibration procedure is crucial, for example, calibration to a lower g‐ratio value than the commonly used one.Abstract:
A recent method, denoted in vivo g-ratio-weighted imaging, has related the microscopic g-ratio, only accessible by ex vivo histology, to noninvasive MRI markers for the fiber volume fraction (FVF) and myelin volume fraction (MVF). Different MRI markers have been proposed for g-ratio weighted imaging, leaving open the question which combination of imaging markers is optimal. To address this question, the repeatability and comparability of four g-ratio methods based on different combinations of, respectively, two imaging markers for FVF (tract-fiber density, TFD, and neurite orientation dispersion and density imaging, NODDI) and two imaging markers for MVF (magnetization transfer saturation rate, MT, and, from proton density maps, macromolecular tissue volume, MTV) were tested in a scan-rescan experiment in two groups. Moreover, it was tested how the repeatability and comparability were affected by two key processing steps, namely the masking of unreliable voxels (e.g., due to partial volume effects) at the group level and the calibration value used to link MRI markers to MVF (and FVF). Our data showed that repeatability and comparability depend largely on the marker for the FVF (NODDI outperformed TFD), and that they were improved by masking. Overall, the g-ratio method based on NODDI and MT showed the highest repeatability (90%) and lowest variability between groups (3.5%). Finally, our results indicate that the calibration procedure is crucial, for example, calibration to a lower g-ratio value (g = 0.6) than the commonly used one (g = 0.7) can change not only repeatability and comparability but also the reported dependency on the FVF imaging marker. Hum Brain Mapp 39:24-41, 2018. © 2017 Wiley Periodicals, Inc.read more
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References
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Journal ArticleDOI
Improved segmentation of deep brain grey matter structures using magnetization transfer (MT) parameter maps
Gunther Helms,Bogdan Draganski,Bogdan Draganski,Richard S. J. Frackowiak,Richard S. J. Frackowiak,John Ashburner,Nikolaus Weiskopf +6 more
TL;DR: Improved automated segmentation of putamen, pallidum, pulvinar and substantia nigra is demonstrated using a novel, semi-quantitative magnetization transfer (MT) imaging protocol that overcomes limitations in T1w images, which are mainly due to their sensitivity to the high iron content in subcortical grey matter.
Journal ArticleDOI
Unified segmentation based correction of R1 brain maps for RF transmit field inhomogeneities (UNICORT).
Nikolaus Weiskopf,Antoine Lutti,Gunther Helms,Marianne J.U. Novak,John Ashburner,Chloe Hutton +5 more
TL;DR: The results suggest that the UNICORT method is robust and generalizes well to wider populations, as it is computationally efficient and its basic framework is implemented as part of the tissue segmentation in SPM8.
Journal ArticleDOI
Episodic demyelination and subsequent remyelination within the murine central nervous system: changes in axonal calibre
TL;DR: Results provide further evidence that the interactions between oligodendrocytes and axons alter axonal calibre and suggest this may be a useful model for certain human demyelinating disorders.
Journal ArticleDOI
White Matter Changes of Neurite Density and Fiber Orientation Dispersion during Human Brain Maturation
Yi Shin Chang,Julia P. Owen,Nicholas J. Pojman,Tony Thieu,Polina Bukshpun,Mari Wakahiro,Jeffrey I. Berman,Timothy P.L. Roberts,Srikantan S. Nagarajan,Elliott H. Sherr,Pratik Mukherjee +10 more
TL;DR: The results suggest that the rise of FA during the first two decades of life is dominated by increasing NDI, while the fall in FA after the fourth decade is driven by the exponential rise of ODI that overcomes the slower increases of NDI.
Journal ArticleDOI
Optimization and Validation of Methods for Mapping of the Radiofrequency Transmit Field at 3T
TL;DR: A comprehensive comparison of the methods for robust B 1+ mapping at 3T in the human brain, focusing on artifacts, reproducibility, and accuracy compared to a reference 2D double angle method found the 3D AFI method showed the highest level of reproducecibility and the 2D STEAM method was the most time‐efficient technique.
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