Journal ArticleDOI
Susceptibility mapping in the human brain using threshold-based k-space division.
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TLDR
An improved approach for high‐pass filtering of field maps, based on using an arrangement of dipoles to model the fields generated by external structures, was developed and tested on simulated field maps from the substantia nigra and red nuclei.Abstract:
A method for calculating quantitative three-dimensional susceptibility maps from field measurements acquired using gradient echo imaging at high field is presented. This method is based on division of the three-dimensional Fourier transforms of high-pass-filtered field maps by a simple function that is the Fourier transform of the convolution kernel linking field and susceptibility, and uses k-space masking to avoid noise enhancement in regions where this function is small. Simulations were used to show that the method can be applied to data acquired from objects that are oriented at one angle or multiple angles with respect to the applied field and that the use of multiple orientations improves the quality of the calculated susceptibility maps. As part of this work, we developed an improved approach for high-pass filtering of field maps, based on using an arrangement of dipoles to model the fields generated by external structures. This approach was tested on simulated field maps from the substantia nigra and red nuclei. Susceptibility mapping was successfully applied to experimental measurements on a structured phantom and then used to make measurements of the susceptibility of the red nuclei and substantia nigra in healthy subjects at 3 and 7 T. Magn Reson Med 63:1292–1304, 2010. © 2010 Wiley-Liss, Inc.read more
Citations
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Journal ArticleDOI
Quantitative imaging of intrinsic magnetic tissue properties using MRI signal phase: an approach to in vivo brain iron metabolism?
TL;DR: The findings suggest that susceptibility contrast, and therewith also phase contrast, are not only linked to the storage iron concentration but are also significantly influenced by other sources such as myelin, and caution should be exercised when drawing conclusions about iron concentrations when directly assessing processed phase information.
Journal ArticleDOI
Quantitative susceptibility mapping (QSM): Decoding MRI data for a tissue magnetic biomarker.
Yi Wang,Tian-Yu Liu +1 more
TL;DR: This paper attempts to summarize the basic physical concepts and essential algorithmic steps in QSM, to describe clinical and technical issues under active development, and to provide references, codes, and testing data for readers interested inQSM.
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Myelin and iron concentration in the human brain: A quantitative study of MRI contrast
Carsten Stüber,Markus Morawski,Markus Morawski,Andreas Schäfer,Christian Labadie,Christian Labadie,Miriam Wähnert,Christoph Leuze,Markus Streicher,Nirav Barapatre,Katja Reimann,Stefan Geyer,Daniel Spemann,Robert Turner +13 more
TL;DR: Iron and myelin concentrations can now be estimated from appropriate MRI measurements in post-mortem brain samples from a linear model and accurately modeled MRI tissue contrasts.
Journal ArticleDOI
Quantitative susceptibility mapping of human brain reflects spatial variation in tissue composition.
Wei Li,Bing Wu,Chunlei Liu +2 more
TL;DR: A novel and accurate susceptibility mapping method that is also phase-wrap insensitive is developed and revealed anisotropic magnetic susceptibility in brain white matter in vivo.
Journal ArticleDOI
Morphology Enabled Dipole Inversion for Quantitative Susceptibility Mapping Using Structural Consistency Between the Magnitude Image and the Susceptibility Map
Jing Liu,Tian Liu,Ludovic de Rochefort,James Robert Ledoux,Ildar Khalidov,Weiwei Chen,A. John Tsiouris,Cynthia Wisnieff,Pascal Spincemaille,Martin R. Prince,Yi Wang,Yi Wang +11 more
TL;DR: A Morphology Enabled Dipole Inversion (MEDI) approach is developed that exploits the structural consistency between the susceptibility map and the magnitude image reconstructed from the same gradient echo MRI, and demonstrates that QSM is feasible in practice.
References
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Journal ArticleDOI
Segmentation of brain MR images through a hidden Markov random field model and the expectation-maximization algorithm
TL;DR: The authors propose a novel hidden Markov random field (HMRF) model, which is a stochastic process generated by a MRF whose state sequence cannot be observed directly but which can be indirectly estimated through observations.
Journal ArticleDOI
Susceptibility weighted imaging (SWI).
TL;DR: In this work, the best approach for combining magnitude and phase images is discussed and Mathematical arguments are presented to determine the number of phase mask multiplications that should take place.
Journal ArticleDOI
Susceptibility-weighted imaging: technical aspects and clinical applications, part 1.
TL;DR: Susceptibility-weighted imaging (SWI) is a new neuroimaging technique, which uses tissue magnetic susceptibility differences to generate a unique contrast, different from that of spin density, T1, T2, and T2*.
Journal ArticleDOI
Imaging iron stores in the brain using magnetic resonance imaging.
E. Mark Haacke,Norman Y.C. Cheng,Michael J. House,Qiang Liu,Jaladhar Neelavalli,Robert J. Ogg,Adnan Khan,Muhammad Ayaz,Wolff M. Kirsch,Andre Obenaus +9 more
TL;DR: This review examines the response of the magnetic resonance visible iron in tissue that produces signal changes in both magnitude and phase images that seem to correlate with brain iron content, but still have not been successfully exploited to accurately and precisely quantify brain iron.
Journal ArticleDOI
Fast, automated, N‐dimensional phase‐unwrapping algorithm
TL;DR: This work investigates the general problem of phase unwrapping for arbitrary N‐dimensional phase maps and a cost function‐based approach is outlined that leads to an integer programming problem, and a best‐pair‐first region merging approach is adopted as the optimization method.