T2* mapping and B0 orientation-dependence at 7T reveal cyto- and myeloarchitecture organization of the human cortex
| Autor: | Julien Cohen-Adad, Caterina Mainero, Bruce R. Rosen, Karl G. Helmer, Jonathan R. Polimeni, Thomas Benner, Jennifer A. McNab, Lawrence L. Wald |
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| Rok vydání: | 2012 |
| Předmět: |
Adult
Cerebral Cortex Physics Brain Mapping medicine.diagnostic_test Orientation (computer vision) Cognitive Neuroscience Magnetic resonance imaging Magnetic Resonance Imaging Brain mapping Article Lateralization of brain function White matter medicine.anatomical_structure Neurology Cytoarchitecture Cerebral cortex Cortex (anatomy) medicine Humans Neuroscience |
| Zdroj: | NeuroImage. 60:1006-1014 |
| ISSN: | 1053-8119 |
| DOI: | 10.1016/j.neuroimage.2012.01.053 |
| Popis: | Ultra-high field MRI (≥ 7 T) has recently shown great sensitivity to depict patterns of tissue microarchitecture. Moreover, recent studies have demonstrated a dependency between T₂* and orientation of white matter fibers with respect to the main magnetic field B₀. In this study we probed the potential of T₂* mapping at 7 T to provide new markers of cortical architecture. We acquired multi-echo measurements at 7 T and mapped T₂* over the entire cortex of eight healthy individuals using surface-based analysis. B₀ dependence was tested by computing the angle θ(z) between the normal of the surface and the direction of B₀, then fitting T₂*(θ(z)) using model from the literature. Average T₂* in the cortex was 32.20 +/- 1.35 ms. Patterns of lower T₂* were detected in the sensorimotor, visual and auditory cortices, likely reflecting higher myelin content. Significantly lower T₂* was detected in the left hemisphere of the auditory region (p0.005), suggesting higher myelin content, in accordance with previous investigations. B₀ orientation dependence was detected in some areas of the cortex, the strongest being in the primary motor cortex (∆R₂*=4.10 Hz). This study demonstrates that quantitative T₂* measures at 7 T MRI can reveal patterns of cytoarchitectural organization of the human cortex in vivo and that B₀ orientation dependence can probe the coherency and orientation of gray matter fibers in the cortex, shedding light into the potential use of this type of contrast to characterize cyto-/myeloarchitecture and to understand the pathophysiology of diseases associated with changes in iron and/or myelin concentration. |
| Databáze: | OpenAIRE |
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