For Publishers
DiscoveryMetadataPeer reviewHostingPublishing
For Researchers
JoinPublishReviewCollect
Register
Blog
About
Search
Advanced search
My ScienceOpen
Search
For Publishers
For Researchers
Blog
About
29
views
34
references
 Top references
cited by
119
    
0 reviews
 Review
0
comments
 Comment
0
recommends
+1 Recommend
0 collections
    0
    shares
      642
      similar
       All similar
      • Record: found
      • Abstract: not found
      • Article: not found

      Layer-specific variation of iron content in cerebral cortex as a source of MRI contrast

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Recent advances in high-field MRI have dramatically improved the visualization of human brain anatomy in vivo. Most notably, in cortical gray matter, strong contrast variations have been observed that appear to reflect the local laminar architecture. This contrast has been attributed to subtle variations in the magnetic properties of brain tissue, possibly reflecting varying iron and myelin content. To establish the origin of this contrast, MRI data from postmortem brain samples were compared with electron microscopy and histological staining for iron and myelin. The results show that iron is distributed over laminae in a pattern that is suggestive of each region's myeloarchitecture and forms the dominant source of the observed MRI contrast.

          Related collections

          Most cited references34

          • Record: found
          • Abstract: found
          • Article: not found

          Imaging iron stores in the brain using magnetic resonance imaging.

          E. Haacke, Norman Y C Cheng, Michael J. House … (2005)
          For the last century, there has been great physiological interest in brain iron and its role in brain function and disease. It is well known that iron accumulates in the brain for people with Huntington's disease, Parkinson's disease, Alzheimer's disease, multiple sclerosis, chronic hemorrhage, cerebral infarction, anemia, thalassemia, hemochromatosis, Hallervorden-Spatz, Down syndrome, AIDS and in the eye for people with macular degeneration. Measuring the amount of nonheme iron in the body may well lead to not only a better understanding of the disease progression but an ability to predict outcome. As there are many forms of iron in the brain, separating them and quantifying each type have been a major challenge. In this review, we present our understanding of attempts to measure brain iron and the potential of doing so with magnetic resonance imaging. Specifically, we examine the response of the magnetic resonance visible iron in tissue that produces signal changes in both magnitude and phase images. These images seem to correlate with brain iron content, perhaps ferritin specifically, but still have not been successfully exploited to accurately and precisely quantify brain iron. For future quantitative studies of iron content we propose four methods: correlating R2' and phase to iron content; applying a special filter to the phase to obtain a susceptibility map; using complex analysis to extract the product of susceptibility and volume content of the susceptibility source; and using early and late echo information to separately predict susceptibility and volume content.
          Article 0 comments Cited 196 times – based on 0 reviews     Review now
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Theory of NMR signal behavior in magnetically inhomogeneous tissues: the static dephasing regime.

            Dmitriy Yablonskiy, E. Haacke (1994)
            This paper is devoted to a theory of the NMR signal behavior in biological tissues in the presence of static magnetic field inhomogeneities. We have developed an approach that analytically describes the NMR signal in the static dephasing regime where diffusion phenomena may be ignored. This approach has been applied to evaluate the NMR signal in the presence of a blood vessel network (with an application to functional imaging), bone marrow (for two specific trabecular structures, asymmetrical and columnar) and a ferrite contrast agent. All investigated systems have some common behavior. If the echo time TE is less than a known characteristic time tc for a given system, then the signal decays exponentially with an argument which depends quadratically on TE. This is equivalent to an R2* relaxation rate which is a linear function of TE. In the opposite case, when TE is greater than tc, the NMR signal follows a simple exponential decay and the relaxation rate does not depend on the echo time. For this time interval, R2* is a linear function of a) volume fraction sigma occupied by the field-creating objects, b) magnetic field Bo or just the objects' magnetic moment for ferrite particles, and c) susceptibility difference delta chi between the objects and the medium.
            Article 0 comments Cited 169 times – based on 0 reviews     Review now
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Relationship of iron to oligodendrocytes and myelination.

              J. R. Connor, S L Menzies (1996)
              Oligodendrocytes are the predominant iron-containing cells in the brain. Iron-containing oligodendrocytes are found near neuronal cell bodies, along blood vessels, and are particularly abundant within white matter tracts. Iron-positive cells in white matter are present from birth and eventually reside in defined patches of cells in the adult. These patches of iron-containing cells typically have a blood vessel in their center. Ferritin, the iron storage protein, is also expressed early in development in oligodendrocytes in a regional and cellular pattern similar to that seen for iron. Recently, the functionally distinct subunits of ferritin have been analyzed; only heavy (H)-chain ferritin is found in oligodendrocytes early in development. H-ferritin is associated with high iron utilization and low iron storage. Consistent with the expression of H-ferritin is the expression of transferrin receptors (for iron acquisition) on immature oligodendrocytes. Transferrin protein accumulation and mRNA expression in the brain are both dependent on a viable population of oligodendrocytes and may have an autocrine function to assist oligodendrocytes in iron acquisition. Although apparently the majority of oligodendrocytes in white matter tracts contain ferritin, transferrin, and iron, not all of them do, indicating that there is a subset of oligodendrocytes in white matter tracts. The only known function of oligodendrocytes is myelin production, and both a direct and indirect relationship exists between iron acquisition and myelin production. Iron is directly involved in myelin production as a required co-factor for cholesterol and lipid biosynthesis and indirectly because of its requirement for oxidative metabolism (which occurs in oligodendrocytes at a higher rate than other brain cells). Factors (such as cytokines) and conditions such as iron deficiency may reduce iron acquisition by oligodendrocytes and the susceptibility of oligodendrocytes to oxidative injury may be a result of their iron-rich cytoplasm. Thus, the many known phenomena that decrease oligodendrocyte survival and/or myelin production may mediate their effect through a final common pathway that involves disruptions in iron availability or intracellular management of iron.
              Article 0 comments Cited 156 times – based on 0 reviews     Review now
                Bookmark
                All references

                Author and article information

                Journal
                Title: Proceedings of the National Academy of Sciences
                Abbreviated Title: Proc Natl Acad Sci USA
                Publisher: Proceedings of the National Academy of Sciences
                ISSN (Print): 0027-8424
                ISSN (Electronic): 1091-6490
                Publication date Created: February 23 2010
                Publication date Created: February 23 2010
                Publication date (Print): February 23 2010
                Publication date (Electronic): February 03 2010
                Volume: 107
                Issue: 8
                Pages: 3834-3839
                Article
                DOI: 10.1073/pnas.0911177107
                PMC ID: 2840419
                PubMed ID: 20133720
                SO-VID: 45ff8365-f8fe-4a5b-8ab7-e6df142e3a81
                Copyright © © 2010
                History

                Data availability:

                Comments

                Comment on this article

                scite_

                Similar content642

                See all similar

                Cited by116

                See all cited by

                Most referenced authors352

                See all reference authors