15
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Regional T 1 relaxation time constants in Ex vivo human brain: Longitudinal effects of formalin exposure

      brief-report

      Read this article at

      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

          Purpose

          Relaxation time constants are useful as markers of tissue properties. Imaging ex vivo tissue is done for research purposes; however, T 1 relaxation time constants are altered by tissue fixation in a time‐dependent manner. This study investigates regional changes in T 1 relaxation time constants in ex vivo brain tissue over 6 months of fixation.

          Methods

          Five ex vivo human brain hemispheres in 10% formalin were scanned over 6 months. Mean T 1 relaxation time constants were measured in regions of interest (ROIs) representing gray matter (GM) and white matter (WM) regions and analyzed as a function of fixation time.

          Results

          Cortical GM ROIs had longer T 1 relaxation time constants than WM ROIs; the thalamus had T 1 relaxation time constants similar to those of WM ROIs. T 1 relaxation time constants showed rapid shortening within the first 6 weeks after fixation followed by a slower rate of decline.

          Conclusion

          Both GM and WM T 1 relaxation time constants of fixed brain tissue show rapid decline within the first 6 weeks after autopsy and slow by 6 months. This information is useful for optimizing MR imaging acquisition parameters according to fixation time for ex vivo brain imaging studies. Magn Reson Med 77:774–778, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

          Related collections

          Most cited references18

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

          Formaldehyde fixation.

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

            Magnetic field and tissue dependencies of human brain longitudinal 1H2O relaxation in vivo.

            Brain water proton (1H2O) longitudinal relaxation time constants (T1) were obtained from three healthy individuals at magnetic field strengths (B0) of 0.2 Tesla (T), 1.0T, 1.5T, 4.0T, and 7.0T. A 5-mm midventricular axial slice was sampled using a modified Look-Locker technique with 1.5 mm in-plane resolution, and 32 time points post-adiabatic inversion. The results confirmed that for most brain tissues, T1 values increased by more than a factor of 3 between 0.2T and 7T, and over this range were well fitted by T1 (s)=0.583(B0)0.382, T1(s)=0.857(B0)0.376, and T1(s)=1.35(B0)0.340 for white matter (WM), internal GM, and blood 1H2O, respectively. The ventricular cerebrospinal fluid (CSF) 1H2O T1 value did not change with B0, and its average value (standard deviation (SD)) across subjects and magnetic fields was 4.3 (+/-0.2) s. The tissue 1/T1 values at each field were well correlated with the macromolecular mass fraction, and to a lesser extent tissue iron content. The field-dependent increases in 1H2O T1 values more than offset the well-known decrease in typical MRI contrast reagent (CR) relaxivity, and simulations predict that this leads to lower CR concentration detection thresholds with increased magnetic field. Copyright (c) 2007 Wiley-Liss, Inc.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: found
              Is Open Access

              Chemical and physical basics of routine formaldehyde fixation

              Formaldehyde is the widely employed fixative that has been studied for decades. The chemistry of fixation has been studied widely since the early 20th century. However, very few studies have been focused on the actual physics/chemistry aspect of process of this fixation. This article attempts to explain the chemistry of formaldehyde fixation and also to study the physical aspects involved in the fixation. The factors involved in the fixation process are discussed using well documented mathematical and physical formulae. The deeper understanding of these factors will enable pathologist to optimize the factors and use them in their favor.
                Bookmark

                Author and article information

                Contributors
                kantarci.kejal@mayo.edu
                Journal
                Magn Reson Med
                Magn Reson Med
                10.1002/(ISSN)1522-2594
                MRM
                Magnetic Resonance in Medicine
                John Wiley and Sons Inc. (Hoboken )
                0740-3194
                1522-2594
                17 February 2016
                February 2017
                : 77
                : 2 ( doiID: 10.1002/mrm.v77.2 )
                : 774-778
                Affiliations
                [ 1 ]Mayo Graduate School, Department of Neurology, Mayo Clinic Rochester MinnesotaUSA
                [ 2 ] Department of RadiologyMayo Clinic Rochester MinnesotaUSA
                [ 3 ] Department of Health Sciences ResearchMayo Clinic Rochester MinnesotaUSA
                Author notes
                [*] [* ]Correspondence to: Kejal Kantarci, M.D., M.S., Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905. E‐mail: kantarci.kejal@ 123456mayo.edu
                Article
                MRM26140
                10.1002/mrm.26140
                5298016
                26888162
                44d9ef0a-d7c6-4fb0-a1e8-49b528389915
                © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine

                This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.

                History
                : 15 July 2015
                : 18 December 2015
                : 26 December 2015
                Page count
                Figures: 2, Tables: 2, Pages: 5, Words: 3403
                Funding
                Funded by: National Institutes of Health
                Award ID: R01‐AG040042
                Categories
                Note
                Imaging Methodology—Notes
                Custom metadata
                2.0
                mrm26140
                February 2017
                Converter:WILEY_ML3GV2_TO_NLMPMC version:5.0.5 mode:remove_FC converted:08.02.2017

                Radiology & Imaging
                t1‐mapping,ex vivo,neuroimaging,brain,mri,fixation
                Radiology & Imaging
                t1‐mapping, ex vivo, neuroimaging, brain, mri, fixation

                Comments

                Comment on this article