Govind Nair1, Stephen Dodd2, Seung-Kwon Ha3, Alan P Koretsky2, Daniel S Reich3. 1. Quantitative MRI Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, United States. Electronic address: bhagavatheeshg@mail.nih.gov. 2. Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, United States. 3. Translational Neuroradiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, United States.
Abstract
PURPOSE: To perform magnetic resonance microscopy (MRM) on human cortex and a cortical lesion as well as the adjacent normal appearing white matter. To shed light on the origins of MRI contrast by comparison with histochemical and immunostaining. METHODS: 3D MRM at a nominal isotropic resolution of 15 and 18 µm was performed on 2 blocks of tissue from the brain of a 77-year-old man who had MS for 47 years. One block contained normal appearing cortical gray matter (CN block) and adjacent normal appearing white matter (NAWM), and the other also included a cortical lesion (CL block). Postmortem ex-vivo MRI was performed at 11.7T using a custom solenoid coil and T2*-weighted 3D GRE sequence. Histochemical and immunostaining were done after paraffin embedding for iron, myelin, oligodendrocytes, neurons, blood vessels, macrophages and microglia, and astrocytes. RESULTS: MRM could identify individual iron-laden oligodendrocytes with high sensitivity (70% decrease in signal compared to surrounding) in CN and CL blocks, as well as some iron-laden activated macrophages and microglia. Iron-deficient oligodendrocytes seemed to cause relative increase in MRI signal within the cortical lesion. High concentration of myelin in the white matter was primarily responsible for its hypointense appearance relative to the cortex, however, signal variations within NAWM could be attributed to changes in density of iron-laden oligodendrocytes. CONCLUSION: Changes in iron accumulation within cells gave rise to imaging contrast seen between cortical lesions and normal cortex, as well as the patchy signal in NAWM. Densely packed myelin and collagen deposition also contributed to MRM signal changes. Even though we studied only one block each from normal appearing and cortical lesions, such studies can help better understand the origins of histopathological and microstructural correlates of MRI signal changes in multiple sclerosis and contextualize the interpretation of lower-resolution in vivo MRI scans.
PURPOSE: To perform magnetic resonance microscopy (MRM) on human cortex and a cortical lesion as well as the adjacent normal appearing white matter. To shed light on the origins of MRI contrast by comparison with histochemical and immunostaining. METHODS: 3D MRM at a nominal isotropic resolution of 15 and 18 µm was performed on 2 blocks of tissue from the brain of a 77-year-old man who had MS for 47 years. One block contained normal appearing cortical gray matter (CN block) and adjacent normal appearing white matter (NAWM), and the other also included a cortical lesion (CL block). Postmortem ex-vivo MRI was performed at 11.7T using a custom solenoid coil and T2*-weighted 3D GRE sequence. Histochemical and immunostaining were done after paraffin embedding for iron, myelin, oligodendrocytes, neurons, blood vessels, macrophages and microglia, and astrocytes. RESULTS: MRM could identify individual iron-laden oligodendrocytes with high sensitivity (70% decrease in signal compared to surrounding) in CN and CL blocks, as well as some iron-laden activated macrophages and microglia. Iron-deficient oligodendrocytes seemed to cause relative increase in MRI signal within the cortical lesion. High concentration of myelin in the white matter was primarily responsible for its hypointense appearance relative to the cortex, however, signal variations within NAWM could be attributed to changes in density of iron-laden oligodendrocytes. CONCLUSION: Changes in iron accumulation within cells gave rise to imaging contrast seen between cortical lesions and normal cortex, as well as the patchy signal in NAWM. Densely packed myelin and collagen deposition also contributed to MRM signal changes. Even though we studied only one block each from normal appearing and cortical lesions, such studies can help better understand the origins of histopathological and microstructural correlates of MRI signal changes in multiple sclerosis and contextualize the interpretation of lower-resolution in vivo MRI scans.
Authors: R W Bowtell; A Peters; J C Sharp; P Mansfield; E W Hsu; N Aiken; A Horsman; S J Blackband Journal: Magn Reson Med Date: 1995-06 Impact factor: 4.668
Authors: Jeremy J Flint; Choong H Lee; Brian Hansen; Michael Fey; Daniel Schmidig; Jonathan D Bui; Michael A King; Peter Vestergaard-Poulsen; Stephen J Blackband Journal: Neuroimage Date: 2009-03-12 Impact factor: 6.556
Authors: Pascal Sati; Jiwon Oh; R Todd Constable; Nikos Evangelou; Charles R G Guttmann; Roland G Henry; Eric C Klawiter; Caterina Mainero; Luca Massacesi; Henry McFarland; Flavia Nelson; Daniel Ontaneda; Alexander Rauscher; William D Rooney; Amal P R Samaraweera; Russell T Shinohara; Raymond A Sobel; Andrew J Solomon; Constantina A Treaba; Jens Wuerfel; Robert Zivadinov; Nancy L Sicotte; Daniel Pelletier; Daniel S Reich Journal: Nat Rev Neurol Date: 2016-11-11 Impact factor: 42.937