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In vivo chromium‐enhanced MRI of the retina
Author(s) -
Chan Kevin C.,
Fan ShuJuan,
Zhou Iris Y.,
Wu Ed X.
Publication year - 2012
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.24123
Subject(s) - chromium , retina , retinal , in vivo , ex vivo , chemistry , hyperintensity , magnetic resonance imaging , nuclear magnetic resonance , biophysics , biology , in vitro , biochemistry , medicine , neuroscience , radiology , physics , microbiology and biotechnology , organic chemistry
Chromium (Cr) has been used histologically to stabilize lipid fractions in the retina and is suggested to enhance oxidizable lipids in brain MRI. This study explored the feasibility, sensitivity, and specificity of in vivo chromium‐enhanced MRI of retinal lipids by determining its spatiotemporal profiles and toxic effect after intravitreal Cr(VI) injection to normal adult rats. One day after 3 μL Cr(VI) administration at 1–100 mM, the retina exhibited a dose‐dependent increase in T 1 ‐weighted hyperintensity until 50 mM. Time‐dependently, significant T 1 ‐weighted hyperintensity persisted up to 2 weeks after 10 mM Cr(VI) administration. Three‐dimensional chromium‐enhanced MRI of ex vivo normal eyes at isotropic 50‐μm resolution showed at least five alternating bands across retinal layers, with the outermost layer being the brightest. This agreed with histology indicating alternating lipid contents with the highest level in the photoreceptor layer of the outer retina. Although Cr(VI) reduction may induce oxidative stress and depolymerize microtubules, manganese‐enhanced MRI after chromium‐enhanced MRI showed a dose‐dependent effect of Cr toxicity on manganese uptake and axonal transport along the visual pathway. These results potentiated future longitudinal chromium‐enhanced MRI studies on retinal lipid metabolism upon further optimization of Cr doses with visual cell viability. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.