In vivo evaluation of optic nerve aging in adult rhesus monkey by diffusion tensor imaging

• Authors: Yumei Yan, Emory University; Longchuan Li, Emory University; Todd M Preuss, Emory University; Xiaoping P Hu, Emory University; James G Herndon Jr., Emory University; Xiaodong Zhang, Emory University
• Journal Title: Quantitative imaging in medicine and surgery
• Volume: Volume 4, Number 1
• Publisher: AME Publishing Company | 2014-02, Pages 43-49
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.3978/j.issn.2223-4292.2014.02.04
• Subjects: Engineering, Biomedical; Biology, Neuroscience; Health Sciences, Opthamology
• Keywords: Optic nerve aging; white matter; mean diffusivity (MD); fractional anisotropy (FA); non-human primate; parallel imaging; GRAPPA

Abstract

Aging of the optic nerve can result in reduced visual sensitivity or vision loss. Normal optic nerve aging has been investigated previously in tissue specimens but poorly explored in vivo. In the present study, the normal aging of optic nerve was evaluated by diffusion tensor imaging (DTI) in non-human primates. Adult female rhesus monkeys at the ages of 9 to 13 years old (young group, n=8) and 21 to 27 years old (old group, n=7) were studied using parallel-imaging-based DTI on a clinical 3T scanner. Compared to young adults, the old monkeys showed 26% lower fractional anisotropy (P<0.01), and 44% greater radial diffusivity, although the latter difference was of marginal statistical significance (P=0.058). These MRI findings are largely consistent with published results of light and electron microscopic studies of optic nerve aging in macaque monkeys, which indicate a loss of fibers and degenerative changes in myelin sheaths.