title: Non-invasive MRI Assessments of Tissue Microstructures and Macromolecules in the Eye upon Biomechanical or Biochemical Modulation.
abstract: The microstructural organization and composition of the corneoscleral shell (CSS) determine the biomechanical behavior of the eye, and are important in diseases such as glaucoma and myopia. However, limited techniques can assess these properties globally, non-invasively and quantitatively. In this study, we hypothesized that multi-modal magnetic resonance imaging (MRI) can reveal the effects of biomechanical or biochemical modulation on CSS. Upon intraocular pressure (IOP) elevation, CSS appeared hyperintense in both freshly prepared ovine eyes and living rat eyes using T2-weighted MRI. Quantitatively, transverse relaxation time (T2) of CSS increased non-linearly with IOP at 0-40 mmHg and remained longer than unloaded tissues after being unpressurized. IOP loading also increased fractional anisotropy of CSS in diffusion tensor MRI without apparent change in magnetization transfer MRI, suggestive of straightening of microstructural fibers without modification of macromolecular contents. Lastly, treatments with increasing glyceraldehyde (mimicking crosslinking conditions) and chondroitinase-ABC concentrations (mimicking glycosaminoglycan depletion) decreased diffusivities and increased magnetization transfer in cornea, whereas glyceraldehyde also increased magnetization transfer in sclera. In summary, we demonstrated the changing profiles of MRI contrast mechanisms resulting from biomechanical or biochemical modulation of the eye non-invasively. Multi-modal MRI may help evaluate the pathophysiological mechanisms in CSS and the efficacy of corneoscleral treatments.
authors: NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA.|UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China.
authors: Leon C
authors: LC
authors: Ho
authors: UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China.|McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Ian A
authors: IA
authors: Sigal
authors: UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Ning-Jiun
authors: NJ
authors: Jan
authors: NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA.|UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Xiaoling
authors: X
authors: Yang
authors: NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA.|UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.|McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Yolandi
authors: Y
authors: van der Merwe
authors: Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Hong Kong, China.
authors: Yu
authors: Y
authors: Yu
authors: Department of Chemical and Biomolecular Engineering, Hong Kong University of Science and Technology, Hong Kong, China.|Division of Biomedical Engineering, Hong Kong University of Science and Technology, Hong Kong, China.
authors: Ying
authors: Y
authors: Chau
authors: University Eye Center, Hong Kong Eye Hospital, Hong Kong, China.|Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
authors: Christopher K
authors: CK
authors: Leung
authors: UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Ian P
authors: IP
authors: Conner
authors: NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA.
authors: Tao
authors: T
authors: Jin
authors: Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, China.
authors: Ed X
authors: EX
authors: Wu
authors: NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA.|Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.|McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA.|Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea.|Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea.
authors: Seong-Gi
authors: SG
authors: Kim
authors: UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.|McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Gadi
authors: G
authors: Wollstein
authors: UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.|McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA.|Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, PA, USA.
authors: Joel S
authors: JS
authors: Schuman
authors: NeuroImaging Laboratory , University of Pittsburgh, Pittsburgh, PA, USA.|UPMC Eye Center, Ophthalmology and Visual Science Research Center, Department of Ophthalmology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.|McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA.|Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pittsburgh, PA, USA.|Center for the Neural Basis of Cognition, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA, USA.
authors: Kevin C
authors: KC
authors: Chan
mesh_terms: D000818:Animals; D002417:Cattle; D005123:Eye / Q000000981:diagnostic imaging / Q000378:metabolism; D005901:Glaucoma / Q000000981:diagnostic imaging / Q000378:metabolism; D007429:Intraocular Pressure; D008279:Magnetic Resonance Imaging / Q000379:methods*; D057054:Molecular Imaging / Q000379:methods*; D009216:Myopia / Q000000981:diagnostic imaging / Q000378:metabolism