Phase-Contrast Micro-Computed Tomography Measurements of the Intraocular Pressure-Induced Deformation of the Porcine Lamina Cribrosa

• Type of Material: Article
• Authors: Baptiste Coudrillier, Georgia Institute of Technology; Diogo M. Geraldes, Imperial College London; Nghia T. Vo, Diamond Light Source Ltd.; Robert Atwood, Diamond Light Source Ltd.; Christina Reinhard, Diamond Light Source Ltd.; Ian C. Campbell, Georgia Institute of Technology; Yazdan Raji, Georgia Institute of Technology; Julie Albon, Cardiff University; Richard L. Abel, Imperial College London; Christopher Ethier, Emory University
• Language: English
• Date: 2016-04-01
• Publisher: Institute of Electrical and Electronics Engineers (IEEE)
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2015 IEEE.
• Final Published Version (URL): http://dx.doi.org/10.1109/TMI.2015.2504440
• Title of Journal or Parent Work: IEEE Transactions on Medical Imaging
• ISSN: 0278-0062
• Volume: 35
• Issue: 4
• Start Page: 988
• End Page: 999
• Grant/Funding Information: The project was supported by grants from the Science & Technology Facilities Council EE8491, EE9825 and EE11407; and by funding from the Georgia Research Alliance (CRE).
• Keywords: ELEVATION; Science & Technology; HUMAN EYES; Engineering, Electrical & Electronic; DIGITAL VOLUME CORRELATION; Engineering, Biomedical; strain measurements; Life Sciences & Biomedicine; Technology; Imaging Science & Photographic Technology; Computer Science; CONNECTIVE-TISSUE; BONE; Engineering; Radiology, Nuclear Medicine & Medical Imaging; Computer Science, Interdisciplinary Applications; OPTIC-NERVE HEAD; x-ray tomography; COHERENCE TOMOGRAPHY; BIOMECHANICS; Biomechanics; OPEN-ANGLE GLAUCOMA; STRAIN
• Research Categories: Engineering, Biomedical; Health Sciences, Radiology; Health Sciences, Opthamology

Abstract

The lamina cribrosa (LC) is a complex mesh-like tissue in the posterior eye. Its biomechanical environment is thought to play a major role in glaucoma, the second most common cause of blindness. Due to its small size and relative inaccessibility, high-resolution measurements of LC deformation, important in characterizing LC biomechanics, are challenging. Here we present a novel noninvasive imaging method, which enables measurement of the three-dimensional deformation of the LC caused by acute elevation of intraocular pressure (IOP). Posterior segments of porcine eyes were imaged using synchrotron radiation phase contrast micro-computed tomography (PC μCT) at IOPs between 6 and 37 mmHg. The complex trabecular architecture of the LC was reconstructed with an isotropic spatial resolution of 3.2 μm. Scans acquired at different IOPs were analyzed with digital volume correlation (DVC) to compute full-field deformation within the LC. IOP elevation caused substantial tensile, shearing and compressive devformation within the LC, with maximum tensile strains at 30 mmHg averaging 5.5%, and compressive strains reaching 20%. We conclude that PC μCT provides a novel high-resolution method for imaging the LC, and when combined with DVC, allows for full-field 3D measurement of ex vivo LC biomechanics at high spatial resolution.