title: Automated segmentation of the lamina cribrosa using Frangi's filter: a novel approach for rapid identification of tissue volume fraction and beam orientation in a trabeculated structure in the eye.
abstract: The lamina cribrosa (LC) is a tissue in the posterior eye with a complex trabecular microstructure. This tissue is of great research interest, as it is likely the initial site of retinal ganglion cell axonal damage in glaucoma. Unfortunately, the LC is difficult to access experimentally, and thus imaging techniques in tandem with image processing have emerged as powerful tools to study the microstructure and biomechanics of this tissue. Here, we present a staining approach to enhance the contrast of the microstructure in micro-computed tomography (micro-CT) imaging as well as a comparison between tissues imaged with micro-CT and second harmonic generation (SHG) microscopy. We then apply a modified version of Frangi's vesselness filter to automatically segment the connective tissue beams of the LC and determine the orientation of each beam. This approach successfully segmented the beams of a porcine optic nerve head from micro-CT in three dimensions and SHG microscopy in two dimensions. As an application of this filter, we present finite-element modelling of the posterior eye that suggests that connective tissue volume fraction is the major driving factor of LC biomechanics. We conclude that segmentation with Frangi's filter is a powerful tool for future image-driven studies of LC biomechanics.
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 315 Ferst Drive NW, Atlanta, GA 30332, USA Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA 30033, USA.
authors.forename: Ian C
authors.identifier: http://orcid.org/0000-0002-4640-2692
authors.initials: IC
authors.lastname: Campbell
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 315 Ferst Drive NW, Atlanta, GA 30332, USA.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Coudrillier
authors.affiliation: MSk Laboratory, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London W6 8RP, UK.
authors.forename: Johanne
authors.initials: J
authors.lastname: Mensah
authors.affiliation: MSk Laboratory, Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London W6 8RP, UK.
authors.forename: Richard L
authors.identifier: http://orcid.org/0000-0002-5197-3086
authors.initials: RL
authors.lastname: Abel
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 315 Ferst Drive NW, Atlanta, GA 30332, USA Atlanta VA Medical Center, 1670 Clairmont Road, Decatur, GA 30033, USA ross.ethier@bme.gatech.edu.
authors.forename: C Ross
authors.identifier: http://orcid.org/0000-0001-6110-3052
authors.initials: CR
authors.lastname: Ethier
mesh_terms: D000818:Animals; D001331:Automation; D001696:Biomechanical Phenomena; D055592:Biophysical Phenomena; D003238:Connective Tissue / Q000473:pathology; D003287:Contrast Media / Q000737:chemistry; D005123:Eye / Q000000981:diagnostic imaging* / Q000473:pathology*; D020342:Finite Element Analysis; D005901:Glaucoma / Q000000981:diagnostic imaging / Q000503:physiopathology; D008853:Microscopy; D018613:Microscopy, Confocal; D009799:Ocular Physiological Phenomena; D009900:Optic Nerve; D011857:Radiographic Image Interpretation, Computer-Assisted; D012165:Retinal Ganglion Cells / Q000378:metabolism*; D013314:Stress, Mechanical; D013552:Swine; D055114:X-Ray Microtomography
chemical_list: D003287:Contrast Media
keywords: computed tomography; confocal microscopy; image processing; lamina cribrosa; ocular biomechanics