A Fourier Domain Directional Filterng Method for Analysis of Collagen Alignment in Ligaments

Chaudhuri, Subhasis; Nguyen, Hieu T. M.; Rangayyan, Rangaraj M.; Walsh, Suzanne; Frank, Cyril B.

doi:10.1109/tbme.1987.325980

Cited by 98 publications

(81 citation statements)

References 21 publications

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“…Local collagen fibril orientation-In order to evaluate collagen fibril orientation in the matrices, we applied a Fourier Transform (FT) analysis procedure previously used in other tissues [35][36][37]. This approach is based on the fact that the relative strength of different angle bands within the FT spectrum is a global indicator of the relative number and magnitude of fibers oriented at 90 degrees to that angle in the original image.…”

Section: Image Processing and Analysismentioning

confidence: 99%

Quantitative assessment of local collagen matrix remodeling in 3-D Culture: The role of Rho kinase

Kim

Lakshman

Petroll

2006

Experimental Cell Research

105

122

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The purpose of this study was to quantitatively assess the role of Rho kinase in modulating the pattern and amount of local cell-induced collagen matrix remodeling.Human corneal fibroblasts were plated inside 100 μm thick fibrillar collagen matrices and cultured for 24 hours in media with or without the Rho kinase inhibitor Y-27632. Cells were then fixed and stained with phalloidin. Fluorescent (for f-actin) and reflected light (for collagen fibrils) 3-D optical section images were acquired using laser confocal microscopy. Fourier transform analysis was used to assess collagen fibril alignment, and 3-D cell morphology and local collagen density were measured using MetaMorph.Culture in serum-containing media induced significant global matrix contraction, which was inhibited by blocking Rho kinase (p < 0.001). Fibroblasts generally had a bipolar morphology and intracellular stress fibers. Collagen fibrils were compacted and aligned parallel to stress fibers and pseudopodia. When Rho kinase was inhibited, cells had a more cortical f-actin distribution and dendritic morphology. Both local collagen fibril density and alignment were significantly reduced (p<0.01).Overall, the data suggests that Rho kinase dependent contractile force generation leads to coalignment of cells and collagen fibrils along the plane of greatest resistance, and that this process contributes to global matrix contraction.

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Section: Image Processing and Analysismentioning

confidence: 99%

Quantitative assessment of local collagen matrix remodeling in 3-D Culture: The role of Rho kinase

Kim

Lakshman

Petroll

2006

Experimental Cell Research

105

122

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“…These methods exhibit spatial resolutions that enable imaging of the ultrastructure of bone, where the ultrastructural elements (mineralized collagen fibrils or fibril bundles) can be visually identified. Quantification of the orientation and arrangement of the ultrastructure is performed by image post-processing of the acquired images, either through specialized orientationsensitive algorithms [53][54][55] or, most commonly, through two-dimensional (2D) or 3D Fourier transform (FT) [56], which allow the orientation and degree of orientation (DO) to be derived [57][58][59][60]. It should be noted that the indirect assessment of the organization of mineralized collagen fibrils by imaging techniques can lead to artefacts, which are discussed in the introduction of the respective subsection.…”

Section: Technique Categorizationmentioning

confidence: 99%

“…By applying image post-processing steps to the gathered image data (e.g. FT) and with the goal to derive orientation-specific information, the organization of the ultrastructure can be analysed [53,[55][56][57][58][59]. The imaging techniques typically have a considerably lower FOV than the orientation-specific techniques employing the same probe ( presented earlier).…”

Section: Imaging Techniquesmentioning

confidence: 99%

“…However, equipment is costly and bone sample preparation procedures labour intensive [2,238]. Secondary electrons allow sample texture and topography to be analysed, and have been used in SEM to determine collagen fibril orientation in different tissues such as ligaments [57], menisci [239], tendons [240,241] and cartilage [242,243], as well as bone [203,209,210]. SEM gives access to mineralization levels and elemental analysis using backscattered electrons and energy-dispersive X-rays, respectively, generated by the interaction of the electron beam with the sample [2,204].…”

Section: Scanning Electron Microscopymentioning

confidence: 99%

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Techniques to assess bone ultrastructure organization: orientation and arrangement of mineralized collagen fibrils

Georgiadis

Müller

Schneider

2016

J. R. Soc. Interface.

108

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Bone's remarkable mechanical properties are a result of its hierarchical structure. The mineralized collagen fibrils, made up of collagen fibrils and crystal platelets, are bone's building blocks at an ultrastructural level. The organization of bone's ultrastructure with respect to the orientation and arrangement of mineralized collagen fibrils has been the matter of numerous studies based on a variety of imaging techniques in the past decades. These techniques either exploit physical principles, such as polarization, diffraction or scattering to examine bone ultrastructure orientation and arrangement, or directly image the fibrils at the sub-micrometre scale. They make use of diverse probes such as visible light, X-rays and electrons at different scales, from centimetres down to nanometres. They allow imaging of bone sections or surfaces in two dimensions or investigating bone tissue truly in three dimensions, in vivo or ex vivo, and sometimes in combination with in situ mechanical experiments. The purpose of this review is to summarize and discuss this broad range of imaging techniques and the different modalities of their use, in order to discuss their advantages and limitations for the assessment of bone ultrastructure organization with respect to the orientation and arrangement of mineralized collagen fibrils.

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“…To quantify local collagen fibril orientation in the matrices, we applied a previously described Fourier transform (FT) analysis procedure (Chaudhuri et al 1987, Kim et al 2006, Kronick and Sacks 1991, Petroll et al 1993). This approach is based on the fact that the relative strength of different angle bands within the FT spectrum is a global indicator of the relative number and magnitude of fibers oriented at 90°to that angle in the original image.…”

Section: Assessment Of Local Collagen Fibril Orientationmentioning

confidence: 99%

Differential interference contrast and confocal reflectance imaging of collagen organization in three‐dimensional matrices

Petroll

2006

Scanning

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Summary:The remodeling of extracellular matrices by cells plays a defining role in developmental morphogenesis and wound healing as well as in tissue engineering. Threedimensional (3-D) type I collagen matrices have been used extensively as an in vitro model for studying cell-induced matrix reorganization at the macroscopic level. However, few studies have directly assessed the process of 3-D extracellular matrix (ECM) remodeling at the cellular and subcellular level. In this study, we directly compare two imaging modalities for both quantitative and qualitative imaging of 3-D collagen organization in vitro: differential interference contrast (DIC) and confocal reflectance imaging. The results demonstrate that two-dimensional (2-D) DIC images allow visualization of the same population of collagen fibrils as observed in 2-D confocal reflectance images. Thus, DIC can be used for qualitative assessment of fibril organization, as well as tracking of fibril movement in sequential time-lapse 2-D images. However, we also found that quantitative techniques that can be applied to confocal reflectance images, such as Fourier transform analysis, give different results when applied to DIC images. Furthermore, common techniques used for 3-D visualization and reconstruction of confocal reflectance datasets are not generally applicable to DIC. Overall, obtaining a complete understanding of cell-matrix mechanical interactions will likely require a combination of both wide-field DIC imaging to study rapid changes in ECM deformation which can occur within minutes, and confocal reflectance imaging to assess more gradual changes in cell-induced compaction and alignment of ECM which occur over a longer time course.

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A Fourier Domain Directional Filterng Method for Analysis of Collagen Alignment in Ligaments

Cited by 98 publications

References 21 publications

Quantitative assessment of local collagen matrix remodeling in 3-D Culture: The role of Rho kinase

Quantitative assessment of local collagen matrix remodeling in 3-D Culture: The role of Rho kinase

Techniques to assess bone ultrastructure organization: orientation and arrangement of mineralized collagen fibrils

Differential interference contrast and confocal reflectance imaging of collagen organization in three‐dimensional matrices

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