Multiscale anisotropy analysis of second-harmonic generation collagen imaging of mouse skin

Abstract

. Significance: Morphological collagen signatures are important for tissue function, particularly in the tumor microenvironment. A single algorithmic framework with quantitative, multiscale morphological collagen feature extraction may further the use of collagen signatures in understanding fundamental tumor progression. Aim: A modification of the 2D wavelet transform modulus maxima (WTMM) anisotropy method was applied to both digitally simulated collagen fibers and second-harmonic-generation imaged collagen fibers of mouse skin to calculate a multiscale anisotropy factor to detect collagen fiber organization. Approach: The modified 2D WTMM anisotropy method was initially validated on synthetic calibration images to establish the robustness and sensitivity of the multiscale fiber organization tool. Upon validation, the algorithm was applied to collagen fiber organization in normal wild-type skin, melanoma stimulated skin, and integrin skin. Results: Normal wild-type skin collagen fibers have an increased anisotropy factor at all sizes scales. Interestingly, the multiscale anisotropy differences highlight important dissimilarities between collagen fiber organization in normal wild-type skin, melanoma stimulated, and integrin skin. At small scales ( to ), the integrin skin was vastly different than normal skin ( ), whereas the melanoma stimulated skin was vastly different than normal at large scales ( to , ). Conclusions: This objective computational collagen fiber organization algorithm is sensitive to collagen fiber organization across multiple scales for effective exploration of collagen morphological alterations associated with melanoma and the lack of integrin binding.

Multiscale anisotropy analysis of second-harmonic generation collagen imaging of human pancreatic cancer

“…Numerically, binning of the PDF is typically fixed to a single number of histogram bins (i.e. 64) at each size scale regardless of the total number of maxima chains ( 26 ). Here, there are significant differences in the number of maxima chains at each scale; therefore, a variable binning approach was developed and implemented.…”

“…A recent publication highlighted the need for a multiscale approach to understanding collagen fiber organization in biological systems using the 2D Wavelet Transform Modulus Maxima (WTMM) anisotropy method on SHG images ( 26 ). The 2D WTMM anisotropy method involves convolving the image with Gaussian derivative wavelets over a continuous range of smoothing scales enabling a multiscale approach to understand organizational changes in an image.…”

“…The 2D WTMM anisotropy method involves convolving the image with Gaussian derivative wavelets over a continuous range of smoothing scales enabling a multiscale approach to understand organizational changes in an image. The method was first developed in the context of Galactic astronomy ( 27 ) and later used in a multitude of applications such as muscle morphogenesis ( 28 – 32 ), artificial bone implants ( 33 ), exploring the relationship between nerve and college in neuropathic adipose tissue ( 34 ), and the aforementioned exploration into comparing mouse melanoma and integrin knockout impact on collagen restructuring ( 26 ). To optimize this method for subtle changes between cancer and fibrotic collagen, updates to the 2D WTMM anisotropy method are being explored and presented in this paper.…”

Elimination of Image Saturation Effects on Multifractal Statistics Using the 2D WTMM Method

“…The 2D Wavelet Transform Modulus Maxima (WTMM) method has been adapted and applied in three different forms: a multiscale segmentation method ( Kestener et al, 2001 ; Khalil et al, 2007 ; Roland et al, 2009 ; Grant et al, 2010 ; Kestener et al, 2010 ; McAteer et al, 2010 ; Batchelder et al, 2014 ; Marin et al, 2018 ; Liu J. et al, 2021 ), a multiscale anisotropy method ( Khalil et al, 2006 , 2009 ; Tilbury et al, 2021 ), and a multifractal formalism ( Arneodo et al, 2000 ; Decoster et al, 2000 ; Roux et al, 2000 ; Arneodo et al, 2003 ; Khalil et al, 2006 ). The 2D WTMM multifractal method is a multiscale formalism perfectly suited for the analysis of self-affine rough surfaces such as mammograms by identifying density fluctuations and spatial correlations within these surfaces ( Batchelder et al, 2014 ; Plourde et al, 2016 ; Marin et al, 2017 ; Gerasimova-Chechkina et al, 2021 ).…”