title: Fully automated muscle quality assessment by Gabor filtering of second harmonic generation images.
abstract: Although structural changes on the sarcomere level of skeletal muscle are known to occur due to various pathologies, rigorous studies of the reduced sarcomere quality remain scarce. This can possibly be explained by the lack of an objective tool for analyzing and comparing sarcomere images across biological conditions. Recent developments in second harmonic generation (SHG) microscopy and increasing insight into the interpretation of sarcomere SHG intensity profiles have made SHG microscopy a valuable tool to study microstructural properties of sarcomeres. Typically, sarcomere integrity is analyzed by fitting a set of manually selected, one-dimensional SHG intensity profiles with a supramolecular SHG model. To circumvent this tedious manual selection step, we developed a fully automated image analysis procedure to map the sarcomere disorder for the entire image at once. The algorithm relies on a single-frequency wavelet-based Gabor approach and includes a newly developed normalization procedure allowing for unambiguous data interpretation. The method was validated by showing the correlation between the sarcomere disorder, quantified by the M-band size obtained from manually selected profiles, and the normalized Gabor value ranging from 0 to 1 for decreasing disorder. Finally, to elucidate the applicability of our newly developed protocol, Gabor analysis was used to study the effect of experimental autoimmune encephalomyelitis on the sarcomere regularity. We believe that the technique developed in this work holds great promise for high-throughput, unbiased, and automated image analysis to study sarcomere integrity by SHG microscopy.
authors: Hasselt University, Biomedical Research Institute, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors: Rik
authors: R
authors: Paesen
authors: Hasselt University, Biomedical Research Institute, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors: Sophie
authors: S
authors: Smolders
authors: Hasselt University, Biomedical Research Institute, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors: José Manolo de Hoyos
authors: JM
authors: Vega
authors: Hasselt University, Biomedical Research Institute, Agoralaan Building C, 3590 Diepenbeek, BelgiumbHasselt University, REVAL-Rehabilitation Research Center, Agoralaan Building A, 3590 Diepenbeek, Belgium.
authors: Bert O
authors: BO
authors: Eijnde
authors: Hasselt University, Biomedical Research Institute, Agoralaan Building C, 3590 Diepenbeek, BelgiumbHasselt University, REVAL-Rehabilitation Research Center, Agoralaan Building A, 3590 Diepenbeek, Belgium.
authors: Dominique
authors: D
authors: Hansen
authors: Hasselt University, Biomedical Research Institute, Agoralaan Building C, 3590 Diepenbeek, Belgium.
authors: Marcel
authors: M
authors: Ameloot
mesh_terms: D000465:Algorithms; D000818:Animals; D003198:Computer Simulation; D005260:Female; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008853:Microscopy / Q000379:methods*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009135:Muscular Diseases / Q000503:physiopathology; D051381:Rats; D012518:Sarcomeres / Q000502:physiology