title: Collagen Content Limits Optical Coherence Tomography Image Depth in Porcine Vocal Fold Tissue.
abstract: Vocal fold scarring, a condition defined by increased collagen content, is challenging to treat without a method of noninvasively assessing vocal fold structure in vivo. The goal of this study was to observe the effects of vocal fold collagen content on optical coherence tomography imaging to develop a quantifiable marker of disease.
  
  
  
  Excised specimen study.
  
  
  
  Massachusetts Eye and Ear Infirmary.
  
  
  
  Porcine vocal folds were injected with collagenase to remove collagen from the lamina propria. Optical coherence tomography imaging was performed preinjection and at 0, 45, 90, and 180 minutes postinjection. Mean pixel intensity (or image brightness) was extracted from images of collagenase- and control-treated hemilarynges. Texture analysis of the lamina propria at each injection site was performed to extract image contrast. Two-factor repeated measure analysis of variance and t tests were used to determine statistical significance. Picrosirius red staining was performed to confirm collagenase activity.
  
  
  
  Mean pixel intensity was higher at injection sites of collagenase-treated vocal folds than control vocal folds (P < .0001). Fold change in image contrast was significantly increased in collagenase-treated vocal folds than control vocal folds (P = .002). Picrosirius red staining in control specimens revealed collagen fibrils most prominent in the subepithelium and above the thyroarytenoid muscle. Specimens treated with collagenase exhibited a loss of these structures.
  
  
  
  Collagen removal from vocal fold tissue increases image brightness of underlying structures. This inverse relationship may be useful in treating vocal fold scarring in patients.
authors.affiliation: Harvard Medical School, Boston, Massachusetts, USA jordan_garcia@hms.harvard.edu jordan_garcia@meei.harvard.edu.
authors.forename: Jordan A
authors.initials: JA
authors.lastname: Garcia
authors.affiliation: Department of Engineering Physics, Polytechnique Montreal, Montreal, Canada.
authors.forename: Fouzi
authors.initials: F
authors.lastname: Benboujja
authors.affiliation: Department of Engineering Physics, Polytechnique Montreal, Montreal, Canada.
authors.forename: Kathy
authors.initials: K
authors.lastname: Beaudette
authors.affiliation: Madigan Army Medical Center, Tacoma, Washington, USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Rogers
authors.affiliation: Brigham and Women's Hospital, Boston, Massachusetts, USA.
authors.forename: Rie
authors.initials: R
authors.lastname: Maurer
authors.affiliation: Department of Engineering Physics, Polytechnique Montreal, Montreal, Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Boudoux
authors.affiliation: Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Hartnick
mesh_terms: D000818:Animals; D002921:Cicatrix / Q000000981:diagnostic imaging* / Q000601:surgery*; D003094:Collagen; D004195:Disease Models, Animal; D066298:In Vitro Techniques; D013552:Swine; D041623:Tomography, Optical Coherence; D014827:Vocal Cords / Q000000981:diagnostic imaging* / Q000601:surgery*
chemical_list: D003094:Collagen
keywords: collagen; optical coherence tomography; vocal fold scarring