title: A robust collagen scoring method for human liver fibrosis by second harmonic microscopy.
abstract: Second Harmonic Generation (SHG) microscopy offers the opportunity to image collagen of type I without staining. We recently showed that a simple scoring method, based on SHG images of histological human liver biopsies, correlates well with the Metavir assessment of fibrosis level (Gailhouste et al., J. Hepatol., 2010). In this article, we present a detailed study of this new scoring method with two different objective lenses. By using measurements of the objectives point spread functions and of the photomultiplier gain, and a simple model of the SHG intensity, we show that our scoring method, applied to human liver biopsies, is robust to the objective's numerical aperture (NA) for low NA, the choice of the reference sample and laser power, and the spatial sampling rate. The simplicity and robustness of our collagen scoring method may open new opportunities in the quantification of collagen content in different organs, which is of main importance in providing diagnostic information and evaluation of therapeutic efficiency.
authors.affiliation: Institut of Physics of Rennes IPR/UMR CNRS 6251, University of Rennes I, Campus de Beaulieu, Bat 11A, 35042 Rennes Cedex, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Guilbert
authors.forename: Christophe
authors.initials: C
authors.lastname: Odin
authors.forename: Yann
authors.initials: Y
authors.lastname: Le Grand
authors.forename: Luc
authors.initials: L
authors.lastname: Gailhouste
authors.forename: Bruno
authors.initials: B
authors.lastname: Turlin
authors.forename: Frédérick
authors.initials: F
authors.lastname: Ezan
authors.forename: Yoann
authors.initials: Y
authors.lastname: Désille
authors.forename: Georges
authors.initials: G
authors.lastname: Baffet
authors.forename: Dominique
authors.initials: D
authors.lastname: Guyader
mesh_terms: D000465:Algorithms; D014408:Biomarkers, Tumor / Q000032:analysis; D024042:Collagen Type I / Q000648:ultrastructure*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008103:Liver Cirrhosis / Q000473:pathology*; D008856:Microscopy, Fluorescence / Q000379:methods*; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D024042:Collagen Type I