title: Nonlinear optical microscopy: use of second harmonic generation and two-photon microscopy for automated quantitative liver fibrosis studies.
abstract: Liver fibrosis is associated with an abnormal increase in an extracellular matrix in chronic liver diseases. Quantitative characterization of fibrillar collagen in intact tissue is essential for both fibrosis studies and clinical applications. Commonly used methods, histological staining followed by either semiquantitative or computerized image analysis, have limited sensitivity, accuracy, and operator-dependent variations. The fibrillar collagen in sinusoids of normal livers could be observed through second-harmonic generation (SHG) microscopy. The two-photon excited fluorescence (TPEF) images, recorded simultaneously with SHG, clearly revealed the hepatocyte morphology. We have systematically optimized the parameters for the quantitative SHG/TPEF imaging of liver tissue and developed fully automated image analysis algorithms to extract the information of collagen changes and cell necrosis. Subtle changes in the distribution and amount of collagen and cell morphology are quantitatively characterized in SHG/TPEF images. By comparing to traditional staining, such as Masson's trichrome and Sirius red, SHG/TPEF is a sensitive quantitative tool for automated collagen characterization in liver tissue. Our system allows for enhanced detection and quantification of sinusoidal collagen fibers in fibrosis research and clinical diagnostics.
authors.affiliation: Institute of Bioengineering and Nanotechnology, The Nanos #4-01, 31 Biopolis Way, Singapore, Singapore 138669.
authors.forename: Wanxin
authors.initials: W
authors.lastname: Sun
authors.forename: Shi
authors.initials: S
authors.lastname: Chang
authors.forename: Dean C S
authors.initials: DC
authors.lastname: Tai
authors.forename: Nancy
authors.initials: N
authors.lastname: Tan
authors.forename: Guangfa
authors.initials: G
authors.lastname: Xiao
authors.forename: Huihuan
authors.initials: H
authors.lastname: Tang
authors.forename: Hanry
authors.initials: H
authors.lastname: Yu
mesh_terms: D000465:Algorithms; D000818:Animals; D001185:Artificial Intelligence; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008103:Liver Cirrhosis / Q000473:pathology*; D008297:Male; D036641:Microscopy, Fluorescence, Multiphoton / Q000379:methods*; D017711:Nonlinear Dynamics; D010363:Pattern Recognition, Automated / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique