The fibrotic area appeared as blue when stained with Masson trichrome stain (A). Quantitative measurement of fibrosis area was performed by summing the amount of areas stained in blue (B), with the assistance of an image analyzer: IPAP (Image Processor for Analytical Pathology, Sumika Technoservice Co., Hyogo, Japan). In this example, % fibrosis area was calculated as 14.8%.