Imaging pancreatobiliary ductal system with optical coherence tomography: A review

Figure 2 In vivo optical coherence tomography image of a normal common bile duct wall. Three recognizable layers were observed from the surface of the duct to a depth of 1 mm (Color online). The inner single layer of epithelial (EL) cells (400-600 μm thick) is visible as a superficial, hypo-reflective layer. The intermediate connective fibro-muscular (FM) layer surrounding the epithelium is visible as a hyper-reflective layer (350-480 μm thick) and the outer connective layer (CL) is visible as a hypo-reflective layer with longitudinal relatively hyper-reflective strips (smooth muscle fibers)[58]. White scale bar: 150 μm.