Introduction
tumor, biliary dysplasia, malignant transformation, LSS, cholangiocarcinoma
MALIGNANT TRANSFORMATION, TUMOR, BILE DUCT CANCER, CHOLANGIOCARCINOMA
Bile duct cancer, also known as cholangiocarcinoma, is characteristically diagnosed late as most people have no identifiable risk factorsEarly detection of cholangiocarcinoma is challenging not only because of its asymptomatic character and anatomically hard-to-access location, but also due to low specificity of most diagnostic modalitiesUnlike radiological imaging, endoscopic techniques allow direct tissue investigation. They can detect structural changes in multiple top layers of the bile duct during early tumor development, thereby improving sensitivity. For example, endoscopic retrograde cholangiopancreatography (ERCP) can obtain samples of the bile duct lining by brush cytology. While conventional ERCP procedures use X-rays for navigation, recently it became possible to directly visualize the lining of the bile duct in cholangioscopy procedures using ancillary endoscopes, with members of our team pioneering cholangioscopy using the SpyGlass (Boston Scientific) cholangioscopeConventional visualization of the bile duct lining has been enhanced by employing narrow-band imaging (NBI)Another optical medical technology tested for detection of biliary dysplasia is optical coherence tomography (OCT)Fiber-optic label-free light scattering and absorption based optical spectroscopic approaches, such as biomedical diffuse reflectance spectroscopy (DRS)In this paper, we combined LSS and DRS modalities, designing and constructing a miniature LSS-DRS fiber optic probe compatible with the 1.2 mm diameter working channel of clinical cholangioscopes and ERCP catheters. This allowed us to investigate the internal cellular composition of the bile duct and detect malignant transformation (see Fig. 