First in vivo optical coherence tomography in the human bile duct

Background and Study Aims: Optical coherence tomography (OCT) is a novel technique for performing high-resolution, cross-sectional tomographic imaging in human tissue, which allows resolution of up to 10 mum. The short depth of penetration allows assessment of the superficial 2 mm of the gastrointestinal tract, an area that is difficult to appraise even with high-frequency ultrasound. This is the first report on in vivo OCT of the human biliary system. The aim was to assess the feasibility of the technique. Patients and Methods: Four cases of intraductal OCT are presented. The probe was inserted through the working channel of a duodenoscope. Results: The connective tissue layer and the underlying retroperitoneal tissue, with less backscattering, could be clearly demonstrated. The images showed a layer architecture which was similar to that found histologically. Conclusions: OCT of the biliary system is feasible in patients with biliary pathology. Interpretable images were obtained, and clinical use needs further assessment. As current OCT probes and processors do not yet provide optimal resolution, further generations of equipment with improved image quality are required.