First in vivo optical coherence tomography in the human bile duct

Background and Study Aims: Optical coherence tomography (OCT) is a novel te chnique 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 gastrointes tinal 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 s ystem. The aim was to assess the feasibility of the technique. Patients and Methods: Four cases of intraductal OCT are presented. The prob e was inserted through the working channel of a duodenoscope. Results: The connective tissue layer and the underlying retroperitoneal tis sue, with less backscattering, could be clearly demonstrated. The images sh owed 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 furt her assessment. As current OCT probes and processors do not yet provide opt imal resolution, further generations of equipment with improved image quali ty are required.