Use of probe-based confocal laser endomicroscopy (pCLE) in the diagnosis of cholangiocarcinoma.

281 Background: Despite technologic advances in endoscopy and new cytologic techniques, cholangiocarcinoma is a challenging diagnosis for the endoscopist and oncologists. Current sampling techniques include cytology brushing, biopsy, and fine needle aspiration but are limited in their sensitivity. Confocal laser endomicroscopy (CLE) is a relatively new modality that offers in-vivo imaging of the gastrointestinal tract with microscopic detail in living cells. Methods: This was an observational study of 10 patients with indeterminate biliary strictures who were evaluated with ERCP, cholangioscopy, and CLE to determine the sensitivity and specificity of tissue biopsy compared to virtual biopsy using this new technology, CLE. All cases were confirmed to be cholangiocarcinoma by histopathology. Fluorescein 10% was used as a contrast agent. Results: The 10 ERCP cases that were reviewed demonstrated biliary strictures that were suspicious for malignancy based on history and clinical presentation. Nearly all initial brushings and traditional biopsies were inconclusive. Subsequent ERCP and cholangioscopy with CLE imaging was performed. The biliary architecture was concerning for malignancy according to the Miami Criteria. Images were reviewed by 2 independent physicians. Every case demonstrated thick bands >20 µm and dark clumps of glands. Bright vessels ( >20 µm) with tortuosity were visualized in seven cases. Other findings include reticular networks of dark bands and small, fine branching bands <20 µm, but these patterns were infrequent. Conclusions: 1.CLE is a novel tool to investigate indeterminate biliary strictures and potentially diagnose cholangiocarcinoma in conjunction with other diagnostic modalities during the initial ERCP and cholangioscopy. 2. Our early experience found sensitivity 90% , specificity of 100% , NPV 90% 3. CLE gives the opportunity to obtain en-vivo targeted biopsies during cholangioscopy as well as reduce repeat procedures and cost.