Second generation optical coherence tomography: Preliminary experience in pancreatic and biliary strictures.

Introduction: Evaluation of indeterminate biliary strictures remains a diagnostic challenge. Optical coherence tomography (OCT) provides in-vivo, wide-field, cross-sectional imaging at the microstructure level. We present the first preliminary data using a second-generation OCT system using volumetric laser endomicroscopy (VLE) in biliary and pancreatic duct strictures.

Methods: 10 consecutive patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) and OCT for indeterminate biliary or pancreatic stricture evaluation were captured in a registry. Following ductal cannulation and guidewire placement, an imaging probe was advanced into the duct and images were interpreted in-vivo. Tissue sampling with cytology brushing was performed in all cases. Demographics, procedural information, imaging data, and histologic findings were collected.

Results: 8 had biliary strictures and 2 had pancreatic duct strictures. VLE was successfully performed in all patients (100%). Histology revealed malignancy in 3 patients (cholangiocarcinoma) and benign disease in the remaining 7 patients, including 1 with primary sclerosing cholangitis (PSC). All 3 cholangiocarcinoma patients demonstrated epithelial thickening with projections, a hyper-reflective surface with shadowing, and layering effacement (loss of visualization and haziness of inner mucosal layers). A PSC patient showed onion skin layering and hyper-reflective sub-surface structures but with preserved wall layering. Benign biliary strictures showed clearly delineated epithelial layer and clear layering in the inner mucosal layers as well as the presence of dilated hypo-reflective structures.

Conclusion: There may be characteristic VLE findings for malignant, inflammatory, and benign biliary strictures.