Intraductal optical coherence tomography during endoscopic retrograde cholangiopancreatography for investigation of biliary strictures

Background and study aims: Optical coherence tomography (OCT) uses infrared light reflectance to produce high-resolution cross-sectional tissue images. The aim of this study was to demonstrate the feasibility of biliary intraductal OCT during endoscopic retrograde cholangiopancreatography (ERCP) and to assess the potential of the method to detect malignant biliary strictures. Patients and methods: Thirty-seven patients with biliary strictures were studied during therapeutic ERCR Malignant strictures were defined as those that demonstrated malignant cells in brushing and/or biopsy specimens, and/or endoscopic ultrasound-guided fine-needle aspiration and/or surgery. Strictures that did not have malignant cells in resected specimens and were without clinical/radiological evidence of disease progression for at least a 12-month follow-up period were considered as benign. Two OCT criteria for malignancy were considered: unrecognizable layer architecture; and presence of large, nonreflective areas compatible with tumor vessels. Sensitivity and specificity for brushings/biopsies as well as OCT criteria were calculated. Results: Nineteen patients had malignant and 16 had benign strictures. In two patients, OCT assessment could not be performed due to tight strictures. Malignancy was confirmed by biliary brushings/biopsies in 12/19 (63%) patients. OCT revealed that two malignancy criteria were encountered in 10/19 (53%) and at least one criterion in 15/19 (79%) patients with malignant strictures. No patient with benign stricture met both criteria and 5/16 met one criterion (31%). Combining brushings/biopsy with the observation of at least one OCT criterion resulted in the diagnosis of malignancy in 16/19 (84%) patients. Conclusions: OCT may improve the sensitivity and diagnostic accuracy of biliary brushings/biopsies alone.