Endoscopic Evaluation of Bile Duct Strictures

Differentiating between malignant and benign bile duct strictures is often challenging. Endoscopic retrograde cholangiopancreatography with brush cytology and/or endobiliary forceps biopsy is routinely performed. Advanced cytologic methods such as fluorescence in situ hybridization or digital image analysis increases the sensitivity of cytology. Endoscopic ultrasonography enables detailed examination of tissues surrounding the bile duct stricture and offers the advantage of fine-needle aspiration. Intraductal ultrasonography enables detailed evaluation of bile duct wall layers, and cholangioscopy offers direct visualization of the bile duct lesions. Novel techniques of probe-based confocal laser endomicroscopy and optical coherence tomography have introduced the era of in vivo histology.

Key points

•

Cholangiographic impression with brush cytology and/or endobiliary forceps biopsy may offer high sensitivity and specificity.
•

Advanced cytologic methods such as fluorescence in situ hybridization and digital image analysis offer modest improvement of sensitivity. These methods may be helpful in patients with presumed malignancy with negative cytology and histology.
•

Endoscopic ultrasonography offers imaging of bile duct stricture, staging of lymph nodes, prediction of portal vein invasion, and fine-needle aspiration. Endoscopic retrograde cholangiopancreatography with intraductal ultrasonography may improve the diagnostic yield of bile duct strictures.
•

Although conventional (percutaneous or mother-and-babyscope) cholangioscopy with or without biopsy shows impressive performance, it requires percutaneous biliary access with subsequent dilations or 2 endoscopists, with a long procedure time.
•

Single-operator cholangioscopy enables peroral cholangioscopy without the need for 2 endoscopists.
•

Probe-based confocal laser endomicroscopy and optical coherence tomography may provide in vivo histology. However, more evaluation and refinement is needed as regards their clinical utility.