What should be done with a dilated bile duct?

Current methods for imaging the biliary tree include ultrasound, CT, MRI, endoscopic retrograde cholangiography, and endoscopic ultrasound (EUS). Bile duct abnormalities may be identified during evaluation of patient symptoms or laboratory abnormalities, or incidentally during imaging for another problem. Biliary dilatation, when identified, may be separated into obstructive or nonobstructive causes. Clinical presentation should guide decisions on which, if any, additional investigations are necessary. Choledocholithiasis is the most common cause of obstructive dilatation and frequently requires decompression. Nonobstructive causes include cystic dilatation, aging, and possibly post-cholecystectomy state. Data are limited regarding the yield of further investigations in patients with incidentally identified modest ductal dilatation without symptoms or laboratory abnormalities. Additional investigations are more likely to identify clinically relevant findings in patients with more pronounced dilatation. EUS is highly accurate, low-invasive, and useful in this setting, whereas ERC should be reserved for cases likely to require therapeutic intervention.