Which imaging modality provides diagnostic and potential therapeutic access to the biliary tree?

• A. ERCP
• B. MRCP
• C. Ultrasound
• D. CT

Answer: (A)

Endoscopic retrograde cholangiopancreatography provides both diagnostic visualization of the biliary tree and the ability to perform therapeutic interventions. By advancing an endoscope to the duodenum and cannulating the common bile duct, clinicians can inject contrast to image the ducts under fluoroscopy and, at the same time, carry out treatments such as stone extraction, biliary sphincterotomy, stent placement, or dilation of strictures.

Other imaging options visualize the biliary system but do not offer access for therapy: MRCP shows detailed ductal anatomy noninvasively but cannot intervene; ultrasound and CT can detect ductal dilation or stones and assess surrounding structures but do not provide a route for therapeutic access to the biliary tree.