This procedure is used to directly view the esophagus, stomach, and duodenum; a biopsy can be obtained.

A. ERCP (Endoscopic Retrograde Cholangiopancreatography): Used for imaging and intervention in bile ducts and pancreatic ducts, not primarily for the stomach and duodenum. B. HIDA Scan: A nuclear medicine scan to assess gallbladder function; does not involve biopsy or direct visualization. C. EGD (Esophagogastroduodenoscopy): This procedure allows direct visualization of the esophagus, stomach, and duodenum, and permits biopsy. D. Liver Biopsy: Used to obtain liver tissue, not to view the GI tract.