Anatomy

• How does ERCP differ from other biliary imaging studies?
  ERCP provides both direct endoscopic access and retrograde contrast injection into the ducts, allowing visualization of the biliary and pancreatic systems simultaneously.
• How does the ampulla of Vater function in bile and enzyme flow?
  It is the common junction where bile and pancreatic enzymes enter the duodenum; obstruction here can block both systems.
• How can pathology alter normal ductal anatomy?
  Obstructions (stones, tumors, or strictures) cause ductal dilation proximal to the site, while leaks result in contrast extravasation into surrounding tissues.

Positioning

• Why is the patient positioned prone or semiprone (RAO)?
  This position projects the duodenal loop and ampulla of Vater away from the spine, providing a clear fluoroscopic window to the ducts.
• Why is the head slightly elevated or turned to the left?
  It facilitates endoscopic passage through the esophagus and stomach and allows secretions to drain away from the airway.
• Why must the patient remain still during the procedure?
  Motion causes blurring of the delicate ductal structures, making it difficult to assess patency or identify small stones.
• Why is the C-arm angled slightly to the right side of the patient?
  It aligns the x-ray beam with the plane of the duodenum and reduces overlap of the spine over the biliary ducts.

Technique & Image Evaluation

• How do you confirm complete ductal opacification?
  The contrast should outline the hepatic ducts, common bile duct, and pancreatic duct, with visible contrast flow into the duodenum.
• How can you identify stones or strictures?
  They appear as filling defects — round or irregular areas where contrast is displaced or abruptly narrowed.
• How can you assess the quality of contrast injection?
  Injection should be smooth and controlled, showing gradual filling without reflux into the pancreatic duct or extravasation.
• How can you verify correct patient rotation on fluoroscopic images?
  The duodenal loop should appear open and free from vertebral superimposition; if overlapped, adjust toward a greater RAO angle.
• How can you detect leakage or perforation?
  Contrast escaping the ductal confines and accumulating outside the expected anatomy indicates a bile leak or perforation.

Clinical Applications

• What does ERCP stand for?
  Endoscopic Retrograde Choleangiopancreatography.
• Why is ERCP both diagnostic and therapeutic?
  It allows visualization of ductal anatomy and enables immediate intervention — such as stone removal, sphincterotomy, or stent placement — in the same session.
• Why is ERCP rarely performed in pediatric patients?
  Because biliary or pancreatic disorders are uncommon in children; when performed, it is usually for congenital anomalies such as biliary atresia or postoperative complications.
• Why is ERCP more common in geriatric patients?
  Older adults have a higher incidence of gallstone disease, biliary obstruction, and pancreatic carcinoma, making ERCP an important diagnostic and therapeutic tool.
• Why might ERCP be performed after gallbladder removal?
  To evaluate for retained stones, post-surgical strictures, or bile leaks, ensuring ductal patency following cholecystectomy.
• Why is NPO status required before ERCP?
  An empty stomach and duodenum reduce aspiration risk and ensure unobstructed passage of the endoscope.
• Why is iodinated contrast used instead of barium?
  Iodinated media are water-soluble, easily absorbed, and safe if leakage occurs; barium could cause severe peritonitis.
• Why must contrast injection be performed under direct fluoroscopic control?
  Real-time visualization prevents overfilling and identifies complications like reflux or perforation immediately.
• Why is patient monitoring essential after ERCP?
  The patient must be observed for post-procedural pancreatitis, bleeding, infection, or perforation, as these can occur within hours of the procedure.