Vicarious Excretion of Contrast by the Gallbladder
Hello Glias !! Vicarious excretion refers to the elimination of contrast media through an alternate organ when the primary pathway (usually kidneys) is impaired or overloaded. When the gallbladder shows opacification after intravenous iodinated contrast, it indicates that the liver and biliary system are partially taking over the role of excreting contrast. Why does it happen? Typically seen when: • Renal function is compromised (AKI, CKD) • High contrast load is administered • Delayed imaging after contrast injection • Hypotension or hemodynamic instability reduces renal clearance The contrast is taken up by hepatocytes and excreted into bile, causing visible density in: • Intrahepatic bile ducts • Common bile duct • Gallbladder lumen CT Findings • Hyperdense bile within gallbladder on delayed or follow-up scans • Densities can mimic stones or sludge • No associated wall thickening or obstruction typically Clinica...