intrahepatic

Intrahepatic is an anatomical term meaning located within the liver. It is used to describe structures, processes, or diseases that occur inside the hepatic parenchyma or within the intrahepatic portions of the biliary system, as distinct from those outside the liver (extrahepatic).

Within the liver, bile is collected from hepatocytes into tiny canaliculi, then into intrahepatic bile ducts that reside in the portal tracts. These ducts merge to form the left and right hepatic ducts at the porta hepatis, which then carry bile to the extrahepatic ducts. The liver’s functional units, the lobules, and their vascular networks (hepatic arteries, portal veins, and hepatic veins) are organized and operate within the intrahepatic region. The term is frequently used to differentiate processes happening inside the liver from those occurring in bile ducts or vessels outside the liver.

Clinically, intrahepatic is used in disease terminology and descriptions. Examples include intrahepatic cholestasis, a condition in which bile flow is impaired within the liver; intrahepatic cholangiocarcinoma, a cancer arising from the intrahepatic bile ducts; and intrahepatic abscesses or intrahepatic metastases, referring to lesions located within hepatic tissue. The term is also used in radiology and surgery to specify the location of findings or procedures.

Imaging and diagnosis typically involve ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) to assess intrahepatic structures and pathologies. Magnetic resonance cholangiopancreatography (MRCP) can visualize the intrahepatic bile ducts, while liver function tests help characterize the pattern of injury or obstruction.

Etymology derives from intra- meaning within and hepaticus meaning of the liver.