Confluent hepatic fibrosis
Confluent hepatic fibrosis is a possible result of chronic injury to the liver, most commonly from cirrhosis or hepatic vascular injury.
Confluent hepatic fibrosis is a cause of wedge-shaped or concave-marginated abnormalities in the cirrhotic liver: It occurs more frequently in the medial and anterior segments of the liver and tends to extend from the hilum to the periphery.
- wedge-shaped regions of hypoattenuation on noncontrast CT
- hypoattenuating on the arterial and portal venous phases
- the fibrosis may gradually enhance
- wedge-shaped regions of moderate T2 hyperintensity
- progressive postcontrast enhancement on the dynamic sequence (does not show enhancement on the delayed phase with Eovist)
- lack of fat signal intensity
- T1 hypointensity (possible increased T1 signal from cholestasis)
Confluent hepatic fibrosis is categorized as LR1 or LR2 in the LI-RADS classification system. If findings are indeterminate between fibrosis and hepatocellular carcinoma, it should be graded LR3 or LR4.
The main differential diagnoses are:
The signal and enhancement characteristics in confluent hepatic fibrosis overlap with other hepatic processes, but important features of confluent hepatic fibrosis include:
- sharply marginated attenuation/signal abnormality
- volume loss (with possible capsular retraction)
Peripheral cholangiocarcinoma may also show capsular retraction, but generally is more masslike. Dilated intrahepatic bile ducts are also more common in cholangiocarcinoma than with confluent hepatic fibrosis.
The enhancement pattern allows differentiation from hepatocellular carcinoma.
Hepatic epithelioid hemangioendothelioma may show capsular retraction, but otherwise has a different appearance and enhancement pattern.
For unknown reasons, confluent fibrosis is more common in primary sclerosing cholangitis and alcohol-related cirrhosis than with viral cirrhosis.
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