Autoimmune Hepatitis

Published on 09/08/2015 by admin

Filed under Radiology

Last modified 09/08/2015

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(Left) Venous phase CT shows heterogeneous liver parenchyma with evidence of periportal edema image, a nonspecific sign often seen in acute hepatitis, among other causes.

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(Right) CT section in the same case shows subcapsular and peripheral wedge-shaped foci of hyperdensity image, representing confluent fibrosis and is usually seen in advanced and more chronic liver damage. Liver biopsy showed acute and advanced liver injury due to autoimmune hepatitis (AIH).
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(Left) Axial CECT of an autoimmune hepatitis-primary sclerosing cholangitis (AIH-PSC) overlap shows a nodular, cirrhotic liver with signs of portal hypertension, including splenomegaly, ascites, and varices image. The intrahepatic ducts image are dilated with an abnormal arborization, suggestive of PSC.

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(Right) Axial CECT in the same patient shows dysmorphic liver, ascites, varices, and dilated, irregular intrahepatic bile ducts typical of primary sclerosing cholangitis.

TERMINOLOGY

Abbreviations

• Autoimmune hepatitis (AIH)

Synonyms

• Chronic active hepatitis

Definitions

• Chronic hepatitis of unknown etiology characterized by hyperglobulinemia, circulating autoantibodies, and inflammatory changes on hepatic histology

IMAGING

General Features

• Best diagnostic clue

image Dysmorphic liver with prominent periportal fibrosis ± signs of portal hypertension ± irregular intrahepatic ductal dilation

– Widened fissures, deep gallbladder fossa, ↑ caudate:right lobe ratio

Radiographic Findings

• AIH is not diagnosed specifically by imaging criteria

CT Findings

• CECT

image Typical signs of cirrhosis + portal hypertension
image Bands of fibrosis may show persistent, increased, delayed enhancement
image Irregular dilation of intrahepatic ducts in autoimmune hepatitis-primary sclerosing cholangitis (AIH-PSC) overlap disease

MR Findings

• Signs of cirrhosis ± portal hypertension
• MRCP is best for detecting irregular dilation of intrahepatic ducts in AIH-PSC overlap disease

Imaging Recommendations

• Best imaging tool

image MR with MRCP

DIFFERENTIAL DIAGNOSIS

Primary Biliary Cirrhosis (PBC)

• Imaging and other features may simulate or coexist with AIH: AIH-PBC overlap disease
• PBC typically affects middle-aged women
• Leads to early cholestatic injury (pruritus + jaundice)
• Imaging: Prominent regenerative nodules, lace-like fibrosis, large perihepatic lymph nodes

Primary Sclerosing Cholangitis (PSC)

• Imaging and clinical features may simulate or coexist with AIH: AIH-PBC overlap disease
• Often associated with ulcerative colitis
• Irregular dilation and arborization of bile ducts with thickened walls

Viral Hepatitis

• Imaging and clinical features may be identical to AIH
• Differentiation relies on serologic testing and evidence of viral antigens ± antibodies

Alcoholic Hepatitis

• Imaging evidence of steatosis
• History of alcohol use, biopsy evidence of steatosis, hepatocyte inflammation, and necrosis

PATHOLOGY

Staging, Grading, & Classification

• May exist as classic or typical form (type 1 AIH)

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