Introduction
Types of infectious cause | Sub-classifications | Organisms |
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Bacterial | Pyogenic abscess | Polymicrobial Escherichia coli Klebsiella pneumoniae |
Bacterial granulomatous disease | Mycobacterium tuberculosis Brucella species Bartonella species | |
Acute viral | Hepatitis A, B, C, D and E virus Human immunodeficiency viruses | |
Fungal | Candida albicans Histoplasma capsulatum | |
Parasitic | Infection of the hepatic parenchyma | Echinococcus species Entamoeba histolytica |
Infection of hepatic vessels | Schistosoma species | |
Infection of bile ducts | Fasciola species Ascaris lumbricoides Clonorchis sinensis |
Hepatic infection | Typical imaging findings | |
---|---|---|
Pyogenic | Uni/multilocular lesion, multiple tiny lesions coalesce to form a larger lesion (cluster sign), “double target” sign | |
Tuberculosis | Hepatomegaly, multiple diffuse tiny lesions (miliary form), a non-specific unilocular lesion | |
Brucellosis | Hepatomegaly, multiple diffuse tiny lesions with possible thick peripheral enhancement, unilocular lesion with central calcification | |
Bartonellosis | Multiple non-specific lesions up to 3 cm | |
Hepatitis viruses | Hepatomegaly, “starry sky” sign on US, periportal edema, hepatic hilum lymph node enlargement, gallbladder wall thickening | |
HIV | Hepatomegaly, periportal lymph node enlargement, HIV cholangiopathy presented with papillary stenosis, long extrahepatic bile duct stenosis and irregular aspect of intrahepatic bile ducts | |
Candidiasis | “Wheel-within-a-wheel” sign, “bull’s eye” sign, focal fibrosis on area of prior inflammation, focal scars and calcifications | |
Histoplasmosis | Multiple non-specific small nodules | |
Cystic echinococcosis | CE | Unilocular anechoic well-defined lesion with imperceptible wall |
CL1 | Snowstorm sign | |
CL2 | Rosette sign | |
CL3a | Water-lily sign | |
CL3b | Cystic lesion containing multiple daughter cysts | |
CL4 | Ball of wool sign | |
CL5 | Partially or entirely calcified cyst | |
Alveolar echinococcosis | Type 1 | Multilocular small cysts without solid component |
Type 2 | Multilocular small cysts with solid component | |
Type 3 | Solid component which envelop large cyst and multiple small cysts | |
Type 4 | Solid component without cystic part | |
Type 5 | A unilocular large cyst | |
Amebic | “Double target” sign, lesions with central hypoattenuation slightly more attenuating than water on CT | |
Schistosomiasis | Hepatomegaly, periportal fibrosis, “turtle back” or “tortoise shell” sign | |
Fascioliasis | Patchy and linear ill-defined subcapsular lesions converging from the hepatic capsule toward the hepatic hilum, focal thickening and enhancement of Glisson capsule, thickening and dilatation of biliary ducts | |
Ascariasis | Tubular structures in the biliary tree corresponding to adult worms, hepatic abscess as non-specific focal lesion | |
Clonorchiasis | Mild diffuse peripheral intrahepatic bile duct dilatation reaching the subcapsular area with relative sparing of extrahepatic bile duct, thickening of bile duct wall with increased periductal enhancement, stenosis of intrahepatic bile ducts |
Bacterial infections
Pyogenic liver abscess
Ultrasonography
Computed tomography
Magnetic resonance imaging
Differential diagnosis
Tuberculosis
Ultrasonography
Computed tomography
Magnetic resonance imaging
Differential diagnosis
Brucellosis
Ultrasonography
Computed tomography
Magnetic resonance imaging
Differential diagnosis
Bartonellosis
Ultrasonography
Computed tomography
Magnetic resonance imaging
Differential diagnosis
Acute viral infection
Viral hepatitis
Ultrasonography
Computed tomography
Magnetic resonance imaging
Differential diagnosis
Human Immunodeficiency Virus (HIV)
Ultrasonography
Computed tomography
Magnetic resonance imaging
Differential diagnosis
Fungal infection
Hepatic candidiasis
Ultrasonography
Computed tomography
Magnetic resonance imaging
Differential diagnosis
Hepatic histoplasmosis
Parasitic infections
Infection of the hepatic parenchyma
Echinococcosis
Echinococcus granulosus
Ultrasonography
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CL (cystic lesions): are well-defined, unilocular, anechoic lesions with an imperceptible wall.
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CE2: is a cystic lesion that contains multiple septa or multiple cystic lesions involving nearly the entire cystic cavity so that the walls of the cysts are very close to each other, with a “rosette” appearance.
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CE3b: is a cystic lesion that encases multiple daughter cysts. The daughter cysts are arranged peripherally in the cystic cavity which contains a solid-appearing matrix compared to the fluid in CE2.
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CE4: presents as a heterogeneous mass that ranges from hypoechoic to hyperechoic on US, with no identifiable daughter cyst.
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CE5: is a partially or entirely calcified cyst. When the cyst wall is calcified, it presents as a hyperechoic peripheral rim with acoustic shadow.