Diagnostic Ultrasound - Abdomen and Pelvis

Cystic Liver Lesion
○ May be solitary or multiple
○ Large, well-defined, cystic liver mass with numerous
peripheral daughter cysts
○ Cyst-within-cyst appearance
○ Floating membrane within cyst
○ Layered cyst wall is diagnostic
– Thickness reduces posterior acoustic enhancement
• Peribiliary Cyst
○ Well-defined cystic lesions of round/oval/tubular shape
along portal triads
○ Usually multiple; discrete or confluent configuration
○ Smooth and thin walls without internal echoes
○ Variable size from 2 mm to 2 cm
○ No communication with biliary tree
• Biliary Hamartoma
○ Numerous small hypoechoic/hyperechoic foci uniformly
distributed throughout liver
– Leads to inhomogeneous and coarse appearance of
liver echotexture
○ Multiple echogenic foci often associated with "comet
tail" artifacts
○ Typically smaller lesions appear as echogenic foci while
larger lesions appear cystic
– Extent of echogenic foci on US is greater than
anticipated
– Small lesions are too small to resolve sonographically
○ Color Doppler US: Twinkling artifact may be associated
with echogenic foci
• Amebic Abscess
○ Sharply demarcated, round or ovoid mass
○ Hypoechoic with low-level internal echoes
○ May see internal septa or wall nodularity
○ May see posterior acoustic enhancement
• Dilated Bile Ducts
○ Ducts may simulate anechoic nodules when viewed on
cross section
○ Ducts follow periportal distribution
– Long axis orientation with hepatic artery/portal vein
provide clues to its nature
Helpful Clues for Less Common Diagnoses
• Hepatic Lymphoma
○ May be irregular or round/oval in shape
○ ± posterior acoustic enhancement, "pseudocystic"
appearance
○ Extrahepatic signs such as lymphadenopathy,
splenomegaly (± splenic infiltration)
• Hepatic Metastases
○ Anechoic hepatic metastasis
– Suggests low degree of differentiation and high-grade
malignancy
○ Usually no posterior acoustic enhancement
○ May have debris, mural nodularity, &/or thick septations
○ May have irregular margins and contour
○ Wall vascularity
• Ciliated Hepatic Foregut Cyst
○ Unilocular subcapsular solitary cyst located in segment
4a
Helpful Clues for Rare Diagnoses
• Caroli Disease
○ Central dot sign: Portal radicles within dilated
intrahepatic bile ducts on color Doppler ultrasound
Technical Issues
• Important to make sure that gain settings are correct
• Gallbladder or inferior vena cava can be used as internal
references for gain settings
○ These anatomic structures should normally look
anechoic
SELECTED REFERENCES
1. Corvino A et al: Contrast-Enhanced Ultrasound in the Characterization of
Complex Cystic Focal Liver Lesions. Ultrasound Med Biol. ePub, 2015
2. Borhani AA et al: Cystic hepatic lesions: a review and an algorithmic
approach. AJR Am J Roentgenol. 203(6):1192-204, 2014
3. Lantinga MA et al: Evaluation of hepatic cystic lesions. World J Gastroenterol.
19(23):3543-54, 2013
4. Vachha B et al: Cystic lesions of the liver. AJR Am J Roentgenol.
196(4):W355-66, 2011
Differential Diagnoses: Liver
Hepatic Cyst
Polycystic Liver Disease
(Left) Transverse color
Doppler US shows a welldefined
round hepatic cyst
with no internal vascularity
ſt, well-defined back wall st,
and posterior acoustic
enhancement , confirming
the cystic nature of the lesion.
(Right) Transverse grayscale
US of the liver shows
numerous cysts st throughout
the liver in a patient with
polycystic liver disease.
Posterior acoustic
enhancement ſt is associated
with each of the cysts,
confirming cystic nature of
lesions.
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