Diagnostic Ultrasound - Abdomen and Pelvis

Multiple Hepatic Masses
○ Cluster sign
– Cluster of small abscesses coalesce into single
septated cavity
○ Complex cyst with septa and debris
○ ± ill-defined borders
○ Mural nodularity and vascularity
○ May contain gas within abscess
– Seen as echogenic foci of air or air-fluid level
○ Adjacent parenchyma may be coarse and hypoechoic
○ Color Doppler may show hypervascularity in inflamed
surrounding liver parenchyma
• HepaticMicroabscesses
○ Multiple, small, hypo-/iso-/hyperechoic lesions
○ Central hypoechoic area of necrosis within hyperechoic
lesion
○ Target sign
– Central hyperechoic inflammation surrounded by
hypoechoic "halo" of fibrosis
○ Similar lesions may be found in spleen
• Cholangitis
○ Circumferential bile duct wall thickening
○ Dilatation of intra- and extrahepatic ducts
○ Periportal hypo-/hyperechogenicity
– Due to periductal edema/inflammation
○ Ascending cholangitis
– Obstructing calculus in extrahepatic duct
○ Recurrent pyogenic cholangitis
– Biliary calculi: Cast-like and often fill duct lumen
– Atrophy of affected lobe/segment
• Vessels
○ Portal veins:Venectasia, varicosities, collaterals from
portal hypertension
○ Hepatic veins:Venectasia, Budd-Chiari syndrome
○ Hepatic arteries:Aneurysms, shunts, vascular
malformation
○ Use color Doppler to confirm vascular nature
Helpful Clues for Less Common Diagnoses
• Hepatic Echinococcus Cyst
○ Large, well-defined hypoechoic masses
○ Numerous peripheral daughter cysts
○ Intrahepatic duct dilatation may be seen
○ May show curvilinear or ring-like pericyst calcification
• HepaticHematoma
○ Lesions commonly in segments 6, 7, 8
○ Round, hyper-/hypoechoic foci
○ Echogenicity evolves over time
– Echogenic initially
– Hypoechoic after 4-5 days
– Internal echoes and septations after 1-4 weeks
○ Ancillary signs: Subcapsular hematoma,
hemoperitoneum, renal or splenic laceration
• Biliary Hamartoma (von Meyenburg Complexes)
○ Numerous small, hypo-/hyperechoic foci uniformly
distributed throughout liver
– Leads to inhomogeneous and coarse appearance of
liver echotexture
○ Multiple echogenic foci
– Often with associated "comet tail" artifacts
○ Typically smaller lesions appear as echogenic foci,
whereas larger lesions appear cystic
– Often extent of echogenic foci on US is greater than
anticipated, based on comparison CT or MR
Helpful Clues for Rare Diagnoses
• Caroli Disease
○ Hypoechoic masses
○ Saccular or fusiform shape
○ Central dot sign
– Small portal venous branches partially or completely
surrounded by dilated ducts
○ May contain calculi, which do not form casts of ducts
SELECTED REFERENCES
1. Forner A et al: Lack of arterial hypervascularity at contrast-enhanced
ultrasound should not define the priority for diagnostic work-up of nodules
< 2 cm. J Hepatol. 62(1):150-5, 2015
2. Kim TK et al: Contrast-enhanced ultrasound in the diagnosis of nodules in
liver cirrhosis. World J Gastroenterol. 20(13):3590-6, 2014
3. Friedrich-Rust M et al: Contrast-Enhanced Ultrasound for the differentiation
of benign and malignant focal liver lesions: a meta-analysis. Liver Int.
33(5):739-55, 2013
Differential Diagnoses: Liver
Hepatic Cysts
Hepatic Metastases
(Left) Transverse grayscale US
of the liver shows innumerable
cysts st throughout the liver
in a patient with polycystic
liver disease. Posterior
acoustic enhancement is
seen associated with each
cyst. (Right) Transverse
abdominal US in a patient with
carcinoid metastases to the
liver shows multiple round and
homogeneous hyperechoic
metastatic nodules in the liver
ſt. Large amount of
perihepatic ascites is seen.
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