Diagnostic Ultrasound - Abdomen and Pelvis

Hepatomegaly
Differential Diagnoses: Liver
DIFFERENTIAL DIAGNOSIS
Common
• Congested Liver
○ Congestive Heart Failure
○ Budd-Chiari Syndrome
• Acute Hepatitis
• Fatty Liver
• Steatohepatitis
• Fatty Cirrhosis
• Venoocclusive Disease
• Diffuse Neoplastic Infiltration
○ Infiltrative Hepatocellular Carcinoma
○ Lymphoma
○ Leukemia
○ Metastases
Less Common
• Sarcoidosis
• Glycogen Storage Disease
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
• Hepatomegaly
○ Commonly accepted to be > 15-16 cm long in mid
clavicular line
– Size varies depending on gender and body size
○ Volumetric measurements are time consuming and may
not be suitable for everyday practice
• Ancillary signs used to identify hepatomegaly
○ Enlargement of caudate lobe
– Differential diagnosis of cirrhosis
○ Extension of right lobe below right kidney
– Differential diagnosis of Riedel lobe
○ Biconvex/rounded hepatic surface contour
○ Blunted, obtuse angle; rounded, inferior tip of right lobe
• Enlargement of left lobe (normally smaller than right)
○ Considered when left lobe is present between spleen
and diaphragm
Helpful Clues for Common Diagnoses
• Congested Liver
○ Congestive Heart Failure
– Dilated hepatic veins and inferior vena cava (IVC)
– Venous "star" appearance at IVC-hepatic vein junction
(instead of "rabbit ears")
– Dilated hepatic veins may extend to periphery of liver
– Hepatic venous flow: Turbulent appearance and
pulsatile waveform on Doppler ultrasound
– Marked pulsatility of portal vein
– Hypoechoic parenchyma, increased posterior
enhancement, soft consistency (dynamic indentation
by cardiac motion)
– Ancillary findings: Ascites, pleural effusion, thickened
visceral walls (gallbladder, bowel, stomach),
splenomegaly
– Cardiomegaly
○ Budd-Chiari Syndrome
– Acute phase
□ Hepatomegaly and parenchymal heterogeneous
echogenicity due to congestion
□ Hepatic veins/IVC: Normal or distended
caliber,partially/completely filled with hypoechoic
material
□ Absent or restricted flow in hepatic veins/IVC
□ Aliasing or reversed flow in patent portions of IVC
due to stenosis
□ Development of small intrahepatic venous
collaterals
– Chronic phase
□ Stenotic or occluded hepatic veins/IVC
□ Compensatory hypertrophy of caudate lobe,
atrophy of involved segments
□ Large regenerative nodules
• Acute Hepatitis
○ Diffuse decrease in echogenicity
○ Echogenicity similar to renal cortex and spleen
○ "Starry sky" appearance
– Increased echogenicity of portal triad walls against
background hypoechoic liver
– Variably seen
○ Periportal hypo-/anechoic areas due to edema
○ Marked circumferential gallbladder wall
edema/thickening
– Associated with hepatitis A virus
○ Elevated hepatic artery peak velocity on Doppler US
• Fatty Liver
○ Increase in size of liver and change in shape as volume of
infiltration increases
– Inferior margin of right lobe has rounded contours
– Left lobe becomes biconvex
○ Increased echogenicity
– Liver significantly more echogenic than kidney
– Echogenicity may vary between segments (areas of
focal fatty sparing)
○ Preservation of hepatic architecture
○ Blurred margins of hepatic veins due to increased
refraction and scattering of sound
○ Vessels course through liver without distortion
– May be spread apart secondary to expansion of liver
parenchyma
○ Posterior segments of liver not clearly seen due to
acoustic attenuation
○ Focal fatty sparing may simulate hypoechoic lesion
○ Soft consistency: Dynamic indentation by cardiac motion
• Steatohepatitis
○ Characterized by inflammation accompanying fat
accumulation
– Definitive diagnosis made by liver biopsy
○ May occur in alcoholic hepatitis and nonalcoholic
steatohepatitis (NASH)
○ Etiology of NASH unknown but frequently seen in
following conditions
– Obesity
– Diabetes
– Hyperlipidemia
– Drugs and toxins
○ Ultrasound findings
– Signs of fatty liver
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