- Pathogenesis:
- 85-90% of all abscesses are bacterial in
origin.
- Bacteria gain access to liver via the
portal or biliary system. Possible causes are iatrogenic, biliary disease,
diverticular disease, trauma, and inflammatory bowel disease.
- E. coli and anaerobes are the two most
common offending agents in pyogenic abscess.
- Most pyogenic abscesses occur in the
right lobe.
- If left untreated, mortality is 100%.
- Radiographic findings:
- U/S: a) heterogeneous, rounded masses
with irregular, thickened walls and poor peripheral definition; b) Fluid
and debris inside the abscess can create internal echoes; c)
Gas-containing lesion also has acoustic shadowing.
- CT: a) heterogeneous lesion with
irregular margin (arrowhead) and possible peripheral enhancement; b) Internal
septations or papillary projections; c) 20% contain gas.
- Nuclear: a) cold defect on sulfur
colloid imaging; b) Increased activity with gallium imaging.
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