Liver abscess

　

History :
59 year-old lady was a patient of HTN and ESRD under hemodialysis three times a week for one and half year. General weakness, fever and drowsy consciousness were noticed.

Image finding :
Heterogeneous hypodense lesion with internal septation at segment 7 & 8 of liver, with right pleural effusion.

Diagnosis :
Liver abscess.

Discussion :
HEPATIC ABSCESS
=localized collection of pus in the liver resulting from any infectious process with destruction of the hepatic parenchyma + stroma Types:
pyogenic (88%), amebic (10%), fungal (2%)

Location:
multiple in 50%
*hepatomegaly
*elevation of right hemidiaphragm
*pleural effusion
*right lower lobe atelectasis / infiltration
*gas within abscess (esp. Klebsiella)

MR:
-hypointense on T1WI + hyperintense on T2WI (72%)
perilesional edema (35%)
-"double target sign" on T2WI = hyperintense center (fluid) + hypointense sharply marginated inner ring (abscess wall) + hyperintense poorly marginated
-ring (perilesional edema) rim enhancement (86%)

CT:
-inhomogeneous hypodense single / multiloculated cavity
-"double target sign" = wall-enhancement + surrounding hypodense zone (6-30%)
-"cluster sign" = several abnormal foci within the same anatomic area; suggestive of biliary origin