CT and MRI features of a hepatic pyogenic abscess
CT and MR imaging features of a hepatic pyogenic abscess?
A hepatic pyogenic abscess may arise from biliary tree infection, from direct spread of infection in adjacent organs, from hematogenous infection, following traumatic injury, or with superinfection of a preexisting hepatic hematoma or necrotic tumor. It is most often caused by gram negative bacilli, most commonly Escherichia coli in adults.
On CT and MRI, a heterogeneous multiloculated cystic lesion is seen, more frequently in the right than left hepatic lobe, commonly with thick rim enhancement and internal septal enhancement, perilesional edema, and perilesional enhancement, and occasionally with internal foci of very low attenuation or very low signal intensity gas that are highly specific for this diagnosis. A “cluster” sign is a characteristic finding, where multiple lesions are clustered in the same region of the liver