Diagnosis of bacterial hepatic abscess by CT.

Background: Bacterial hepatic abscess usually is acute and progressive, often resulting in sepsis, impairment of liver function and disseminated intravascular coagulation. The mortality rate was as high as 80% in the past. For the purpose of early diagnosis and differential diagnosis of this disease, we probed the imaging manifestations and their characteristics in bacterial hepatic abscesses by CT scan.

Methods: Twenty-four lesions from 21 patients with bacterial hepatic abscesses that were confirmed by clinical features, puncture and culture were reviewed for CT manifestations. Fourteen patients were male and 7 were female, with an average age of 56.2 years. All lesions underwent CT plain scan and three-phase enhanced scan and 15 patients underwent delayed-phase imaging. Three senior radiologists read the films in accordance with a standard.

Results: Among 24 lesions, 18 (75%) were situated in the right liver with diameters of 1.4-9.3 cm (average 4.5 cm). Nineteen (79.2%) lesions were round or sub-round in shape, and 22 (91.7%) had smooth, uninterrupted and sharp edges. All lesions showed low attenuation of less than 20 Hu. Twenty-two enhanced lesions (91.7%) had rim-shaped enhancement in the abscess wall, and 13 (54.2%) showed single or double-ring signs. Eighteen (75%) displayed honeycomb-like, grid-like or strip-like enhancement. Eighteen (75%) were regionally enhanced in the surroundings or upper or lower layers. Only 2 (8.3%) displayed a gas-liquid surface sign.

Conclusions: The CT findings of bacterial hepatic abscess are usually typical, and the diagnosis of the abscess is not difficult. To precisely diagnose atypical cases, it is necessary to combine CT with clinical observations and follow-up.