CT Diagnosis of Atypical Liver Abscess

Objective To study the CT appearances of atypical liver abscess (ALA), with emphasis on the enhanced and dynamic enhanced CT.Methods Ninety-two cases of liver abscesses,proved by surgery, aspiration or clinical data were reviewed. All of them were examined by plain CT scan, 65 cases were examined by enhanced scan. Among them,26 cases were of atypical CT features.Results ALA was mostly seen in the suppurative inflammation stage or the initial abscessation stage of bacterial abscesses. In plain CT scan, the abscesses usually exhibited as hypodense mass. On enhanced CT scan, the following signs should be noticed: (1) mass diminution sign; (2) peripheral congestion sign; (3) cluster sign;(4) rosette sign, and (5) delayed enhancement sign. Conclusion The plain CT appearance of ALA is nonspecific. The enhanced CT, especially the dynamic enhanced CT, is characteristic so the diagnosis of ALA could be improved.