369.Hepatic Abscesses

每天朗读一段医学影像学英语文章

Hepatic abscesses can be either pyogenic (bacterial) or amebic (parasitic) in origin. It is often difficult to differentiate between amebic and pyogenic liver abscesses based on CT appearance alone, but some radiological clues may be of use:

-Pyogenic abscess can present without any signs of infection and shows uniform ring enhancement after contrast injection, air fluid level may be seen inside the abscess, and it shows microabscesses (satellite lesions), which are occasionally seen as hypodense lesions >2 cm around the main abscess. A pyogenic abscess classically reveals yellowish fluid after aspiration.

-Amebic abscess characteristically shows a halo of hypodensity surrounding the enhanced ring of the abscess, due to peripheral edema (Fig. 11.3.5). After aspiration, an amebic abscess classically reveals brown fluid (anchovy sauce appearance), although it may be a pyogenic abscess mixed with hemorrhage from the needle. An acute amebic abscess can transform into a chronic abscess, which is characterized by fibrosis and hard mass formation that can be mistaken for hepatocellular carcinoma.

Fig. 11.3.5 Axial hepatic postcontrast-enhanced CT images in two different patients with hepatic abscesses. In one patient (a), an amebic liver abscess is illustrated with its characteristic halo (arrowhead). Notice the multiple splenic microabscesses. In the other patient (b), a pyogenic liver abscess is demonstrated for comparison. Notice the lack of the surrounding halo, with the presence of multiple small satellite lesions 

Notes：

1.pyogenic /ˌpaiəu'dʒenik/ /ˌpaɪəˈdʒɛnɪk/ adj. [医]化脓的；[医]生脓的

2.Amebic abscess  阿米巴脓肿

3.hepatocellular carcinoma  肝细胞癌

来源：每天朗读一段医学影像学英语文章

圈主

深圳市人民医院放射科副主任医师杨敏洁

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