Analysis of contrast-enhanced ultrasound (CEUS) and pathological images of hepatic alveolar echinococcosis (HAE) lesions

OBJECTIVE: Contrast-Enhanced Ultrasound (CEUS) has been introduced as a promising imaging technique for diagnosis of hepatic alveolar echinococcosis (HAE). But the correlation between the image features and the underlying complex pathology of HAE has not been fully understood. In this study, we reviewed CEUS and pathological images of 31 lesions in 24 patients with HAE from Aba Tibetan Qiang Autonomous Prefecture, an epidemic area in China. MATERIALS AND METHODS: 24 patients who received CEUS examination for suspicion of HAE and with pathologically confirmed HAE were retrospectively reviewed. Parasitic lesions obtained from surgery were sectioned and stained with hematoxylin and eosin (HE). RESULTS: US examination showed that the 12 lesions were hypoechoic and 19 lesions were hyperechoic. The hypoechoic images of HAE quite resemble the images of hepatocellular carcinoma and hemangioma. For the CEUS images of lesions >= 3 cm, 9 lesions (9/25, 36%) were hypoechoic with mixed content without circular rim enhancement; 16 lesions (16/25, 64%) had circular rim enhancement. All the lesions < 3 cm (n=6) were with circular rim enhancement and non-enhancement internal area. Pathological examination showed that the cysts are surrounded by an inner necrotic zone and peripheral granulomatous and fibrous tissues. CONCLUSIONS: CEUS images of large HAE lesions are more complex than that of the small lesions. Large HAE lesions can be hypoechoic with mixed content with or without circular rim enhancement, and no internal area enhancement with circular rim enhancement. The small lesions are more likely to show circular rim enhancement and non-enhancement internal area.