Usefulness of contrast-enhanced ultrasound with Sonazoid for evaluating liver abscess in comparison with conventional B-mode ultrasound.

AIM: The purpose of this study was to evaluate the usefulness of contrast-enhanced ultrasound (CEUS) with Sonazoid (perfluorobutane) in patients with liver abscess. Sonazoid is a contrast agent with a low mechanical index and is phagocytosed by Kupffer cells. METHODS: Twenty-two patients with liver abscess were evaluated with conventional US, real-time CEUS with Sonazoid, and enhanced computed tomography (CT). After 0.5 mL of Sonazoid was administrated i.v., CEUS images in the vascular and post-vascular phases were observed. RESULTS: Conventional US showed hypoechoic lesions in 13 (59.1%), isoechoic in four (18.2%), hyperechoic in two (9.1%), mixed echoic in two (9.1%) and undetected in one (4.8%) patient. CEUS showed perilesional enhancement in 19 (86.4%) lesions in the vascular phase and well-defined unenhanced areas in 22 (100%) lesions in the post-vascular phase. CEUS revealed that 18 abscesses were cystic type and three were honeycomb type. Twenty-one abscesses (95.5%) had clearer appearances on CEUS than on conventional US in regard to the extent of necrotic or liquefied lesions seen. We could confirm reduction of the lesions after therapy in 13 (92.9%) of 14 patients followed up by CEUS. CONCLUSION: Most of the liver abscesses showed perilesional enhancement in the vascular phase and unenhanced areas in the post-vascular phase. The appearance of liver abscesses was clearer on CEUS than on conventional US. CEUS with Sonazoid can be a more effective diagnostic and therapeutic tool for liver abscess.