1) Protocols for Contrast-enhanced US (CEUS) of the liver. 2) CEUS features of malignant lesions in cirrhotic liver. 3) CEUS features of malignant lesions in non cirrhotic liver.
The introduction of ultrasound (US) microbubble contrast agents and the development of contrast-specific US techniques have improved the ability of US of detecting and characterizing liver lesions. In particular currently available US contrast agents allow a continuous real time monitoring of vascular perfusion of the liver. Contrast-enhanced US (CEUS) characterisation of liver lesions is based on the comparison of enhancement level of the lesion to normal liver parenchyma during all the three vascular contrast phases, i.e. arterial, portal-venous and late phase. Blood supply of malignant liver lesions is, in fact, nearly completely provided by arteries and AV shunts are frequently present; the washout in most liver malignancies is much quicker compared to normal liver parenchyma. Therefore the main difference between benign and malignant lesions is that during the late phase benign lesions (except cysts - which never enhance - and thrombosed hemangiomas) exhibit iso-enhancement or slight hyperenhancement as compared to surrounding liver tissue, whereas malignant liver lesions exhibit hypoenhancement . During the arterial phase, liver metastases exhibit different degrees of vascularisation, from rim enhancement to homogeneous complete enhancement, while hepatocellular carcinomas exhibit specific kinetics in most cases, with strong enhancement during the arterial phase of CEUS followed by a rapid wash-out in subsequent phases.
Crocetti, L,
Malignant Liver Tumors. Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL.
http://archive.rsna.org/2010/9000168.html
