الفهرس 
ANATOMY OF THE LIVEROnly 14 pages are availabe for public view
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Abstract
The liver is a common site for benign and malignant neoplasms. Hepatocellular carcinoma is a leading cause of death from cancer throughout the world, (Abaza, 2000) while haemangioma is considered the most common benign liver tumor. (Edmondson, 1958), in additition the liver is also considered one of the most common sites for metastatic deposits (yoshida et al., 1987).
Both color & power Doppler were used to detect these vasculature in attempt for evaluation &DD between hepatic focal lesions, but it is still limited by its lack of sensitivity in the detection of slow flow or flow in deeply located lesions.
The advent of intravascular US microbubble contrast is a new dimension in the recent technical advances of US imaging. It is based on the high difference in acoustic impedance between the highly reflective gas in the microbubble and surrounding tissues. Such bubbles when exposed to the US beam, they show non-linear response.
Second harmonic US is a recently developed US technique that involves the use of the non-linear backscatter property of resonant microbubbles produced by an intravenously administered contrast agent. THI has improved both the axial and lateral resolution with increased signal to noise ratio.
Combined USCAs and THI markedly improved the sensitivity of US in detecting hepatic focal lesions and enhanced color Doppler sonography in detecting and perilesional vascularity. Thus, failureb to detect any vascularity is highly suggestive of benign nature with limited specificity.
However, some benign lesions would demonstrate intralesional or perilesional vascularity. Strictly perilesional vascularity in relation to a cystic lesion is likely an abscess; while in relation to a solid lesion in cirrhotic liver is a feature of regenerative nodule. Focal nodular hyperplasia has a chgarecteristic centrifugal arterial vascularity with a central artery.
The intralesinal vascularity in many haemangiomata is not typical and can be mistaken for HCC. Morever CEUS can not differentiate between HCC, Cholangiocarcinoma and hypervascular metastases.
USCAs have a potential role in assessing and influencing the different therapeutic measures for HCC. They can also provide valuable data regarding the hepatic perfusion and transit time in the assessment of diffuse hepaic diseases and transplanted liver.