2014 Volume 41 Issue 3 Pages 325-337
This article mainly provides a guideline for contrast-enhanced ultrasound diagnosis of hepatic tumors in Japan. Liver tumor diagnostic criteria were first published in 1988 by Japan Society of Ultrasonics in Medicine. With recent advances in ultrasound equipment and changes in the concept of liver tumors, various issues have emerged that cannot be handled by the previous guideline. Currently, Sonazoid® (Daiichi-Sankyo, Tokyo, Japan), a lipid stabilized suspension of perfluorobutane gas microbubbles, has been licensed in Japan. In the present revision, typical findings necessary for differentiation of 6 major diseases (hepatocellular carcinoma, intrahepatic cholangiocarcinoma [cholangiocellular carcinoma], metastatic liver tumor, hepatocellular adenoma, hepatic hemangioma, and focal nodular hyperplasia [FNH]) are described. Ultrasound findings were divided into B-mode findings, Doppler findings, and contrast-enhanced findings. B-mode findings are based on the tumor shape, border and contour, tumor margin, intra-tumor, posterior echo, and additional findings. Doppler findings are based on the degree of blood flow, vascularity, blood flow characteristics (pulsatile wave and steady wave), and additional findings. The phases of contrast-enhanced ultrasound are classified into the vascular phase and post-vascular phase. The vascular phase is further divided into the arterial [predominant] phase and the portal [predominant] phase. The characterization of liver tumors is made by the findings of three phases. The vascular phase is used for characterization, and the post-vascular phase is used for detection. The post-vascular image is also called the “Kupffer image” and is closely correlated with the presence or absence of Kupffer cells in the tumor. However, this term is controversial and requires further consideration.
