Figure 6. 25-year-old man with focal nodular hyperplasia. (a) Grey scale fundamental ultrasound shows a hyperechoic lesion, 6.4 cm in diameter, in S4 of the liver (arrows). (b) Contrast-enhanced ultrasound images by coded harmonic imaging at 30 s after administration of Levovist. A tortuous artery flows into tumour centre (arrow). Vessels appear to be radially located in the mass (arrowheads). (c) Contrast-enhanced ultrasound images acquired by 1-s intermittent transmissions at 90 s after administration. Perfusion flow images are seen as a diffuse vascular pattern within the tumour similar to findings seen in hepatocellular carcinoma (arrows).