Figure 15a. Liver metastasis in a 48-year-old woman with colon cancer. (a) Baseline US image shows a barely appreciable hypoechoic lesion (arrow). (b) Portal phase US image obtained 54 seconds after contrast material injection demonstrates an enhancement defect (arrow) with parenchymal enhancement. Small intralesional echoic dots appear on real-time images as fine internal echo pollution (microcirculation).