Figure 3. Dynamic CT images of a 2.1 cm-diameter well-differentiated HCC in segment III of the liver in a 54-year-old man. (a) The tumour was hypodense in unenhanced scan (arrow). (b) Positive enhancement of the tumour was demonstrated in arterial-dominant phase (arrow). (c) In portal venous phase, the tumour was again hypodense (arrow), representing the "low-high-low" pattern on dynamic CT scan.