Fig. 5

Multiphasic spectral CT of a 73-year-old man with known HCC. The known tumor (arrows) shows typical hypervascularity on the conventional arterial phase (a) which is more prominent on 50 keV mono-energetic image (b), and was ablated with good treatment response (asterisk) on the 1-month follow-up (c). However, there was an additional lesion (curved arrow) which should have been suspected by the radiologist on baseline imaging but was missed owing to its minimal arterial enhancement (d). This lesion would not have been missed if 50 keV mono-energetic images had been reviewed prospectively (e), and on follow-up imaging showed definite washout and enlargement (dashed arrow), when the patient returned with advancing disease including tumor thrombus in the portal vein