*2.1. PET-CT Imaging*

FDG PET-CT were performed on General Electric Discovery 690 (General Electric Healthcare, Waukesha, WI, USA) according to standard procedures. Reconstructed images were examined and interpreted by an experienced nuclear medicine physician (EL). The tumour areas with different metabolic activities at PET-CT were preoperatively identified. In each ICC, we considered sampling only the spots with the highest and with the lowest standardised uptake value (SUVmax and SUVmin, respectively) within the tumour. The low-uptake areas corresponding to necrosis at morphologic imaging (CT and MRI) were not considered.
