Correlation between [18F]FDG PET/CT and volume perfusion CT in primary tumours and mediastinal lymph nodes of non-small-cell lung cancer

The aim of this study was to investigate correlations between glucose metabolism as determined by [F-18]FDG PET/CT and tumour perfusion as quantified by volume perfusion CT in primary tumours and mediastinal lymph nodes (MLN) of patients with non-small-cell lung cancer (NSCLC). Enrolled in the study were 17 patients with NSCLC. [F-18]FDG uptake was quantified in terms of SUVmax and SUVavg. Blood flow (BF), blood volume (BV) and flow extraction product (K-trans) were determined as perfusion parameters. The correlations between the perfusion parameters and [F-18]FDG uptake values were subsequently evaluated. For the primary tumours, no correlations were found between perfusion parameters and [F-18]FDG uptake. In MLN, there were negative correlations between BF and SUVavg (r = -0.383), BV and SUVavg (r = -0.406), and BV and SUVmax (r = -0.377), but not between BF and SUVmax, K-trans and SUVavg, or K-trans and SUVmax. Additionally, in MLN with SUVmax > 2.5 there were negative correlations between BF and SUVavg (r = -0.510), BV and SUVavg (r = -0.390), BF and SUVmax (r = -0.536), as well as BV and SUVmax (r = -0.346). Perfusion and glucose metabolism seemed to be uncoupled in large primary tumours, but an inverse correlation was observed in MLN. This information may help improve therapy planning and response evaluation.