Single-source Dual-energy CT as a Part of ¹⁸F-FDG PET/CT: Direct Comparison of Iodine-related and Metabolic Parameters in Non-small Cell Lung Cancer

Abstract

Aim: The aim of the study was to assess possible correlation of fluorogeoxyglucose (FDG) uptake and iodinerelated attenuation values derived from positron-emission tomography/computed tomography (PET/CT) using singlesource dual-energy CT scan (DE-CT) in non-small cell lung cancer (NSCLC). Materials and Methods: Forty-eight patients with histologically-proven NSCLC underwent 18 F-FDG-PET/CT within their staging process. PET/CT included single-source DE-CT in late post-contrast phase. Direct comparison of PET and DE-related values was performed. A sub-study regarding different histological types and various thresholds for quantification of volume metabolic values was also performed. Results: A strong correlation was found of metabolic tumor volume and total lesion glycolysis with total iodine content using Pearson correlation analysis (r=0.965-0.983; p<0.0001) with various thresholds for FDG lesion segmentation. The strongest correlations with iodine content were reached using 10% threshold for segmentation. Only a weak correlation was found between iodine content and the maximal standard uptake value. A significant difference between adenocarcinomas and other histological subtypes was found for selected parameters of metabolic PET and DE-CT data. Conclusion: Our study demonstrated a strong correlation of the iodine content calculated from single-source DE-CT with volumetric FDG parameters in NSCLC. without a significant effect of the threshold value for FDG lesion segmentation.

Assessment of Correlation between Dual-Energy Ct (De-Ct)-Derived Iodine Concentration and Local Flourodeoxyglucose (Fdg) Uptake in Patients with Primary Non-Small-Cell Lung Cancer

“…We found a positive correlation between SUV max and Iodine max (R = 0.64, p = 0.002) and a strong positive correlation between metabolic tumor volume (MTV) and total iodine content (R = 0.91, p < 0.0001), similar to previous studies ( Figure 2 ) [ 11 , 17 ].…”

“…We found a positive correlation between SUVmax and Iodinemax (R = 0.64, p = 0.002) and a strong positive correlation between metabolic tumor volume (MTV) and total iodine content (R = 0.91, p < 0.0001), similar to previous studies (Figure 2) [11,17]. A total overview of the Pearson correlations between FDG uptake and iodine-related parameters is presented in Table 2.…”

“…Baxa et al and Schmid-Bindert et al found a correlation between metabolic parameters and iodine-related parameters, which is in contrast to the results of Kupik et al and Masahiko et al, who found no correlation. In addition, Kupik et al found a moderate negative correlation for tumors <3 cm [ 11 , 16 , 17 , 18 ]. In this current study, we accounted for intratumoral heterogeneity by first performing an image registration between the DE-CT and the 18 F-FDG PET/CT followed by a correlation of maximum iodine concentration with SUV peak both within the entire tumor and in a sphere around the SUV peak .…”

“…Similar to studies on DCE-CT parameters, there are discrepancies in the current literature. The studies of Schmid-Bindert et al and Baxa et al found a strong correlation between SUV max and DE-CT parameters in patients with non-small-cell lung cancer (NSCLC), whereas the studies of Kupik et al and Aoki et al found no correlation regardless of tumor histology, but a moderate negative correlation for small primary tumors (<3 cm) [ 11 , 16 , 17 , 18 ].…”

“…In all previous studies, either a small region of interest (ROI) or the entire tumor volume was assessed. As NSCLC often exhibits high intra- and intertumoral heterogeneity, assessment of a small region of the tumor is a limitation [ 11 , 16 , 17 , 18 ].…”