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

• Published in: Tomography (Ann Arbor) Vol. 8; no. 4; pp. 1770 - 1780
• Main Authors: Andersen, Michael Brun, Drljevic-Nielsen, Aska, Thygesen, Jesper, Kruis, Matthijs Ferdinand, Hjorthaug, Karin, Rasmussen, Finn, Nijkamp, Jasper Albertus
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 08.07.2022; MDPI AG
• Subjects: 18F-Flourodeoxyglucose PET/CT; Carcinoma, Non-Small-Cell Lung - diagnostic imaging; computed tomography; Fluorodeoxyglucose F18; Humans; Iodine; lung cancer; Lung Neoplasms - diagnostic imaging; Positron Emission Tomography Computed Tomography - methods; Radiopharmaceuticals; Retrospective Studies; Tomography, X-Ray Computed - methods; computed tomography; lung cancer; 18F-Flourodeoxyglucose PET/CT
• ISSN: 2379-139X; 2379-1381; 2379-139X
• DOI: 10.3390/tomography8040149

(1) The current literature contains several studies investigating the correlation between dual-energy-derived iodine concentration (IC) and positron emission tomography (PET)-derived Flourodeoxyglucose (18F-FDG) uptake in patients with non-small-cell lung cancer (NSCLC). In previously published studies, either the entire tumor volume or a region of interest containing the maximum IC or 18F-FDG was assessed. However, the results have been inconsistent. The objective of this study was to correlate IC with FDG both within the entire volume and regional sub-volumes of primary tumors in patients with NSCLC. (2) In this retrospective study, a total of 22 patients with NSCLC who underwent both dual-energy CT (DE-CT) and 18F-FDG PET/CT were included. A region of interest (ROI) encircling the entire primary tumor was delineated, and a rigid registration of the DE-CT, iodine maps and FDG images was performed for the ROI. The correlation between tumor measurements and area-specific measurements of ICpeak and the peak standardized uptake value (SUVpeak) was found. Finally, a correlation between tumor volume and the distance between SUVpeak and ICpeak centroids was found. (3) For the entire tumor, moderate-to-strong correlations were found between SUVmax and ICmax (R = 0.62, p = 0.002), and metabolic tumor volume vs. total iodine content (R = 0.91, p < 0.001), respectively. For local tumor sub-volumes, a negative correlation was found between ICpeak and SUVpeak (R = −0.58, p = 0.0046). Furthermore, a strong correlation was found between the tumor volume and the distance in millimeters between SUVpeak and ICpeak centroids (R = 0.81, p < 0.0001). (4) In patients with NSCLC, high FDG uptakes and high DE-CT-derived iodine concentrations correlated on a whole-tumor level, but the peak areas were positioned at different locations within the tumor. 18F-FDG PET/CT and DE-CT provide complementary information and might represent different underlying patho-physiologies.