Lung tumors evaluated with FDG-PET and dynamic CT: the relationship between vascular density and glucose metabolism.

Purpose: The aim of the current study was to evaluate the relationship between FDG-PET and dynamic CT in lung tumors.

Method: Forty consecutive patients with pulmonary tumors underwent whole-body FDG-PET and contrast-enhanced dynamic CT. The size of tumors was 2.6 +/- 0.2 cm (mean +/- SD) at the largest diameter. The standardized uptake value (SUV) of FDG-PET, peak attenuation (APA), and relative flow (RF) of dynamic CT were evaluated. All patients underwent surgery, and tissue samples were available to be studied. The intratumoral microvessel densities (MVDs) were counted and compared with the radiologic parameters. The duration between radiologic examinations and surgery was within 2 weeks in all patients.

Results: The mean SUV, APA, and RF of lung cancers were significantly higher than those of benign lesions (p < 0.05). The mean APA and RF of lung cancers correlated with mean SUV (APA : r = 0.665, p < 0.0001; RF: r = 0.848, p < 0.05) and mean MVD (APA: r = 0.801, p < 0.0001; RF: r = 0.723, p < 0.05). The mean SUV of lung cancers correlated with the mean MVD (r = 0.612, p < 0.001). No correlation was found between the mean APA, RF, SUV, and MVD in benign tumors.

Conclusion: The APA and RF of dynamic CT correlated with the SUV of FDG-PET imaging in lung cancer. The APA and RF of dynamic CT as an index of blood pooling may be related to increased glucose metabolism in lung cancer.