18F-FDG PET Metabolic Parameters and MRI Perfusion and Diffusion Parameters in Hepatocellular Carcinoma: A Preliminary Study

OBJECTIVES Glucose metabolism, perfusion, and water diffusion may have a relationship or affect each other in the same tumor. The understanding of their relationship could expand the knowledge of tumor characteristics and contribute to the field of oncologic imaging. The purpose of this study was to evaluate the relationships between metabolism, vasculature and cellularity of advanced hepatocellular carcinoma (HCC), using multimodality imaging such as ¹⁸F-FDG positron emission tomography (PET), dynamic contrast enhanced (DCE)-MRI, and diffusion weighted imaging(DWI). MATERIALS AND METHODS Twenty-one patients with advanced HCC underwent ¹⁸F-FDG PET, DCE-MRI, and DWI before treatment. Maximum standard uptake values (SUV(max)) from ¹⁸F-FDG-PET, variables of the volume transfer constant (K(trans)) from DCE-MRI and apparent diffusion coefficient (ADC) from DWI were obtained for the tumor and their relationships were examined by Spearman's correlation analysis. The influence of portal vein thrombosis on SUV(max) and variables of K(trans) and ADC was evaluated by Mann-Whitney test. RESULTS SUV(max) showed significant negative correlation with K(trans)(max) (ρ = -0.622, p = 0.002). However, variables of ADC showed no relationship with variables of K(trans) or SUV(max) (p>0.05). Whether portal vein thrombosis was present or not did not influence the SUV max and variables of ADC and K(trans) (p>0.05). CONCLUSION In this study, SUV was shown to be correlated with K(trans) in advanced HCCs; the higher the glucose metabolism a tumor had, the lower the perfusion it had, which might help in guiding target therapy.