ABSTRACT
AIM: The aim of this study was to investigate the relationship between 2-deoxy-2[(18)F]fluoro-D-glucose ([(18)F]FDG) positron emission tomography (PET) and diffusion-weighted magnetic resonance imaging (DWI) with apparent diffusion coefficients (ADC) in brain tumors. METHODS: Fifteen patients with 18 metastatic brain lesions underwent gadolinium-enhanced fast spoiled gradient echo (Gd-FSPGR), DWI with ADC maps, and [(18)F]FDG PET. Spherical three-dimensional tumor and contralateral control regions of interest (ROIs) were drawn on Gd-FSPGR, ADC and PET images, Gd-FSPGR being the target for statistical parametric mapping with realigned ADC and PET to calculate ROI ratios; linear regression analysis was performed. RESULTS: An inverse correlation (r(2)=0.2746, P=0.0256) was found between PET and ADC ratios; plotting ratios: when PET ratios were high, ADC ratios were low, while, when ADC ratios were high, PET ratios were low. CONCLUSIONS: Our preliminary data suggest an inverse relationship between PET and ADC indices. Hypercellular areas could increase impedance to water diffusion, resulting in low ADC values and high [(18)F]FDG uptake, while lower cellularity areas show increased ADC with decreased [(18)F]FDG uptake.
