Fig. 1
From: Assessment of 18F-FDG uptake in idiopathic pulmonary fibrosis: influence of lung density changes
Representative CT, uncorrected and corrected [18F]-FDG PET images. The value of the correction for the tissue fraction is illustrated by representative CT and [18F]-FDG PET images obtained in two patients (a and b). Interstitial abnormalities were significantly more pronounced in patient a than in patient b, as shown on CT images (left panels). The corresponding uncorrected PET images (middle panels) showed, in patient a, an increased [18F]-FDG uptake in the dense areas of the lung. This increase probably resulted, at least in part, from the increased lung density in addition to the intrinsic disease activity. Accordingly, the corresponding [18F]-FDG uptake corrected for the tissue fraction (SUVmean-corr, right panels) was lower in patient a (2.49) than in patient B (3.24), whereas the difference in SUVmean uncorrected for the tissue fraction (SUVmean-uncorr) was small and inverse (0.94 in patient b vs. 1.13 in patient a)