Effect of corrections for blood glucose and body size on [¹⁸F]FDG PET standardised uptake values in lung cancer

Abstract.

Standardised uptake values (SUVs) are commonly used as a semi-quantitative index of 2-[¹⁸F]fluoro-2-deoxy-D-glucose (FDG) tracer uptake in positron emission tomography (PET). Studies have shown that SUVs may depend on body size and blood glucose concentration and corrections for these effects have been proposed in the literature. This retrospective study investigated the effect of the proposed corrections on SUVs from a group of 154 patients with lung cancer who had scans on a dedicated PET scanner. A total of 252 SUVs were requested as an aid to staging during consideration for surgical resection. SUVs were calculated normalised to body weight (SUV_W), lean body mass (SUV_LBM) and body surface area (SUV_BSA). The following correlations were examined: SUV with height, weight and body surface area for the different body size normalisations; SUV_W and SUV_W × blood glucose (SUV_BG) with blood glucose; SUV_W with scan time post injection; and SUV_W with apparent lesion diameter. Significant correlations were only observed between: SUV_LBM and height (P=0.007); SUV_W and scan time (P=0.007); SUV_W and lesion diameter (P=0.0005); and SUV_BG and blood glucose (P<0.00001). The correlation between SUV_LBM and height suggests that lean body mass as a function of height alone should not be used to normalise SUVs; however, the lean body mass calculated from a height and weight nomogram did not show this effect. The strong correlation between SUV_BG and blood glucose concentration suggests that for non-diabetic fasted patients, lung tumour SUVs should not be adjusted for blood glucose.