Quantitative CT density histogram values and standardized uptake values of FDG-PET/CT with respiratory gating can...

To assess the ability of parameters derived from computed tomography (CT) histograms and the maximum standardized uptake value (SUV_max) of 18F-fludeoxyglucose-positron emission tomography/CT (FDG-PET/CT) images to distinguish solid lung adenocarcinomas from squamous cell carcinomas and to determine if these parameters are correlated.

This study comprised 43 consecutive patients with solid lung cancer (<3 cm in diameter), who underwent both plain chest CT and FDG-PET/CT (adenocarcinoma, n = 25; squamous cell carcinoma, n = 18). Density histograms of targeted lung cancers were created from chest CT images, and kurtosis and skewness were calculated. On FDG-PET/CT, the SUV_max without/with respiratory gating (RG) were calculated for each lesion. The values for the 4 parameters determined for patients in each diagnostic group were compared by the Mann-Whitney test. The diagnostic characteristics of the parameters were assessed by receiver operating characteristic (ROC) curve analysis. Differences between these parameters were assessed by the chi-square test. SUV_max with RG, kurtosis, and skewness were combined for binary logistic regression analysis, and the differences between the combined parameters and SUV_max with RG were also assessed. Spearman rank correlation analysis was used to determine the correlations for kurtosis or for skewness with SUV_max without/with RG.

The differences in kurtosis and SUV_max without/with RG between the diagnostic groups were significant (kurtosis, P < 0.004; SUV_max without/with RG both P < 0.0001). ROC curve analysis indicated that each parameter (kurtosis value, skewness value, SUV_max, without/with RG) provided low-high ability to differentiate between 2 groups (area under the curve [AUC]: 0.760, 0.593, 0.900, 0.931, respectively). The ROC of the combined parameters provided the highest ability (AUC: 0.949). Both kurtosis and skewness were significantly correlated with SUV_max without/with RG. Kurtosis and SUV_max with RG were most strongly correlated (ρ = 0.618).

Quantitative CT histogram values and SUV assessment can differentiate solid lung adenocarcinomas from squamous cell carcinomas. Kurtosis and SUV_max values were strongly correlated. The addition of RG and further combination of the parameters improved the results.