Predicting pleural invasion using HRCT and ^sup 18^F-FDG PET/CT in lung adenocarcinoma with pleural contact

Objective To evaluate the relevance of high-resolution computed tomography (HRCT) findings and fluorine-18-fluorodeoxyglucose (^sup 18^F-FDG) uptake for risk stratification of visceral pleural invasion by lung adenocarcinoma. Methods The HRCT findings and ^sup 18^F-FDG uptake for lung adenocarcinomas with pleural contact on CT were retrospectively analyzed in 208 consecutive patients (94 females and 114 males; median age, 69.0 years) between January 2009 and December 2013, with institutional review board approval. The HRCT findings and maximum standardized uptake value (SUVmax) were recorded for each patient. Multivariate logistic regression was used for statistical analysis, and subgroup analysis stratified for whole tumor size [less than or equal to]3 cm was also performed. Results Multivariate analysis showed that SUVmax [odds ratio (OR) 1.09, 95 % confidence interval (CI) 1.02-1.16, P = 0.014] and obtuse angle (OR 4.14, 95 % CI 1.97-8.74, P < 0.001) were significant independent predictors for visceral pleural invasion. Receiver operating characteristic (ROC) analysis showed that, compared with the multivariate models [area under the curve (Az) 0.819-0.829], SUVmax alone (Az 0.815) was useful in predicting visceral pleural invasion. In the subgroup analysis, multivariate analysis showed that SUVmax (OR 1.29, 95 % CI 1.12-1.50, P = 0.001) and contact length with the pleura (OR 1.13, 95 % CI 1.05-1.22, P = 0.001) were significant independent predictors for visceral pleural invasion. ROC analysis showed that SUVmax alone (Az 0.844) showed similar diagnostic performance to the multivariate models (Az 0.845-0.857). Conclusions SUVmax alone and multivariate models including SUVmax are useful for the prediction of visceral pleural invasion by lung adenocarcinoma.