ABSTRACT
Objective:To explore and compare the value of radiomic features based on 18F-fluorodeoxyglucose (FDG) PET and CT in distinguishing epidermal growth factor receptor (EGFR) mutation status in patients with lung adenocarcinoma. Methods:Pretreatment 18F-FDG PET/CT images and EGFR gene status of 114 patients (64 males and 50 females, aged range: 35-84 (average age: 61) years) with primary lung adenocarcinoma between January 2017 and December 2017 were retrospectively collected. The volume of interest was drawn manually slice by slice, then the features were extracted by the LIFEx software. The parameters were screened by least absolute shrinkage and selection operator (LASSO) method for 200 times, and ten-fold cross-validation was used to select the best tuning parameter λ. Three models, namely M PET, M CT, M PET+ CT, were constructed by binary logistic stepwise regression. The receiver operating characteristic (ROC) curve was generated and the corresponding area under the curve (AUC), sensitivity, specificity and accuracy were calculated. The AUCs of three models were compared by Delong test. Results:Totally, 53.51%(61/114) patients were with wild type EGFR and 46.49%(53/114) patients had EGFR mutation. There were 3, 3, 7 parameters selected to form M PET, M CT, M PET+ CT, respectively. The AUCs for M PET, M CT, M PET+ CT were 0.730, 0.752 and 0.866 respectively. When the cut-off values were 0.427, 0.522, 0.378 for M PET, M CT and M PET+ CT, the Youden index were up to the maximum as 0.420, 0.405, 0.630, with sensitivities of 83.0%(44/53), 58.5%(31/53), 92.5%(49/53), specificities of 59.0%(36/61), 82.0%(50/61), 70.5%(43/61) and accuracies of 70.2%(80/114), 71.1%(81/114), 80.7%(92/114), respectively. There was no significant difference between AUC of M PET and M CT ( z=-0.320, P>0.05). The differences of AUCs between M PET+ CT and M PET, M PET+ CT and M CT were statistically significant ( z values: 2.963, 2.523, both P<0.05). Conclusions:PET, CT and PET+ CT radiomic features are all associated with EGFR gene expression in lung adenocarcinoma. M PET+ CT has the highest predictive efficiency.