“…The quantitative imaging method for assessing tumor heterogeneity adopted in this study was CT texture analysis (CTTA) which has been shown to be related to risk of mediastinal metastasis and overall prognosis for patients with Non-Small Cell Lung Cancer (NSCLC). The reasons for this selection were: a) the high incidence of NSCLC, b) the established role of CT in the clinical management of patients with this tumour, including routine presentation of imaging findings at the MDT meeting, c) the ability to extract heterogeneity information from images currently acquired in routine clinical practice, thereby avoiding the need for additional imaging procedures, and d) increasing research evidence for the prognostic value of CTTA in this patient population [6][7][8][9][10][11]. CTTA parameters were derived using TexRAD software (Feedback, Cambridge, UK) which implements the filtration-histogram method [15].…”