Figure 1

Flowchart of patient selection process including inclusion and exclusion criteria. Patients in the development cohort were selected from First Affiliated Hospitals of Shantou University Medical College and Second Affiliated Hospitals of Shantou University Medical College between May 2013 and June 2018 (A). Patients in the validation cohort were selected from Affiliated Jieyang Hospital of Sun Yat-sen University between March 2015 and June 2018 (B). CT noncontrast computed tomography.