Fig. 4

Computed tomography (CT) scanners used by China Medical University Hospital (CMUH; purple bars) and other hospitals (red bars) for CT imaging were manufactured by various different vendors. The bar indicates the number of CT images of arterial phase that were scanned using the particular scanner. CT images within CMUH contained arterial phase images in the training and validation sets while CT images from other hospitals included images in the external data set. There was a larger variety of scanners that were used by other hospitals compared to CMUH for imaging. CT images taken at CMUH were mainly scanned using scanners of these four types: BrightSpeed, LightSpeed VCT, LightSpeed16 and Optima CT 660