CT image acquisition
primary pancreatic tumors
Contrast-enhanced CT examinations were performed using a 128-row dual-source CT scanner (SOMATOM Definition Flash, Siemens, Germany) at 120 kV, tube current modulation, and 1 mm reconstructed section thickness. All patients were instructed to fast for at least 8 h before administering intravenous contrast (Iohexol, 1.5mL per kilogram of body weight, at a rate of 3 ml/s). After the injection of contrast agent, patients were subjected to double-helical scanning during the arterial and portal venous phases. The region of interest (ROI) was selected in primary pancreatic tumors during the arterial phase.