Objective: To compare the pressure and image quality of two types of intravenous trocar in head and neck CT angiography (HNCTA), and to propose a method to predict image quality and pressure value of HNCTA using test bolus scan. Methods: Totally 102 patients underwent HNCTA were equally divided into two groups. Patients in Group A were embedded with 20G intravenous trocar, while patients in Group B with 22G intravenous trocar. CT value was measured, and pressure was recorded from test bolus and HNCTA image, respectively. CT value and the pressure of HNCTA scan were compared between Group A and Group B. Linear regression analysis was made between test bolus scan and HNCTA scan regarding CT value and pressure, respectively. Results: No statistical difference was found between Group A ([488.9±121.5]HU) and Group B ([512.2±94.3]HU) regarding CT value of HNCTA. Statistical difference was found between Group A ([153.3±23.5]PSI) and Group B ([233.2±26.5]PSI) regarding pressure of HNCT A. The regression equation between test bolus scan and HNCTA in Group A was Y=306.815+0.922X for CT value and Y=100.031+0.448X for pressure valre, respectively, and in Group B, it was Y=320.853+0.804X for CT value and Y=93.914+0.853X for pressure value, respectively. Conclusion: Diagnostic image quality can be obtained using 22G venous trocar in HNCTA. Pressure and CT value of test bolus may have guideline value to safety and image quality of HNCTA. Copyright © 2013 by the Press of Chinese Journal of Medical Imaging Technology.