Abstract: Objective:To investigate the effect of contrast material flow rate and dose on intracranial vascular spiral computed tomographic angiography(SCTA)imaging.Materials and Methods:96 patients(BMI18.5~22.9) suspected cerebral-diseases were divided into three groups randomly and received MSCT cerebral-angiography with three different injection protocols respectively.Group A:370 mg·mL^-1×4.5 mL·s^-1, 75 mL contrast material was injected with an SF.Group B:370 mg·mL^-1×4.5 mL·s^-1, 50 mL of contrast material with an SF.Group C: 370 mg·mL^-1×4.0 mL·s^-1, 50 mL contrast material with an SF.The attenuation of the internal carotid,middle cerebral,and anterior cerebral arteries were measured.The demonstration of vessels was also assessed.Results: There were no significant attenuation differences of the arteries among the three groups,neither were any significant differences noted on the visual assessment.Conclusion:Contrast quantity and injection velocity may be decreased,but the imaging should still be clear.