Abstract: Objective: To investigate the feasibility and value of 128 slice spiral CT angiography (CTA) using CARE Dose 4D techniques combined with low dose contrast agent to optimize the scanning protocol. Methods: a total of 60 patients with head and neck vascular imaging were selected and randomly divided into control group (A group) and low dose group (B group), each group with a total of 30 cases. The control group (A group) 120 kV tube voltage, using CARE Dose4D technology reference tube current of 120 mA, dosage of contrast agent was 65 ml; double low dose group (B group) tube voltage 80 kV, using CARE Dose4D technology reference tube current of 120 mA, contrast agent dosage is 45 ml. Objective to evaluate the image quality of CT, noise and signal to noise ratio (SNR) of bilateral common carotid artery, bilateral internal carotid artery and bilateral middle cerebral artery (M1). The evaluation of image quality was performed by two double blind methods. Comparison of radiation dose between group A and group B. Results: two attending physicians had a higher consistency of P < 0.05 (Kappa=0.782). There was no significant difference between the two groups in arterial image quality score and SNR score (P > 0.05). The double low dose group arterial enhancement CT value were higher than the control group; double low dose volume CT dose index and dose length product and effective dose were significantly lower than the control group; the differences were statistically significant (P < 0.05). Conclusion: low kV imaging using 128 slice MSCT and CARE Dose 4D head and neck vascular technique combined with low dose contrast scanning scheme, not only reduce the radiation dose of 68%, while the amount of contrast agent is reduced by 30.7%, reduce the contrast agent risk and cost savings, ensure the diagnostic image quality is worthy of promotion.