The value of low-tube voltage and low contrast agent concentration for head and neck CT angiography

Objective To evaluate the image quality and radiation dose of craniocervical CT angiography (CTA) using low-tube voltage and low volume of contrast material(CM). Methods A total of seventy-five patients who underwent craniocervical CTA in the Taihu county people's hospital were randomly assigned into four groups. The number and dosage of each group were as follows. Group A include 20 cases with 100 kV and 1.0 ml/kg iodine and (1.2-1.0)ml/kg 0.9% normal saline; Group B include 19 cases with 100 kV and 0.8ml/kg iodine and (1.2-0.8)ml/kg 0.9% normal saline; Group C include 18 cases with 80 kV and 1.0 ml/kg iodine and (1.2-1.0)ml/kg 0.9% normal saline; Group D include 18 cases with 80 kV and 0.8 ml/kg iodine and (1.2-0.8)ml/kg 0.9% normal saline; The imaging quality score, dose-length product(DLP), effective dose(ED), the CT value of carotid artery and the CT value of sternocleidomastoid and also the volume of contrast agent were recorded. Results The image quality score of the four groups all reached the diagnostic requirement. The radiation dose of group C and group D was significantly lower than that of group A and group B. The volume of contrast agent in group B and group D was lower than that of group A and C, and the CT value of total carotid artery in group C was significantly higher than those of group A and group B, and there was no significant difference in CT value of the sternocleidomastoid muscle in the four groups. Conclusion Using low-tube voltage and and low volume of CM not only provide images of diagnostic quality but also reduce both radiation dose and iodine intake in craniocervical CTA.