Feasibility of Peripheral Artery CT Angiography under 70 kV with 50 ml Contrast Medium on the Third-generation Dual-source CT / 中国医学科学院学报

ABSTRACT

Objective To evaluate the feasibility of peripheral artery CT angiography (CTA)under 70 kV with 50 ml contrast medium on the third-generation dual-source CT. Methods Totally 82 patients who were equally randomized into two groups70 kV groupthe scan was performed under 70 kV tube voltage+50 ml iopromide on the third-generation dual-source CT;and 100 kV groupthe scan was performed under 100 kV tube voltage+90 ml iopromide on the second-generation dual-source CT. The CT number of abdominal aorta,bilateral common iliac arteries,common femoral arteries,superficial femoral arteries,popliteal arteries and arteries of the calf were measured and contrast to noise ratio(CNR),signal to noise ratio(SNR)were calculated. The image quality was compared between these two groups. Results The dose-length product was (195.8±46.9)mGy·cm in 70 kV group,which was significantly lower than that in 100 kV group (461.6±57.9)mGy·cm,and was decreased by 57% (t=-22.848,P=0.000). Compared with the 100 kV group,the CT number of the proximal abdominal aorta in 70 kV group was significantly lower(t=-2.502,P=0.014),while the CT number of superficial femoral arteries (t=3.053,P=0.003)and popliteal arteries (t=4.013,P=0.000)was much higher in 70 kV group. SNR and CNR of proximal abdominal aorta,distal abdominal aorta,bilateral common iliac arteries,common femoral arteries,superficial femoral arteries,popliteal arteries and arteries of the calf were significantly lower in 70 kV group than those in 100 kV group (all P<0.05). The artifacts in abdominal aorta (t=2.893,P=0.000)and feet arteries (t=3.776,P=0.000)were higher in 70 kV group than those in 100 kV group,the enhancement of abdominal aorta (t=-1.000,P=0.002)and feet arteries (t=2.893,P=0.010)were lower in 70 kV group,the enhancement of femoral-popliteal arteries (t=-1.000,P=0.000)and arteries of calf (t=4.261,P=0.000)were higher in 70 kV group. Compared with the 100 kV group,the image noise in aorta (t=2.048,P=0.044),femoral-popliteal arteries (t=8.370,P=0.000),arteries of the calf (t=8.315,P=0.000)and feet arteries (t=7.202,P=0.000)were higher in 70 kV group. Conclusion Compared to conventional scan protocol,using 70 kV tube voltage with 50 ml contrast medium to perform peripheral artery CTA can assure the image quality and meanwhile remarkably reduce the radiation dose and the use of contrast medium.