Feasibility of Low Tube Voltage Combined with Low Contrast Dose in 64-slice Spiral CT Cerebral and Carotid Arteriography / 中国医学影像学杂志

ABSTRACT

PurposeTo evaluate the feasibility of a low-dose contrast medium protocol for 64-slice spiral CT angiography (CTA) of cerebral and carotid using a low-tube-voltage setting, and to compare the display effect of cerebral and carotid arteries by low-tube-voltage low-dose contrast medium and routine-tube-voltage routine-dose contrast medium scanning, and to assess the effect on radiation dose.Materials and MethodsEighty consecutive patients were prospectively selected to perform cerebral and carotid CTA inspection. The patients were randomly divided into control group and low dose group with 40 people in each group. The voltage in control group was 120 kV and the contrast agent was 80 ml; those in low dose group were 80 kV and 50 ml, respectively. The artery image quality was evaluated and venous interference was scored. The CT value, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and radiation dose in both groups were statistically analyzed.Results The consistency of uniform in artery image quality score and venous interference score was rather high according to the assessment of two physicians (Kappa=0.782 and 0.867). There was no statistical difference in artery image quality score, venous interference score, SNR and CNR between the two groups (Z=-0.864--0.032,P>0.05). The CT value in low dose group was higher than that in control group (differences with statistical significance,t=-8.789-1.715,P<0.05). The CT dose index of volume, dose-length product and effective dose in low dose group were all signiifcantly lower than those in control group (Z=-8.888,t=78.092 and 78.350, respectively,P<0.05).Conclusion The use of low tube voltage and low contrast dose in cerebral and carotid CTA examination can result in high quality images which meets the diagnostic needs and obviously reduce radiation dosage.