目的 评估双源CT低管电压及低剂量等渗对比剂对头颈部CT血管造影图像质量和辐射剂量的影响.方法 选取头颈部CTA患者60例,随机分成两组(各30例).A组:管电压80/Sn140 kVp,对比剂32ml (270mgI/ml).B组:管电压100/Sn140 kVp,对比剂40ml(370mgI/ml).记录各段动脉CT值、噪声值、对比噪声比、信噪比,以及辐射剂量、碘摄入量、图像质量主观评分等,进行统计分析.结果 除了A组的升主动脉噪声值明显高于B组(P<0.01),两组图像的血管CT值、噪声值、信噪比、对比噪声比无统计学差异(P值均>0.05).A组辐射剂量明显低于B组,减少了23.8%(P<0.001).A组每例患者的碘摄入量较B组下降了41.6%.两组图像质量评分无统计学差异(P=0.844).两名医生对图像质量一致性检验的Kappa值为0.663(P<0.001).结论 双源CT低管电压及低剂量等渗对比剂可以用于头颈部CT血管造影,在满足诊断要求的基础上,能同时减少辐射剂量及碘摄入量.%Objective To evaluate the image quality and radiation dose of craniocervical CT angiography (CTA) using low tube voltage and low volume of isotonic contrast material (CM).Methods A total of sixty patients who underwent craniocervical CTA were randomly assigned into 2 groups (each with 30 cases): gorup A with 80/Sn140 kVp and 32 ml of 270 mgI/ml CM, and group B with 100/Sn140 kVp and 40 ml of 370 mgI/ml CM.The CT attenuation, effective dose (ED), image noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of each arterial segment were compared between the two protocols using the Student t test.Qualitative analysis between the protocols was also performed.Results Both groups of CTA achieved comparable CT attenuation, image noise, SNR and CNR in each arterial segment, except for the image noise of ascending aorta (P<0.01).Using the double low-dose mode, the ED was reduced by about 23.8 % (P<0.001), and iodine intake of patients in group A was reduced by 41.6%.There was no significant difference in image quality between the two groups (P=0.844).The consistency between the two observers was good (kappa value=0.663, P<0.001).Conclusion In craniocervical dual source CTA, using low tube voltage and and low volume of isotonic CM not only provided images of diagnostic quality but also reduced both radiation dose and iodine intake.
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