目的 探讨低浓度对比剂和低 管电压技术联合迭代重建算法在头颈部 CTA检查的可行性。方法 前瞻性将100例 行头颈部CTA的患者随机分为A、B两组， 每组50例，A组管电压100kVp，使用威视 派克(270mgI/ml)对比剂和迭代重建算法 (iDose4)重建，B组管电压120kVp，使用 碘海醇(350mgI/ml)对比剂和滤波反投影 算法(FBP)重建，记录两组患者颈内动脉 的CT值和噪声值、背景CT值、剂量长度 乘积(DLP)，并计算信噪比(SNR)、对比 噪声比(CNR)、有效辐射剂量(ED)及碘摄 入量，由两位放射科医生采用盲法对图 像质量进行评分(5分值)。结果 A组血管 平均CT值、CNR、SNR值高于B组，而ED及 碘摄入量低于B组，两组之间的差异具有 统计学意义(P<0.05)，两组图像质量评 分无统计学意义(P>0.05)。结论 双低剂 量技术联合迭代重建算法进行头颈部CTA 检查，在保证图像质量的同时明显减少 辐射剂量和对比剂碘的摄入量。

Objective To investigate the feasibility of using low concentration contrast agent and low tube voltage combined iterative reconstruction in head and neck CT Angiography(CTA). Methods 100 patients underwent head and neck CTA were prospectively enrolled in this study. They were randomly divided into group A and group B. For patients of group A 100kVp tube voltage, low concentration contrast agent (Visipaque 270mgI/ml) and iterative reconstruction (iDose4) were used in CTA, while for patients of group B 120kVp tube voltage, usual-concentration contrast agent (iohexol 350mgI/ml) and filter back projection (FBP) reconstruction were employed in CTA. The mean CT value and noise of carotid artery, the background CT value, the dose length product (DLP) were recorded, and then calculated the signal-to-noise ratio (SNR), contrast to noise ratio (CNR), effective dose (ED) and iodine intake. Using 5 point scale the image quality was evaluated by two radiologists. Results The mean CT value, CNR, SNR value of group A were higher than that of group B, while ED and iodine intake of group A were lower than that of group B, the differences were statistically significant between two groups (P<0.05). The image quality score had no statistically difference between two groups (P>0.05). Conclusion Double low dose technique combined with iterative reconstruction in head and neck CTA can get high quality images, meanwhile significantly reduce the radiation dose and the intake of contrast agent iodine.