目的利用双低剂量(80kV, 30ml 碘对比剂)结合迭代重建全主动脉CT血 管成像，评价图像质量及应用可行性。 材料和方法 前瞻性收集60例主动脉术 后接受主动脉CTA检查的患者，并分为 两组。第一组采用120kv、60ml对比剂扫 描方案，第二组采用80kv、30ml对比剂 扫描方案扫描。第一组采用滤波反投影 法(FBP)重建，第二组组采用迭代算法 (SAFIRE)重建。比较两组间的主观(主动 脉图像质量评分)和客观图像质量(图像 噪声、信噪比SNR、对比噪声比CNR)的差 异。记录两组辐射剂量。结果 与第一组 相比，第二组总体主观图像质量无明显差 异(p>0.05)，部分主动脉节段的图像噪 声和SNR略有降低；第二组辐射剂量比第 一组降低约72%(2.12±0.15mSv mSv vs. 7.47±0.54，p<0.0001)，对比剂用量减 少50%(30ml vs 60ml,p<0.0001)。结论 80kv、30ml对比剂全主动脉CTA扫描方案 结合迭代重建算法显著降低辐射剂量和对 比剂用量，其图像质量可满足诊断。

Objective To assess the image quality and the feasibility of double-low dose (80 kv and 30 mL contrast medium) combined with iterative reconstruction (IR) in whole aortic CT angiography. Methods Sixty post-operative patients were prospectively enrolled in this study and randomly separate into two groups with a routine dose CTA protocol (FLASH, reference parameters 120 kv, 60 mL contrast medium, RD) and a low dose CTA protocol (FLASH, reference parameters 80 kv, 30 mL contrast medium, LD), respectively. Images were reconstructed using filtered back projection (FBP) for RD dataset and using IR for LD dataset. Two radiologist reviewed the image quality using a 5-point scale (1 = non-diagnostic, 5 = excellent), measured objective image noise and calculated the signal to noise ratio (SNR), contrast to noise ratio (CNR). The radiation dose was recorded. Results The subjective image quality and CNR was no significantly statistical difference in LD, compared with RD ( all p > 0.05), but image noise and SNR was decreased in part of aortic segment. Compared with RD, the effective radiation dose and contrast medium volume in LD decreased by 72% and 50%, respectively (2.12 ± 0.15 mSv vs. 7.47 ± 0.54 mSv, 30 mL vs. 60 mL, all p < 0.05). Conclusion 30 mL contrast medium at 80kV for aorta CT angiography significantly reduces radiation and contrast agent volume while maintaining the diagnostically image quality.