目的 探讨低辐射剂量及低碘含量对比剂在冠状动脉CT血管成像（CTA）中的临床应用价值。方法 选择2014年1~7月我院拟诊冠心病患者90例，随机分为A、B、C三组（每组30例），均行CTA检查。扫描时，A组采用常规管电压120 kV及70 mL的对比剂碘海醇（350 mgI/mL），B组采用低管电压100 kV及70 mL的对比剂碘海醇（300 mgI/mL），C采用低管电压100 kV及50 mL的对比剂碘海醇（300 mgI/mL）。对CTA图像进行后处理，比较分析3组的图像质量及诊断结果。结果 A、B、C组相比，CTA图像质量评分的差异无统计学意义（P>0.05）；节段的可诊断率分别为97.40%、96.61%和96.36%，3组相比差异无统计学意义（χ²=0.73，P>0.05）；图像节段的优良率分别为93.23%、92.69%和92.47%，3组相比差异无统计学意义（χ²=0.18，P>0.05）；辐射剂量分别为（3.87±0.58）、（2.89±0.54）、（2.33±0.48） mSv，3组相比差异有统计学意义（P<0.05）；碘用量分别为24.5、21.0、15.0 g，3组相比差异有统计学意义（P<0.05）。结论 使用低辐射剂量及低碘含量对比剂进行CTA检查时，可在图像质量满足临床诊断需要的前提下，明显降低辐射剂量和碘对比剂用量，具有良好的临床应用价值。

Objective To study the effectiveness of application of low radiation dose and low-iodine-content contrast agent in coronary CTA (Computed Tomography Angiography). Methods Altogether 90 volunteers were selected from the patients who had hypothesized as suspected coronary diseases from January 2014 to July 2014 in the hospital. Having been randomly and evenly divided into 3 groups, all the patients underwent coronary CTA. The conventional tube voltage (120 kV) and 70 mL iohexol contrast agent (350 mgI/mL) were adopted in Group A. The low tube voltage (100 kV) and 70 mL iohexol contrast agent (300 mgI/mL) were used in Group B. As for Group C, the low tube voltage (100 kV) and 50mL iohexol contrast agent (300 mgI/mL) were used. After segmental analysis of the coronary artery through post-process of CTA images, comparisons were made among three groups in the aspects of image quality and diagnostic results. Results There were no statistically significant differences among three groups in the evaluation scores of their image quality (P>0.05). The segment evaluation rate of three groups were 97.40%, 96.61% and 96.36% respectively without statistically significant differences (χ²=0.73, P>0.05). The excellent rate of segments in three groups were 93.23%, 92.69% and 92.47% respectively without statistically significant differences (χ²=0.18, P>0.05). The radiation dose of the three group were (3.87±0.58), (2.89±0.54) and (2.33±0.48) mSv with statistically significant differences (P<0.05). And the iodine content of the three groups were 24.5, 21.0 and 15.0g with statistically significant differences (P<0.05). Conclusion When the low radiation dose and low-iodine-content contrast agent were used in CTA, it was recommended to obviously reduce the radiation dose and iodine content while the image quality could meet the requirements of clinical diagnosis. This methodology was of great significance in clinical applications.