第三代双源CT+flash模式扫描联合胸围指数降低冠状动脉CTA辐射剂量及碘摄入量

The third-generation dual-source CT+flash mode scan combined with chest circumference index to reduce the radiation dose and iodine intake of coronary CTA

目的:第三代双源CT+flash模式扫描联合胸围指数降低冠状动脉CT血管造影(CTA)辐射剂量及碘摄入量的临床应用价值。方法:连续选取临床怀疑冠心病需要行冠状动脉CTA检查的160例患者,均采用trube-flash大螺距扫描结合迭代重建技术,开启管电流自动调节技术care Dose 4D完成检查,60例作为对照组,管电压为120 kV,其余100例为低剂量组,根据胸围参数的不同将患者分为A、B、C 3组,其中A组胸围≤85 cm,管电压为70 kV;B组胸围85~95 cm,管电压为80 kV;C组胸围≥95 cm,管电压为90 kV。采用单因素方差分析对4组患者的性别、年龄、BMI、胸围、管电压、管电流、右冠状动脉CT值、SD值、SNR、CTD、DLP、辐射剂量进行比较;图像质量主观评分差异比较采用非参数秩和检验。结果:常规组、低剂量组(A组、B组、C组)患者冠脉图像质量评分分别为3.26±0.23、3.18±0.19、3.23±0.31和3.21±0.25,各组间比较差异无统计学意义(P>0.05),图像质量符合临床诊断要求。4组患者的年龄、性别和心率差异比较差异无统计学意义(P>0.05)。4组右冠脉CT值分别为(425.94±69.59)Hu、(505.23±41.41)Hu、(463.83±59.68)Hu和(444.70±70.36)Hu,低剂量组与常规组比较差异有统计学意义(P<0.01)。辐射剂量分别为(1.03±0.15)mSv、(0.36±0.09)mSv、(0.57±0.05)mSv和(0.80±0.10)mSv(P>0.05);低剂量组的辐射剂量及碘摄入量均低于常规组(P<0.01)。结论:采用第三代双源CT+flash模式扫描联合胸围指数调节管电压,同时采用低碘浓度对比剂,调整对比剂速率及总量,在保证图像质量的同时,可以有效降低辐射剂量和碘摄入量。

Objective: To explore the clinical application value of third-generation dual-source CT+flash mode scan combined with chest circumference index to reduce the radiation dose and iodine intake of coronary artery CT angiography(CTA). Methods: A total of 160 patients with clinically suspected coronary heart disease requiring coronary CTA examination were continuously selected and examined by trube-flash large pitch scan combined with iterative reconstruction technology. Tube current automatic adjustment technology care Dose 4 D was operated. The control group included 60 cases, with tube voltage=120 kV, and the remaining 100 cases were in the low-dose group, which were sub-divided into groups A, B, and C according to the parameters of the chest circumference. Among them, the chest circumference of group A was≤85 cm, the tube voltage was 70 kV;group B was 85-90 cm, tube voltage=80 kV;group C was≥95 cm, tube voltage=90 kV. One-way analysis of variance was used to compare gender, age, BMI, chest circumference, tube voltage, tube current, right coronary CT value, SD value, SNR, CTD, DLP, radiation dose in four groups of patients;the comparison of subjective image quality score was performed by a nonparametric rank sum test. Results: The coronary image quality scores of the conventional group and the low-dose group(group A, group B, and group C) were 3.26±0.23, 3.18±0.19, 3.23±0.31, and 3.21±0.25, respectively. There was no significant difference between the groups(P>0.05), and the image quality met the requirements of clinical diagnosis. There were no significant differences in age, gender and heart rate between the 4 groups(P>0.05). The CT values of the four groups of right coronary artery were(425.94±69.59)Hu,(505.23±41.41) Hu,(463.83±59.68) Hu and(444.70±70.36) Hu, respectively, and there was statistical difference among the low-dose groups and the conventional group(P<0.01). The radiation doses were(1.03±0.15) mSv,(0.36±0.09) mSv,(0.57±0.05) mSv and(0.80±0.10) mSv(P>0.05);the iodine intakes were 18.50 g, 9.45 g, 12.80 g, and 14.40 g, respectively. The radiation dose and iodine intake of the low-dose groups were lower than the conventional group(P<0.01). Conclusion: The third-generation dual-source CT+flash mode scanning combined with chest circumference index can be applied to adjust the tube voltage and meanwhile the contrast agent with low iodine concentration can be taken to adjust the rate and total amount of contrast agent, thus effectively reducing the radiation dose and iodine intake while the image quality is ensured.