低管电压结合个体化碘对比剂方案在颈动脉CT血管成像的优势

Advantages of Low Tube Voltage Combined with Individual Iodine Contrast Agent in Carotid CT Angiography

目的探讨低管电压结合个体化碘对比剂应用方案在颈动脉CT血管成像(CTA)中的应用价值。方法前瞻性纳入在能谱CT行颈动脉CTA成像的受检者120例,采用序贯设计依次分为常规组和低剂量组,每组60例。常规组管电压120kV,滤波反投影重建(FBP);低剂量组管电压100kV,50%自适应统计迭代重建(ASIR);余各项扫描参数均相同。常规组对比剂流速5 mL/s,对比剂用量采用经验值法;低剂量组对比剂流速4mL/s,对比剂用量采用个体化方案:碘对比剂用量=(Ttest-bolus峰值时间+2s-5s)×注射速率。所有受检者均采用碘佛醇对比剂(320mgI/mL)。数据上传至GE AW4.5工作站,行图像重建分析。记录受检者的性别、年龄等各项客观数值,计算信噪比(SNR)等数值,结合主观评分,行统计学分析。结果低剂量组碘对比剂用量(57.67±9.44)mL,低于常规组(68.83±12.80)mL(P<0.001);低剂量组有效电离辐射剂量(1.82±0.00)mSv,低于常规组(3.08±0.19)mSv(P<0.001);低剂量组颈动脉SNR、对比噪声比(CNR)(51.60±20.50,64.73±24.98)分别高于常规组颈动脉SNR、CNR(31.24±11.18,39.70±13.51)(P<0.001);低剂量组主动脉弓SNR、CNR(46.40±18.11,59.53±22.57)分别高于常规组(27.21±8.82,35.67±11.11)(P<0.001);2组性别、年龄、身高、体质量指数、颈动脉平均CT值和图像质量主观评分差别均无统计学意义(P>0.05)。结论在颈动脉CTA成像中,管电压100kV结合个体化碘对比剂应用方案,不仅能很好满足临床诊断需求,而且能有效降低电离辐射剂量及碘对比剂用量,具有较大应用优势。

ual iodine contrast cry CT 750 HD. Objective To explore the application value of low tube voltage combined with individ- agent in carotid CTA. Method 120 patients were enrolled and underwent GE Discov- Following the study design, the patients were divided into two groups, the conventional group and the low dose group, with 60 cases in each group. The conventional group used 120 kV tube voltage and filtered backprojection （FBP）. The low dose group used 100 kV tube voltage with 50% adap- tive statistical iterative reconstruction （ASIR）. The rest of the scanning parameters were the same in both groups. In the conventional group, flow rate for the was 5 mL/s, and the amount of contrast agent was used by the method of empirical value. In the low dose group, the flow rate was 4 mL/s, and the dosage of iodine contrast agent was individualized： Contrast agent dosage = （t test-bolus peak timeq-2 s -5 s） X injection velocity. The contrast agent ioversol （320 mgI/mL） was used in all tests. The data were uploaded to GE AW4.5 workstation for reconstruction and analysis. Objective values including gen- der, age and other objective values were recorded, combined with the subjective score for statistical analy- sis. Data were analyzed by independent samples t test and non parametric test. Results The iodine contrast agent in the low dose group of iodine contrast agent （57.67±9.44） mL was lower than that in the conventional group （68.83±12.80） mL （P〈0. 001）. The effective dose of ionizing radiation in the low dose group （1.82±0） mSv was lower than that in the conventional group （3.08±0.19） mSv （P〈0. 001）. The SNR value and CNR value of carotid artery in the low dose group（51.60±20.50,64.73±24.98） were higher than those in the conventional group（31.24± 11.18,39.70±13.51）（P〈0. 001）, respectively. The SNR value and CNR value of aortic arch in the low dose group（46.40±18.11,59.53±22.57）were higher than those in the conventional group（27.21± 8.82,35.67 ± 11. 11）（P〈0. 001）, respectively. There were no significant differences in gender, age, height, weight, CT value of carotid artery and the image quality between the two groups （P〈0.05）. Conclusion In carotid CTA, using the tube voltage of 100 kV combined with individual iodine contrast agent not only can meet the needs of clinical diagnosis, but also can effectively reduce the radiation dose and the dosage of iodine contrast agent.