第3代双源CT自动管电压选择技术在行超低对比剂用量冠状动脉CT血管成像体质量指数20～30 kg/m2患者中的应用价值

摘要

目的 评估第3代双源CT自动管电压选择技术在行超低对比剂用量冠状动脉CT血管成像(CTA)体质量指数(BMI)为20～30 kg/m2患者中的应用价值.方法 将134例BMI为20～ 30 kg/m2、接受第3代双源CT自动管电压选择冠状动脉CTA扫描的患者根据自动选择电压值分为2组:(1)70 kV组(n=91):正常BMI (20 kg/m2≤BMI≤25 kg/m2)患者65例,高BMI (25 kg/m2＜ BMI≤30 kg/m2)患者26例;(2) 80 kV组(n=43):正常BMI患者12例,高BMI患者31例.70 kV组患者对比剂注射总量为18 ml(速率为3.0 ml/s),80 kV组患者对比剂注射总量为21ml(速率为3.0 ml/s).比较两组间和亚组间的有效剂量(ED)、客观图像质量和主观图像质量.结果 70 kV组的ED为(0.24±0.04) mSv,较80 kV组的(0.51±0.05)msy低53％ (H=3.37,P=0.02).70 kV组和80 kV组中正常BMI患者间(H=1.81,P=0.23)及高BMI患者间(H=0.91,P=0.84)的CNR和SNR差异均无统计学意义.70 kV组和80 kV组中正常BMI患者间(Z =0.79,P=0.76)及高BMI患者间(Z =0.77,P=0.81)的主观图像质量评分差异均无统计学意义.结论 第3代双源CT自动管电压选择技术在BMI为20 ～ 30 kg/m2患者进行冠状动脉CTA检查时,部分患者管电压选择值会高于其同水平BMI患者,以保证得出相同水平图像质量.自动管电压选择技术可以帮助技师更加准确、合理地选择适合患者的最佳电压值.%Objective To investigate the application of automatic tube voltage selection (CARE-kV) coronary CT angiography (CCTA) using ultra-low contrast media (CM) protocols in patients with body mass index (BMI) between 20 kg/m2 and 30 kg/m2 on third-generation dual-source CT (DSCT).Methods We prospectively included 134 consecutive patients with BMI between 20 kg/m2 and 30 kg/m2who underwent CARE-kV prospective high-pitch CCTA on third-generation DSCT using the ultra-low CM protocols and divided them into two groups according to the CARE-kV results:70 kV group (n =91):65 patients with normal BMI (20 kg/m2≤ BMI ≤25 kg/m2) and 26 patients with high BMI (25 kg/m2 ＜ BMI ≤30 kg/m2);and 80 kV group (n =43):12 patients with normal BMI and 31 patients with high BMI.The 70 kV group and 80 kV group used the CM protocols of 18 ml (3.0 ml/s) and 21 ml (3.0 ml/s), respectively.The effective dose (ED), objective and subjective image quality (IQ), and results of patients in each group and subgroup were evaluated and compared.Results The ED of 70 kV group was (0.24 ±0.04) mSv, which was 53％ lower (H =3.37, P =0.02) than that of 80 kV group [(0.51 ± 0.05) mSv].No significant difference of CNR and SNR had been found in normal BMI patients (H =1.81, P =0.23) and high BMI patients (H =0.91, P =0.84) among 70 kV group and 80 kV group, as well as the subjective IQ in normal BMI patients (Z =0.79, P =0.76) and high BMI patients (Z =0.77, P =0.81) among 70 kV group and 80 kV group.Conclusions When patients with BMI between 20 kg/m2 and 30 kg/m2 receive CARE-kV prospective high-pitch CCTA on third-generation DSCT, the CARE-kV results for a portion of patients may be higher than other patients with the same BMI level, so as to guarantee the equivalent IQ.The CARE-kV can help to select the patients' optimal tube voltage value more accurately and reasonably.