640层CT前瞻性心电门控低kV设置降低辐射剂量的效果评价  

CT coronary angiography using 640 slice spiral CT:a comparative study in low tube voltage setting combined with prospective electrocardiographic(ECG)gated scanning mode

作　　者：刘世合[1] 付青[2] 杨青[1] 柳澄[3] 胡亚彬[1] 于华龙[1] 段峰[1] 张传玉[1] 

机构地区：[1]青岛大学附属医院放射科,山东青岛266000 [2]青岛大学附属医院腹部超声科,山东青岛266000 [3]山东大学附属山东省医学影像学研究所,山东济南250021

出　　处：《医学影像学杂志》2015年第9期1579-1583,共5页Journal of Medical Imaging

摘　　要：目的 探讨640层CT前瞻性心电门控扫描模式下低kV设置降低辐射剂量的效果。方法 连续收集怀疑冠心病或查体患者400例,分为4组：1管电压120kV组200例,本组中再按心率≥65次采用30%~80%时相曝光（A组）和心率〈65次采用70%~80%时相曝光（B组）两组;（2）管电压100kV组200例,本组中再按心率≥65次采用30%~80%时相曝光（A组）和心率〈65次采用70%~80%时相曝光（B组）两组。对120kV组和100kV组CT图像的客观指标、主观图像质量评价、CT容积剂量指数（CTDIvol）和有效吸收剂量（ED）进行比较,使用方差分析及post hoc检验对4组数据进行统计学分析。结果 100kV A组较120kV A组平均CTDIvol和ED分别下降25.9%（8.9/34.4）和26.6%（2.5/9.4）,2组差异有统计学意义（q=1.135,P=0.000）（q=1.472,P=0.000）;100kV B组较120kV B组平均CTDIvol和ED分别下降21.4%（2.4/11.2）和22.6%（0.7/3.1）,2组差异有统计学意义（q=0.522,P=0.012）（q=0.613,P=0.001）。采用相同的kV设置不同的曝光时相时,辐射剂量有明显差别,120kV B组较120kV A组平均CTDIvol和ED分别下降约64.5%（22.2/34.4）和67.0%（6.3/9.4）,100kV B组较100kV A组平均CTDIvol和ED分别下降约65.4%（16.7/25.5）和65.2%（4.5/6.9）,差别均有明显统计学意义（q=3.380,P=0.000）（q=4.455,P=0.000）（q=7.380,P=0.000）（q=4.652,P=0.000）;100kV A组、B组的平均SNR、CNR和图像主观评分均低于120kV A、B组,但差异无统计学意义（P〉0.05）。结论 DVCTA前瞻性心电门控扫描模式下应用低kV设置对于不同时间窗曝光患者均可进一步有效减低辐射剂量。Objective To investigate the effect of low tube voltage on image quality and radiation dose at the 640 slice CT coronary CT angiography （CTA） with prospective electrocardiographic （ECG） gated scanning mode. Methods 400 pa- tients requiring coronary CTA for clinical reasons were divided into 4 groups： ① 200 cases in the 120 kV tube voltage group, this group was assigned two groups： group A（112 cases） with HR≥65 bpm and exposuring in 30%-80% R-R interval; group B（88 cases） with HR≥65 bpm and exposuring in 70%-80% R-R interval; ② 200 cases in the 100 kV tube voltage group, this group was assigned two groups： group A（109 eases） with HR≥65 bpm and exposuring in 30% -80%R-R interval. The objective and subjective indexes for assessing CT image quality, CT dose index volume （CTDIvol） and effective received dose （ED） were compared between 120 kV group （A,B） and 100 kV group （A,B）, The variance a- nalysis and post hoc test were employed for the statistical analysis. Results Compared with 120 kV group （A, B）, the CTDIvol of 100 kV group （A,B） decreased for 25. 9% （8.9/34.4） and 21.4% （2.4/11.2）, and the ED decreased for 26.6% （2.5/9.4） and 22.6% （0.7/3. 1） separately, with a significant- difference between 2 groups （ q = 1. 135, P = 0.000） （q=0.522, P =0.012） （q=1.472, P =0.000） （q =0.613, P =0.001） but subjective index for the image quality demonstrated no differences （ P 〈0.05）, Using the same set of kV but different exposure phase, there are obviousdifferences between the radiation dose, the CTDIvol and ED of 120 kV group B decreased for 64.5% （22.2/34.4） and 67%（6.3/9.4） compared with 120 kV group A, the CTDIvol and ED of 100 kV group B decreased for 65.4% （16. 7/ 25.5） and 65.2%（4.5/6.9）, compared with 100 kV group A, with significant difference （ q =8. 380, P =0. 000）（ q = 4. 455, P =0. 000）（ q = 7. 380, P = 0. 000）（ q = 4. 652, P =0. 000）. Conclusion Application of low kV settings for dif

关 键 词：冠状动脉 血管造影术 体层摄影术 X线计算机 辐射剂量 

分 类 号：R814.42[医药卫生—影像医学与核医学] R543.3[医药卫生—放射医学]