70kVp管电压和30mL对比剂的前瞻性心电门控触发大螺距CT冠状动脉成像  

The feasibility of coronary CT angiography using a tube voltage of 70kVp and 30mL of contrast material

作　　者：祁丽[1,2] 张龙江[1,2] 周长圣[1,2] 郑玲[1,2] 顾海峰[1,2] 卢光明[1,2] 

机构地区：[1]南京军区南京总医院 [2]南京大学附属金陵医院医学影像科,南京210002

出　　处：《放射学实践》2014年第6期601-605,共5页Radiologic Practice

摘　　要：目的:联合前瞻性心电门控及大螺距技术,探讨70kVp管电压、30mL对比剂CT冠状动脉成像(CTCA)的可行性。方法:将80例体质指数≤25kg/m2、心率≤70次/分行CTCA的患者随机分为两组,其中40例患者采用100kVp,60mL对比剂的扫描方案行CTCA检查,另40例患者采用70kVp,30mL对比剂的扫描方案行CTCA检查。所有CTCA检查都在前瞻性心电门控及大螺距(3.4)模式下进行。100kVp组数据采用滤波反投影重建算法进行重建,而70kVp组数据采用迭代重建算法进行重建。测量每例患者主动脉根部、各冠状动脉起始处部及纵膈脂肪CT值和标准差并计算各段血管的信噪比(SNR)和对比噪声比(CNR)。两名放射科医师对所有图像以4分法进行评分。比较两组图像质量及辐射剂量。结果:70kVp组的平均冠状动脉CT值[(603±86)HU]及图像噪声[(42±5)HU]均明显高于100kVp组的平均冠状动脉CT值[(503±68)HU,P<0.001]及图像噪声[(25±4)HU,P<0.01],而70kVp组的SNR及CNR(14.6±3.0,17.8±3.4)均明显低于100kVp组(20.7±3.8,24.4±4.1,P<0.001)。两组间各冠状动脉主观图像质量评分无统计学差异(P>0.05)。70kVp组患者所接受的辐射剂量比100kVp组降低了76%,对比剂用量降低了50%。结论:联合前瞻性心电门控、大螺距及迭代重建技术,70kVp管电压、30mL对比剂CTCA在体质量指数≤25kg/m2、心率≤70次/分的患者中是可行的,可在大幅度降低辐射剂量及对比剂用量的条件下获得满足诊断的图像质量。Objective：To investigate the feasibility of computed tomography coronary angiography （CTCA）using 70kVp tube voltage and 30mL contrast material combined with prospectively ECG-triggering,high-pitch and iterative reconstruction.Methods：A total of 80 patients with BMI less than 25kg/m^2 and heart rate （HR）lower than 70bmp were randomized devided into two groups and underwent CTCA examination.Forty patients were scanned using a tube voltage of 100kVp after administration of 60mL of iodinated contrast material （100kVp group）.Another 40 patients were scanned using 70kVp and 30mL contrast material （70kVp group）.CT images were reconstructed with filter back projection （FBP）al-gorithm in 100kVp group and with iterative reconstruction algorithm in 70kVp group.The mean CT attenuation and standard deviation （SD）of coronaries and adjacent perivascular tissue were measured and SNR and CNR were calculated.Two radiologists reviewed all images and scored using a 4-point scale.The image quality and radiation dose were compared between the two groups.Results：The mean attenuation in 70kVp group [（603 ±86）HU]was significantly higher than in 100kVp group [（503±68）HU,P〈0.001],as well as the image noise [（42±5）HU vs （25±4）HU,P〈0.001].SNR and CNR in 70kVp （14.6±3.0,17.8±3.4）was significantly lower than in 100kVp group （20.7±3.8,24.4±4.1,P〈0.001）.There was no difference in the subjective image quality between the two groups （all P〉0.05）.The radiation dose and contrast material in patients of 70kVp group were reduced by 76% and 50% respectively when compared with 100kVp group.Conclusion：Our study shows that prospectively ECG-triggered high-pitch CTCA at 70kVp with 30mL iodinated con-trast medium volume can obtain diagnostic image quality with substantially reduced radiation dose in selected patients with BMI less than 25kg/m^2 and heart rate lower than 70bmp.

关 键 词：血管成像 冠状动脉疾病 辐射剂量 对比剂 体层摄影术 X线计算机 

分 类 号：R816.2[医药卫生—放射医学]