低浓度对比剂和超低辐射剂量在双源 CT 冠状动脉成像中的应用  

Low-concentration contrast media and low dose scan protocol in high-pitch spiral coronary CT angiography：feasibility study

作　　者：李剑[1] 宦怡[1] 印弘[1] 石明国[1] 赵宏亮[1] 王颖[1] 刘莹[1] 魏梦绮[1] 郑敏文[1] 

机构地区：[1]第四军医大学西京医院放射科,陕西西安710032

出　　处：《实用放射学杂志》2015年第2期300-304,共5页Journal of Practical Radiology

摘　　要：目的：探讨低浓度对比剂和低管电压在双源CT前瞻性心电触发大螺距螺旋扫描进行冠状动脉成像的可行性。方法连续选取120例体质量指数（BMI）≤25 kg/m^2和心率（HR）≤65次/min 的患者,随机分配到 A 和 B 2组。A 组采用高浓度对比剂370 mg I/mL 和100 kV 管电压进行双源 CT 冠状动脉前瞻性心电触发大螺距螺旋扫描,图像重建采用滤过反投影重建技术（FBP）。B 组采用低浓度对比剂270 mg I/mL 和80 kV 管电压进行扫描,图像重建采用迭代重建技术（SAFIRE）。比较2组的 CT强化值和噪声,并计算信噪比（SNR）和对比噪声比（CNR）。采用双盲法对冠状动脉节段以4分法进行评价,其中4分为不可诊断的图像。结果B 组各测量层面的平均强化 CT 值明显高于 A 组,差异具有统计学意义（P 〈0.05）。B 组图像噪声、SNR、CNR 较A 组略高,但差异均无统计学意义（P 〉0.05）。B 组有效辐射剂量较 A 组明显降低（0.25 mSv ±0.05 mSv 和0.55 mSv ±0.11 mSv,P 〈0.001）。结论低浓度对比剂270 mg I/mL 和80 kV 管电压在 BMI≤25 kg/m^2的患者中,应用双源 CT 前瞻性心电触发大螺距螺旋扫描,图像进行迭代重建,在保证冠状动脉图像质量的情况下使患者的辐射剂量降低约54.5%。Objective To evaluate the feasibility and image quality of prospectively electrocardiographic（ECG）triggered high-pitch spiral acquisition using dual source CT with low tube voltage and low iodine-concentration contrast material.Methods One hundren and twenty consecutive patients （BMI≤25 kg/m^2 ,HR≤65 beats per minute）were randomized into two groups and scanned using a prospectively ECG triggered high-pitch spiral protocol on a dual-source CT scanner.Group A were examined using a routine radia-tion dose protocol at 100 kV and images were reconstructed with FBP.Group B were examined using a low dose protocol at 80 kV and images were reconstructed with SAFIRE.Contrast materials with iodine concentrations of 370 and 270 mg I/mL were adminis-tered to patients in groups A and B,respectively.Two blinded observers independently assessed the image quality of each coronary segment using a 4-point scale （1 =non-diagnostic,4 = excellent）and measured the objective parameters image noise,signal-to-noise ratio （SNR）,and contrast-to-noise ratio （CNR）.Radiation dose was calculated.Results There was significant difference in the mean CT attenuation achieved at each anatomic site between group B and group A.There were no significant differences in image noise, SNR and CNR.The effective radiation dose were （0.25±0.05）mSv and （0.55±0.1 1）mSv for group B and group A（P 〈0.001）. Conclusion Low iodine-concentration contrast material of 270mg/ml and 80 kV high-pitch spiral coronary CT angiography is feasi-ble for patient with BMI≤25kg/m^2 which can save 54.5% dose than 100 kV group,while maintain diagnosable image quality.

关 键 词：冠状动脉 辐射剂量 计算机体层成像 对比剂 迭代重建 

分 类 号：R322.121[医药卫生—人体解剖和组织胚胎学] R814.42[医药卫生—基础医学]