双源CT大螺距、70kV管电压结合迭代算法低辐射低对比剂CCTA研究  

Dual source CT high pitch and 70Kv tube voltage combined iterative algorithm for low radiation low contrast agent CCTA

作　　者：曹希明[1] 郑君惠[1] 张静[2] 王振邦[1] CAO Ximing;ZHENG Junhui;ZHANG Jing;WANG Zhenbang(Department of Radiology,Guangdong General Hospital,Guangdong Academy of Medical Science,Guangzhou 510080,P.R.China;The Second School of Clinical Medicine,Southern Medical University,Guangzhou 510515,P.R.China)

机构地区：[1]广东省人民医院(广东省医学科学院)放射科,广东广州510080 [2]南方医科大学第二临床医学院,广东广州510515

出　　处：《医学影像学杂志》2019年第10期1694-1699,共6页Journal of Medical Imaging

基　　金：广东省医学科学技术研究基金项目(编号:A2017232)

摘　　要：目的探讨双源CT前瞻性心电门控大螺距扫描模式下70kV管电压结合迭代算法在CCTA检查中降低辐射剂量及对比剂用量的可行性,并探讨图像最佳迭代重建等级。方法收集本院90例行CCTA检查的患者,体质量指数(BMI)≤25kg/m^2,分为2组,每组45例。A组扫描方案:前瞻性心电门控大螺距螺旋扫描模式,固定管电压70kV,自动管电流调制,参考管电流500mAs;对比剂注射流率及容量分别为4.0ml/s、0.8ml/kg;B组扫描方案:自适应前瞻性心电门控触发序列,自动管电压及管电流调制,参考管电压120kV,参考管电流320mAs,对比剂注射流率及容量分别为5.0ml/s、1.0ml/kg。A组图像采用FBP及SAFIRE1~5等级重建,B组采用SAFIRE3级重建。比较A组各迭代等级及FBP重建间的图像质量,得出最佳迭代等级图像后与B组图像比较图像质量、图像噪声、SNR、CNR及辐射剂量等;并比较两组患者的一般资料。结果A组SAFIRE 3图像质量评分最高;两组患者一般资料、图像噪声、图像质量评分无统计学差异(P>0.05)。部分节段血管SNR、CNR具有统计学差异,但A组高于B组。A组CTDIvol(0.70±0.12)mGy、DLP(12.56±2.37)mGy cm、ED(0.18±0.33)mSv均明显低于B组CTDIvol(12.24±6.82)mGy、DLP(158.80±81.57)mGy cm、ED(2.22±1.14)mSv。结论对于BMI≤25kg/m^2的患者,双源CT大螺距扫描模式下70kV管电压结合迭代算法CCTA检查,能够在得到满足临床诊断要求的图像质量的同时,明显降低有效辐射剂量(ED<0.3mSv)及对比剂用量。Objective To explore the feasibility of reducing radiation dose and dosage of contrast agent in CCTA with 70 kV tube voltage combined with iterative algorithm under dual source CT high pitch scanning mode,and to explore the optimal iterative reconstruction level of images.Methods 90 patients with CCTA were divided into two groups,45 in each group,whose BMI was less than 25 kg/m 2.Group A:Prospective ECG-gated high pitch spiral scanning mode,fixed tube voltage 70 kV,automatic tube current modulation,reference tube current 500 mAs;contrast medium injection flow rate and capacity were 4.0 ml/s,0.8 ml/kg;Group B:adaptive prospective ECG-gated trigger sequence scanning,Automatic tube voltage and tube current modulation,reference tube voltage 120 kV,reference tube current 320 mAs,contrast agent injection flow rate and capacity were 5.0 ml/s,1.0 ml/kg,respectively.Group A was reconstructed by FBP and SAFIRE1~5 level,and group B was reconstructed by SAFIRE3 level.The image quality of group A compared with group B.The best image quality,image noise,SNR,CNR,radiation dose and the general data of patients in two groups were compared.Results The SAFIRE 3 subjective image quality score was the highest in group A,and there was no significant difference in general information,image noise and image quality between the two groups(P>0.05).There were statistical differences in SNR and CNR of some segmental vessels,but group A was higher than group B.CTDIvol(0.70±0.12)mGy,DLP(12.56±2.37)mGy.cm,ED(0.18±0.33)mSv in group A were significantly lower than those in group B(12.24±6.82)mGy,DLP(158.80±81.57)mGy.cm,ED(2.22±1.14)mSv.Conclusion For patients with BMI<25 kg/m 2,70 kV tube voltage combined with iterative CCTA under dual source CT large pitch scanning mode can obtain image quality that meets the requirements of clinical diagnosis and significantly reduce effective radiation dose(ED<0.3 mSv)and dosage of contrast agent.

关 键 词：冠状动脉 大螺距 迭代算法 辐射剂量 体层摄影术 X线计算机 

分 类 号：R543.3[医药卫生—心血管疾病] R814.42[医药卫生—内科学]