64层螺旋CT超低剂量前门控轴面扫描在冠状动脉血管成像的应用

目的 评价64层CT冠状动脉成像中前瞻性轴面扫描不同kV设置对射线剂量及图像质量的影响及临床应用价值,探讨＜1 mSv冠状动脉检查的可行性.方法 从拟行冠状动脉成像的患者中连续选取90例体质量指数(BMI)＜21.5 kg/m~2,且心率满足前瞻性门控轴面扫描条件的患者,平均心率(54±6)次/min(bpm).90例患者数字表法随机分成A、B 2组,A组45例扫描时管电压为100 kV,B组45例扫描时管电压为120 kV,根据患者BMI选择管电流,记录扫描中患者所受射线剂量,并对其图像质量进行评价(5分优,1分差).采用配对t检验对2组的射线剂量和图像质量进行统计学分析.结果 A组平均扫描剂量为(0.88±0.32)mSv,图像质量评分平均为(4.32±0.28)分;B组平均扫描剂量为(1.47±0.41)mSv,图像质量评分平均为(4.52±0.34)分.A、B组之间图像质量评分差异无统计学意义(t=0.771,P＞0.05).A组扫描剂量与B组相比较差异有统计学意义(t=12.125,P＜0.01),平均减少40%.结论 64层CT冠状动脉成像前瞻性轴面扫描中,对于BMI＜21.5 ks/m~2的患者,可采用100 kV管电压扫描,其辐射剂量可降到1 mSv以下,并且其图像质量能满足临床诊断需要.

Low radiation dose coronary 64-slice spiral CT angiography using prospective electrocardiograph triggered scan

Objective To evaluate radiation dose and image quality of prospective electrocardiograph (ECG)-triggered coronary 64-slice CT angiography (CTA) with different kV,and the feasibility of coronary scan with＜ 1 mSv radiation dose.Methods Ninety consecutive patients[heart rate:(54±6)bpm,BMI＜ 21.5 kg/m~2]underwent 64-slice CTA using prospective ECG-triggered axial scan protocol.They were divided into two groups:45 were in group A(100 kV),45 were in group B(120 kV),and their electric currents were tailored to patient's BMI.The radiation dose was recorded and the image quality (5 for excellent,1 for bad)was blindly evaluated.Statistical t-test was performed between two groups on dose and image quality.Results The radiation dose of group A,B was (0.88±0.32),(1.47±0.41) mSy respectively.There was no significant difference between image quality of group A with 100 kV (4.32±0.28) and that of group B with 120 kV (4.52±0.34) (t=0.771 ,P ＞0.05).And radiation dose of the patient using axial scan protocol at 100 kV was decreased by 40% compared with that of group B at 120 kV(t=12.125,P＜ 0.01).Conclusion Prospective ECG-triggered axial scan in 64-slice coronary CTA can significantly reduce radiation exposure.For low-BMI (＜21.5 kg/m~2) patients,super low dose scan (＜ 1 mSv) at 100 kV using prospective ECG-triggered axial scan could be selected.And the image quality can meet clinical diagnostic needs.