体重指数适应性电流、电压结合前置门控技术对降低CCTA辐射剂量可行性的研究

Feasibility of Reducing Coronary CT Angiography Dosage:The Body Mass Index Dependent mA and kV Selection Combined

目的探讨体重指数(BMI)适应性电流、电压结合前置门控技术对降低冠状动脉CT血管成像(CCTA)辐射剂量及提高图像噪声均匀度的可行性。资料与方法将120例拟行CCTA检查的患者随机分成A、B两组。A组采用固定电流、电压的回顾性心电门控模式;B组采用BMI适应性电流、电压的前置心电门控模式,记录患者的身高、体重、BMI、电流、电压、噪声值、CT剂量指数(CTDI)、有效剂量(ED)等。图像质量评分采用4点评分法。采用SPSS13.0软件对数据进行统计学处理。结果对A组图像噪声与体重、身高、BMI行回顾性相关分析显示:噪声与BMI呈较显著正相关且相关性最大,相关系数为0.557。A组噪声均值小于B组,但B组噪声均匀度好于A组。A组ED为(21.27±1.53)mSv,B组ED为(6.04±1.45)mSv,两组间剂量差异均有统计学意义(P<0.05)。两组之间图像质量无差异。结论在心率<70次/min且心律稳定时,BMI适应性电流、电压结合前置门控技术可以在提高图像噪声均匀度的同时降低ED 71.6%。

Objective To evaluate the feasibility of reducing radiation dose of coronary CT angiography（CCTA） and improving the image noise uniformity through the body mass index（BMI） adapted mA and kV selection combined with prospective electrocardiographic（ECG）-gating technology.Materials and Methods 120 patients underwent CCTA were divided into control group（group A） and experimental group（group B）.The retrospective ECG-gating protocol with fixed mA and kV was applied to the patients of group A.The prospective ECG-gating protocol with the BMI-adapted mA and kV was applied to group B.All of the patient＇s height,weight,BMI,electric current（mA）,voltage（kV）,noise value,CT dosage index（CTDI）,effective dose（ED） were recorded.Four point scoring method was used for evaluating the image quality.Statistical processing was performed by the SPSS13.0 software.Results Correlation analysis was performed between image noise and the body weight,the height,the BMI respectively in group A.The result displayed that the image noise and BMI had significant correlation with the correlation coefficient of 0.557.The mean value of image noise in group A was smaller than that in group B,but Image noise uniformity in group B was better than that in group A.The ED of group A and group B was（21.27±1.53）mSv and（6.04±1.45）mSv.There was significant difference（P〈0.05） of radiation dosage between two groups,but there was no difference of image quality.Conclusion When the heart rate was lower than 70bpm and the heart rhythm was stable,the BMI-adapted mA and kV combined with prospective ECG-gating technique could reduce ED by 71.6% meanwhile the image noise uniformity be improved.