256层螺旋CT iDose4技术在BMI指导下降低冠脉成像辐射剂量的可行性

Feasibility of Reducing Radiation Dose of Coronary CT Angiography by iDose4 on 256-slice CT Under the Guide of Body Mass Index

目的:探讨256层螺旋CT iDose4技术结合体重指数(BMI)指导下的低剂量技术对改善冠状动脉CT血管成像(CCTA)图像质量及降低辐射剂量的可行性。方法:对74例怀疑冠心病患者行CCTA,随机分成两组:A组采用固定电流、电压的回顾性心电门控模式,滤波反投影(BFP)重建成像;B组采用BMI适应性低电压、低电流的回顾性心电门控模式,高级迭代重建-iDose4重建成像。然后对两组图像信号噪声比、对比度噪声比和有效剂量进行评估。结果:A组及B组的信号噪声比分别为(16.15±3.76)和(16.65±3.47),差异无统计学意义(t=0.591,P>0.05)。A组及B组的对比度噪声比分别为(13.76±3.61)和(14.22±3.28),差异无统计学意义(t=0.571,P>0.05)。A组及B组的有效剂量分别为(8.15±0.44)mSv和(4.18±0.72)mSv,差异有统计学意义(t=28.55,P<0.05)。结论:256层螺旋CT冠状动脉血管成像中,与常规剂量、FBP重建比较,iDose4重建技术与BMI指导下的低剂量技术的有效结合,在不降低图像质量的前提下,均衡控制不同个体射线剂量,射线剂量较常规降低约49%,同时降低了对比剂浓度。

Purpose：To evaluate the feasibility of reducing radiation dose of coronary CT angiography and improving the image quality though iDose4 on 256-slice CT combined with dose reduction techniques under the guide of the body mass index.Methods：256-slice CT coronary angiography was performed in 74 patients who were doubted with coronary atherosclerotic disease.Patients were divided into two groups,group A was performed with fixed kV/mA and Filtered back-projection （FBP）,and group B was performed with the BMI-adapted kV/mA and advanced iterative reconstruction algorithm （iDose4）.The signal-to-noise radio （SNR）,contrast-to-noise radio （CNR）,volume CT dose index （CTDIVOL） and effective dose （E） were evaluated,respectively.Results：The mean SNRs of the images were （16.15± 3.76） and （16.65 ± 3.47） for group A and group B respectively,and were with no significant difference between them （t=0.591,P＞0.05）.The mean CNRs were （13.76±3.61） and （14.22-t-3.28） for group A and group B respectively,and were with no significant difference between them （t=0.571,P＞0.05）.The average effective doses （ED） were （8.15±0.44） mSv and （4.18±0.72） mSv for group A and group B respectively,and were with significant difference between them （t=28.55,P＜0.05）.Conclusions：In 256-slice CT coronary angiography,by using iDose4 of 256-slice CT combined with dose reduction techniques under the guide of body mass index,consistent image quality across patients population and optimized dose delivery to patients can be obtained,and can reduce dose can be reduced （about 49％）.