正常体质量指数患者低管电压条件下行CT冠状动脉成像的研究

目的 评估正常体质量指数(BMI)患者在80 kV管电压条件下行冠状动脉CT血管成像(CCTA)的图像质量,探讨降低辐射剂量的可行性.方法 将60例在本院疑诊冠状动脉疾病且BMI在18.6~25 kg/m2的患者行CCTA检查,随机分为A、B组,2组均采用Flash spiral螺旋心脏模式扫描.A组(n=30)采用100 kV及滤波反投影重建(FBP)算法,B组(n=30)采用80 kV及自适应迭代重建(IR)算法.测量主动脉根部、右冠状动脉(RCA)、左冠状动脉前降支(LAD)及左冠状动脉回旋支(LCX)CT值及噪声,计算信噪比(SNR)及对比噪声比(CNR).采用3分法对所有图像进行主观质量评分.记录CT剂量指数CTDIovl,并进行有效辐射剂量(ED)计算.结果 A组平均ED为0.8 mSv,B组平均ED为0.41 mSv,2组之间差异有统计学意义.本研究中图像噪声A组(28±6) HU,B组(46±9) HU,差异有统计学意义;升主动脉根部、RCA、LAD、LCX的CT值80 kV下显著升高,差异有统计学意义.RCA-SNR、LAD-SNR、RCA-CNR 2组比较无统计学差异;LCX-SNR、LAD-CNR、LCX-CNR 2组比较有统计学差异.2组之间可用于诊断的冠状动脉节段数无统计学差异.结论 对于正常BMI的患者,采用80 kV管电压行双源Flash spiral CCTA可满足冠状动脉疾病诊断要求,并能够明显降低辐射剂量.

Application research of coronary CT angiography using low tube voltage in patients with a normal body mass index

Objective To assess the image quality of coronary CT angiography(CCTA) by using high-pitch spiral CT under 80 kV in patients with a normal body mass index(BMI), and to investigate the feasibility of low radiation dose.Methods 60 patients,who suspicious coronary artery diseases and BMI between 18.6-25.0 kg/m2 underwent CCTA in our hospital.All patients were randomly divided into group A and group B(each with 30).Patients in group A were given 100 kV CCTA and filter back-projection algorithm (FBP), and patients in group B were given 80 kV CCTA and iterative reconstruction(IR).CT values of aortic root, right coronary artery (RCA), left anterior descending artery (LAD), left circumflex (LCX) and standard deviation (SD) were measured.Then signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated.All images were given quality subjective scoring by using 3-score method.The CT dose index was recorded and effective radiation dose (ED) was calculated.Results ED of group A and group B was 0.8 mSv and 0.41 mSv, respectively.Statistically significant difference was found between these two groups.In the study, SD was (28±6) HU in group A and (46±9) HU in group B, and the difference was statistically significant between the two groups.The CT values of aortic root, RCA, LAD and LCX under 80 kV were significantly increased, and the difference was statistically significant between the two groups.There was no statistically significant difference between two groups in RCA-SNR, LAD-SNR and RCA-CNR.But in LCX-SNR, LAD-CNR, LCX-CNR, there was statistically significant difference between two groups.There was no significant difference between the two groups in coronary artery segments which could be used for diagnosis.Conclusion For patients with a normal BMI, CCTA using Flash spiral CT under 80 kV could diagnose coronary artery disease and significantly reduce the radiation dose.