【摘要】 目的探讨双源CT冠脉成像中胸廓前后径及左右径与图像质量的相关性,以获得最优化降低辐射剂量的可能性。方法收集我院双源CT冠脉成像检查的患者118例,分为A〔25kg/m2≤体质量指数(BMI)值<30〕、B(BMI值<25kg/m2)两组。A组患者58例,平均年龄59.9岁;B组患者60例,平均年龄60.1岁。扫描参数:准直64×0.6mm,重建层厚0.75mm,重建间隔0.7mm,FOV 150～180mm,根据心率自动调整螺距。A组:管电压100kV,管电流330mAs;B组:管电压100kV,管电流220mAs。采集图像后,测量胸廓前后径(AP)、左右径(RL),及所在层面(共5个层面)冠脉、背脊肌的CT值和噪声(SD),并计算冠脉相对于背脊肌的对比噪声比(CNRa)、信噪比(SNRa)。应用统计学软件进行CNRa、SNRa与胸廓AP、RL、BMI的相关性检验。结果 A、B两组RL的5个层面与CNRa具有相关性(P<0.05),A、B两组中除A组第iii、iv层外,均与CNRa具有相关性(P<0.05),除A组第ii、iv层、B组第v层外,BMI均与CNRa具有相关性(P<0.05)。A组CNRa与RL的相关系数除第ii层面外,都大于其与AP的相关系数,B组CNRa、SNRa与RL的相关系数均大于其与AP的相关系数。A组除第iii层面外,CNRa、SNRa与AP的相关系数大于其与BMI的相关系数;B组除第ii层面外,CNRa与AP的相关系数大于其与BMI的相关系数。结论在双源CT冠脉成像检查中,图像质量与胸廓径线(左右径、前后径)的相关性大于与BMI的相关性。采用胸廓径线作为降低射线剂量的参考标准更具有临床实用意义。更多还原

【Abstract】 Objective To evaluate the correlation between image quality and thoracic diameters,anteroposterior diameter(AP) and right-left diameter(RL) for the optimization of reducing radiation dose in coronary artery imaging with Dual-source CT.Methods 118 patients underwent CT coronary artery imaging(CTCA)were divided into two groups(A and B) according to body mass index(BMI).There were 58 patients in group A with BMI values ≥25 kg/m2 and <30 kg/m2;and 60 patients in group B with BMI values <25 kg/m2.Scan parameters: collimation 64×0.6 mm,reconstruction slice thickness 0.75 mm,reconstructin interval 0.7 mm,FOV 150-180 mm,the pitch adjusted according to heart rate automatically.CT imagings were obtained with tube voltage 100 kV,tube current 330 mAs(group A) and 100 kV,tube current 220 mAs(group B).The contrast-noise ratio(CNR),signal to noise ratio(SNR),as well as blind correlation test score values were calculated to establish the relationship among BMI,AP,RL and CNR,SNR;Results RL of five levels in groups of A,B were correlated to CNRa(P<0.05).In group A and B(except iii,iv level of Group A),AP were associated with CNRa(P<0.05).In addition to ii,iv level of group A,v level of group B,BMI were associated with CNRa(P<0.05).The correlation coefficient of CNRa and RL of group A except ii level was greater than that of CNRa and AP.The correlation coefficient of CNRa,SNRa and RL of group B was greater than that of CNRa,SNRa and AP.Except iii level,the correlation coefficient of CNRa,SNRa and AP of group A was greater than that of CNRa,SNRa and BMI.Except ii level,the correlation coefficient of CNRa and AP of group B was greater than that of CNRa and BMI.Conclusion Thoracic diameter of RL can be used as a guider to select the appropriate scan protocol in the coronary imaging acqusition with dual-source CT.更多还原