双源CT准确评估冠状动脉钙化斑块所致狭窄的价值

The Value of Dual-Source CT to Accurately Assess the Stenosis of Coronary Artery Calcification Plaque

目的探讨使用双源CT单能谱成像技术提高对冠状动脉钙化斑块所致狭窄程度评估的准确性。方法搜集80例至少一支冠状动脉钙化积分值大于100的患者,并随机分为A、B两组每组40例,其中A组使用回顾性心脏双能量模式扫描,重组单能谱值为100 ke V的图像;B组使用常规回顾性心脏螺旋扫描,重组100 ke V混合能量图像。记录CT容积剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效辐射剂量(ED)。一周内均行冠状动脉造影(CAG)检查,以其为金标准。利用双盲法评估严重钙化节段的狭窄程度,根据金标准计算两组的诊断准确率、敏感度、特异度、阳性预测值(PV+)、阴性预测值(PV-)。利用Kappa检验评价两位观察者的评估一致性。对A组所有钙化严重节段每隔10 ke V重组一组图像,评估狭窄程度,并采用配对t检验与CAG结果比较,以P<0.05为差异有统计学意义。结果 A组的诊断准确率、特异度和PV+均明显高于B组,敏感度和PV-与B组相差不大;A组的Kappa系数大于B组;A组的CTDIvol、DLP及ED与B组比较无明显统计学差异(P>0.05)。A组内能量级100 ke V的图像测得的狭窄程度与CAG比较误差最小(P>0.05)。结论采用冠状动脉CT双能量模式扫描,后处理时利用单能谱100 ke V重组可以有效减轻冠状动脉钙化斑块伪影,提高评估的客观性和准确性,并且没有明显增大辐射剂量。

Objective To investigate the accuracy of the assessment of stenosis caused by coronary artery calcification plaque using dual-source CT single-energy imaging.Methods Eighty patients with at least one coronary calcification score greater than 100 were randomly selected as the study subjects,and divided into two groups of 40 patients.Group A was retrospectively used to reconstruct single-energy spectral values.Images of 100 ke V;Group B reconstructed a 100 k V mixed energy image using a conventional retrospective cardiac spiral scan.CT volume dose index(CTDIvol),dose length product(DLP),effective dose(ED)was recorded.Coronary angiography(CAG)was performed within one week as the gold standard.The double-blind method was used to assess the degree of stenosis in severe calcification,and the diagnostic accuracy,sensitivity(Se),specificity(Sp),positive predictive value(PV+),and negative predictive value(PV-)of the two groups were calculated according to the gold standard..The Kappa test was used to evaluate the consistency of evaluation between the two observers.A group of images were reconstructed every 10 ke V in all severe calcified segments of group A.The degree of stenosis was evaluated and compared with CAG results by paired t-test.P<0.05 was considered statistically significant.Results The diagnostic accuracy,Sp and PV+of group A were significantly higher than those of group B.Se and PV-were not much different from group B.Kappa coefficient of group A was higher than group B.CTDIvol,DLP and ED of group A were compared with group B.There was no significant statistical difference(P>0.05).The stenosis measured by the image of energy level 100 ke V in group A was the smallest compared with CAG(P>0.05).Conclusion Coronary CT dual energy mode scanning is used.The single-energy spectrum 100 ke V reconstruction can effectively reduce the coronary calcification plaque artifacts,improve the objectivity and accuracy of the evaluation,and does not significantly increase the radiation dose.