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目的探讨CT减影冠状动脉血管成像(subtraction coronary computed tomography angiography,SubCCTA)在具有严重钙化节段冠心病中的诊断价值。方法对同时接受320层减影CCTA扫描和传统冠状动脉血管造影(digital subtraction angiography,DSA)检查的27例患者行回顾性分析。对照DSA检查结果,分别计算常规CCTA(conventional CCTA,Con-CCTA)和Sub-CCTA的灵敏度、特异度、阳性预测值、阴性预测值及准确度;采用受试者工作特征(receiver operating characteristic,ROC)曲线评价两种成像方法的临床诊断准确性。冠脉病变节段的狭窄分为Ⅰ、Ⅱ、Ⅲ、Ⅳ4个等级;采用Kappa系数描述两种成像方法与DSA结果之间的一致性。对于剪影前后的图像质量采用4等级评分法,并行t检验对比两者成像质量差异。结果共评估严重钙化节段52个,其图像质量在Con-CCTA和Sub-CCTA中的得分分别为2.8±0.5和3.4±0.7,两者间差异有统计学意义(t=5.9,P<0.05)。Con-CCTA与DSA对定量评估冠脉狭窄程度的一致性为0.55;Sub-CCTA与DSA之间的一致性为0.81。Con-CCTA诊断冠脉明显狭窄的灵敏度、特异度、阳性预测值、阴性预测值及准确度分别为81.0%、63.1%、63.1%、81.1%及70.8%;Sub-CCTA各值分别为90.5%、85.2%、82.1%、92.0%及87.5%。与Con-CCTA的ROC曲线下面积0.84(95%CI:0.70~0.93)相比,Sub-CCTA为0.96(95%CI:0.86~1.00),两者差异有明显统计学意义(P=0.03)。结论 Sub-CCTA可以提高严重钙化节段冠状动脉狭窄程度的诊断准确性;减影技术在冠状动脉成像中的应用可以减少甚至消除严重钙化斑块产生的伪影,具有较好的临床应用前景。
Objective To investigate the diagnostic value of subtraction coronary computed tomography angiography (SubCCTA) in the diagnosis of coronary heart disease with severe calcification. Methods A retrospective analysis was performed on 27 patients who underwent both 320-slice subtraction CCTA scan and conventional digital subtraction angiography (DSA). The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of conventional CCTA (Con-CCTA) and Sub-CCTA were calculated respectively according to the results of DSA. Receiver operating characteristic (ROC ) Curve was used to evaluate the clinical diagnostic accuracy of the two imaging methods. The stenosis of coronary lesions was divided into four grades Ⅰ, Ⅱ, Ⅲ and Ⅳ. Kappa coefficient was used to describe the consistency between the two imaging methods and DSA results. For the before and after the silhouette of the image quality using 4-grade score method, parallel t-test contrast between the two imaging quality differences. Results A total of 52 severe calcified segments were evaluated. The scores of image quality in Con-CCTA and Sub-CCTA were 2.8 ± 0.5 and 3.4 ± 0.7, respectively, with significant differences between the two groups (t = 5.9, P <0.05 ). The concordance of Con-CCTA with DSA for the quantitative assessment of coronary stenosis was 0.55; the agreement between Sub-CCTA and DSA was 0.81. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of Con-CCTA in diagnosing significant coronary stenosis were 81.0%, 63.1%, 63.1%, 81.1% and 70.8% respectively; the Sub-CCTA values were 90.5% , 85.2%, 82.1%, 92.0% and 87.5% respectively. Sub-CCTA was 0.96 (95% CI: 0.86-1.00), with a statistically significant difference (P = 0.03) from the area under the ROC curve of Con-CCTA of 0.84 (95% CI: 0.70-0.93) . Conclusion Sub-CCTA can improve the diagnostic accuracy of coronary artery stenosis in severely calcified segments. The application of subtraction technique in coronary angiography can reduce or even eliminate artifacts caused by severe calcified plaque, and has a good clinical application prospect.