Double Flash扫描模式在冠状动脉支架植入术后的应用

Application of Double Flash Scanning in Patients with Coronary Artery Stent

目的探讨Double Flash扫描模式应用于冠状动脉支架植入术后患者的图像质量、辐射剂量和诊断准确性。资料与方法 63例冠状动脉支架植入术后患者行冠状动脉CT造影,心率≤70次/min者采用Double Flash扫描模式,心率>70次/min者采用螺旋扫描模式。比较两组支架节段图像质量主观评分、血管CT值、噪声、信噪比(SNR)和对比噪声比(CNR);以冠状动脉造影作为"金标准",评估两种扫描模式的诊断效能,并计算两组辐射剂量。结果 Double Flash组冠状动脉共植入支架59枚,其中57枚可诊断;螺旋组冠状动脉共植入支架58枚,均可诊断。Double Flash组和螺旋组图像质量主观评分、首次扫描过程中CT值、噪声、SNR、CNR差异无统计学意义(P>0.05);Double Flash组第2次扫描过程中图像质量评分与首次扫描和螺旋组差异有统计学意义(P<0.05)。Double Flash组的敏感度、特异度、阳性预测值、阴性预测值和准确度分别为90.0%、89.8%、64.3%、97.8%和89.8%,螺旋组分别为83.3%、95.7%、83.3%、95.7%和93.1%。Double Flash组对于直径≥3.0 mm支架敏感度、特异度、阳性预测值、阴性预测值和准确度明显高于直径<3.0 mm支架。Double Flash组整个扫描过程及冠状动脉CT造影增强扫描中的有效剂量、剂量长度乘积、容积CT剂量指数均显著低于螺旋组(P<0.05)。结论Double Flash扫描模式用于冠状动脉支架植入术后患者,可以获得较好的图像质量,与冠状动脉血管造影具有较好的一致性,且辐射剂量低,而对直径≥3.0 mm支架评估明显优于直径<3.0 mm支架。

Purpose To explore the image quality, radiation dose and diagnostic accuracy of double flash scanning mode in patients with coronary artery stent. Materials and Methods Sixty-three patients with coronary stents underwent CT coronary artery imaging using conventional coronary artery angiography as the gold standard. Double flash mode was used in patients with heart rate ≤ 70 beats per minute. Spiral scanning was used in patients with heart rate between 70-100 beats per minute. The image quality, vascular CT value, noise, SNR and CNR were compared. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were determined, and the radiation dose was calculated. Results There were 59 stents in Double flash group （57 were diagnostic） and 58 stents in spiral group （all diagnostic）. There was no statistically significant difference in image quality, CT value, noise, SNR or CNR for the first scan between two groups （P〉0.05）. Image quality for the second scan in Double flash group showed statistical difference with the first scan and spiral group （P〈0.05）. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of Double flash and spiral group were 90.0%, 89.8%, 64.3%, 97.8%, 89.8% and 83.3%, 95.7%, 83.3%, 95.7% 93.1%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy for stents with diameter ≥ 3.0 mm were significantly higher than stents with diameter 〈3.0 mm. The radiation doses of Double flash group were significantly lower than the spiral group （P〈0.05）. Conclusion Double Flash mode scanning provides good image quality and diagnostic accuracy with lower radiation dose in patients with coronary artery stents. Imaging of stents with diameter ≥ 3.0 mm is superior to stents with diameter 〈3.0 mm.