低管电压和低流速低剂量对比剂联合高权重深度学习图像重建在冠状动脉计算机体层摄影血管造影中的应用价值

目的　探讨低管电压和低流速低剂量对比剂联合高权重深度学习图像重建（DLIR-H）在冠状动脉计算机体层摄影血管造影（CCTA）中的应用价值。方法　选择2022年5～7月新乡市中心医院收治的体质量指数（BMI）为20～27 kg·m^-2的60例疑似冠状动脉性心脏病患者为研究对象，按随机数字表法将患者分为观察组和对照组，每组30例。所有患者采用256排宽体探测器CT行CCTA前瞻性心电门控扫描。观察组扫描参数设置:管电压80 kV、自动管电流500～1 300 mA，对比剂注射流速3.5～4.0 mL·s^-1，对比剂碘海醇（350 g·L^-1）剂量35～40 mL，采用DLIR-H法重建。对照组扫描参数设置:管电压100 kV、自动管电流500～1 040 mA，对比剂注射流速5.0～5.5 mL·s^-1，对比剂碘海醇（350 g·L^-1）剂量50～55 mL，采用多模型迭代重建50%算法重建。对图像质量进行定量和定性分析，定量指标包括主动脉根部（AO）、左前降支（LAD）、左旋支（LCX）、右冠状动脉（RCA）近段血管的CT值及冠状动脉CT图像信噪比（SNR）和对比噪声比（CNR），定性指标包括图像条纹伪影、血管边缘锐利度及总体图像质量的评分。扫描结束后，统计患者CT剂量指数（CTDI）、放射剂量长度乘积（DLP）及有效辐射剂量（ED）。结果　观察组患者AO、LAD和RCA的CT值显著高于对照组（P<0.05），2组患者LCX的CT值比较差异无统计学意义（P>0.05）。观察组患者冠状动脉CT图像的SNR显著低于对照组（P<0.05），观察组患者冠状动脉CT图像的CNR显著高于对照组（P<0.05）。观察组患者冠状动脉CT图像条纹伪影、血管边缘锐利度及总体图像质量的评分显著高于对照组（P<0.05）；观察组患者ED、DLP、CTDI显著低于对照组（P<0.05）。结论　对于BMI为20～27 kg·m^-2的患者，低管电压和低流速低剂量对比剂联合DLIR-H可生成高质量的CCTA图像。

Application value of low tube voltage,low flow rate and low dose contrast agent combined with high-strength deep learning image reconstruction in coronary computed tomography angiography

Objective　To investigate the application value of low tube voltage,low flow rate and low dose contrast agent combined with high-strength deep learning image reconstruction (DLIR-H) in coronary computed tomography angiography (CCTA).
Methods　A total of 60 patients with suspected coronary heart disease with the body mass index (BMI) of 20-27 kg·m^-2 admitted to Xinxiang Central Hospital from May to July 2022 were selected as the research subjects,and the patients were divided into observation group and control group according to the random number table method,with 30 patients in each group.All patients underwent CCTA prospective electrocardiogram gating scan with 256-row wide body detector CT.The parameters in the observation group were set as tube voltage 80 kV,automatic tube current 500-1 300 mA,flow rate of contrast medium 3.5-4.0 mL·s^-1,dose of 350 g·L^-1contrast medium iohexol 35-40 mL;DLIR-H method was used for reconstruction.The parameters in the control group were set as tube voltage 100 kV,automatic tube current 500-1 040 mA,flow rate of contrast medium 5.0-5.5 mL·s^-1,and dose of 350 g·L^-1contrast agent iohexol 50-55 mL;the adaptive statistical iterative reconstruction-V 50%algorithm was used for reconstruction.The image quality was analyzed quantitatively and qualitatively.The quantitative indexes included the CT values of aortic root (AO),left anterior descending(LAD),left circumflex(LCX) and proximal vessels of right coronary artery (RCA),as well as the signal to noise ratio (SNR) and contrast to noise ratio (CNR) of coronary artery CT images.The qualitative indexes included the score of image fringe artifacts,vascular edge sharpness and overall image quality.After scanning,the CT dose index(CTDI),radiation dose length product (DLP)and effective dose (ED) of patients were counted.
Results　The CT values of AO,LAD and RCA of patients in the observation group were significantly higher than those in the control group (P<0.05).There was no significant difference in the CT value of LCX of patients between the two groups (P>0.05).The SNR of coronary artery CT image of patients in the observation group was significantly lower than that in the control group (P<0.05),and the CNR of coronary artery CT image of patients in the observation group was significantly higher than that in the control group (P<0.05).The scores of fringe artifacts,vascular edge sharpness and overall image quality of coronary artery CT image in the observation group were significantly higher than those in the control group (P<0.05).The ED,DLP and CTDI of patients in the observation group were significantly lower than those in the control group (P<0.05).
Conclusion　For the patients with BMI of 20-27 kg·m^-2,the low tube voltage,low flow rate and low dose contrast agent combined with DLIR-H can achieve better quality CCTA imaging.