冠脉追踪冻结技术对冠脉CT血管成像优化研究

Further improving image quality of coronary CT angiography with a novel motion correction algorithm(SSF)

目的:探索冠脉追踪冻结技术(SSF)对不同扫描模式的冠脉CT血管成像(CCTA)图像质量的改善作用。方法:回顾性分析134例行CCTA检查患者图像资料,根据扫描所采用序列不同,入组患者分为常规屏气组(n=73)和自由呼吸组(n=61)。各组数据均行标准算法和SSF运动校正算法重建图像,并分别进行图像质量评价。结果:常规屏气组与自由呼吸组内SSF算法图像的图像质量均优于标准算法图像,但2组间SSF算法图像的平均图像质量得分、图像噪声、冠脉血管密度值、信噪比及对比噪声比之间差异均无统计学意义(均P>0.05)。自由呼吸组SSF算法与标准算法的图像质量评分差值(1.00±2.00)显著大于常规屏气组差异有统计学意义(0.25±1.25,P<0.05),即与常规屏气组相比,SSF算法在自由呼吸组中对图像质量改善更显著。结论:SSF算法有助于改善CCTA图像质量,尤其是对自由呼吸扫描模式的CCTA图像。

Objective:To evaluate the effectiveness of a novel motion correction algorithm snapshot-freeze(SSF)in improving image quality of coronary CT angiography with different scanning protocols.Methods:A total of 134 consecutive patients underwent coronary CT angiography were enrolled and divided into breathholding and free-breathing groups according to different scanning protocol.All images were reconstructed by standard algorithm(STD)and motion correction SSF algorithm(SSF).Data sets were assessed by two independent observers for subjective(four-point grading score,1=nondiagnostic,4=excellent image quality)and objective image quality scoring(image noise,attenuation values in coronary arteries,signal-to-noise and contrastto-noise).Wilcoxon rank sum test was used for two related samples to compare subjective image quality scores between STD and SSF images in each group.Mann-Whitney U test or Independent-sample T test was used to compare image quality scores of SSF images between the two groups.Results:The subjective image quality scores using SSF were both significantly higher than those using STD in both groups.Neither subjective nor objective image quality scores of SSF images showed statistically significant difference between the two groups(P>0.05).The difference of subjective image quality score between SSF and STD images in free-breathing group was larger than the one in breath-holding group[(1.00±2.00)vs(0.25±1.25),P<0.05].Conclusion:The motion correction SSF algorithm can significantly improve image quality,especially for freebreathing CCTA images.