混合迭代算法和全模型迭代重建算法在冠状动脉CT血管造影中的应用研究

Application and analysis of iDose4 and IMR algorithms in coronary CCTA

目的:探究混合迭代算法(iDose^(4))和全模型迭代重建(IMR)算法在冠状动脉CT血管造影(CCTA)中的应用价值。方法:选取医院收治的60例待确诊冠心病患者,按照随机数表法将其分为iDose组和IMR组,每组30例。所有患者均进行CCTA检查,并将所有患者原始数据传输到飞利浦ISP工作站进行处理分析,iDose组原始数据采用iDose^(4)(4级算法重建),IMR组原始数据采用IMR(L1 Cardiac-Routine)重建。对两组碘负荷、主客观图像质量评价指标、图像效果噪声值、对比噪声比(CNR)和信噪比进行比较。结果:iDose组对比剂使用量、碘负荷水平明显高于IMR组,差异有统计学意义(t=12.521,t=11.247;P<0.05)。iDose组管腔边缘锐利度、伪影和图像总体质量评分均明显低于IMR组,噪声高于IMR组,差异有统计学意义(t=9.632,t=10.328,t=11.723,t=13.698;P<0.05)。两组各段冠状动脉CT值差异无统计学意义,但IMR组左冠状动脉前降支远段CT值显著高于iDose组,差异有统计学意义(t=14.259,P<0.05),iDose组噪声值显著高于IMR组,而CNR和信噪比均显著低于IMR组,差异有统计学意义(t=14.529,t=12.369,t=13.027;P<0.05)。结论:IMR重建算法与iDose^(4)相比可进一步降低碘负荷以及噪声,提高图像质量。

Objective:To explore the application value of merge iterative algorithm(iDose^(4))and iterative model reconstruction(IMR)algorithms in coronary computed tomography angiography(CCTA).Methods:Sixty patients with suspected coronary heart disease(CHD)who admitted to hospital were selected and were divided into iDose group and IMR group according to random number table method,with 30 cases in each group.All patients underwent CCTA examination,and the original data of all patients were transferred to Philips ISP workstation for processing and analysis.The original data of iDose group were reconstructed using iDose^(4)4 grade algorithm,and the original data of IMR group were reconstructed using IMR(L1 Cardiac-Routine)reconstruction.Iodine load,evaluation indexes of subjective and objective image quality,noise value of image effects,contrast noise ratio(CNR)and signal noise ratio(SNR)were compared between the two groups.Results:The usage amount of contrast agent and the level of load iodine of iDose group were significantly higher than those of IMR group(t=12.521,t=11.247,P<0.05).The scores of the sharpness of lumen edge,artifact and overall quality of image of iDose group were significantly lower than those of IMR group,and the noise of iDose group was significantly higher than that of IMR group(t=9.632,t=10.328,t=11.723,t=13.698,P<0.05).There were no significant differences in CT values of each segment of coronary artery between two groups,but CT value of the distal segment of the ramus descendens anterior of left coronary artery in IMR group were significantly higher than that of iDose group(t=14.259,P<0.05).In addition,noise value of iDose group were significantly higher than that in IMR group,while CNR and SNR of iDose group were significantly lower than those of IMR group(t=14.529,t=12.369,t=13.027,P<0.05).Conclusion:Compared with iDose^(4),IMR reconstruction algorithm can further reduce iodine load and noise,and improve image quality.