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目的比较冠状动脉CT血管造影(coronary CT angiography,CCTA)应用前瞻性心电门控扫描+滤波反投影算法(filter back projection,FBP)、纯化单能谱最佳单能量+FBP法、纯化单能谱最佳单能量+迭代重建(sinogram affirmed iterative reconstruction,SAFIRE)的图像质量差异,探讨冠状动脉双源CCTA成像的优化方案。方法拟诊或冠心病复诊、行冠状动脉双源CT血管造影超体质量患者80例,随机分为对照组和观察组各40例,对照组采用前瞻性心电门控触发序列扫描,采用FBP法重建;观察组采用双能量模式扫描,将自动获得的100、140kVp数据导入Heart PBV软件,经Mononergetic程序处理获得65、70、75、80、85、90keV单能量图像,进行FBP法重建,比较不同单能量重建图像主动脉根部(左冠状动脉开口处)CT值、噪声(noise determination,SD)、信噪比(signal noise ratio,SNR)、对比噪声比(contrast noise ratio,CNR)后选择最佳单能量,然后对最佳单能量数据行SAFIRE法重建。比较对照组心电门控扫描+FBP重建和观察组最佳单能量+SAFIRE重建、最佳单能量+FBP重建的主动脉根部CT值、SD、SNR、CNR、图像质量评分。结果观察组有效辐射剂量[(3.31±0.43)mSv]与对照组[(3.52±0.59)mSv]比较差异无统计学意义(P>0.05);观察组在75keV单能量时主动脉CT值[(438.21±38.34)Hu]较高,SNR、CNR*(23.52±3.23、0.99±0.01)最高,SD[(18.65±3.81)Hu]较低,为最佳纯化单能谱图像keV水平;观察组采用最佳单能量+SAFIRE重建时,SNR(32.61±2.11)、CNR(39.24±2.34)高于对照组心电门控+FBP重建(17.61±3.22、22.13±3.62)和观察组最佳单能量+FBP重建(23.52±3.23、28.32±2.51),SD[(13.45±3.68)Hu]低于对照组心电门控+FBP重建[(22.63±5.18)Hu]和观察组最佳单能量+FBP重建[(18.65±3.81)Hu](P<0.05),主动脉CT值[(437.34±38.21)Hu]、图像质量评分[(4.84±0.05)分]高于对照组心电门控+FBP重建[(398.76±46.62)Hu,(4.66±0.15)分](P<0.05),且图像质量评分高于观察组最佳单能量+FBP重建[(4.78±0.06)分](P<0.05)。结论 CCTA采用纯化75keV单能谱单能量+SAFIRE重建可获得最佳图像质量。
Objective To compare prospective ECG gated scan + filter back projection (FBP) with coronary CT angiography (CCTA) and purify single energy spectrum + FBP method to purify single energy Spectral optimal single energy + iterative reconstruction (sinogram affirmed iterative reconstruction, SAFIRE) image quality differences, to explore coronary dual-source CCTA imaging optimization program. Methods Totally 80 patients with coronary artery dual-source CT angiography overweight were enrolled in this study. They were randomly divided into control group and observation group, 40 cases in each group. The control group was treated with prospective ECG gated trigger sequence and FBP Methods The observation group was scanned with dual-energy mode. The 100,140 kVp data was automatically imported into the Heart PBV software. Single-energy images of 65, 70, 75, 80, 85 and 90 keV were obtained by Mononergetic program and reconstructed by FBP method The CT values, noise determination (SD), signal noise ratio (SNR) and contrast noise ratio (CNR) of the aortic root (left coronary artery) Good single energy, then SAFIRE reconstruction of the best single energy data. The best single energy + SAFIRE reconstruction, best single energy + FBP reconstruction of the aortic root CT value, SD, SNR, CNR and image quality score were compared between the control group, ECG gated scan + FBP reconstruction and observation group. Results There was no significant difference in the effective radiation dose between the observation group and the control group [(3.31 ± 0.43) mSv vs [3.52 ± 0.59 mSv] (P> 0.05) 438.21 ± 38.34), SNR, CNR * (23.52 ± 3.23,0.99 ± 0.01), and SD [(18.65 ± 3.81) Hu] were the lowest, which were the best values for keV level in single- SNR (32.61 ± 2.11) and CNR (39.24 ± 2.34) were higher than those of the control group (17.61 ± 3.22,22.13 ± 3.62) and the best single energy + FBP reconstruction (23.52 ± 3.23,28.32 ± 2.51), SD [(13.45 ± 3.68) Hu] was lower than that of the control group, and the best single energy + FBP reconstruction [(18.65 ± 3.81) Hu] (P <0.05), CT value of aorta (437.34 ± 38.21) Hu and image quality score [(4.84 ± 0.05) (398.76 ± 46.62) Hu, (4.66 ± 0.15) points (P <0.05), and the image quality score was higher than that of the observation group (4.78 ± 0.06) (P <0.05). Conclusion The CCTA achieves the best image quality with the purified 75 keV single energy spectrum + SAFIRE reconstruction.