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目的:探讨前瞻性心电门控扫描、低管电压结合迭代重建算法在256层螺旋CT冠脉造影中的应用价值。方法:回顾性分析行256层螺旋CT冠状动脉成像(CCTA)、体质量指数正常的受检者130例。常规剂量组(A组)50例:应用回顾性心电门控扫描模式,管电压120 kv;低剂量组(B组)80例,心率<70次/分者50例,心率≧70次/分者30例:应用前瞻性心电门控扫描模式,管电压100 kv。B组患者原始数据分别应用迭代算法(Idose3)重建及标准滤波反投影法(FBP)重建。比较A、B两组的有效辐射剂量,对各组客观图像质量及主观图像质量进行统计学分析。结果:A、B两组平均有效辐射剂量分别为(15.34±3.89)、(1.43±0.12)m Sv。B组患者应用迭代重建图像噪声降低,差异有统计学意义(P<0.05)。应用FBP重建,B组图像噪声高于A组,两者比较差异有统计学意义(P<0.05)。各组主观图像质量评分差异无统计学意义(P>0.05)。结论:前瞻性心电门控低千伏扫描模式联合迭代重建算法在提供满足诊断的冠状动脉CTA图像的同时,辐射剂量降幅高达90.6%。心率70次/分-85次/分的患者也可行256层CT前门控扫描,降低管电压造成的图像噪声增加可以通过迭代重建弥补。
Objective: To explore the value of prospective ECG gated scan and low-voltage combined with iterative reconstruction in 256-slice spiral CT coronary angiography. Methods: Retrospective analysis of 256 cases of spiral CT coronary angiography (CCTA), body mass index of the normal subjects in 130 cases. 50 patients in the conventional dose group (group A) underwent retrospective electrocardiographic gating scanning with a tube voltage of 120 kv; 80 patients in the low-dose group (group B), 50 patients with heart rate <70 beats / Divided in 30 cases: the application of prospective ECG gated scanning mode, the tube voltage 100 kv. The original data of patients in group B were reconstructed with iterative algorithm (Idose3) and standard filtered back projection (FBP) respectively. The effective radiation doses of A and B groups were compared, and the objective image quality and subjective image quality of each group were statistically analyzed. Results: The average effective radiation doses of group A and B were (15.34 ± 3.89) and (1.43 ± 0.12) m Sv, respectively. The image noise of patients in group B was reduced by iterative reconstruction, the difference was statistically significant (P <0.05). FBP reconstruction, image noise of group B was higher than group A, the difference was statistically significant (P <0.05). There was no significant difference in subjective image quality score between groups (P> 0.05). Conclusions: The prospective ECG-gated low-kV scanning mode combined with iterative reconstruction algorithm provides 90.6% reduction in radiation dose while providing CTA images for diagnosis. Patients with a heart rate of 70 beats / min to 85 beats / min are also eligible for a 256-slice CT front gated scans, and reducing the increase in image noise caused by the tube voltage can be made up by iterative reconstruction.