目的：探讨能谱冠状动脉 CT 血管成像（coronary CT angiography，CCTA）联合自适应统计迭代重建技术（ASIR）在冠状动脉旁路移植术后桥血管图像质量评价中的价值。方法选取60例冠状动脉旁路移植术后拟行 CCTA 的患者为研究对象，随机分为 A、B 两组，每组各30例。A 组患者行能谱 CCTA 扫描，B 组患者行常规 CCTA 扫描，A 组图像分别经 FBP 和40%权重的 ASIR 重建，B 组图像行常规 FBP 重建；两组均采用前瞻性心电门控扫描技术，对比两组患者检查中所接受的有效辐射剂量（ED）和三组图像质量。结果 A 组患者 CT 剂量指数（CTDIvol）、剂量长度乘积（DLP）和 ED均低于 B 组（P ＜0.05），ED 降低了约18.46%。A 组和 A1组患者桥血管分级比较差异具有显著性（χ2＝5.968，P ＝0.015），A 组和 B 组患者桥血管分级比较差异具有显著性（χ2＝6.296，P ＝0.015），A1组和 B 组患者桥血管分级比较差异无显著性（χ2＝0.00，P ＝0.982）。B 组与 A1组桥血管信噪比（SNR）和对比噪声比（CNR）均高于 A 组（P ＜0.05）。A1组和 B 组图像质量、桥血管的 SNR 和 CNR 比较差异均无显著性（P ＞0.05）。结论能谱 CCTA 联合 ASIR 可获得良好的图像质量，对桥血管的评估与常规扫描模式差异不明显，且可明显减少辐射剂量。%Objective To explore the value of coronary CT angiography (CCTA) in spectrum mode with ASIR reconstruction in evaluating the grafts after coronary artery bypass grafting (CAGB). Method 60 patients after CAGB were randomly divided into two groups (A and B). All cases were checked by prospective ECG-gated scanning technology. The images of group A checked by spectral CCTA were reconstructed by FBP and 40% ASIR, and the images checked by normal CCTA were reconstructed by FBP of group B. The radiation dose and the image quality of grafts were analyzed. Result The CTDIvol, DLP and ED of spectral CCTA in group A were lower than group B (P < 0.05), and the ED was reduced by about 18.46%. The difference of grafts grade between group A and group A1 was significant (χ2 = 5.968, P = 0.015), and the difference of grafts grade between group A and group B was significant (χ2 = 0.00, P = 0.982), but the difference of grafts grade between group A1 and group B was not significant (χ2 = 0.00, P = 0.982). The SNR and CNR of group A1 and group B were both higher than group A (P < 0.05). There were no significant differences of the image quality of SNR and CNR vascular bridge between group A1 and group B (P>0.05). Conclusion Spectral CCTA with ASIR reconstruction can reduce the radiation dose, and the images can meet the needs of diagnosis, which are similar with the images of normal CCTA.
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