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目的评价不同比例ASIR重建技术在能谱CT冠状动脉单能量图像中的应用价值,以寻求图像质量最佳的ASIR比例。方法共30例接受冠状动脉CT(Discovery CT750 HD)能谱扫描者入组。一次能谱成像获得5组单能量图像(60、65、70、75、80 ke V),同时每一组单能量图像分别进行不同比例ASIR重建(0%,20%,40%,60%,80%和100%),共30组重建图像,对混合能量图像及各组单能量不同比例ASIR图像进行感兴趣区SNR值、CNR值的测定,并且按李克特量表4分法进行图像质量评价。结果与传统混合能量图像相比,能谱成像所得65 ke V单能量图像和100%ASIR比例重建显示的CNR和SNR最大改善,分别是144%,P<0.001;173%,P<0.001。而主观评价图像质量方面,则显示60~65 ke V与40%~60%ASIR相结合,较传统混合能量图像质量改善50%以上(P<0.001)。结论冠状动脉CTA低剂量扫描技术[平均剂量(2.43±0.42)m SV],能谱CT 65~75ke V单能量和ASIR 40%~60%重建方案可以明显降低噪声,改善图像质量。
Objective To evaluate the value of ASIR reconstruction with different proportions in single-energy coronary angiography with energy-dispersive X-ray computed tomography (CT) to find the best ASIR image quality. Methods A total of 30 patients underwent CT scan with CT scan. Five single-energy images (60, 65, 70, 75, 80 keV) were obtained in one time spectral imaging, and each single energy image was reconstructed with different proportions of ASIR (0%, 20%, 40%, 60% 80%, 100%). A total of 30 images were reconstructed. The SNR and CNR values of the region of interest (ROI) of mixed energy images and different proportions of single energy ASIR images of each group were measured. Quality Evaluation. Results Compared with the traditional mixed energy images, the single-energy images of 65 ke V and 100% ASIR scaled images showed the largest improvement of CNR and SNR, 144%, P <0.001; 173%, P <0.001 respectively. Subjective evaluation of image quality showed that the combination of 60-65 ke V with 40% -60% ASIR improved more than 50% (P <0.001) compared with the traditional mixed energy image quality. Conclusion CTA low dose scanning technique [mean dose (2.43 ± 0.42) m SV], energy spectrum CT 65 ~ 75ke V single energy and ASIR 40% ~ 60% reconstruction can significantly reduce the noise and improve the image quality.