OBJECTIVE:To determine the optimal pre-adaptive and post-adaptive level statistical iterative reconstruction V (ASiR-V) for improving image quality and reducing radiation dose in coronary computed tomography angiography (CCTA). METHODS:The study was divided into two parts. In part I, 150 patients for CCTA were prospectively enrolled and randomly divided into 5 groups (A, B, C, D, and E) with progressive scanning from 40% to 80% pre-ASiR-V with 10% intervals and reconstructing with 70% post-ASiR-V. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Subjective image quality was assessed using a 5-point scale. The CT dose index volume (CTDIvol) and dose-length product (DLP) of each patient were recorded and the effective radiation dose (ED) was calculated after statistical analysis by optimizing for the best pre-ASiR-V value with the lowest radiation dose while maintaining overall image quality. In part II, the images were reconstructed with the recommended optimal pre-ASiR-V values in part I (D group) and 40%–90% of post-ASiR-V. The reconstruction group (D group) was divided into 6 subgroups (interval 10%, D0:40% post-ASiR-V, D1:50% post - ASiR-V, D2:60% post-ASiR-V, D3:70% post-ASiR-V, D4:80% post-ASiR-V, and D5:90% post-ASiR-V).The SNR and CNR of D0-D5 subgroups were calculated and analyzed using one-way analysis of variance, and the consistency of the subjective scores used the k test. RESULTS:There was no significant difference in the SNRs, CNRs, and image quality scores among A, B, C, and D groups (P > 0.05). The SNR, CNR, and image quality scores of the E group were lower than those of the A, B, C, and D groups (P < 0.05). The mean EDs in the B, C, and D groups were reduced by 7.01%, 13.37%, and 18.87%, respectively, when compared with that of the A group. The SNR and CNR of the D4–D5 subgroups were higher than the D0-D3 subgroups, and the image quality scores of the D4 subgroups were higher than the other subgroups (P < 0.05). CONCLUSION:The wide-detector combined with 70% pre-ASiR-V and 80% post-ASiR-V significantly reduces the radiation dose of CCTA while maintaining overall image quality as compared with the manufacture’s recommendation of 40% pre-ASiR-V.

中文翻译：

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在冠状动脉计算机断层扫描血管造影中使用不同的 pre-ASiR-V 和 post-ASiR-V 水平的图像质量和辐射剂量比较

目的：确定最佳的自适应前和自适应后水平统计迭代重建V（ASiR-V），以提高冠状动脉计算机断层扫描血管造影（CCTA）的图像质量和减少辐射剂量。方法：研究分为两部分。在第一部分中，前瞻性招募了 150 名 CCTA 患者，并随机分为 5 组（A、B、C、D 和 E），从 40% 到 80% pre-ASiR-V 进行逐行扫描，间隔 10%，并用70% 后 ASiR-V。计算信噪比 (SNR) 和对比度噪声比 (CNR)。使用 5 分制评估主观图像质量。记录每位患者的CT剂量指数体积（CTDIvol）和剂量长度乘积（DLP），并通过优化以最低辐射剂量获得最佳pre-ASiR-V值进行统计分析计算有效辐射剂量（ED）同时保持整体图像质量。在第二部分中，使用第一部分（D 组）推荐的最佳 ASiR-V 前值和 ASiR-V 后 40%–90% 的图像重建图像。重建组（D 组）分为 6 个亚组（间隔 10%、D0:40% post-ASiR-V、D1:50% post-ASiR-V、D2:60% post-ASiR-V、D3:70 % post-ASiR-V, D4:80% post-ASiR-V, and D5:90% post-ASiR-V)。使用单因素方差分析计算和分析 D0-D5 亚组的 SNR 和 CNR，主观评分的一致性采用k检验。结果：SNR、CNR、A、B、C、D组的图像质量得分（P > 0.05）。E组的SNR、CNR和图像质量得分低于A、B、C、D组（P < 0.05）。与 A 组相比，B、C 和 D 组的平均 ED 分别降低了 7.01%、13.37% 和 18.87%。D4~D5亚组的SNR和CNR高于D0~D3亚组，D4亚组的图像质量得分高于其他亚组（P < 0.05）。结论：与制造商推荐的 40% pre-ASiR-V 相比，宽探测器结合 70% pre-ASiR-V 和 80% post-ASiR-V 显着降低了 CCTA 的辐射剂量，同时保持了整体图像质量。E组和图像质量得分均低于A、B、C、D组（P < 0.05）。与 A 组相比，B、C 和 D 组的平均 ED 分别降低了 7.01%、13.37% 和 18.87%。D4~D5亚组的SNR和CNR高于D0~D3亚组，D4亚组的图像质量得分高于其他亚组（P < 0.05）。结论：与制造商推荐的 40% pre-ASiR-V 相比，宽探测器结合 70% pre-ASiR-V 和 80% post-ASiR-V 显着降低了 CCTA 的辐射剂量，同时保持了整体图像质量。E组和图像质量得分均低于A、B、C、D组（P < 0.05）。与 A 组相比，B、C 和 D 组的平均 ED 分别降低了 7.01%、13.37% 和 18.87%。D4~D5亚组的SNR和CNR高于D0~D3亚组，D4亚组的图像质量得分高于其他亚组（P < 0.05）。结论：与制造商推荐的 40% pre-ASiR-V 相比，宽探测器结合 70% pre-ASiR-V 和 80% post-ASiR-V 显着降低了 CCTA 的辐射剂量，同时保持了整体图像质量。D4~D5亚组的SNR和CNR高于D0~D3亚组，D4亚组的图像质量得分高于其他亚组（P < 0.05）。结论：与制造商推荐的 40% pre-ASiR-V 相比，宽探测器结合 70% pre-ASiR-V 和 80% post-ASiR-V 显着降低了 CCTA 的辐射剂量，同时保持了整体图像质量。D4~D5亚组的SNR和CNR高于D0~D3亚组，D4亚组的图像质量得分高于其他亚组（P < 0.05）。结论：与制造商推荐的 40% pre-ASiR-V 相比，宽探测器结合 70% pre-ASiR-V 和 80% post-ASiR-V 显着降低了 CCTA 的辐射剂量，同时保持了整体图像质量。