Department of Radiology, The Affiliated Hospital of Hebei University, Baoding, China.
Department of Radiology, Baoding No. 2 Hospital, Baoding, China.
J Xray Sci Technol. 2021;29(1):125-134. doi: 10.3233/XST-200754.
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).
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.
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).
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.
确定最佳的预适应和后适应统计迭代重建 V（ASiR-V）水平，以改善冠状动脉 CT 血管造影（CCTA）的图像质量并降低辐射剂量。
该研究分为两部分。在第一部分中，前瞻性纳入 150 例 CCTA 患者，并随机分为 5 组（A、B、C、D 和 E），从 40%到 80%的预 ASiR-V 进行逐步扫描，间隔 10%，以 70%的后 ASiR-V 进行重建。计算信噪比（SNR）和对比噪声比（CNR）。使用 5 分制对主观图像质量进行评估。记录每位患者的 CT 剂量指数容积（CTDIvol）和剂量长度乘积（DLP），并通过优化最佳预 ASiR-V 值来计算有效辐射剂量（ED），同时保持整体图像质量，以获得最低的辐射剂量。在第二部分中，使用第一部分中确定的推荐最佳预 ASiR-V 值（D 组）和 40%-90%的后 ASiR-V 值对图像进行重建。重建组（D 组）分为 6 个子组（间隔 10%，D0：40%后 ASiR-V、D1：50%后 ASiR-V、D2：60%后 ASiR-V、D3：70%后 ASiR-V、D4：80%后 ASiR-V 和 D5：90%后 ASiR-V）。使用单因素方差分析计算和分析 D0-D5 亚组的 SNR 和 CNR，并使用 k 检验一致性评估主观评分。
A、B、C 和 D 组的 SNR、CNR 和图像质量评分无统计学差异（P＞0.05）。E 组的 SNR、CNR 和图像质量评分均低于 A、B、C 和 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 亚组的图像质量评分高于其他亚组（P＜0.05）。
与制造商推荐的 40%预 ASiR-V 相比，宽探测器联合使用 70%的预 ASiR-V 和 80%的后 ASiR-V 可显著降低 CCTA 的辐射剂量，同时保持整体图像质量。
