Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang 712000, Shaanxi, China; The Second Affiliated Hospital of Shaanxi University of Chinese Medicine, Xianyang, Shaanxi, China.
Affiliated Hospital of Shaanxi University of Chinese Medicine, Weiyang western road- 2#, Xianyang 712000, Shaanxi, China.
Acad Radiol. 2020 Feb;27(2):233-243. doi: 10.1016/j.acra.2019.02.022. Epub 2019 Apr 25.
To explore the feasibility of reducing radiation dose and improving image quality in CT portal venography (CTPV) using 80 kV and adaptive statistical iterative reconstruction-V(ASIR-V) in slender patients in comparison with conventional protocol using 120 kV and ASIR.
Sixty slender patients for enhanced abdominal CT scanning were randomly divided into group A and group B. Group A used the conventional 120 kV tube voltage, 600 mgI/kg contrast dose and reconstructed with the recommended 40% ASIR. Group B used 80 kV tube voltage, 350 mgI/kg contrast dose and reconstructed with ASIR-V from 40% to 100% with 10% interval. The CT values and standard deviation (SD) values of the main portal vein, left branch, and right branch of portal vein, liver, and erector spinae at the same level were measured to calculate the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The image quality was subjectively scored by two experienced radiologists blindly using a 5-point criterion. The contrast dose, volumetric CT dose index, and dose length product were recorded in both groups and the effective dose was calculated.
There was no significant difference in general data between the two groups (p > 0.05), the effective dose and contrast dose in group B were reduced by 63.3% (p < 0.001) and 39.7% (p < 0.001), respectively compared with group A. With the percentage of ASIR-V increased in group B, the CT values showed no significant difference, while the SD values gradually decreased and SNR values and CNR values increased accordingly. Compared with group A, group B demonstrated similar CT values (p > 0.05), while the SD values with 80% ASIR-V to 100% ASIR-V were significantly lower than those of 40% ASIR (p < 0.001), and the SNR values and CNR values with 70% ASIR-V to 100% ASIR-V were significantly higher than those of 40% ASIR (p < 0.001). The subjective image quality scores by the two radiologists had excellent consistency (kappa value>0.75, p < 0.001), and the final subjective image quality scores and the subjective scores in each of the 5 scoring categories with 60% ASIR-V to 100% ASIR-V were all significantly higher than those of 40% ASIR, and 80% ASIR-V obtained the highest subjective score among different reconstructions.
In CTPV, the application of 80 kV and ASIR-V reconstruction in slender patients can significantly reduce radiation dose (by 63.3%) and contrast agent dose (by 39.7%). Compared with the recommended 40% ASIR using 120 kV, ASIR-V with 80% to 100% percentages can further improve image quality and with 80% ASIR-V being the best reconstruction algorithm.
CTPV with 80 kV and ASIR-V algorithm in slender patients can significantly reduce radiation dose and contrast agent dose as well as improve image quality, compared with the conventional 120 kV protocol using 40% ASIR.
探讨在较瘦患者中使用 80kV 和自适应统计迭代重建-V（ASIR-V）与传统的 120kV 和 ASIR 协议相比，降低 CT 门静脉造影（CTPV）的辐射剂量并提高图像质量的可行性。
将 60 例进行增强腹部 CT 扫描的较瘦患者随机分为 A 组和 B 组。A 组采用常规的 120kV 管电压、600mgI/kg 对比剂剂量，以推荐的 40%ASIR 重建。B 组采用 80kV 管电压、350mgI/kg 对比剂剂量，以 40%至 100%的 ASIR-V 进行重建，间隔为 10%。测量主门静脉、左支和右支、肝和同水平竖脊肌的 CT 值和标准偏差（SD）值，以计算信噪比（SNR）和对比噪声比（CNR）。两位有经验的放射科医生盲法使用 5 分制对图像质量进行主观评分。记录两组的对比剂剂量、容积 CT 剂量指数和剂量长度乘积，并计算有效剂量。
两组一般资料比较差异无统计学意义（p>0.05），B 组有效剂量和对比剂剂量分别降低了 63.3%（p<0.001）和 39.7%（p<0.001）。随着 B 组中 ASIR-V 百分比的增加，CT 值无显著差异，而 SD 值逐渐降低，SNR 值和 CNR 值相应增加。与 A 组相比，B 组 CT 值相似（p>0.05），但 80%ASIR-V 至 100%ASIR-V 的 SD 值明显低于 40%ASIR（p<0.001），而 70%ASIR-V 至 100%ASIR-V 的 SNR 值和 CNR 值明显高于 40%ASIR（p<0.001）。两位放射科医生的主观图像质量评分具有极好的一致性（kappa 值>0.75，p<0.001），60%ASIR-V 至 100%ASIR-V 的最终主观图像质量评分和 5 个评分类别中的每个评分均明显高于 40%ASIR，而 80%ASIR-V 在不同重建中获得了最高的主观评分。
在 CTPV 中，80kV 和 ASIR-V 重建在较瘦患者中应用可显著降低辐射剂量（降低 63.3%）和对比剂剂量（降低 39.7%）。与使用 120kV 推荐的 40%ASIR 相比，80%至 100%的 ASIR-V 可进一步提高图像质量，其中 80%ASIR-V 是最佳的重建算法。
在较瘦患者中使用 80kV 和 ASIR-V 算法的 CTPV 可显著降低辐射剂量和对比剂剂量，同时提高图像质量，与传统的 120kV 协议使用 40%ASIR 相比。
