基于多模型迭代重建和80kV在肾动脉CT血管成像中的应用价值

Objective: To explore the application of adaptive statistical iterative reconstruction Veo (ASIR-V) and 80 kV in renal computed tomography angiography(CTA). Methods: Eighty patients with renal computed tomography angiography were prospectively collected from April 2018 to July 2018 in the Affiliated Hospital of Shaanxi University of Chinese Medicine and randomly divided into group A and group B. The patients in group A adopted tube voltage 120 kV and contrast agent concentration 600 mgI/kg and reconstructed with filtered back projection (FBP), while the patients in group B were scanned with tube voltage 80 kV and contrast agent concentration 350 mgI/kg and reconstructed with FBP and ASIR-V from 10% to 100% with 10% interval. The CT values and standard deviation (SD) of the right renal artery, left renal artery were measured respectively to calculate the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR).The image quality of renal CTA was subjectively scored by two experienced radiologists blindly using a 5-point criteria.The contrast agent,CT volume dose index(CTDI(vol)) and dose length product(DLP) in both groups were recorded and the effective radiation dose(ED) was calculated. Results: The ED ((2.11±0.19)mSv) and contrast agent ((21.9±3.0)g) in group B were 65.1% (P<0.05) and 42.2% (P<0.05) lower than those in group A ((6.04±1.89)mSv and (38.0±3.8)g).With the increase of ASIR-V percentage in group B, CT values showed no significant difference, SD values gradually decreased, SNR values and CNR values gradually increased.The CT values with different reconstruction algorithm showed no statistically significant difference (all P>0.05) between group A and group B. The SD values with 40%ASIR-V to 100%ASIR-V reconstruction in group B were significantly lower than those of group A (all P<0.05).The SNR values with 50% ASIR-V to 100% ASIR-V reconstruction and CNR values with 70%ASIR-V to 100%ASIR-V were significantly higher than those of group A(all P<0.5).Two radiologists had excellent consistency in subjective scores of image quality for renal CTA(all kappa>0.75, P<0.05). The subjective scores with 60% ASIR-V to 90% ASIR-V in group B were significantly higher than those in group A (P<0.05), of which 70%ASIR-V reconstruction achieved the highest subjective score for renal CTA. Conclusion: ASIR-V and 80 kV can significantly reduce radiation dose (about 65.1%) and contrast agent (about 42.2%) in renal CTA, ASIR-V reconstruction can significantly improve the image quality of renal CTA, of which 70% ASIR-V reconstruction achieved the best image quality in 80 kV renal CTA.目的： 探讨基于多模型迭代重建（ASIR-V）和80 kV在肾动脉CT血管成像（CTA）中的应用价值。 方法： 前瞻性收集2018年4至7月在陕西中医药大学附属医院行肾动脉CTA患者80例并随机分为A、B两组。A组管电压120 kV，对比剂浓度600 mgI/kg，滤波反投影法（FBP）重建；B组管电压80 kV，对比剂浓度350 mgI/kg，FBP及10%ASIR-V至100%ASIR-V重建（间隔10%ASIR-V）。测量右肾动脉、左肾动脉CT值和标准差（SD），计算信噪比（SNR）和对比噪声比（CNR）。由两名医师采用五分法对图像质量进行主观评分。记录两组对比剂用量、CT容积剂量指数（CTDI(vol)）、剂量长度乘积（DLP），并计算有效辐射剂量（ED）。 结果： B组ED[（2.11±0.19）mSv]及对比剂用量[（21.9±3.0）g]较A组[（6.04±1.89）mSv和（38.0±3.8）g]分别降低65.1%（P<0.05）和42.2%（P<0.05）。B组随着ASIR-V增加CT值无显著变化，SD值逐渐降低，SNR值和CNR值逐渐增加。A、B两组各重建图像CT值差异均无统计学意义（均P>0.05），B组40%ASIR-V至100%ASIR-V重建SD值低于A组（均P<0.5），50%ASIR-V至100%ASIR-V重建SNR值和70%ASIR-V至100%ASIR-V重建CNR值显著高于A组（均P<0.5）。两名医师对图像质量主观评分一致性极好（kappa值均>0.75，P<0.05），60%ASIR-V至90%ASIR-V重建主观评分均高于A组（均P<0.5），其中70%ASIR-V重建图像质量主观评分最高。 结论： 基于多模型迭代重建和80 kV可以显著降低肾动脉CTA的辐射剂量（65.1%）和对比剂用量（42.2%），ASIR-V重建可以显著提高肾动脉CTA图像质量，其中70%ASIR-V为80 kV肾动脉CTA最佳重建比例。.