前置迭代重建技术对低剂量头颈CT血管造影图像质量及辐射剂量的影响

Effect of preiterative reconstruction technique on low dose head and neck CTA image quality and radiation dose

目的探讨Revolution CT前置迭代重建算法(Asir-V)对低剂量头颈CT血管造影(CTA)图像质量及辐射剂量的影响。方法选取2019年6~9月在我院通过Revolution CT接受头颈CTA检查的患者210例随机分为7组,前置Asir-V分别为20%组(A组)、30%组(B组)、40%组(C组)、50%组(D组)、60%组(E组)、70%组(F组)、80%组(G组),每组30例,管电压为80 kVp;另选取接受头颈CTA检查30例患者为对照组,管电压为100 kVp,前置Asir-V为50%。计算信号噪声比值(SNR)和对比噪声比值(CNR)及有效辐射剂量(ED)。结果 80 kVp管电压下,E组颈内动脉、大脑中动脉SD最低。各组头颈目标血管CNR及SNR比较,差异有统计学意义(P<0.01)。与对照组比较,其他7组不同头颈目标血管CNR明显升高,ED明显降低(P<0.01)。与A组比较,E组、F组、G组ED下降明显,分别为(1.43±0.11)mSv,(1.27±0.10)mSv,(1.12±0.15)mSv。结论低剂量头颈CTA联合前置Asir-V技术,在Asir-V为60%权重时,能够有效降低辐射剂量和图像噪声,保证图像质量。

Objective To study the effect of preiterative Asir-V on low dose head-neck CTA image quality and radiation dose.Methods Two hundred and ten patients who underwent head-neck CTA in our hospital were randomly divided into group A,group B,group C,group D,group E,group F,and group G with a preAsir-V of 20%,30%,40%,50%.60%,70% and 80% respectively and a tube voltage of 80 kVp(n=30).Another 30 patients who underwent head-neck CTA in our hospital served as a control group with a tube voltage of 100 kVp and a preAsir-V of 50%.The SNR,CNR and ERD were recorded.Results The SD of internal carotid artery and middle cerebral artery was lower in group E than in groups A-D and groups F-G.The CNR and SNR of the target brain vessels were significantly different in different groups(P<0.01).The SNR of the target brain vessels was significantly higher while the ERD of the target brain vessels was significantly lower in groups A-G than in control group(P<0.01).The ERD in groups E-G was 1.43±0.11 mSv, 1.27±0.10 mSv, 1.12±0.15 mSv respectively, which were lower than those in group A.Conclusion PreAsir-V can improve the CTA image quality by reducing the radiation dose and image noise when its weight value is 60%.