迭代算法(Asir-V)在婴幼儿心脏CTA中的应用价值

Application value of adaptive statistical iterative reconstruction-V technique on cardiac CTA in infants

目的不同权重迭代算法(Asir-V)在婴幼儿心脏血管造影(CT angiography,CTA)中的应用价值。方法先天性心脏病患儿60例,随机分为两组,A组:30例,Asir-V:40%,B组:30例,Asir-V:80%,两组扫描条件相同:80kV,自动毫安,噪声指数(noise index,NI):22,探测器宽度120～160mm,扫描时间0. 28s,对比剂(碘克沙醇320mgI/ml)用量1～2ml/kg,记录升主动脉、降主动脉、肺动脉主干、左心室的CT值及同层面背部软组织CT值,并根据标准差SD计算各兴趣区信噪比(signal-to-noise ratio,SNR)及对比信噪比(contrast-to-noise ratio,CNR),记录每个病例的剂量长度乘积(doselength product,DLP),并根据公式换算有效剂量(effective doses,ED)。结果 A组各兴趣区SNR及CNR与B组相当,差异无统计学意义(P> 0. 05),A组DLP:11. 41±1. 25; ED:0. 43±0. 07,大于B组DLP:10. 73±1. 49及ED:0. 39±0. 12,比较差异有统计学意义(P <0. 05),两位医师读片显示两组病例图像质量均为良好,读片结果一致性良好(K=0. 675、0. 668)。结论 CTA是小儿先天性心脏病的重要诊断手段,相同的扫描条件下,提高ASIR-V的权重(80%)可以保证图像质量,并且降低辐射剂量,对婴幼儿心脏CTA扫描有重要的价值。

Objective To explore the application value of different grade iterative algorithms （Asir-V） on cardiac CTA in infants.Methods 60 infants with congenital heart disease were randomly divided into two groups, i.e., Group A： 30 cases, Asir-V：40%, Group B： 30 cases, Asir-V：80%. The scanning conditions of the two groups were as follows： 80kV, auto mA, detector width 120~160 mm, scanning time 0.28 s, contrast agent： 320 mgI/ml, dosage of 1~2 ml/kg. Then, we recorded the computerized tomography number of the ascending aorta, descending aorta, pulmonary artery and left ventricle, recorded the computerized tomography number and SD of soft tissue at the same level according to the SD calculation of the area of interest signal-to-noise ratio （SNR） and the contrast ratio of the signal to noise ratio （CNR）, recorded the dose length product （product dose-length, DLP） of each case, as well as converted the effective dose （doses effective, ED） according to the formula.Results SNR and CNR in each interest area of group A were similar to those in group B, but the difference was not statistically significant （ P 〉0.05）. The DLP and ED in group B were smaller than those in group A, the difference was statistically significant （ P 〈0.05）. Two doctors read the film and the image quality of each case was shown to be well. The consistency was good （ K =0.675, 0.668）.Conclusion CTA is an important means in the diagnosis of congenital heart disease in Infants. At the same scanning conditions, the elevation of the weight of ASIR-V can ensure the image quality and reduce the radiation dose, which has an important value in pediatric cardiac CTA scan.