iDose4迭代重建技术对低剂量肺部平扫CT图像质量的影响分析

Effect of iDose4 Iterative Reconstruction Technique(AIR) on Image Quality of Low-dose Lung Plain CT

目的研究iDose4迭代重建技术(Advanced Iterative Reconstruction,AIR)对低剂量肺部平扫CT图像质量的影响。方法分析2015-12—2016-12间到广东省惠东县人民医院进行健康体检的150例临床资料,所有对象均行肺部CT平扫,且依据扫描顺序分成常规剂量组(100mAs)与低剂量组(50mAs、25mAs),将100mAs选择常规滤波反投影方法重建设为对照组,低剂量组分别采用常规滤波反投影和iDose4 AIR方法重建,对不同剂量、重建算法曝光剂量与图像噪声及图像质量进行对比。结果 50mAs和25mAs低剂量组有效剂量比常规剂量组低,50mAs低剂量组选择AIR法比常规滤波反投影图像噪声降低,且信噪比SNR和CNR提高(P<0.05);50mAs借助AIR比常规剂量组图像噪声降低,且信噪比SNR和CNR比常规剂量组升高(P<0.05);管电流降到25mAs时,常规滤波反投影评分下降,AIR图像较常规滤波反投影优;管电压降到50mAs时,AIR图像较常规滤波反投影优。结论和常规滤波反投影法相比,50mAs、25mAs借助AIR可降低有效辐射的剂量,且对图像质量不产生影响。

Objective To explore the effect of iDose4 iterativere construction technique（ AIR） on image quality of low-dose lung plain CT. Methods The clinical data of 150 people who had received physical examination in the hospital from December,2015 to December,2016 were analyzed,and lung plain CT was applied in all these people. On the basis of the scanning sequence,these people were divided into routine dose（ 100mAs） group and low-dose（ 50mAs,25mAs） groups. Those given 100mAs and choosing to receive conventional filtered back projection were set as control group. People in the low-dose group were treated with conventional filtered back projection and iDose 4AIR reconstruction. The differentmAs,exposure dose of reconstruction algorithm and image noise as well as image quality were compared. Results The effective dose in group 50mAs and group 25mAs was lower than that in the conventional dose group; among the 50mAs low-dose group,the image noise of those reconstructed with AIR was reduced more significantly compared with that of those with filtered back projection,and the signal-to-noise ratio of SNR and CNR in the former group was increased more significantly compared to that in the routine dose group（ P 〈 0. 05）; when the tube current was reduced to 25mAs,the scores of filtered back projection began to decrease and AIR image was better than filtered back projection; when it was reduced to 50mAs,image AIR score of the conventional filter back projection decreased more significantly compared with the conventional filtered back projection. Conclusion Compared with the conventional filtered back projection,AIR with doses of 50mAs and 25mAs can reduce the dose of radiation,and produce no impact on the image quality.