CAJ | 학술논문

目的评价iDose4迭代重建技术(AIR)与传统滤波反投影(FBP)重建在常规剂量和低剂量胸部CT平扫中应用的图像质量差别.方法对120名健康体检者按扫描顺序依次分为常规剂量组(100 mAs)、低剂量50 mAs组和低剂量25 mAs组,分别采用100、50、25 mAs进行全肺屏气CT扫描,100 mAs采用FBP重建作为常规对照组,低剂量扫描组分别采用FBP及iDose4 AIR对图像进行重建.2名放射科医师进行双盲法阅片,比较不同毫安秒和重建算法的曝光剂量、图像噪声(MSD)、对比信噪比(CNR)、信噪比(SNR)以及图像质量.有效剂量及MSD比较行t检验；图像质量比较行Mann-Whitney检验；医师对图像诊断一致性检验行Kappa分析.结果低剂量组(50和25 mAs)有效剂量分别为(1.30 ±0.17)、(0.66 ±0.08) mSv,较常规组(2.73 ±0.27) mSv分别降低52.4％和75.8％.50 mAs组采用AIR较FBP组MSD降低[(21.33 ±6.44)和(31.01 ±7.51),P＜0.01],CNR提高[分别为(41.73 ±9.94)和(28.02±10.23),P＜0.01],SNR提高[分别为(44.09±10.34)和(29.61 ±9.34),P＜0.01].25 mAs采用AIR重建较FBP组MSD降低[分别为(30.28±10.68)和(45.89±18.66),P＜0.01],CNR提高[分别为(31.68 ±11.23)和(22.83±10.24),P＜0.01],SNR提高[分别为(32.91 ±14.25)和(21.60±10.21),P＜0.01].50 mAs采用AIR较常规剂量组MSD(28.43 ±9.33)降低(P＜0.01)、CNR及SNR较常规剂量组(分别为33.54±10.21和34.44±12.01)升高(P值均＜0.01).2名医师图像质量评价之间Kappa为0.56.结论与FBP相比,50和25 mAs采用AIR能使有效辐射剂量分别降低52.4％和75.8％,同时不影响图像质量.
목적 평개iDose4질대중건기술(AIR)여전통려파반투영(FBP)중건재상규제량화저제량흉부CT평소중응용적도상질량차별.방법 대120명건강체검자안소묘순서의차분위상규제량조(100 mAs)、저제량50 mAs조화저제량25 mAs조,분별채용100、50、25 mAs진행전폐병기CT소묘,100 mAs채용FBP중건작위상규대조조,저제량소묘조분별채용FBP급iDose4 AIR대도상진행중건.2명방사과의사진행쌍맹법열편,비교불동호안초화중건산법적폭광제량、도상조성(MSD)、대비신조비(CNR)、신조비(SNR)이급도상질량.유효제량급MSD비교행t검험；도상질량비교행Mann-Whitney검험；의사대도상진단일치성검험행Kappa분석.결과 저제량조(50화25 mAs)유효제량분별위(1.30 ±0.17)、(0.66 ±0.08) mSv,교상규조(2.73 ±0.27) mSv분별강저52.4％화75.8％.50 mAs조채용AIR교FBP조MSD강저[(21.33 ±6.44)화(31.01 ±7.51),P＜0.01],CNR제고[분별위(41.73 ±9.94)화(28.02±10.23),P＜0.01],SNR제고[분별위(44.09±10.34)화(29.61 ±9.34),P＜0.01].25 mAs채용AIR중건교FBP조MSD강저[분별위(30.28±10.68)화(45.89±18.66),P＜0.01],CNR제고[분별위(31.68 ±11.23)화(22.83±10.24),P＜0.01],SNR제고[분별위(32.91 ±14.25)화(21.60±10.21),P＜0.01].50 mAs채용AIR교상규제량조MSD(28.43 ±9.33)강저(P＜0.01)、CNR급SNR교상규제량조(분별위33.54±10.21화34.44±12.01)승고(P치균＜0.01).2명의사도상질량평개지간Kappa위0.56.결론 여FBP상비,50화25 mAs채용AIR능사유효복사제량분별강저52.4％화75.8％,동시불영향도상질량.
Objective To evaluate the image quality and dosage reduction of chest low dose CT (LDCT) using advanced iterative reconstruction (AIR)technique and filtered back projection (FBP).Methods One hundred and twenty patients underwent non-contrast chest CT examinations,they were randomly assigned into three groups:control group (standard dose protocol 120 kV,100 mAs) (n =40) ;50 mAs group (low-dose protocol 120 kV,50 mAs) (n =40) ; and 25 mAs group (lower dose protocol 120 kV,25 mAs) (n =40).Images from control group were reconstructed by FBP,and low-dose groups were reconstructed by FBP and AIR.Quantitative noise,signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured,image quality was scored subjectively by three experienced radiologists.The radiation dose,image noise and the image quality of the 3 groups were compared and analyzed statistically.Differences of radiation dose and noise among groups were determined with t test,image quality with Mann-Whitney test and the consistency of diagnosis with Kappa test.Results The mean effective radiation dose in low dose groups 50 mAs (1.30 ±0.17) mSv and 25 mAs (0.66 ±0.08) mSv was reduced by 52.4％ and 75.8％respectively compared with control group (2.73 ± 0.27) mSv.Image noise (MSD) in 50 mAs group with AIR compared with FBP was reduced[(21.33 ±6.44) and (31.01 ±7.51),P ＜0.01].CNR was improved [(41.73 ±9.94) and (28.02 ± 10.23),P＜0.01],and SNR was improved [(44.09 ± 10.34) and (29.61 ±9.34),P ＜0.01],MSD in 25 mAs group with AIR compared with FBP was reduced [(30.28 ± 10.68) and (45.89 ±18.66),P＜0.01].CNR was improved [(31.68 ±11.23) and (22.83 ±10.24),P ＜ 0.01],and SNR was improved [(32.91 ± 14.25) and (21.60 ± 10.21),P ＜ 0.01].MSD in 50 mAs with AIR was reduced compared with control group(100 mAs FBP) (28.43 ± 9.33) (P ＜ 0.01),CNR and SNR were improved[CNR and SNR in contrd group was (33.54 ± 10.21) and (34.44 ± 12.01)] (P ＜0.01).Kappa value of the two reviewers were 0.56.Conclusion Compared with FBP,50 and 25 mAs groups with AIR technique (iDose4) could maintain or improve image quality on pulmonary CT while reducing radiation dose by 52.4％ and 75.8％ respectively.