应用自适应统计迭代重建技术降低儿童腹部多层螺旋CT辐射剂量  

Radiation dose reduction on mutidetector abdominal CT using adaptive statistical iterative reconstruction technique in children

作　　者：张祺丰[1] 彭芸[1] 段晓岷[1] 孙记航[1] 于彤[1] 韩忠龙[1] 

机构地区：[1]首都医科大学附属北京儿童医院影像中心,100045

出　　处：《中华放射学杂志》2013年第2期112-115,共4页Chinese Journal of Radiology

基　　金：首都医学发展基金资助项目（2009-2077）;科技重大专项项目（课题）资助项目（2011ZX09302-007-01）

摘　　要：目的探讨儿童腹部MSCT在配合自动管电流调节技术（ATCM）条件下应用自适应统计迭代重建（ASIR）技术减低辐射剂量可行性。方法收集冈临床需要行2次腹部CT扫描的患儿30例，第1次扫描采用单纯ATCM技术，第2次扫描采用ATCM技术结合40％ASIR重建技术。噪声指数根据年龄确定，第1次扫描（单纯ATCM组）：≤5岁、噪声指数为9，〉5岁、噪声指数为11；第2次扫描（ATCM结合ASIR组）：≤5岁、噪声指数为11，〉5岁、噪声指数为15。由2名放射科医师分别对图像质量和图像噪声进行主观评分（5分制），并采用Kappa检验观察不同医师间评定结果的一致性。记录2组的容积cT剂量指数（CTDIvol），并采用配对样本t检验比较。结果ATCM结合ASIR组CTDIvol为（1．384±0．64）mGy，单纯ATCM组CTDIvol为（3．56±1．23）mGy，结合ASIR技术可以降低约60％的剂量，2组差异有统计学意义（t=33．483，P〈0．05）。单纯ATCM组，2名医师的图像质量评分分别为（4．434±0．57）和（4．37±0．61）分，Kappa=0．878，P〈0．01；ATCM结合ASIR组，2名医师的图像质量评分分别为（4．704±0．47）和（4．60±0．50）分，Kappa=0．783，P〈0．01。单纯ATCM组，2名医师的图像噪声评分分别为（4．03±0．56）和（3．83±0．53）分，Kappa=0．572．P〈0．01；ATCM结合ASIR组，2名医师的图像噪声评分分别为（4．20±0．48）和（4．10±0．48）分，Kappa=0．748，P〈0．01。所有图像质量评分均达到满足影像诊断的要求。结论儿童腹部cT扫描可提升噪声指数并应用ASIR技术获得的图像能够保证图像质量符合临床诊断要求，并进一步减低了辐射剂量。Objective To investigate the feasibility to reduce radiation doses on pediatric mutideteetor abdominal CT using the adaptive statistical iterative reconstruction technique （ASIR） associated with automated tube current modulation technique（ATCM）. Methods Thirty patients underwent abdominal CT with ATCM and the follow-up scan with ATCM cooperated with 40% ASIR. ATCM was used with age-dependent noise index （NI） settings ： NI = 9 for 0-5 year old and NI = 11 for 〉 5 years old for simple ATCM group, NI = 11 for 0-5 year old and NI = 15 for 〉 5 years old for ATCM cooperated with 40% ASIR group（ AISR group）. Two radiologists independently evaluated images for diagnostic quality and image noise with subjectively image quality score and image noise score using a 5-point scale. Interobserver agreement was assessed by Kappa test. The volume CT dose indexes （CTDIvol） for the two groups were recorded. Statistical significance for the CTDIvol value was analyzed by pair-sample t test. Results The average CTDIvol for the ASIR group was （ l. 38 ± 0.64）mGy, about 60% lower than （3.56 ± 1.23）mGy for the simple ATCM group, and the CTDIvol of two groups had statistically significant differences. （ t = 33. 483, P 〈 0. 05 ）. The subjective image quality scores for the simple ATCM group were 4. 43 ± 0. 57 and 4. 37 ±0. 61 ,Kappa = 0. 878, P 〈 0. 01 （ASIR group： 4. 70 ± 0. 47 and 4. 60 ± 0. 50, Kappa = 0. 783,P 〈 0. 01 ）, by two observers. The image noise score for the simple ATCM group were 4.03 ± 0. 56 and 3.83 ± 0. 53, Kappa =0.572,P 〈0.01 （ASIR group： 4.20 ±0.48 and 4.10 ±0.48,Kappa =0.748,P 〈0.01）,by two observers. All images had acceptable diagnostic image quality. Conclusion Lower radiation dose can be achieved by elevating NI with ASIR in pediatric CT abdominal studies, while maintaining diagnostically acceptable images.

关 键 词：辐射剂量 儿童 对比研究 

分 类 号：R142[医药卫生—公共卫生与预防医学] R816.92