摘要
目的 应用胸部模型评价3种CT迭代重建技术对低剂量CT图像质量及肺磨玻璃密度（GGO）结节体积测量准确性的影响.方法 应用2台多层螺旋CT（HDCT和iCT）扫描含有GGO结节的胸部模型,应用30％自适应统计迭代重建算法（ASIR）、基于模型的迭代重建（MBIR）算法和iDose4 L3、L6算法进行重建,由2名放射科医师测量重建图像上ROI的CT值,计算平均噪声和对比噪声比（CNR）.并应用肺结节评估软件测量GGO结节的体积,计算CT测量结节体积的绝对百分误差（APE）.不同重建方法下平均噪声值及对比噪声值之间的差异应用重复测量方差分析,比较不同重建方法对结节体积测量的差异时应用Kruskal-WallisH秩和检验.结果 HDCT在有效剂量（ED）为0.36 mSv时,标准的滤波反投影（FBP）、30％ ASIR和MBIR算法重建图像的平均噪声值分别为40.38±4.49、30.06±20.17和10.55±1.56,CNR值分别为5.00±2.36、8.43±3.89和20.27±7.35,MBIR与FBP、30％ ASIR算法图像比较,图像噪声值分别下降了73.9％和64.9％,CNR值分别提高了75.3％和58.4％,差异有统计学意义（F值分别为13.053、9.459,P值均＜0.01）；iCT在ED为0.64 mSv时,iDose L6与FBP算法比较,图像噪声值降低了36.5％,CNR值提高了78.4％.不同重建算法、不同NI和管电流在肺结节体积测量的APE上差异均无统计学意义（P值均＞0.05）.结论 3种迭代重建算法均能够降低较低剂量图像的平均噪声,提高图像质量.
Objective To evaluate the potential of three commercial CT iterative reconstruction methods （ASIR,MBIR and iDose4） for the image quality and accuracy of volumetric measurement of ground-glass opacity （GGO） nodules on low-dose chest computed tomography （CT） using a phantom study.Methods A phantom containing GGO nodules was examined in volumetric mode on 2 multi-detector CT scanners at low dose.CT images were reconstructed with adaptive statistical iterative reconstruction （30% ASIR）,model-based iterative reconstruction （MBIR）,iDose4 L3,L6 reconstruction algorithm.Then two radiologists measured CT value of the region of interests （ROI） on reconstruction images,and calculated average noise and contrast to noise ratio （CNR） of reconstruction images.And they applied the lung nodules evaluation software to measure the volume of GGO nodules on the reconstruction images,and calculated the absolute percentage error （APE） of nodule volume measurement.The difference of noise and CNR at different reconstructions was compared with ANOVA test,and Kruskal-Wallis H ranking test was used to the difference of GGO measurements at different reconstructions.Results The average noises of CT image reconstructed with the standard FBP algorithm,30% ASIR algorithm,MBIR algorithm were 40.38 ± 4.49,30.06 ± 20.17,10.55 ± 1.56,and the CNRs were 5.00 ± 2.36,8.43 ± 3.89,20.27 ± 7.35,respectively.Compared to CT image reconstructed with the standard FBP algorithm and 30% ASIR algorithm,CT image noise reconstructed with MBIR algorithm decreased by 73.9% and 64.9%,while the CNR increased by 75.3% and 58.4% with effective dose of 0.36 mSv in HDCT,respectively（F =13.053,9.459,P 〈0.01）.When effective dose was equal to 0.64 mSv in iCT,the image noise reconstructed with iDose L6 algorithms decreased by 36.5% compared with the standard FBP algorithm,and CNR increased by 78.4%.The reconstruction algorithm,NI and tube current were no significant difference in lung nodule volume measurement of absolute percentage error（P 〉 0.05）.Conclusions Three kinds of iterative reconstruction algorithms are able to reduce the image noise in low-dose CT and improve the image quality.
出处
《中华放射学杂志》
CAS
CSCD
北大核心
2013年第10期926-931,共6页
Chinese Journal of Radiology
基金
2010年首都医科大学附属北京友谊医院启动基金项目（2010-17）
作者简介
通信作者：贺文，Email：hewen1724@gmail．com
