前置与后置多模型迭代重组算法在腹部体模CT扫描中的对比研究  

Performance of Preset and Postpositive Adaptive Statistical Iterative Reconstruction-V in Abdominal CT:Comparative Study in A Phantom

作　　者：王同明[1] WANG Tongming(Department of Radiology,Traditional Chinese Medicine Hospital of Henan, Zhengzhou, Henan Province 450002, P. R. Chin)

机构地区：[1]河南省中医院放射科

出　　处：《临床放射学杂志》2018年第5期878-881,共4页Journal of Clinical Radiology

摘　　要：目的对比分析腹部CT扫描中不同比例前置和后置多模型迭代重组算法（ASIR-V）的图像质量和辐射剂量,探讨优化腹部图像质量和辐射剂量的合适ASIR-V比例。方法扫描设备为Revolution CT机,扫描对象为腹部仿真体模。根据噪声指数（NI）设置5个组别（6、8、10、12、14）,每组根据前置ASIR-V水平设置0~100%（间隔10%）11个亚组进行扫描,共扫描55组数据。0%前置ASIR-V亚组,重组10%~100%（间隔10%）后置ASIR-V图像。分析各组别图像主观评分、CT值、噪声及辐射剂量随前置和后置ASIR-V比例的变化规律,寻找优化腹部CT图像质量和辐射剂量的最佳前置和后置ASIR-V比例。各组图像主观评分比较采用秩和检验,CT值、噪声和辐射剂量比较采用单因素方差分析和t检验。结果在0~40%前置ASIR-V和0~60%后置ASIR-V,NI为6、8组图像主观评分呈基本稳定状态;NI为10、12、14组,图像主观评分呈略升高趋势,至40%前置ASIR-V或60%后置ASIR-V达最优。50%以上前置ASIR-V及70%以上后置ASIR-V图像主观评分逐渐下降,NI为6、8组超过70%前置ASIR-V和80%后置ASIR-V图像主观评分降至3分以下;NI为10、12、14组超过60%前置ASIR-V和80%后置ASIR-V图像主观评分降至3分以下。图像各部位CT值随前置ASIR-V比例的增高呈基本稳定状态,后置ASIR-V对图像CT值无影响。图像各部位的噪声随前置ASIR-V比例增高呈基本稳定状态,随后置ASIR-V比例增高呈逐渐降低。各个NI组别CT容积剂量指数（CTDIvol）随前置ASIR-V比例的增高,呈逐渐下降趋势,40%前置ASIR-V其CTDIvol下降比率约48.7%。CTDIvol随后置ASIR-V比例的改变无变化,随NI值增高而降低。结论 40%~60%前置ASIR-V可在保证图像质量的条件下降低辐射剂量;后置ASIR-V可优化图像质量,需通过设置高NI降低辐射剂量。Objective To compare the image quality and radiation dose of different ratio pre-and post-position multimodel iterative reconstruction algorithms（ASIR-V） in abdominal CT scans,and to explore the appropriate ASIR-V ratio for optimizing abdominal image quality and radiation dose.Methods The scanning equipment was a Revolution CT machine and the subject of the scan was an abdominal simulation phantom.According to the noise index（NI） settings（6,8,10,12,14） 5 groups,each group according to pre-ASIR-V level settings 0% ~ 100%（interval 10%） 11 subgroup scanning,a total of Scan 55 sets of data.0% pre-ASIR-V subgroup,reconstruction of 10% to 100%（10% interval） post-ASIR-V images.The changes of subjective scores,CT values,noise and radiation doses of pre-and post-ASIR-V ratios in each group of images were analyzed to find the optimal pre-and post-ASIR-V ratios for optimizing abdominal CT image quality and radiation dose..Rank sum test was used to compare subjective scores in each group of images.CT value,noise,and radiation dose were compared using one-way analysis of variance and t-test.Results 0% ~ 40% pre-ASIR-V and 0% ~ 60% posterior ASIR-V.The subjective scores of NI were 6 and 8 groups were basically stable;NI was 10,12 and 14 groups,and the images were subjective.The scores showed a slight upward trend,with 40% pre-ASIR-V or 60% post-ASIR-V being optimal.More than 50% of pre-ASIR-V and more than 70% of post-ASIR-V images have progressively decreased subjective scores.NI is subjective scores of 6 and 8 groups with over 70% pre-ASIR-V and 80% post-ASIR-V images.Below 3 points;NI is subjective scores of over 60% pre-ASIR-V and 80% post-ASIR-V images in groups 10,12,and 14 to less than3 points.The CT value of each part of the image is basically stable with the increase of the pre-ASIR-V ratio.Post-ASIRV has no effect on the CT value of the image.The noise of each part of the image is basically stable with the increase of the pre-ASIR-V ratio,and then the ASIR-V ratio is gradually increased and gradua

关 键 词：体层摄影术 X线计算机 迭代重组 图像质量 辐射剂量 体模 

分 类 号：R816.5[医药卫生—放射医学]