眼眶能谱CT低剂量扫描的参数优化  

Low-dose scanning parameters optimization for orbital gem energy spectrum CT

作　　者：赵冬青[1] 杜凡[1] 王志中[2] 马怿民 付建军[1] 梁万琴[1] 

机构地区：[1]解放军474医院放射科,乌鲁木齐830011 [2]解放军474医院康复科,乌鲁木齐830011

出　　处：《医疗卫生装备》2016年第3期93-96,共4页Chinese Medical Equipment Journal

摘　　要：目的:探讨能谱CT低毫安秒联合自适应统计迭代重建(adaptive statistical iterative reconstruction,ASi R)技术在眼部成像中的应用,并优化其扫描参数。方法:将临床需要行眼部CT检查并符合纳入标准的患者80例,按就诊时间先后分为4组,每组20例。A组(对照组)为常规剂量扫描,扫描参数为120 k V、200 m As(卫生部推荐眼科CT检查标准);B、C、D组为低剂量扫描,扫描参数分别为120 k V、120 m As,120 k V、90 m As,120 k V、60 m As,进行眼眶轴位螺旋扫描,采用ASi R找出最佳ASi R权重,然后将B、C、D 3组中的最佳ASi R权重组(B3、C3、D3组)与对照组对比分析CT图像质量,包括图像噪声、对比噪声比(contrast to noise,CNR)、图像质量评分及容积CT剂量指数(CTDIvol)。计量资料采用单因素方差分析进行统计分析。结果:(1)B、C、D 3组最佳ASi R权重为40%。(2)最佳权重组B、C、D 3组(B3、C3、D3组)与A组噪声比较,B3组与A组差异无统计学意义,C3、D3组与A组有统计学意义(P<0.05)。(3)各组间CNR比较,差异无统计学意义(P>0.05)。(4)图像质量主观评分比较,差异有统计学意义(P<0.05),但各组评分均高于2分,满足诊断要求。(5)B3、C3、D3 3组CTDIvol较A组辐射剂量依次降低了40%、55%、70%。结论:眼眶能谱CT低剂量(120 k V、60 m As、40%ASi R)扫描既可降低患者的辐射剂量,又可满足眼部诊断要求,可以代替常规剂量的螺旋CT扫描。Objective To study the application in ocular imaging of low-dose gem energy spectrum CT combined with adaptive statistical iterative reconstruction（ASi R）, and to optimize the scanning parameters. Methods Totally 80 patients were enrolled to undergo ocular CT examination, who were equally divided into four groups as group A（control group）, group B, group C and group D. Group A went through conventional-dose scanning with the parameters of 120 k V and 200 m As, i.e. the recommended ocular CT examination standard by National Health and Family Planning Commission. Groups B, C and D underwent low-dose CT axial spiral scanning with the parameters of 120 k V and 120 m As, 120 k V and 90 m As, and 120 k V and 60 m As respectively. The optimal ASi R weight was determined, and then the sub-groups B3, C3 and D3 with the optimal Asi R from groups B, C and D were compared with the control group for CT image quality, involving in image noise, contrast to noise ratio（CNR）, image quality score and radiation dose（CTDIvol）. One-factor analysis of variance was used for statistical analysis. Results The optimal ASi R weight of groups B, C and D was 40%. There were no significant differences between the image noises of subgroup B3 and those of group A,while statistical ones between the image noises of subgroups C3, D3 and those of group A（P〈0.05）. There were no significant differences between the CNRs of subgroups B3, C3, D3 and group A（P〈0.05）. There were significant differences between the image quality scores of subgroups B3, C3, D3 and group A（P〈0.05）, while the average scores were both more than 2 so that clinical diagnosis could be performed. When compared with group A, subgroups B3, C3 and D3 had CTDIvoldecreased by 40%, 55% and70% respectively. Conclusion Orbital gem energy spectrum CT with the parameters of 120 k V, 60 m As and 40% ASi R can decrease the patient＇s radiation dose while meet the diagnostic requirements, and thus can replace spiral CT with conventional dose.

关 键 词：眼眶能谱CT 低剂量 ASI R技术 

分 类 号：R816.97[医药卫生—放射医学]