极低剂量扫描模式对婴幼儿大气道病变筛查的可行性研究  

Very low dose(0.04 mSv) CT scan for screening airway disease in infants:feasibility study

作　　者：李昊岩 段晓岷[1] 刘勇[1] 王冬潜[1] 蒋玲[1] 于彤[1] 张琪丰 孙记航[1] 彭芸[1] 

机构地区：[1]首都医科大学附属北京儿童医院影像中心,北京100045

出　　处：《医学影像学杂志》2017年第6期1073-1078,共6页Journal of Medical Imaging

基　　金：基金项目:首都临床特色应用研究(编号:Z141107002514005)

摘　　要：目的探究使用0.04m Sv极低剂量CT联用自适应性迭代重建的(adaptive statistical iterative reconstruction,ASIR)算法成像技术,实现3岁以内婴幼儿胸部及气道疾病的诊断筛查。方法选取三岁以下的临床怀疑气道畸形,气道狭窄,血管环等大气道病变行增强CT检查的患儿共22例。平扫运用80k V,4m As极低剂量扫描作为实验组。实质期使用常规辐射剂量100k V,噪声指数为12的自动管电流调节技术扫描图像作为对照组。将实验组原始图像分别重建为层厚5mm的滤波反投影(FBP)、40%权重的ASIR、100%权重的ASIR共六组图像,对照组重建为层厚5mm的40%权重的ASIR图像。比较同一患者平扫与静脉期放射剂量及主观、客观图像质量,主观图像质量评价由两位医师应用1~4分制评价(4分最好,3分合格)图像总体噪声、大气道显示情况及肺内病变显示情况。客观噪声测量左心室最大层面内的左心室内、背部均匀的肌肉、脂肪、降主动脉及肺野,并计算优化信噪比(signal noise ratio,SNR)。使用秩和检验评价主观图像质量评分结果的差异,配对方差分析评价客观图像质量及放射剂量的差异。结果实验组有效剂量为(0.04±0.01)m Sv,对照组辐射有效剂量(0.55±0.13)m Sv。层厚5mm的FBP、40%ASIR、100%ASIR及对照组主观图像评分分别为1.71±0.68,2.01±0.76,2.59±0.99,3.59±0.50;大气道的主观评分分别为2.32±0.56,2.89±0.39,3.82±0.39,3.89±0.32。左心室噪声值分别为38.72±7.36,31.55±7.15,21.00±5.15,7.83±1.20。运用100%权重的ASIR,图像噪声降低明显,主观评分上升明显。实验组与对照组之间的客观评分、主观评分依然差异明显(P<0.05),图像不能满足胸部病变的诊断要求,但完全能显示肺部病变的位置、范围、边缘,以及纵隔的形态异常情况,达到定位定量的诊断要求。而对于大气道的显示主观评分均可满足诊断要求,100%ASIR试验组与对照组差异不明显(P>0.05),达Objective To assess the clinical value for children＇s lung and airway disease within three years using 0. 04 m Sv low radiation dose and full adaptive statistical iterative reconstruction（ ASIR）. Methods 22 patients（ age 2 month ~ 3 y,mean1. 8 y） suspected airway malformation,airway constriction,circulus vasculosus and other main airway disease underwent contrastmedium CT examination. Scan protocol： 80 k V,4 m As was used in non-enhance phase as experiment group and 100 k V tube voltage with automatic tube current modulation（ ATCM） in venous phase as control group. Dose index was 12. We reformated the original images to layer 5 mm filtered back-projection（ FBP）,40% ASIR ＋ 60% FBP and 100% ASIR. Two radiologists independently evaluated images on 4-point scale with 3 being clinically acceptable. Objective diagnosis evaluations containing the noise of left ventricle（ LV）,muscle,fat,descending aorta and lung field at the layer with the largest cross-section area of LV were measured,and signal-to-noise ratio（ SNR） and the indexes of radiation dose were calculated. Results The effective dose of experimental group and control group were（ 0. 04 ± 0. 01） m Sv,（ 0. 55 ± 0. 13） m Sv. The subjective quality were 1. 71 ± 0. 68,2. 01 ± 0. 76,2. 59 ± 0. 99,3. 59 ± 0. 50; from 5mm FBP,40% ASIR,100% ASIR and control group. The subjective quality of main airway were 2. 32 ± 0. 56,2. 89 ± 0. 39,3. 82 ± 0. 39,3. 89 ± 0. 32. The corresponding left ventricular noise values were38. 72 ± 7. 36,31. 55 ± 7. 15,21. 00 ± 5. 15,7. 83 ± 1. 20. Images noise reduced significantly,subjective quality increased significantly. The subjective quality difference between experimental groups and the control groups were obvious,as well as objective quality（ P〈0. 05）. The images were not acceptable in diagnosis of chest diseases,while images show location,range,edge of lung lesions,and abnormal morphology of the mediastinalit. Especially to the diagnosis of airway diseases,it has already achieved

关 键 词：体层摄影术 X线计算机 自适应迭代重建 儿童 辐射剂量 

分 类 号：R814.42[医药卫生—影像医学与核医学] R725.6[医药卫生—放射医学]