High-resolution computed tomography in the early detection of asbestosis

Summary A group of 21 former asbestos sprayers was studied with high-resolution computed tomography (HRCT), and the findings were compared with radiographic, exposure and lung function variables. HRCT was superior to plain radiography in detecting parenchymal and pleural changes. It showed changes indicative of lung fibrosis, especially septal lines and parenchymal bands, in 9 of the 12 subjects (75%) with a plain radiographic category of 0/0 in the International Labour Office (ILO) 1980 classification of radiographs of pneumoconioses. The HRCT findings were classified according to a method developed by the authors, and an HRCT parenchymal score was calculated. The HRCT revealed pleural plaques in 19 of the 21 (90%) asbestos sprayers, whereas plain radiography detected pleural plaques in only 5 (24%) sprayers. Changes in the visceral pleura were detected twice as often with HRCT as with plain radiography. In the group without radiographic evidence of lung fibrosis (ILO < 1/0) and without evidence of emphysema in either the radiographs or the HRCT examination, there was a correlation between the HRCT parenchymal score and diffusion capacity (r = –0.64, P = 0.03) and total lung capacity (r = –0.61, P = 0.04). This finding indicates that parenchymal changes seen only with HRCT are of clinical importance. The study strongly suggests that for asbestos exposed workers with an ILO classification of < 1/0 and functional impairment, an HRCT examination should always be considered.     

Selection of reference films based on reliability assessment of a classification of high-resolution computed tomography for pneumoconioses

Objective: Worldwide demand has increased for the development of a computed tomography (CT) classification system that supplements the ILO classification of radiographs for pneumoconioses. The authors aimed to show preliminary reliability test results for selected referent films for the CT classification system developed through an international effort by researchers from seven countries. Methods: Reading trials by eight physicians who have considerable experience in pneumoconioses using a total of 114 lung zones consisting of 6 lung zones of 19 CT films of dust-exposed workers were performed to assess reliability of the classification system by weighted κ. The results were also utilized for selecting reference films. Results: A good agreement was observed for both first and second reading trials for rounded opacities (weighted κ=0.76, 0.74, first and second trial results, respectively), irregular opacities (0.60, 0.48), emphysema (0.56, 0.70) and honeycombing (0.72, 0.79). Ground glass opacities, on the other hand, showed moderate agreement (0.43, 0.38). Intra-reader agreements among eight readers were shown in the same table as the mean and standard deviation of weighted κ statistics. The inter-reader agreement for pleural thickening was not as good as for parenchymal lesions. Discussion: The CT classification development may pioneer noble and sensitive medical screening for dust-exposed workers in selected settings. This system may be applied to radiographic borderline cases of profusion 0/1 and 1/0 by the ILO classification, in a setting that assures the occupational safety and health of workers exposed to some newly developed chemical compounds.     

Pleural thickening: a comparison of oblique chest radiographs and high-resolution computed tomography in subjects exposed to low levels of asbestos pollution

Summary The present study was conducted to investigate the value of oblique chest radiographs, compared with high-resolution computed tomography (HRCT), in the assessment of pleural asbestosis in a group of subjects exposed to low levels of asbestos pollution. The study population consisted of 23 people derived from a previously reported cohort of subjects working in university buildings insulated with asbestos-containing material. Subjects were selected on a voluntary basis from among patients whose initial oblique chest X-rays showed pleural thickening. Sixteen patients were maintenance workers occupationally exposed to asbestos; the remaining seven were environmentally exposed to asbestos. For each subject, two standard chest radiographs [posteroanterior (PA) and right anterior oblique (RAO) views] were taken and HRCT was performed. Films were interpreted after agreement by three chest physicians and a radiologist. Pleural thickening was considered present in all 23 patients on RAO films and in six patients on PA films. HRCT revealed unequivocal pleural plaques in three maintenance workers and doubtful pleural abnormalities in three other maintenance workers. Considering HRCT as the gold standard, the positive predictive value of RAO film was only 13%–26%. Most of the 17 false-positive diagnoses of pleural fibrosis were due to significant subpleural fat. These results suggest that the routine use of oblique radiographs as a screening test in cohorts of subjects exposed to low levels of pollution by asbestos should be reevaluated.     

利用Barracuda系统测量医用CT剂量指数量值不确定度评定

目的为保证医用CT剂量指数量值的准确性,评定其不确定度。方法建立Barracuda系统10 cm长杆电离室测量CT剂量指数数学模型,分析不确定度来源,通过计算给出不确定度。结果相对扩展不确定度为6.5%。结论利用Bar-racuda系统测量医用CT剂量指数量值不确定度主要受测量系统不确定度、校准因子、层厚偏差等分量的影响。     

正电子发射断层扫描/计算机断层扫描（PET/CT）成像在肿瘤筛查中的应用进展

我国是世界癌症发病最多的国家,筛查可以实现肿瘤早期诊断、改善患者预后、提高生存质量、降低死亡率。正电子发射断层扫描/计算机断层扫描（PET/CT）提供的代谢信息有助于肿瘤筛查初始分期、治疗计划、反应评估,并在较小程度上可用于肿瘤的随访;PET/CT成像在放射治疗中的渐进式整合在肿瘤间和肿瘤内恶性病变的生物异质性中具有其基本原理,需要单独调整辐射剂量以获得癌症患者的有效局部肿瘤控制;PET/CT提供有关肿瘤病变的生物学特征（如代谢、缺氧和增殖）的信息,可以识别放射性耐药区域并利用这些信息来优化治疗计划,PET/CT减少了肿瘤部位解剖学描绘的不确定性和可变性。本文主要就目前常见肿瘤在PET/CT研究中的应用进展进行综述。     

肺功能及高分辨CT在间质性肺疾病中的相关性研究

目的 对间质性肺疾病患者影像学、肺功能及临床表现进行相关分析，评价肺功能特别是脉冲振荡（IOS）测定呼吸阻抗在该疾病诊断中的意义。方法 对56例间质性肺疾病患者的呼吸阻抗、常规肺功能、静息时动脉血氧分压（PaO2）及肺部高分辨CT评分和呼吸困难评分进行分析。结果 振荡频率在5Hz时的电抗（X5）、在20Hz时的电抗（X20）与肺活量（VC）呈正相关（r=0．699、0．537，P〈0．05），与用力肺活量（FVC）呈正相关（r=0．690、0．473，P〈0．05），与一氧化碳弥散量（DLCO）呈正相关（r=0．494、0．301，P〈0．05），与PaO2呈负相关（r=-0．621、-0．411，P〈0．05）；响应频率与VC、FVC、DLCO呈负相关（r=-0．658、-0．639、-0．352，P〈0．05），与PaO2呈正相关（r=0．277，P〈0．05）；特发性肺间质纤维化患者的病程较结缔组织病所致间质性肺疾病患者的病程明显延长（P〈0．05），其余观察指标差异无统计学意义（P〉0．05）。结论 常规肺功能指标VC、FVC、DLCO及呼吸阻抗指标响应频率、X5对肺间质纤维化的诊断有一定的意义；IOS测定呼吸阻抗对间质性肺疾病患者肺功能损害的动态监测和疗效评价具有一定的应用前景；应重视结缔组织病患者的影像学和肺功能检查以便及时发现肺部早期病变。     

河南省城市地区低剂量螺旋CT肺癌筛查依从性及其影响因素分析

目的 评价2013-2017年河南省城市地区肺癌高危人群的低剂量螺旋CT（LDCT）筛查依从性并探索可能的影响因素。方法 采取整群抽样的方法,选取河南省40～74岁城市户籍居民进行癌症危险因素调查和肺癌风险评估,并对评估出的肺癌高危人群进行LDCT检查。采用χ²检验比较不同特征人群的LDCT筛查参与率差异,并采用Cochran-Armitage趋势检验对筛查参与率的时间趋势进行检验;采用多因素logistic回归模型分析LDCT筛查参与率的影响因素。结果 共纳入符合研究要求的肺癌高危人群35 672例,其中13 383例接受了LDCT检查,总体参与率为37.52%。LDCT筛查的参与率存在显著的地区和时间差异：最高和最低城市的参与率分别为38.47%和26.73%;2013-2014年的总体筛查参与率最低,为29.22%,2014-2015年最高,为43.30%（P<0.05）,且随着筛查年份增加,筛查参与率逐渐增加（P<0.001）。多因素logistic回归分析显示,女性、45～69岁、具有初/高中文化程度、既往吸烟、正在饮酒或既往饮酒、不经常体育锻炼、有肺结核史、有慢性支气管炎史、有肺气肿史、有哮喘支气管扩张史和有肺癌家族史的人群更愿意接受LDCT检查（均P<0.05）。结论 河南省城市肺癌高危人群的LDCT筛查参与率仍不高。针对本研究识别出的特定高危人群采取相应的干预措施可能会在将来的肺癌筛查中提升LDCT检查的总体依从性。     

多层螺旋CT血管成像在烟雾病诊断中的应用

目的 探讨多层螺旋CT血管成像(MSCTA)在烟雾病诊断中的价值以及应用前景.方法 回顾性分析10例烟雾病患者的MSCTA及数字减影血管造影(DSA)的影像学资料.结果 MSCTA可清晰显示狭窄、闭塞以及异常增多的脑血管.容积重建有利于显示病变血管与周围结构的空间关系,综合最大密度投影法重建和多曲面重建图像分析可清晰显示异常增多的脑血管,即烟雾状血管.MSCTA对狭窄及闭塞血管的检出率为66.2%(53/80);DSA对狭窄及闭塞血管的检出率为67.5%(54/80).两者比较差异无统计学意义(P>0.05).MSCTA对颅底异常血管网的显示及分布情况与DSA大致相似.结论 MSCTA诊断烟雾病的灵敏度高,是早期诊断烟雾病的重要依据,早期诊断、及时治疗是改善烟雾病患者预后的有效方法.     

Pulmonary function,smoking habits,and high resolution computed tomography (HRCT) early abnormalities of lung and pleural fibrosis in shipyard workers exposed to asbestos

To evaluate the presence of asbestos-related pleural and parenchymal abnormalities and their correlation with pulmonary function and smoking habits, 119 asbestos-exposed asymptomatic workers (mean age, 46.2 years; mean duration of asbestos exposure, 8.6 years; mean latency time, 21.6 years) with normal standard P-A chest radiographs were submitted to HRCT, CO-diffusing capacity, and pulmonary function tests. HRCT scans were normal only in 31 (26%) examined workers; 31 (26%) subjects showed both pleural and parenchymal involvement, and 50 (42%) and seven (6%) had exclusively pleural and parenchymal abnormalities, respectively. Based on CO-diffusing capacity and pulmonary function tests, no significant difference was demonstrated between workers with pleural lesions and subjects with normal pleura; however, lower values of FVC were observed in the nonsmoking workers with parenchymal abnormalities in comparison with nonsmoking subjects with normal parenchyma (78.2 vs. 89.7% of predicted values; p = 0.03 by student's two-tailedttest), and lower values of FEV₁/FVC in the smokers with parenchymal lesions with respect to smokers with normal parenchyma (93.7 vs. 100.2% of predicted values; p = 0.005 by student's two-tailedttest). In conclusion, our results demonstrate that HRCT may detect early parenchymal abnormalities which correlate with exposure to asbestos and respiratory function impairment, including a reduction in obstructive indices in smokers occupationally exposed to asbestos, without any clinically evident disease. © 1996 Wiley-Liss, Inc.     

Early detection of interstitial lung disease in asbestos exposed non-smoking workers by mid-expiratory flow rate and high resolution computed tomography.

Ten years of lung function and radiological findings in six non-smoking asbestos exposed subjects who had increased mid-expiratory flow rate (FEF 25-75%) as the only functional abnormality were prospectively analysed. A biphasic change in FEF25-75% was noted. It initially increased up to the fifth year, and then a decrease was seen. In the final three years of the study, FEF25-75% reduction correlated well with a decrease in pulmonary capacity for CO (DLCO). During that time high resolution computed tomography (HRCT) probability scores correlated inversely with FEF25-75% and with DLCO, whereas chest radiography was unchanged (International Labour Organisation (ILO) profusion below 1/1). For five of the six subjects HRCT probability of asbestosis was intermediate. An increase in FEF25-75% in some asbestos exposed non-smoking workers may be one of the earliest functional signs indicative of future development of parenchymal asbestosis. Early asbestos related parenchymal abnormalities are seen more frequently on HRCT than on chest radiography.     

Early detection of interstitial lung disease in asbestos exposed non-smoking workers by mid-expiratory flow rate and high resolution computed tomography.

Ten years of lung function and radiological findings in six non-smoking asbestos exposed subjects who had increased mid-expiratory flow rate (FEF 25-75%) as the only functional abnormality were prospectively analysed. A biphasic change in FEF25-75% was noted. It initially increased up to the fifth year, and then a decrease was seen. In the final three years of the study, FEF25-75% reduction correlated well with a decrease in pulmonary capacity for CO (DLCO). During that time high resolution computed tomography (HRCT) probability scores correlated inversely with FEF25-75% and with DLCO, whereas chest radiography was unchanged (International Labour Organisation (ILO) profusion below 1/1). For five of the six subjects HRCT probability of asbestosis was intermediate. An increase in FEF25-75% in some asbestos exposed non-smoking workers may be one of the earliest functional signs indicative of future development of parenchymal asbestosis. Early asbestos related parenchymal abnormalities are seen more frequently on HRCT than on chest radiography.     

浅析CT室专职岗位护理人员应具备的职业素质

目的：对CT室专职岗位护理人员应具备的职业素质进行分析和探讨。方法：根据CT室专职岗位护理人员在CT室工作中的经验总结。结果：规范专职护理人员的操作,杜绝或减少CT增强检查中的事故。结论：通过对CT室专职岗位护理人员职业素质的规范,消除了患者的顾虑、顺利的实施CT增强检查和防范医疗风险的目的。     

64排螺旋CT血管成像检测颈动脉易损斑块与进展性脑卒中的相关性

目的 利用64排螺旋CT血管成像检测颈动脉粥样硬化斑块,探讨颈动脉易损斑块与进展性脑卒中的相关性.方法 将101例新发缺血性脑卒中患者根据病情的演变分为进展性脑卒中组(32例)和非进展性脑卒中组(69例),分析各组颈动脉粥样硬化斑块的狭窄程度及其易损性并进行统计学分析.结果 进展性脑卒中组重度狭窄或闭塞率为28.1％(9/32),明显高于非进展性脑卒中组的8.7％(6/69),差异有统计学意义(P=0.0ll).进展性脑卒中组的易损斑块率为75.0％(24/32),明显高于非进展性脑卒中组的42.0％ (29/69),差异有统计学意义(P=0.002);在不同类型的易损斑块(脂质核心、表面不规则、溃疡斑块)中,两组溃疡斑块率比较差异有统计学意义(P=0.016).将年龄、性别、心血管危险因素、狭窄程度、易损斑块等因素与进展性脑卒中进行单因素、多因素Logistic回归分析,显示糖尿病(OR=3.327,95％CI:1.211 ～ 9.145)和易损斑块(OR=3.699,95％CI:1.292～ 10.589)与进展性脑卒中有关.结论 颈动脉易损斑块是进展性脑卒中的独立危险因素.64排螺旋CT血管成像能为确定颈动脉易损斑块提供一定的诊断信息,对临床治疗具有重要指导意义.     

CT受检者体表屏蔽防护存在的问题与对策

CT非检查区域体表屏蔽防护是降低受检者辐射剂量简单而有效的方法,也是国家行业标准规定的基本要求。一些调查报道回顾显示,在我国的不同的地区和不同级别的医疗机构CT受检者个人放射防护用品配置合理性欠缺、使用率不高、穿戴方法不当、日常维护不到位以及医务人员、公众或受检者对放射防护的基本知识认知不足等问题不同程度地存在,需要不断改进。     

Biological monitoring of workers exposed to N,N-dimethylformamide in the synthetic fibre industry

Objectives: Monitoring of workplace air and biological monitoring of 23 workers exposed to N,N-dimethylformamide (DMF) in the polyacrylic fibre industry was carried out on 4 consecutive days. The main focus of the investigation was to study the relationship between external and internal exposure, the suitability of the metabolites of DMF for biological monitoring and their toxicokinetic behaviour in humans.Methods: Air samples were collected using personal air samplers. The limit of detection (LOD) for DMF using an analytical method recommended by the Deutsche Forschungsgemeinschaft (DFG) was 0.1 ppm. The urinary metabolites, N-hydroxymethyl-N-methylformamide (HMMF), N-methylformamide (NMF), and N-acetyl-S-(N-methylcarbamoyl)-cysteine (AMCC), were determined in one analytical run by gas chromatography with thermionic sensitive detection (GC/TSD). The total sum of HMMF and NMF was determined in the form of NMF. The LOD was 1.0 mg/l for NMF and 0.5 mg/l for AMCC. Results and conclusions: The external exposure to DMF vapour varied greatly depending on the workplace (median 1.74 ppm, range <0.1–159.77 ppm). Urinary NMF concentrations were highest in post-shift samples. They also covered a wide range (<1.0–108.7 mg/l). This variation was probably the result of different concentrations of DMF in the air at different workplaces, dermal absorption and differences in the protective measures implemented by each individual (gloves, gas masks etc.). The urinary NMF concentrations had decreased almost to zero by the beginning of the next shift. The median half-time for NMF was determined to be 5.1 h. The concentrations of AMCC in urine were determined to be in the range from <0.5 to 204.9 mg/l. Unlike the concentrations of NMF, the AMCC concentrations did not decrease during the intervals between the shifts. For the exposure situation investigated in our study, a steady state was found between the external exposure to DMF and the levels of AMCC excreted in urine about 2  days after the beginning of exposure. AMCC is therefore excreted more slowly than NMF. The half-time for AMCC is more than 16 h. Linear regression analysis for external exposure and urinary excretion of metabolites was carried out for a sub-group of 12 workers. External exposure to 10 ppm DMF in air (the current German MAK value) corresponds to an average NMF concentration of about 27.9 mg/l in post-shift urine from the same day and an average AMCC concentration of 69.2 mg/l in pre-shift urine from the following day. NMF in urine samples therefore represents an index of daily exposure to DMF, while AMCC represents an index of the average exposure over the preceding working days. AMCC is considered to be better suited for biomonitoring purposes because (1) it has a longer half-time than NMF and (2) its formation in humans is more closely related to DMF toxicity. Received: 25 June 1999 / Accepted: 2 October 1999     

Biological assessment of exposure to antimony and lead in the glass-producing industry

Summary The oxide of trivalent antimony is used in the glass-producing industry as a refining agent and as a glass colouring. The batch contains up to 2% Sb₂O₃, a substance which has shown carcinogenic properties in animal experiments. The internal levels of antimony and lead in blood (SbB and PbB) as well as the excretion with the urine (SbU and PbU) were determined by hydrid and electrothermal atomic absorption (HY-AAS and ET-AAS), respectively. In addition, measurements of airborne Sb₂O₃-concentrations were performed. The 109 volunteers were employed in four different fields: melting area, batch bunker, glass-washing area, and transport/maintenance. Differences between the concentrations of antimony and lead in blood and urine with respect to the fields of activity were evaluated statistically. The highest values of airborne Sb₂O₃ with up to 840 g/m³ (TWA), were detected in the batch bunker. Correspondingly, significantly enhanced SbU-values from 1.5 to 15.7 g/l (median: 5.0 g/l were found in specimens collected from the batch mixers. In the same group, the lead excretion (PbU) with values from 9 to 110 g/l (median: 43 g/l) was also found to be the highest. Due to the fast renal excretion of antimony, the determination of SbU is useful for biological monitoring.