磁共振弥散张量成像在中枢神经系统病变中的应用

现代医学影像学已从解剖学研究深入到分子水平的代谢和功能研究。磁共振（MR）弥散成像技术是目前在活体上测量水分子弥散运动与成像的唯一方法。弥散成像技术包括弥散加权成像（diffusion weighted imaging，DWI）和弥散张量成像（diffusion tensor imaging，DTI）。DTI利用纤维示踪重建技术可在三维图像上显示白质纤维束的走行，可了解病变所致的白质纤维束受压与移位、浸润与破坏情况，为病变的诊断与鉴别诊断提供更多信息，为治疗方案的制定提供依据。它已成为脑功能成像技术研究的最新热点之一。     

计算弥散加权成像在胆囊良恶性病变诊断中的价值

目的 ：探讨计算弥散加权成像(computed diffusion-weighted imaging,cDWI)诊断胆囊良恶性病变的价值。方法 ：回顾性选取某院2018年2月至2022年2月经病理确诊的54例胆囊疾病患者的临床资料,其中胆囊恶性肿瘤患者27例(恶性组)、胆囊良性病变患者27例(良性组)。使用MR设备对2组患者进行检查并生成表观扩散系数(apparent diffusion coefficient,ADC)图像,将生成的ADC图像传输到Ziostation,根据标准的单指数拟合生成b值分别为1 500、2 000、3 000、4 000 s/mm²的c DWI图像。对比2组患者的ADC值并采用ROC曲线分析ADC的诊断效能;对比不同高b值下cDWI及cDWI联合ADC对胆囊良恶性病变的诊断效能,以及在b=1 000 s/mm²和b=1 500 s/mm²下单独的常规弥散加权成像(common diffusion weighted imaging,mDWI)、cDWI及m DWI联合ADC、cDWI联合ADC...     

磁共振弥散成像在中枢神经损伤与再生中的应用

中枢神经系统损伤后可造成广泛的感觉与运动功能缺陷。弥散成像技术是近几年发展起来的新技术,可以通过神经组织中水分子的弥散特性,定量反映白质纤维束的完整性及各种病变。本文主要对弥散成像技术在中枢神经损伤与再生中的应用作简要概述。     

磁共振弥散张量成像在婴幼儿痉挛型脑瘫中的应用

目的:探讨在婴幼儿痉挛型脑瘫中应用磁共振弥散张量成像(DTI)的价值.方法:选取某医院初次住院诊断为痉挛型脑瘫的33例患儿为研究组,与之年龄配对的33例正常小儿作为对照组,所有研究对象均行常规颅MRI平扫和DTI检查,测量弥散各向异性(FA),研究组在我院行综合康复治疗一年后复查上述两项检查.结果:研究组和对照组髓鞘发育存在一定规律,前者各部位FA值低于后者.研究组治疗后FA值较治疗前有增长.除了胼胝体膝部其余部位低年龄组FA值增长幅度大于高年龄组.结论:DTI能客观反应婴幼儿白质纤维束发育情况及髓鞘化规律,动态监测FA值为患儿病情评估和预后判断提供客观依据.     

磁共振弥散加权成像技术在脑梗死诊断中的应用

磁共振检查已从过去单一的观测生理、病理条件下的生物体解剖结构以及形态学上的变化,发展到研究生物体功能与活动机制,并进入到分子影像与功能性磁共振成像（fMRI）,而弥散加权磁共振成像技术（DWI）就是这其中之一,主要用于脑梗死的早期诊断。通过对磁共振弥散加权成像技术、DWI鉴别急性和非急性脑梗死的病理生理基础、DWI检查的时间价值的阐述,认为应用DWI区分急性和非急性脑梗死对临床治疗该疾病有着积极的意义,临床医师可以根据脑梗死的不同时期采取有针对性的治疗方案,回避不安全的治疗,避免不必要的具有风险性的治疗方法。     

磁共振弥散加权成像在直肠癌诊断中的应用价值

磁共振扩散加权成像作为无创性反映活体内水分子微观运动的新兴MR技术,已经开始应用于直肠癌的早期诊断。本文就磁共振扩散加权成像在直肠癌诊断中的应用现状予以综述。     

磁共振全身弥散成像在全身肿瘤筛查中的应用

目的探讨磁共振全身弥散成像在全身肿瘤筛查中的应用。方法通过对磁共振全身弥散成像技术原理的阐述,分析这项新的技术成像的特点。结果与正电子发射计算机断层扫描（PositronEmissionTomography-ComputedTomography,PET—CT）检查技术相比,磁共振全身弥散成像技术有易行、便捷、高敏感、无辐射等优点,对于全身肿瘤筛查有很高的敏感性,低辐射,费用相对较低。结论磁共振弥散成像非常适合临床对于全身肿瘤的筛查。     

3.0T磁共振弥散加权成像在肝脏良恶性肿瘤鉴别诊断中的应用价值

目的:探讨3.0T弥散加权成像(DWI)鉴别诊断肝脏良恶性占位性病变的意义和价值.方法:自2018年11月～2019年11月,选取福建中医药大学附属人民医院收治肝脏占位性病变96例(158个病灶).所有患者均行常规扫描、D W I和高分辨率T2加权自旋回波平面成像,比较病灶三个感兴趣区与正常肝组织的表观弥散系数(ADC...     

弥散加权成像在前列腺癌诊断中的应用体会

目的探讨将DWI（弥散加权成像）用于诊断PCa（前列腺癌）之中的体会。方法我院收集71例PSA出现异常升高状况的患者,经活检病理诊断,31例为PCa者,称作：探究组,40例为BPH（前列腺增生）者,称作：探讨组,选21名非BPH（前列腺增生）以及PCa（前列腺癌）的正常人员,当做比对组,行DWI扫描。对探讨组（前列腺增生者）和探究组（前列腺癌者）、比对组（正常人员）的ADC数值、b值显示的不同信号强度予以检验分析。结果除比对组和探讨组的前列腺周围带显示的ADC值无显著差异,P〉0．05,剩余小组进行两两对比,ADC值都有显著差异,P〈0．05。结论PCa（前列腺癌）经DWI具备特征性,并且和前列腺增生者所行DWI以及前列腺正常人员所行DWI的特征表现差异显著,所以将DWI（弥散加权成像）用于诊断PCa（前列腺癌）之中,诊断价值很高。     

弥散张量成像在腰椎间盘早期退化研究中的应用价值

目的弥散张量成像(DTI)可以无创伤地探测人体腰椎间盘退化中的间质改变,本研究应用弥散张量成像来研究人体腰椎间盘在不同年龄段的早期退化现象。方法本研究招募了30名25~67岁无腰部受伤史且无腰痛症状的正常志愿者。所有被试在本院一台1.5T临床磁共振上行单次激发回波平面DTI扫描,DTI图像经离线后处理得到定量的弥散各向异性图(FA)和平均弥散系数(MD),随后对腰椎间盘髓核区域的FA和MD数值提取后进行直方图分析。应用非参数Mann-Whitney test在两个不同年龄组之间比较FA和MD的平均值。结果老年组腰椎间盘的MD显著降低(P<0.001),FA显著升高(P<0.001)。结论衰老过程中人体腰椎间盘的早期退化性改变可以通过DTI的定量参数来反映,而此时常规解剖图像上并无发现。很有必要进一步研究腰椎间盘退化级别和DTI定量参数的相关性,这样可以推进DTI在椎间盘退化的临床应用。     

Identification of the cholera diffusion process in Ibadan, 1971

The paper tries to examine and identify which spatial diffusion process was responsible for generating the pattern of cholera diffusion (an epidemic spread which was apparently wave-like) within Ibadan City in 1971. In this paper one of Moran's statistics, the BW join-count measure of spatial autocorrelation is employed. Five different plannar graphs are used in the study. The results show that contagion was apparent on the various models of spatial processes employed and on their different combinations. But it is the radial contact diffusion which was discovered to be most important in the spread of the epidemic. But even, though such a radial contact diffusion process was discovered to be the most important, during the advance and peak phases of the epidemic wave; as the epidemic intensity rose to a spread phase, a mixture of the various models became a best contributor to the contagion.     

大空间建筑有毒有害气体扩散的仿真模拟研究

采用基于K-ε湍流模型的CFD方法,对氯气在公共大空间建筑内的扩散情况进行仿真分析。首先利用Gambit软件进行建模,而后输入到Fluent软件进行仿真模拟,得到氯气的扩散云图,并且通过分析比较不同空调工况下的模拟结果数据,发现氯气重气贴地扩散趋势明显。空调工作时,室内流场对其扩散影响显著,氯气扩散速度变快,范围变大,但浓度比空调不工作时相对较低。通过研究氯气的扩散规律和影响其扩散的因素,可以优化大空间建筑通风设计,为化学恐怖袭击的应急处置提供参考。     

The diffusion model and the social-hierarchical process of change

This article presents some critical comments on the use of Rogers' innovation-diffusion model, which is often referred to in health promotion research as an explanation of how behavioural changes occur over time. The analytical focus is on the belief that there is a social pattern in the process of diffusion, so that higher socio-economic groups lead the way in adopting 'preventive innovations', and lower socio-economic groups subsequently follow as 'late adopters'. This view of the diffusion process - closely akin to the notion of 'imitational/social role modelling' - will be reviewed here within a sociological framework.     

Understanding the spatial diffusion process of severe acute respiratory syndrome in Beijing

OBJECTIVES: To measure the spatial contagion of severe acute respiratory syndrome (SARS) in Beijing and to test the different epidemic factors of the spread of SARS in different periods. METHODS: A join-count spatial statistic study was conducted and the given hypothetical processes of the spread of SARS in Beijing were tested using various definitions of 'joins'. RESULTS: The spatial statistics showed that of the six diffusion processes, the highest negative autocorrelation occurred in the doctor-number model (M-5) and the lowest negative autocorrelation was found in the population-amount model (M-3). The results also showed that in the whole 29-day research period, about hour or more days experienced a significant degree of contagion. CONCLUSIONS: Spatial analysis is helpful in understanding the spatial diffusion process of an epidemic. The geographical relationships were important during the early phase of the SARS epidemic in Beijing. The statistic based on the number of doctors was significant and more informative than that of the number of hospitals. It reveals that doctors were important in the spread of SARS in Beijing, and hospitals were not as important as doctors in the contagion period. People are the key to the spread of SARS, but the population density was more significant than the population size, although they were both important throughout the whole period.     

Research and implementation of diffusion simulation of hazardous gases leakage accidents

在工业生产中,常常需要储存氯气、氨、甲烷、硫化氢等危险性气体,这些物质易燃易爆、有毒有害,一旦泄漏,将污染环境,并对周围居民带来危害.本文运用ArcEngine9.3作为GIS组件,用高级语言C#.NET,利用高斯模型算出事发地点周围一定区域规则格网内格网格点的浓度值,利用等值线算法在GIS电子地图上动态模拟某泄漏气体在某扩散时刻的警戒、危险和致死区域,并自动查询和统计警戒区域内受影响的单位和重要设施等,为事故发生后的应急决策和救援行动等提供技术支持和信息支持.     

Uptake,metabolism and elimination of cyclohexanone in humans

The metabolism and toxicokinetics of cyclohexanone (CH-one), an important solvent and chemical intermediate, have been studied in volunteers during and after 8-h exposures to CH-one vapour at a concentration of 101, 207 and 406 mg · m^–3. The pulmonary ventilation in these experiments was typically 11 1 · min^–1 and retention in the respiratory tract was 58%. After exposure to CH-one, 207 mg · m^–3, the metabolic yields of cyclohexanol (CH-ol), 1,2- and 1,4-cyclohexanediol (CH-diol) as determined in urine by a gas chromatographic method involving hydrolysis of glucuronide conjugate were 1.0% ±0.3%, 39% ± 5% and 18% ± 2% (n = 8), respectively. Peak excretion of CH-ol was achieved at the end of the exposure period, after which it decayed rapidly. Elimination of 1,2- and 1,4-CH-diol reached maximum values a few hours following exposure, with subsequent elimination half-times of 16 ± 2 and 18 ± 4 h, respectively. Repeated exposure to CH-one vapour (around 200 mg · m^–3) for five consecutive days (8 h/day) resulted in cumulative excretion of CH-diols. The permeation rate of CH-one liquid through the skin was 0.037–0.069 mg · cm^–2 · h^–1 (n = 3), indicating that the contribution of percutaneous absorption to total CH-one occupational intake is of minor importance. CH-diols are recommended as biomarkers of exposure to CH-one.     

Application of porous foams for size-selective measurements of airborne wheat allergen

BACKGROUND: Exposure to airborne wheat allergen is a well-known cause of bakers' allergy and asthma. Airborne wheat allergen can be measured by enzyme immunoassays (EIAs) in extracts of inhalable dust samples, but only limited knowledge is available on the size distribution of wheat allergen-carrying particles. Recently, a new sampling medium, porous polyurethane foam, has been introduced for the size-selective sampling of airborne dust in various occupational settings. We investigated the applicability of these foams for size-selective wheat allergen measurements. METHODS: Personal and stationary measurements were performed in a flour mill, using respirable and thoracic foams inserted into the conventional IOM inhalable sampler, together with PTFE (Teflon) filters. Foams and filters were eluted and wheat allergen levels determined by human IgG4 inhibition EIA. RESULTS: Wheat allergen levels could be determined in both filter and foam eluates. Inhalable dust levels from filters and foams ranged from 1.4 to 53 mg m(-3), and wheat allergen levels from 15 to 580 microg m(-3). The allergen was mainly borne on particles with D(ae) (particle aerodynamic diameter) > 10 microm and particles with 4 microm < D(ae) < or = 10 microm, accounting for 54.5-77.5% and 18.9-43.2% of the total allergen yield, respectively. Less than 4% of airborne wheat allergen was carried by particles smaller than 4 mum (respirable fraction). CONCLUSIONS: Measurement of wheat allergen in dust fractions trapped in respirable and thoracic foams is technically feasible. Both wheat flour dust and wheat allergen are mainly concentrated in larger particle-size fractions (extrathoracic and tracheobronchial).     

创新扩散理论在临床路径推广中的应用

临床路径作为一种单病种质量管理的新模式，能够有效规范医疗行为，提高医疗质量，降低医疗费用。作者阐述了创新扩散理论的基本构架和创新扩散的一般规律，介绍了制定临床路径的基本步骤，进一步探讨了我国临床路径推广应用缓慢的原因，提出依据创新扩散理论，加速发展我国临床路径的对策。     

The stress process of hot-dry climatic conditions in a simulation chamber

On the basis of investigations in the potash mining industry of GDR were formulated the starting conditions for experiments in a simulation chamber. The results of the experiments in a climatic chamber to complex dry-hot mining climatics are published and compared with hitherto existing results. Comprehensions to work load limits for dry-hot climatic conditions are established.