国际医用磁共振会议综述

本文介绍了国际医用磁共振协会及其主办的国际会议情况,即ＩｎｔｅｒｎａｔｉｏｎａｌＳｏｃｉｅｔｙｆｏｒＲｅｓｏｎａｎｃｅｉｎＭｅｄｉｃｉｎｅ－ＩＳＭＲＭ。该协会代表了世界上医用磁共振成像方面的最高水平,从第４次年会开始,会议在每年的４月份进行。本文作者参加了１９９７年在加拿大温哥华召开和１９９８年在澳大利亚悉尼召开的年会。会议主要讨论的题目包括功能磁共成像（ｆＭＲＩ）,结构磁共振成像（ａＭＲＩ）波谱成像（ＭＲＩ／Ｓ）和血管造影等方面的内容,以及磁共振成像技术协会方面关于诊断方法,显像增强剂技术,磁共振成像设备及其部件技术,以及数据处理方面的技术进步等课题。推动该领域发展的主要动力显然是对人类自身的研究和对疾病诊疗的需要,尤其对脑功能研究、功能性疾病的诊断和治疗的需要。但是磁共振成像目前在心脏、肺脏以至软骨方面的诊断已经有很大进步,在设备技术和数据处理方法方面的进步同样也是很快的。     

MR成像中脂肪抑制技术的应用

本文措施了磁共振成像中的几种脂肪抑制技术，包括相位对比，短ＴＩ反转恢复和脂肪饱合技术，介绍了脂肪抑制的磁共振扫描床适应症，指出脂肪抑制磁共振扫描可对脂肪来源病变作出特征诊断，还可增加ＴＩ加权成像中造影剂增强效果。     

书讯:《磁共振成像临床应用入门(第2版)》已出版

<正>《磁共振成像临床应用入门(第2版)》由王振常教授、孙波教授、徐建民教授担任名誉主编,靳二虎教授、蒋涛教授、张辉教授担任主编,范占明教授、刘佩芳教授、程晓光教授担任副主编,集全国21位磁共振成像临床应用专家之智慧,在《磁共振成像临床应用入门(第1版)》的基础上耗时1年修订而成。人民卫生出版社已于2015年2月出版该书。《磁共振成像临床应用入门(第1版)》自2009年10月出版以来,深受读者欢迎,期间虽     

磁共振成像早期诊断激素诱导股骨头缺血性坏死

目的探讨激素诱导股骨头缺血性坏死早期磁共振成像特征,和激素应用剂量,时间长短与股骨头缺血性坏死之间关系。材料和方法对108例患者有短期大量激素应用史患者行双髋关节平片及磁共振成像检查,分析图像特征,并应用统计学方法评价股骨头坏死与激素的关系。结果108例平片检查均为阴性,磁共振成像出现异常征象者35例,激素总量,日最大剂量及应用时间与股骨头坏死有统计学意义。结论:磁共振成像可以早期诊断激素诱导股骨头缺血性坏死,影像上单线征和双线征具有特异性;激素可以导致股骨头缺血性坏死。     

西门子公司AR·C断面扫描系统和IMPACT－磁共振成像系统在煤炭部总医院应用的经验

西门子公司ＡＲ·Ｃ断面扫描系统和ＩＭＰＡＣＴ－磁共振成像系统在煤炭部总医院应用的经验煤炭部总医院影像科，１０００２８数字形像设备的配置和应用情况，已成为衡量现代化医院的重要标准．而Ｘ线计算机断面扫描系统和磁共振成像系统，又是最重要的两大数字影像设备．...     

快速成像：磁共振成像技术的进展

本文复习了大部分快速成像磁共振扫描技术，包括：半傅里叶技术，矩形视野，多层激励，快速自旋回波，快速梯度回波和回波平面技术。磁共振快速成像技术的使用可减少检查时间和运动伪影，提高病人检查耐受性以及获取动态影像等。使磁共振扫描有一更广的临床适应症。     

MRCP在肝内外胆管梗阻中的临床应用

目的:评价磁共振胆胰管成像在肝内外胆管梗阻中的临床应用.方法:回顾分析49例磁共振水成像在胆胰管成像临床中的应用.使用GE1.5T超导型磁共振扫描仪,软件aw4.2,利用重T2使胰胆管显影并结合常规MR检查.结果:MRCP结合常规MR扫描,共49例.定位准确率100%,定性准确率91.8%.结论:MRCP结合常规MR扫描,能更好地显示腔内及腔外病变,更准确地定位、定性.     

《磁共振成像造影剂及临床应用》一书简介

磁共振成像(MRI)是继X线CT之后的另一举世公认的医学伟大成就，对医学实践产生了巨大影响。近十年来新的MRI技术不断发展，除屏气动态增强扫描等各种成像序列外，更加安全可靠、特异性高的新型磁共振造影剂不断涌现，使MRI既能显示组织器官的形态     

磁敏感加权成像对羊脑静脉血管的实验研究

目的:探讨超高场强磁共振SWI对脑静脉血管的检出率和诊断价值。方法:选取5只健康绵羊,然后对羊脑部静脉血管进行3.0T超高场强磁共振成像,对磁共振成像所得T1WI、T2WI及SWI图像进行对比分析。结果:分析所得T1WI、T2WI及SWI图像,将额部脑浅静脉在MRI图像上的表现分为4级(Ⅰ-未显示,Ⅱ-显示模糊,Ⅲ-显示较清楚,Ⅳ-显示清楚),在20支脑静脉血管中,SWI显示Ⅲ级共2支血管,Ⅳ级共18支血管,无I级和Ⅱ级血管显示。结论:超高场强磁共振SWI序列对检测脑静脉血管具有重要价值。     

《轻松学习磁共振成像100问》已出版

《轻松学习磁共振成像100问》由首都医科大学附属北京友谊医院靳二虎主任医师和牛明哲工程师主编,马大庆教授与贺文教授审阅。     

Development of an Information and Database System for the IERS: Status and outlook

The focus of this paper is to present the concepts for a new dynamic, i.e. database-driven information system for the International Earth Rotation and Reference Systems Service (IERS). Its goal is to coordinate the data and information flow between the participating institutions. Therefore, all relevant data and products of the IERS should be archived to guarantee their long-term availability. At the same time the consistency and timeliness of the contents of the information system can be guaranteed by managing the information in a database. Additionally, the metadata of all products (including the IERS publications) should be modelled in a database to allow the users to search for specific data or topics with respect to space, time and content. In order to be able to link related data the heterogeneous formats of the products have to be transformed into a common format. The eXtensible Markup Language (XML) is going to be used, to perform this ambitious task. The usage of XML not only allows to link related data but also to easily exchange data and to present them in different ways like Web pages, pdf, etc. The system will be completed by several tools to manage and coordinate the tasks of the Central Bureau (CB) and by an information system with respect to IERS-related topics. The standardised database tools will also allow an easy exchange of information with and links to other databases within the IGGOS project to realize a powerful instrument to serve the Earth observing system.     

The responses of hydrological processes and sediment yield to land‐use and climate change in the Be River Catchment,Vietnam

In this study, we investigated the responses of hydrology and sediment yield with impacts of land‐use and climate change scenarios in the Be River Catchment, using the Soil and Water Assessment Tool (SWAT) hydrological model. The calibration and validation results indicated that the SWAT model is a powerful tool for simulating the impact of environmental change on hydrology and sediment yield in this catchment. The hydrologic and sediment yield responses to land‐use and climate changes were simulated based on the calibrated model. The results indicated that a 16.3% decrease in forest land is likely to increase streamflow (0.2 to 0.4%), sediment load (1.8 to 3.0%), and surface runoff (SURQ) (4.8 to 10.7%) and to decrease groundwater discharge (GW_Q) (3.5 to 7.9%). Climate change in the catchment leads to decreases in streamflow (0.7 to 6.9%) and GW_Q (3.0 to 8.4%), increase in evapotranspiration (0.5 to 2.9%), and changes in SURQ (?5.3 to 2.3%) and sediment load (?5.3 to 4.4%). The combined impacts of land‐use and climate changes decrease streamflow (2.0 to 3.9%) and GW_Q (12.3 to 14.0%), increase evapotranspiration (0.7 to 2.8%), SURQ (8.2 to 12.4%), and sediment load (2.0 to 7.9%). In general, the separate impacts of climate and land‐use changes on streamflow, sediment load, and water balance components are offset each other. However, SURQ and some component of subsurface flow are more sensitive to land‐use change than to climate change. Furthermore, the results emphasized water scarcity during the dry season and increased soil erosion during the wet season. Copyright © 2012 John Wiley & Sons, Ltd.     

Data use and information creation: challenges for marine scientists and for managers

In the coastal waters of European countries and in the offshore waters of the north-east Atlantic, there is an increasing need for scientists to meet challenging objectives, such as to identify meaningful measures of 'quality', and to recommend 'indicators' to underpin implementation of directives, conventions, statutes and other more informal national and international initiatives. Those indicators may relate to particular species or habitats, to changes in physical and chemical characteristics, and even to the use to which the system is put. The problems to be overcome are difficult, but new and developing approaches will make a significant contribution. The approaches include: criteria to identify 'sensitivity' and 'importance', structures to organise information and electronic information resources to access data.The real challenge is to make the results of the various scientific initiatives relevant to and understandable by a wide range of customers with similar overlapping requirements, and thus make a genuine contribution to protecting the marine environment. Above and beyond that is the need for scientists to drive the agenda to enable real and lasting progress to be made towards ecosystem-based management of our seas and a proper consideration of what 'sustainability' may mean in the marine environment and how we utilise its resources.     

A Least-Squares Standard Deviation Method to Interpret Gravity Data due to Finite Vertical Cylinders and Sheets

We have developed a least-squares approach to determine simultaneously the depth to both the top and base of a buried finite vertical cylinder (vertical line element approximation) and a 2-D vertical thin sheet from moving average residual anomaly profiles obtained from gravity data using filters of successive window lengths. The method involves using a relationship between the depth to the top, and base of the source and a combination of windowed observations. The method is based on computing the standard deviation of the depths to the top, determined from all moving average residual anomalies for each value of the depth to the base. The standard deviation may generally be considered a criterion for determining the correct depth to the top and base of the buried structure. When the correct depth to the base value is used, the standard deviation of the depths to the top is less than the standard deviation using incorrect values of the depth to the base. This method can be applied to residuals as well as to the observed gravity data. The method is applied to synthetic examples with and without random errors and tested on two field examples from the USA and Canada.     

我国科学数据共享现状的调查

本文是科学数据共享政策法规体系研究系列文章的收笔之作.撰写本文的目的,就是为说明科学数据共享政策法规体系的研究是建立在大量的基础调研之上.调查研究是谋事之基、成事之道.从实践中寻求解决现实问题的方法,才能制定出切实可行的政策、法规,调查研究是制定政策、法规的客观依据.为使制订政策、 规章制度适应社会经济发展和变化的新情况,就深入开展调查研究,认真听取各方面的意见,深入研究相应的管理规律和运行机制.本文详述了调查过程、调查方法,以佐证政策法规研究不能脱离实际.     

高频GNSS实时地震学与地震预警研究现状

为实现从注重灾后救助向注重灾前预防转变,如何提高地震灾害监测预警和风险防范能力成为我们关注的重点.本文给出了国际上GNSS位移记录、强震动加速度记录、测震速度记录在地震预警中的应用现状,并总结了各自的特点,归纳出围绕高频GNSS地震学在震级与破裂过程实时反演中的几个需要进一步研究的关键问题：（1）引入北斗系统,基于高频GNSS（GPS/BDS）双系统的实时位移解算方法来提高实时单站位移解算精度,使实时解算精度达到厘米级;（2）开展强震仪加速度记录基线偏移校正研究,弥补地震近场GNSS站密度不足问题;（3）强震仪加速度记录与GNSS位移记录特点不同,开展强震仪加速度数据与GNSS位移数据实时融合处理研究,快速获得包含丰富地震形变和速率的波形数据;（4）测震学方法可快速估算震级,但是在强震发生时会出现震级饱和现象,造成震级估算偏低.需要开展基于GNSS位移时间序列的多种方法相结合的实时震级估算方法研究,通过与地震学方法比较和结合,来得到精度高、计算快的震级估值算法;（5）基于高频GNSS、断层初始模型快速选取、断层尺度、参数自适应调整是快速判断断层破裂方向的基础,在断层破裂过程自适应准实时反演算法方面需要进一步加强.通过国内外研究现状调研、分析,表明基于高频GNSS地震学的震级快速确定、震源破裂过程准实时反演算法的发展将对我国地震预警系统从"二网融合"到"三网融合"提供坚实的技术支撑.     

普通民众认知与响应汶川M_S8.0地震特征分析——以陕西勉县为例

为进一步了解普通民众对汶川MS8.0地震灾害的认知与响应程度,并为政府防震减灾战略的制定和实施提供科学依据,根据地震灾害认知与响应结构体系设计了普通民众地震灾害认知与响应调查问卷,主要指标体系包括地震灾害知识、防震减灾技能、自救互救和震后信息传播等4个方面。基于权重和赋分,构建了指标体系各部分评价模型和地震灾害认知与响应总体评价模型,以此来计算普通民众地震灾害认知与响应的综合得分。测评结果表明:1)勉县灾区民众认知与响应地震灾害的综合水平与能力均处于不及格水平;2)在认知与响应地震灾害方面,民众的防震减灾技能最差,对地震灾害知识的了解水平次之,而震时及震后自救互救与震后信息传播2个层面稍好一些;3)普通民众对地震知识和观点的理解还停留在表面现象上,对复杂、抽象的地震知识的理解和掌握,特别是对地震知识掌握的准确性和深层次理解还有待于进一步提高;4)从震后民众获取地震灾害信息的主渠道来看,加大政府关于地震灾害知识和防灾技能的宣传力度以及使地震信息公开透明化是降低地震灾害风险的有效途径之一     

坑（井）-地电阻率成像技术数据处理方法研究

开发坑（井）一地电阻率成像技术数据处理软件包,对分布式地面一坑道电磁信号接收仪记录的时间序列进行分析处理,最终得到相应的视电阻率和相位参数。实际资料处理结果表明,在远区情况下,需考虑信噪比水平,选择合适的计算方法。当信噪比很低或较高时,可选择根据卡尼亚电阻率定义式直接比值的方法,该方法计算简便、效率高;当信噪比一般时,采用最小二乘或Robust等估算方法,能在一定程度上改善数据处理质量。     

Applying Fractal Dimensions and Energy-Budget Analysis to Characterize Fracturing Processes During Magma Migration and Eruption: 2011–2012 El Hierro (Canary Islands) Submarine Eruption

The impossibility of observing magma migration inside the crust obliges us to rely on geophysical data and mathematical modelling to interpret precursors and to forecast volcanic eruptions. Of the geophysical signals that may be recorded before and during an eruption, deformation and seismicity are two of the most relevant as they are directly related to its dynamic. The final phase of the unrest episode that preceded the 2011–2012 eruption on El Hierro (Canary Islands) was characterized by local and accelerated deformation and seismic energy release indicating an increasing fracturing and a migration of the magma. Application of time varying fractal analysis to the seismic data and the characterization of the seismicity pattern and the strain and the stress rates allow us to identify different stages in the source mechanism and to infer the geometry of the path used by the magma and associated fluids to reach the Earth’s surface. The results obtained illustrate the relevance of such studies to understanding volcanic unrest and the causes that govern the initiation of volcanic eruptions.     

Sediment budget and riverbed deformation in the uppermost part of the lower Yangtze River,China

The Yangtze River(YR), similar to most large rivers in the world, has experienced significant changes in its depositional environment due to anthropogenic disturbances and climatic influences in recent decades. However, knowledge of how the river channel and bed deformation respond to these changes in the uppermost part of the lower YR, a 200-km-long branched channel, is limited. In the current study,historical bathymetric data collected from 1992 to 2013 and high-resolution multibeam echo sound...