SWI在早期脑出血及出血性脑梗死的应用价值

目的:探讨磁共振磁敏感加权成像(SWI)对超急性期脑出血和急性出血性脑梗死的诊断价值。方法:收集我院2010年2月～2011年11月超急性期脑出血患者25例,平均年龄58岁,发病时间均在6h以内;急性出血性脑梗死患者22例,平均年龄54岁,发病时间在24h以内。磁共振检查采用GESigna1.5THDMR系统,头颅8通道线圈。行常规T1WI、T2WI、FLAIR、DWI序列扫描,每个病例均加扫SWI序列。结果:25例脑出血病例中20例在T2WI上病灶周边可见到低信号环,显示率为80%。T1WI、T2FLAIR及DWI序列无特征表现提示出血。在SWI上均可见到低信号,显示率为100%,且显示的范围更大、更明显;22例出血性脑梗死病例中2例在T1WI内可见到轻微高信号,显示率约为9%。T2WI、T2FLAIR及DWI序列对出血性脑梗死没有特征性表现。SWI序列显示22例梗死区内均可见点片状不均匀低信号,显示率达到100%。结论:SWI序列较常规MRI序列对诊断早期脑卒中的类型和及早检测出脑梗死出血性转化有更大帮助,对临床治疗有重要指导意义。     

磁共振T2WI 3D-SPACE序列在直肠癌术前分期中的应用

目的:探讨T2WI 3D-SPACE联合EPI DWI成像技术在直肠癌术前评估中的应用价值.方法:回顾性收集2018年1月1日至2019年8月30日于我院行直肠磁共振(MR)扫描的直肠癌患者36例纳入本组研究,扫描三方位高分辨T2WI序列、T2WI 3D-SPACE序列、EPI DWI序列.分别计算高分辨T2WI序列联...     

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.     

项型纤维瘤的CT和MRI诊断

目的:探讨项型纤维瘤的CT和MRI特征。方法:回顾性分析8例NTF的影像学表现,病变均经外科切除和病理证实,其中2例行CT平扫检查,6例行MRI扫描,2例同时行MRI增强扫描,分析NTF的临床表现和CT、MRI征象。结果:8例肿物位于骶尾部皮下,质韧;CT和MRI显示病灶局部皮肤增厚,皮下脂肪内见片状、条索状影;CT呈稍高密度,T1WI呈低信号,T1WI压脂呈低-等信号,T2WI压脂呈低信号,DWI呈等信号,内见交错脂肪样密度或信号影;形态不规则,边界不清,无明确包膜。2例行增强扫描,均呈轻度强化。结论:项型纤维瘤的MRI和CT表现具有特征性,结合病史、症状及体征,有助于项型纤维瘤的诊断。      

2000例低场MRI临床应用评价

本文分析了0.15T 低场 MRI 系统所检查的2000例患者的图像.从技术参数、图像质量、MR表现,临床应用及诊断价值进行评价,结果是疾病检出率的74.2%.检出病变经临床实验诊断、随访、追踪复查、手术及病理等证实的准确率达92%.作者认为低场 MRI 图像清晰,软组织密度分辨率高,空间分辨率较好.对体内一些实质性的脏器能观察其结构和病变,对 X-CT 诊断困难的一些部位及病变如大脑中线结构和后颅凹的病变、脑白质的病变、脊髓病变等可作出明确诊断.又因低场 MRI 有“流动效应”的特性,所以对血管性的病变如脑动脉畸性、真层动脉瘤、血管栓塞等显示清楚,并且容易鉴别一些内脏器官如纵隔、心脏、大血管、肝脾、胃等血管与肿块,淋巴结的病变.但低场 MRI 存在一些不足之处:肺部 MR 信号低。空间分辨率低,加上运动伪影等因素的影响,使其对一些病变如结核、炎症、弥漫性小病灶的鉴别诊断困难;对钙化性病灶、骨皮质显示差;对腹部脏器的小病灶如:T_1WI 和 T_2WI 均是等信号时(如某些小肝癌)则诊断困难.     

急性桥臂梗死的临床及影像学特征

目的:探讨急性桥臂梗死的临床及影像学特点。方法:回顾性分析2014年8月至2017年9月我院收治的20例急性桥臂梗死患者的临床及影像学资料。患者均于发病48 h内完成首次颅脑CT检查,3d内完成首次颅脑MRI检查,8例病程中有MRA检查资料。结果:本组患者均急性起病,均伴眩晕,共济失调性步态16例,恶心呕吐13例,耳鸣、听力下降7例,水平性眼震5例,一侧眼球外展受限3例,面瘫3例,Horner综合征3例,肢体瘫痪1例。首次CT检查阴性13例,随访CT可见桥臂低密度灶。头颅MRI均示桥臂T1WI低、T2WI、FLAIR及DWI高信号,ADC低信号,其中单侧16例,双侧4例。MRI还显示10例伴发的其他后循环区域急性梗死。结论:急性桥臂梗死临床表现复杂多样,多以前庭神经和小脑损害的表现为主。影像学检查尤其是及时的MRI有助于诊断及鉴别诊断。      

良性对称性脂肪瘤病的影像诊断

目的探讨Madelung`s病的CT及MR表现。资料与方法结合文献回顾分析16例良性对称性脂肪瘤病患者的临床资料。回顾性分析2003年5月～2005年12月间我院影像及临床科室证实的Madelung`s病16例。男性15例,女性1例。应用GE Process F-II型多层螺旋CT扫描机以及XGY OPER-0.35T永磁性磁共振扫描仪。行颈部及下颌部扫描。磁共振扫描常规应用脂肪抑制序列。结果16例病人中4人表现为颈后部、双侧肩部皮下脂肪过度堆积;9例患者表现为双侧颌下脂肪层增厚、双侧咽旁间隙、腮腺周围间隙脂肪过度堆积;3例病人表现为双侧颌下、颈前部、双侧锁骨上窝深浅筋膜间隙脂肪组织过度堆积。CT及MR增强扫描未见异常强化,其内血管分布与走行未见异常。磁共振压脂像显示为正常脂肪组织,未见其它异常信号显示。     

3种不同肠道准备方法在CT小肠造影中的应用研究

目的:探讨3种不同肠道准备方法在CT小肠造影（CTE）中的应用价值。方法:对156例临床怀疑为小肠病变而行CTE的病例进行前瞻性研究。156例随机分为A、B和C组各52例,肠道造影剂均采用口服法。A和B两组在扫描前16h进食半流质饮食,并均以番泻叶6g导泄,扫描前12h禁食,扫描前1h起每隔15min A组尽量口服等渗甘露醇、B组同法尽量口服引用水。C组扫描前6h禁食,扫描前1h起每隔15min尽量口服饮用水。3组均在口服对比剂10min后进行CTE检查。统计比较3组小肠的充盈效果及对小肠病变的诊断价值。结果:小肠充盈效果比较A组最佳,B组次之,C组最差;对小肠病变的诊断结果显示A组对小肠各段病变的诊断价值均较显著;B组对十二指肠、空肠病变诊断价值较大,对回肠的细小病变诊断效果较差;C组对十二指肠及空肠上段病变诊断效果较好,但不利于空肠上段以远细小病变的诊断。结论:充分的肠道准备是CTE的重要技术因素,分次口服等渗甘露醇尽量充盈小肠有利于小肠病变的显示,是一种安全可靠、经济方便的肠道准备方法。      

CT和MRI对桥脑中央髓鞘溶解症的诊断价值

目的:探讨桥脑中央髓鞘溶解症(CPM)的CT、MRI表现,以提高诊断水平,并评估其在CPM诊断及随访中的价值。方法:回顾性分析8例经我院临床确诊的CPM的临床和影像学资料,总结其影像学特征。结果:4例患者行CT检查,其中阳性2例,阴性2例,阳性病例中桥脑、双侧大脑脚及右侧小脑多发斑片状低密度灶1例,桥脑低密度灶1例;8例患者行MRI检查均有阳性表现,其中桥脑中央病灶8例,对称性分布,边缘清晰,呈圆形、卵圆形或蝶翼状,4例伴桥脑外病变,包括小脑半球、大脑脚、丘脑、基底节及放射冠等区域,病灶在T1WI序列均呈等、低信号,T2WI及T2FLAIR序列呈高信号,DWI序列呈明显高信号,灶周无水肿,增强扫描未见强化。结论:MRI对该病的诊断价值明显优于CT,T2FLAIR及DWI序列对CPM病灶显示敏感,对其诊断、指导临床治疗及评估预后具有较大价值。      

GD—DTPA脊髓造影磁共振扫描技术应用的研究

本文目的,通过将ＧＤ－ＤＴＰＡ直接注入蛛网膜下腔后进行脊髓造影ＭＲ扫描,探索一种新的ＭＲ检查方法,材料方法：对１１例患者进行ＧＤ－ＤＴＰＡ蛛网膜腔直接注射脊髓造影前后ＭＲ扫描,保持扫描序列不变。造影剂量为０．５～１．０ｍｌ,结果：所有患者脊髓造影后即刻扫描显示脑脊液信号反转,Ｔ１Ｗ高信号。Ｔ２Ｗ低信与,结论：小剂量ＧＤ－ＤＴＰＡ直接蛛网膜注射脊髓造影ＭＲ扫描是一种安全可靠的检查方法。对观察脑脊液动     

A Monte Carlo study of rainfall forecasting with a stochastic model

A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities.     

Earthquake Engineering and Engineering Vibration Aims And Scope

正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and     

Foreword

Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.     

WORLD ASSOCIATION FOR SEDIMENTATION AND EROSION RESEARCH(WASER)

正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases     

Dissolved Carbohydrate Concentration,Composition, and Bioavailability to Microbial Heterotrophs in Stream Water

Dissolved total carbohydrates (DTCH), dissolved free monosaccharides (DFMS), dissolved organic carbon (DOC), biodegradable DOC (BDOC), and humic substances (HS) were measured in White Clay Creek (WCC), a stream in southeastern Pennsylvania Piedmont, USA. Samples were collected over different seasons and under baseflow and stormflow conditions. DOC concentrations ranged from 1.0 to 12.8 mg/L C with the highest concentrations associated with stormflows. Carbohydrates ranged from 0.42 to 12.4 μM and accounted for 2.9 to 12.7% of the DOC. Humic substances represented the major DOC fraction, accounting for 55 to 72% of the DOC pool under all flow conditions. The humic fraction had a lower carbohydrate content (4.4%) than the non-humic fraction of DOC (7.2%). Stormflow DOC was enriched in carbohydrates relative to baseflow DOC, but the percentage of humic-C changed little. Carbohydrates were primarily present as dissolved polysaccharides (55%), but a significant fraction was bound to humic substances (40%), while a small proportion was present as monosaccharides (5%). The major monosaccharides in stream water, listed in order of decreasing concentration, included glucose, galactose, rhamnose, xylose, arabinose, mannose, and fucose. On average (30.6 ± 7.4)% (n = 44) of the stream water DOC was biodegradable, and carbohydrates accounted for 9.9 to 17.7% of the BDOC.