期刊文献+
共找到841篇文章
< 1 2 43 >
每页显示 20 50 100
线性钆对比剂多次静脉注射后苍白球T1加权信号变化的初步观察
1
作者 孔莹 徐凯 +3 位作者 叶新春 韩翠平 李梦双 陈柱典 《中华医学杂志》 CAS CSCD 北大核心 2019年第19期1468-1472,共5页
目的探讨多次静脉注射线性钆对比剂后,苍白球在颅脑平扫T1WI上的信号变化情况。方法回顾分析2016年1月至2018年4月期间在徐州医科大学附属医院行磁共振增强检查(连续进行至少4次)的114例患者的临床及影像学资料。在多次增强前后T1WI分... 目的探讨多次静脉注射线性钆对比剂后,苍白球在颅脑平扫T1WI上的信号变化情况。方法回顾分析2016年1月至2018年4月期间在徐州医科大学附属医院行磁共振增强检查(连续进行至少4次)的114例患者的临床及影像学资料。在多次增强前后T1WI分别测量苍白球、丘脑及脑脊液的平均信号强度,计算苍白球/丘脑、苍白球/脑脊液的信号强度比值,采用非参数检验分析同一患者多次增强前后信号强度比之间的差异,采用线性回归对多种临床因素进行分析。结果多次注射线性钆对比剂后苍白球/丘脑、苍白球/脑脊液的信号强度比均大于增强前信号强度比,差异有统计学意义[增强前、后信号比分别为1.036(1.010,1.075)、1.104(1.074,1.168);4.215(3.590,5.614)、5.409(4.213,6.502),均P<0.01]。信号强度比差值与增强次数存在正相关(苍白球/丘脑b=0.023,P<0.01,苍白球/脑脊液b=0.279,P=0.034);与时间间隔存在负相关(苍白球/丘脑b=-0.002,P<0.01,苍白球/脑脊液b=-0.023,P=0.039);与本研究涉及的其他临床因素无关(均P>0.05)。结论多次接受钆对比剂注射的患者,T1WI苍白球信号增高,且与增强检查次数呈正相关,与时间间隔呈负相关。 展开更多
关键词 苍白球 对比剂
Astragaloside IV attenuates myocardial ischemia/reperfusion injury in rats via inhibition of calcium-sensing receptor-mediated apoptotic signaling pathways
2
作者 Bo Yin Xu-wei Hou Mei-li Lu 《中国药理学报:英文版》 SCIE CAS CSCD 2019年第5期599-607,共9页
Astragaloside IV (AsIV) is an active saponin extracted from Astragalus membranaceus, which has shown cardioprotective effects in a number of experimental animals. In this study we investigated the molecular mechanisms... Astragaloside IV (AsIV) is an active saponin extracted from Astragalus membranaceus, which has shown cardioprotective effects in a number of experimental animals. In this study we investigated the molecular mechanisms by which AsIV attenuated the myocardial ischemia reperfusion (MI/R)-induced injury in vitro and in vivo by focusing on calcium-sensing receptor (CaSR) and extracellular signal-regulated kinase 1/2 (ERK1/2). Rat neonatal cardiac myocytes were subjected to a hypoxia/reoxygenation (H/R) procedure in vitro, which significantly decreased the cell viability, increased lactate dehydrogenase (LDH) release, induced cardiomyocyte apoptosis, and increased [Ca^2+]i. H/R also increased the expression of CaSR and decreased ERK1/2 phosphorylation levels in H/R-exposed myocytes. Pretreatment with AsIV (60μmol/L) significantly improved the cell viability and decreased LDH release, attenuated myocyte apoptosis, decreased [Ca^2+]i and CaSR expression, and increased the ERK1/2 phosphorylation levels. The protective effects of AsIV against H/R injury were partially inhibited by co-treatment with a CaSR agonist, gadolinium chloride (GdCl3) or with a specific ERK1/2 inhibitor U0126. For in vivo studies, a rat MI/R model was established. Pre-administration of AsIV (80mg/kg every day, ig) significantly decreased the myocardium infarct size, creatine kinase-MB (CK-MB) production, serum cardiac troponin (cTnI) levels, and cardiomyocyte apoptosis in the rats with MI/R injury. The therapeutic effects of AsIV were associated with the downregulation of CaSR expression and upregulation of ERK1/2 phosphorylation in myocardial tissues. In summary, astragaloside IV attenuates myocardial I/R injury via inhibition of CaSR/ERK1/2 and the related apoptotic signaling pathways. 展开更多
关键词 ASTRAGALOSIDE IV MYOCARDIAL ISCHEMIA/REPERFUSION apoptosis calcium-sensing receptor ERK1/2 GADOLINIUM chloride U0126
Heavy metal free primers: Polymorphism of gadolinium and titanium in the context of GSR glass phase 预览
3
作者 Felice Nunziata 《Defence Technology(防务技术)》 CAS CSCD 2019年第3期272-275,共4页
The possibility of identifying gunshot residue (GSR) particles produced by non-toxic primers containing only titanium and zinc is a very difficult task using SEM/EDX analysis employed in the analysis of GSR originatin... The possibility of identifying gunshot residue (GSR) particles produced by non-toxic primers containing only titanium and zinc is a very difficult task using SEM/EDX analysis employed in the analysis of GSR originating from primers containing lead, barium and antimony. However, Bauer et al. demonstrated that non-toxic (TieZn) primers form a TiZn2O4 spinel crystalline structure using SEM/EDX with EBSD (Electron Back Scatter Diffraction) and TKD (Transmission Kikuchi Diffraction), whereas GSR originating from gadolinium-doped TieZn primers form a non-crystalline glass phase. Here, a possible explanation of these different phenomena is hypothesized. 展开更多
关键词 GSR Heavy metal free PRIMERS GADOLINIUM Glass phase EBSD TKD
在线阅读 免费下载
Electrospun and in situ self-polymerization of polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection
4
作者 Chun-Hong Wang Li-Min Hu +1 位作者 Zhi-Feng Wang Ming Zhang 《稀有金属:英文版》 SCIE EI CAS CSCD 2019年第3期252-258,共7页
In this work, the polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection were successfully fabricated by electrospunning and followed by in situ self-polymerization. Scanning electron micros... In this work, the polyacrylonitrile containing gadolinium nanofibers for thermal neutron protection were successfully fabricated by electrospunning and followed by in situ self-polymerization. Scanning electron microscopy(SEM) and energy-dispersive spectroscopy(EDS) results show that there are no beads on the smooth surface of the nanofibers and gadolinium elements are uniformly dispersed in the matrix. The thermal analysis and FTIR results prove that gadolinium methacrylate is induced in situ selfpolymerization during the heat treatment. The leaching rate of Gd3+ decreases from 79.97% to 10.74% tested by lowfield nuclear magnetic resonance(LF-NMR) method after the self-polymerization of gadolinium methacrylate in the matrix when the nanofibers were immersed in water for7 days. The thermal neutron shielding analysis calculated by MCNP program shows that above 99% thermal neutrons are absorbed when traveling through the 2-mm-thick polyacrylonitrile containing gadolinium nanofibers. 展开更多
关键词 GADOLINIUM POLYACRYLONITRILE ELECTROSPINNING In situ SELF-POLYMERIZATION Thermal neutron shielding
Evolution of microstructures and optical properties of gadolinium oxide with oxygen flow rate and annealing temperature
5
作者 Zhenhuai Yang Lei Yang +8 位作者 Bing Dai Pei Lei Shuai Guo Peng Wang Qiang Wang Yujie Ding Yumin Zhang Jiecai Han Jiaqi Zhu 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2019年第4期410-415,共6页
In this study, the effects of oxygen flow rate and annealing temperature on Gd2 O3 structures and optical properties were systematically analyzed. Gd2 O3 films were deposited on both quartz and ZnS substrates by magne... In this study, the effects of oxygen flow rate and annealing temperature on Gd2 O3 structures and optical properties were systematically analyzed. Gd2 O3 films were deposited on both quartz and ZnS substrates by magnetron sputtering and then annealed under vacuum at 700, 800 and 900℃, Restructure and phase transformation from cubic to monoclinic occur at different temperatures depending on the oxygen flow rate. The optical band gap, which is more sensitive to the annealing temperature than oxygen flow rate changes from 5.32 to 5.65 eV. The refractive index is approximately 1.75 at 550 nm and is adjustable by the oxygen flow rate. The transmittance of the ZnS substrate with Gd2 O3 film exceeds 80% and reaches82% at the 7.5-9.5 μm range. When ZnS is coated on both sides, the transmittance is increased to approximately 90%. Our results indicate that Gd2 O3 films are promising new candidates for anti-reflective coatings in the infrared region. 展开更多
关键词 GADOLINIUM oxide MAGNETRON SPUTTERING Structures Infrared materials OPTICAL properties Rare earths
Gadoxetic acid-enhanced magnetic resonance imaging can predict the pathologic stage of solitary hepatocellular carcinoma 预览
6
作者 Yi-Chen Chou I-Ha Lao +8 位作者 Pei-Ling Hsieh Ying-Ying Su Chee-Wai Mak Ding-Ping Sun Ming-Jen Sheu Hsing-Tao Kuo Tzu-Ju Chen Chung-Han Ho Yu-Ting Kuo 《世界胃肠病学杂志:英文版》 SCIE CAS 2019年第21期2636-2649,共14页
BACKGROUND Although important for determining long-term outcome, pathologic stage of hepatocellular carcinoma (HCC) is difficult to predict before surgery. Current state-of-the-art magnetic resonance imaging (MRI) usi... BACKGROUND Although important for determining long-term outcome, pathologic stage of hepatocellular carcinoma (HCC) is difficult to predict before surgery. Current state-of-the-art magnetic resonance imaging (MRI) using gadoxetic acid provides many imaging features that could potentially be used to classify single HCC as pT1 or pT2. AIM To determine which gadoxetic acid-enhanced MRI (EOB-MRI) findings predict pathologic stage T2 in patients with solitary HCC (cT1). METHODS Pre-operative EOB-MRI findings were reviewed in a retrospective cohort of patients with solitary HCC. The following imaging features were examined: Hyperintensity in unenhanced T2-weighted images, hypointensity in unenhanced T1-weighted images, arterial enhancement, corona enhancement, washout appearance, capsular appearance, hypointensity in the tumor tissue during the hepatobiliary (HB) phase, peritumoral hypointensity in the HB phase, hypointense rim in the HB phase, intratumoral fat, hyperintensity on diffusionweighted imaging, hypointensity on apparent diffusion coefficient map, mosaic appearance, nodule-in-nodule appearance, and the margin (smooth or irregular). Surgical pathology was used as the reference method for tumor staging. Univariate and multivariate analyses were performed to identify predictors of microvascular invasion or satellite nodules. RESULTS There were 39 (34.2%;39 of 114) and 75 (65.8%;75 of 114) pathological stage T2 and T1 HCCs, respectively. Large tumor size (≥ 2.3 cm) and two MRI findings, i.e., corona enhancement [odds ratio = 2.67;95% confidence interval: 1.101-6.480] and peritumoral hypointensity in HB phase images (odds ratio = 2.203;95% confidence interval: 0.961-5.049) were associated with high risk of pT2 HCC. The positive likelihood ratio was 6.25 (95% confidence interval: 1.788-21.845), and sensitivity of EOB-MRI for detecting pT2 HCC was 86.2% when two or three of these MRI features were present. Small tumor size and hypointense rim in the HB phase were regarded as benign features. Small HCCs with hypoi 展开更多
关键词 Tumor INVASIVENESS GADOLINIUM ethoxybenzyl diethylenetriaminepentaacetic acid HEPATOBILIARY Contrast agent Magnetic resonance imaging Hepatocellular carcinoma
在线阅读 免费下载
肥厚型心肌病磁共振钆剂延迟增强与心电图QTe/RR的关系 预览
7
作者 黄恒贵 高伟铿 《天津医药》 CAS 北大核心 2019年第5期500-504,共5页
目的探讨肥厚型心肌病(HCM)磁共振钆剂延迟增强与动态心电图QTe/RR斜率的关系。方法将本院2016年1月 2017年6月接诊的96例HCM患者,根据心脏磁共振扫描(CMR)是否出现钆剂延迟增强(LGE)分为LGE阳性组和LGE阴性组。采用评分法评估LGE阳性... 目的探讨肥厚型心肌病(HCM)磁共振钆剂延迟增强与动态心电图QTe/RR斜率的关系。方法将本院2016年1月 2017年6月接诊的96例HCM患者,根据心脏磁共振扫描(CMR)是否出现钆剂延迟增强(LGE)分为LGE阳性组和LGE阴性组。采用评分法评估LGE阳性组患者LGE透壁程度。所有受试者行24h动态心电图检查,计算心率(H R)、 QT间期及QTe/RR斜率。分析LGE阳性组总LGE评分与QTe/RR斜率之间的相关性,分析LGE透壁程度和QTe/RR斜率与患者预后的关系。结果 CMR结果显示LGE阳性51例(53.13%), LGE阴性45例(46.87%);LGE阳性组与LGE阴性组左心室射血分数(LVEF:0.412±0.092vs.0.508±0.083)、左心室舒张末期容积[LVEDV( mL):173.91±43.68 vs.148.52±31.77]及左心室舒张末期后壁厚度[LVPWD( mm): 13.26±2.81 vs. 12.15±2.37]比较差异有统计学意义(t分别为5.301、 3.219、 2.077,均P<0 .05);LGE阳性组QT间期(m s:439.67±25.82vs.411.53±31.66)、 QTe/RR斜率(0.20±0.05vs.0.16±0.03)均高于LGE阴性组(t分别为4.794、 4.674,均 P<0 .05);LGE阳性组总LGE评分为(26.37±7.52)分,与QTe/RR斜率呈正相关(r=0.742,P <0.001);LGE阳性组室性心律失常、心源性猝死等不良反应发生率高于LGE阴性组(17.65%vs.4.44%,c2=4.107,P <0.05);总 LGE评分、QTe/RR斜率与患者室性心律失常、心源性猝死有关(P<0.05)。结论 HCM患者LGE程度与QTe/RR斜率显著相关,综合评估两项指标可能更有助于HCM预后判断。 展开更多
关键词 心肌病 肥厚性 心电描记术 磁共振成像 24H动态心电图 QTe/RR斜率
在线阅读 下载PDF
一类基于1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸-酰肼结构的新型含钆磁共振对比剂的设计、合成及性能表征
8
作者 孙宏顺 周进 +5 位作者 李玉龙 蒋蕻 张艳 王建强 郭成 沈临江 《有机化学》 SCIE CAS CSCD 北大核心 2019年第3期778-785,共8页
磁共振成像技术被广泛应用于诊断医学和软组织成像,而磁共振对比剂有助于提高成像对比度.报道了一类共十二种基于钆-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸(DOTA)-酰肼结构的新型磁共振对比剂的设计、合成及性能表征. 0.5 T 磁场下... 磁共振成像技术被广泛应用于诊断医学和软组织成像,而磁共振对比剂有助于提高成像对比度.报道了一类共十二种基于钆-1,4,7,10-四氮杂环十二烷-1,4,7,10-四乙酸(DOTA)-酰肼结构的新型磁共振对比剂的设计、合成及性能表征. 0.5 T 磁场下测得的弛豫率结果显示,对比剂 5d、5h 和 5l 的纵向弛豫率优于临床使用对比剂 Gd-DOTA,分别达到4.67、4.85 和 5.33 L·mmol^-1·s^-1.进一步动物活体体内肝靶向磁共振成像研究显示,对比剂 5d 具有作为肝靶向磁共振对比剂的应用潜力. 展开更多
关键词 磁共振成像 对比剂 肝靶向 DOTA-酰肼 合成
Tetranuclear yttrium and gadolinium 2-acetylcyclopentanoate clusters:Synthesis and their use as spin-coating precursors for metal oxide film formation for field-effect transistor fabrication
9
作者 Elaheh Pousaneh Andrea Preuβ +6 位作者 Khaybar Assim Tobias Rüffer Marcus Korb Jana Tittmann-Otto Sascha Hermann Stefan E.Schulz Heinrich Lang 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2018年第10期1098-1105,共8页
关键词 金属氧化物 晶体管 涂层 纺纱 Haccp 制造 合成 拍摄
Recent advances in gadolinium-based MRI metal responsive agent
10
作者 ZHANG Lei LI JingJing LIU Kai 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2018年第9期1329-1333,共5页
关键词 代理人 MRI 金属 应答 过程系统 声成像
Development of a microfluidic-chip system based on parallel flow for intensified Gd(Ⅲ) extraction from nitrate media using cationic extractant
11
作者 All Abbasi Ahmad Rahbar-Kelishami Mohammad Javad Ghaserni 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2018年第11期1198-1204,共7页
关键词 抽取系统 提炼 GD 硝酸盐 开发 薄片 流动 平行
有症状颅内动脉粥样硬化性狭窄患者斑块增强的临床意义:高分辨率磁共振成像研究
12
作者 梁萌 王朋 +4 位作者 马延 张晓浩 戴正泽 朱武生 刘新峰 《国际脑血管病杂志》 2018年第1期15-20,共6页
目的探讨有症状颅内动脉粥样硬化(intracranial atherosclerosis, ICAS)患者高分辨率磁共振成像(high-resolution magnetic renounce imaging, HR-MRI)斑块强化的影响因素和临床意义。方法前瞻性纳入经数字减影血管造影证实的有症状... 目的探讨有症状颅内动脉粥样硬化(intracranial atherosclerosis, ICAS)患者高分辨率磁共振成像(high-resolution magnetic renounce imaging, HR-MRI)斑块强化的影响因素和临床意义。方法前瞻性纳入经数字减影血管造影证实的有症状ICAS狭窄患者进行HR-MRI检查。根据斑块是否强化分组,比较人口统计学资料、血管危险因素、实验室检查和斑块的影像学特征。根据弥散加权成像结果分为缺血性卒中组和短暂性脑缺血发作(transient ischemic attack, TIA)组,分析斑块强化与缺血性卒中之间的关系。结果纳入35例有症状ICAS狭窄患者,平均年龄(53±13)岁,男性25例;缺血性卒中21例,TIA 14例;斑块强化22例,未强化13例。斑块强化组的白细胞计数[(7.50±2.30)×10^9/L对(5.80±1.00)×10^9/L;t=2.487,P=0.018]和重度狭窄比例(86.4%对53.8%;P=0.040)显著高于未强化组,吸烟比例显著低于未强化组(13.6%对46.2%;P=0.050)。缺血性卒中组的斑块强化率高于TIA组(71.4%对50.0%;P=0.288),但未达到统计学差异。结论在有症状ICAS患者中,病变血管狭窄程度和白细胞水平与斑块强化相关。此外,斑块强化与有症状ICAS患者是否发生缺血性卒中无显著相关性。 展开更多
关键词 颅内动脉硬化 斑块 动脉粥样硬化 卒中 脑缺血 脑缺血发作 短暂性 磁共振成像 图像增强
新型放疗增敏纳米药物AGUIX的研究进展
13
作者 孙昊 王彦 +2 位作者 徐畅 杜利清 刘强 《国际生物医学工程杂志》 CAS 2018年第3期271-274,280共5页
为了有效地提高肿瘤辐射敏感性,减少放射治疗(放疗)过程中的副作用,人们一直致力于辐射增敏剂的研制。近年来,高原子序数元素作为放射增敏剂的纳米粒子的研究正在全面展开,研究人员最近开发合成了一种基于金属元素钆的辐射增敏纳... 为了有效地提高肿瘤辐射敏感性,减少放射治疗(放疗)过程中的副作用,人们一直致力于辐射增敏剂的研制。近年来,高原子序数元素作为放射增敏剂的纳米粒子的研究正在全面展开,研究人员最近开发合成了一种基于金属元素钆的辐射增敏纳米颗粒AGUIX。这种纳米粒子是由聚硅氧烷核心及其周围与之共价相连的钆螯合物网络组成,其流体动力学直径小于5nm,可通过静脉注射的方式(肾清除,肿瘤部位优先累积)给药,具有低毒性、低质量以及辐射激发药物活性等特点。研究结果证明,AGUIX在多种照射条件下均可作为安全有效的辐射增敏剂。此外,由于钆元素的存在,AGUIX本身也可作为磁共振成像(MRI)造影剂来监测药物的生物分布及肿瘤演变,进而指导放疗方案的制定。针对近年来对AGUIX的研究进展进行综述。 展开更多
关键词 AGUIX 钆元素 放疗 辐射增敏 纳米颗粒
C/Gd纳米复合物用于兔舌间质磁共振淋巴造影的应用价值评价
14
作者 单俊 曾文霞 +6 位作者 刘世恩 徐豪越 朱海涛 宋凯 冯元勇 吴大雄 尚伟 《中国口腔颌面外科杂志》 CAS 2018年第3期205-208,共4页
目的 :探讨新型淋巴造影剂C/Gd纳米复合物经兔舌黏膜下注射后间质磁共振颈淋巴显影的应用价值。方法 :选择健康纯种成年新西兰大白兔12只,在大白兔左右两侧舌缘中后1/3交界黏膜下各注射0.2 mL C/Gd纳米复合物,按摩注射部位30 s。分别... 目的 :探讨新型淋巴造影剂C/Gd纳米复合物经兔舌黏膜下注射后间质磁共振颈淋巴显影的应用价值。方法 :选择健康纯种成年新西兰大白兔12只,在大白兔左右两侧舌缘中后1/3交界黏膜下各注射0.2 mL C/Gd纳米复合物,按摩注射部位30 s。分别于注射造影剂前及注射、按摩后5、10、15、20、40 min进行三维增强磁共振淋巴造影成像。测量增强前、后不同时间段引流区颈淋巴结的信号强度,计算对应时间的信号强化率(E%),采用SPSS17.0软件包对数据进行统计学分析。结果:C/Gd纳米复合物迅速进入引流区,可清晰显影兔颈部淋巴结及淋巴管,无明显血管显影。颈部淋巴结在注射造影剂后约10 min信号强度达到峰值,注射后5~20 min可获得最佳显影效果,40 min后影像基本廓清。结论:C/Gd纳米复合物作为间质磁共振显影剂,能以较小剂量快速有效地显示颈部淋巴结及淋巴管的形态及走行特征。 展开更多
关键词 颈部淋巴结 纳米碳 间质淋巴造影 新西兰大白兔
Electrochemical properties of gadolinium on liquid gallium electrode in LiC1-KCI eutectic
15
作者 Bo Li Kui Liu +3 位作者 Jingwen Pang Liyong Yuan Yalan Liu Mingzhang Lin 《中国稀土学报:英文版》 SCIE EI CAS CSCD 2018年第6期656-661,共6页
This work presents the electrochemical properties of gadolinium(Gd), a significant rare earth element in spent nuclear fuel(SNF), in the LiCl-KCl eutectic. To explore thermodynamic properties of Gd at the liquid g... This work presents the electrochemical properties of gadolinium(Gd), a significant rare earth element in spent nuclear fuel(SNF), in the LiCl-KCl eutectic. To explore thermodynamic properties of Gd at the liquid gallium(Ga) electrode, experiments were performed both on the inert tungsten(W) and liquid gallium(Ga) electrode at different temperatures in a range from 723 to 823 K, which show that the Gd metal can be oxidized to Gd(Ⅲ) by exchanging of 3 electrons. Electrochemical techniques including cyclic voltammetry(CV), open circuit potential(OCP), potentiostatic electrolysis and galvanostatic electrolysis were utilized to detect the electrochemical behavior and evaluate standard apparent potential of the Gd(Ⅲ)/Gd couple,and EGd(Ⅲ)/Gd*=-3.456 + 6.2×10-4T(±0.046)( vs Cl2/Cl-) is obtained.In addition, electromotive force(EMF) and coulometric titration were employed to calculate the activity and activity coefficient of Gd in metal Ga. After calculation, the activity is 1.791×10-15 at 723 K and function of activity coefficient and temperature is lgγ = 3.485-10927/T(±0.0875). 展开更多
关键词 LiCI-KCI EUTECTIC ELECTROCHEMICAL properties GADOLINIUM LIQUID Ga Rare earths
Optimized cardiac magnetic resonance imaging inversion recovery sequence for metal artifact reduction and accurate myocardial scar assessment in patients with cardiac implantable electronic devices 预览
16
作者 El-Sayed H Ibrahim Mason Runge +6 位作者 Jadranka Stojanovska Prachi Agarwal Maryam Ghadimi-Mahani Anil Attili Thomas Chenevert Chiel den Harder Frank Bogun 《世界放射学杂志:英文版(电子版)》 2018年第9期100-107,共8页
Late gadolinium enhancement(LGE)cardiovascular magnetic resonance(CMR)is the gold standard for imaging myocardial viability.An important application of LGE CMR is the assessment of the location and extent of the myoca... Late gadolinium enhancement(LGE)cardiovascular magnetic resonance(CMR)is the gold standard for imaging myocardial viability.An important application of LGE CMR is the assessment of the location and extent of the myocardial scar in patients with ventricular tachycardia(VT),which allows for more accurate identification of the ablation targets.However,a large percentage of patients with VT have cardiac implantable electronic devices(CIEDs),which is a relative contraindication for cardiac magnetic resonance imaging due to safety and image artifact concerns.Previous studies showed that these patients can be safely scanned on 1.5 T scanners provided that an adequate imaging protocol is adopted.Nevertheless,imaging patients with a CIED result in metal artifacts due to the strong frequency off-resonance effects near the device;therefore,the spins in the surrounding myocardium are not completely inverted,and thus give rise to hyperintensity artifacts.These artifacts obscure the myocardial scar tissue and limit the ability to study the correlation between the myocardial scar structure and the electro-anatomical map during catheter ablation.In this study,we developed a modified inversion recovery technique to alleviate the CIED-induced metal artifacts and improve the diagnostic image quality of LGE images in patients with CIEDs without increasing scan time or requiring additional hardware.The developed technique was tested in phantom experiments and in vivo scans,which showed its capability for suppressing the hyperintensity artifacts without compromising myocardium nulling in the resulting LGE images. 展开更多
关键词 Magnetic resonance IMAGING Heart Late GADOLINIUM enhancement VIABILITY IMAGING INVERSION recovery CARDIAC IMPLANTABLE electronic devices
在线阅读 免费下载
多次使用钆对比剂后MRI平扫小脑齿状核T1WI信号增高的初步研究
17
作者 孔莹 李梦双 +2 位作者 陈柱典 韩翠平 徐凯 《中华放射学杂志》 CSCD 北大核心 2018年第12期892-896,共5页
目的研究多次使用线性钆对比剂后,小脑齿状核、脑桥和脑脊液在MR平扫T1WI上的信号强度的变化。方法回顾性分析2017年1月至12月49例连续进行至少4次MR增强检查的患者的临床及影像学资料(多次增强检查前后均进行了颅脑MR平扫检查)。在多... 目的研究多次使用线性钆对比剂后,小脑齿状核、脑桥和脑脊液在MR平扫T1WI上的信号强度的变化。方法回顾性分析2017年1月至12月49例连续进行至少4次MR增强检查的患者的临床及影像学资料(多次增强检查前后均进行了颅脑MR平扫检查)。在多次增强前后T1WI上测量齿状核、脑桥及脑脊液的平均信号强度,计算齿状核/脑桥、齿状核/脑脊液的信号强度比值。采用配对样本t检验分析同一患者多次增强检查前后T1WI上齿状核/脑桥、齿状核/脑脊液信号强度比之间是否存在差异。采用线性回归分析方法,分析多种临床因素与多次增强前后齿状核/脑桥、齿状核/脑脊液信号强度变化是否相关。结果多次增强后齿状核/脑桥、齿状核/脑脊液的信号强度比均大于增强前的信号强度比,差异具有统计学意义。多次增强前、后齿状核/脑桥、齿状核/脑脊液信号强度比分别为0.98±0.62、1.05±0.54,3.89±0.94、4.97±1.61(t=-8.494、-4.526,P值均<0.001)。接受线性钆对比剂注射次数与信号强度比之间存在正相关(齿状核/脑桥回归系数=0.006,P=0.003,齿状核/脑脊液回归系数=0.144,P=0.009),与其他临床因素无关(P值均>0.05)。结论多次接受钆对比剂注射的患者,T1WI齿状核信号增高,且与增强检查次数呈正相关。 展开更多
关键词 齿状核 磁共振成像
构建及应用针对非小细胞肺癌整合素αvβ3受体靶向性纳米分子探针:体外实验研究 预览
18
作者 沈爱军 张旭南 +3 位作者 李永勇 冯峰 张建泉 王培军 《中国医学影像技术》 CSCD 北大核心 2018年第10期1445-1450,共6页
目的 构建以整合素αvβ3为靶点的纳米分子探针,探讨其理化、生物学特征及对非小细胞肺癌A549细胞靶向性MR成像能力。方法 构建以精氨酸-甘氨酸-天冬氨酸多肽(RGD)为靶向基团的分子探针RGD-Gd@BSA,检测其T1弛豫率、水合动力学直径、... 目的 构建以整合素αvβ3为靶点的纳米分子探针,探讨其理化、生物学特征及对非小细胞肺癌A549细胞靶向性MR成像能力。方法 构建以精氨酸-甘氨酸-天冬氨酸多肽(RGD)为靶向基团的分子探针RGD-Gd@BSA,检测其T1弛豫率、水合动力学直径、Zeta电位、分散稳定性和细胞毒性,并比较RGD-Gd@BSA(靶向组)和Gd@BSA(非靶向组)与肺癌A549细胞的靶向能力。结果 线性拟合获得RGD-Gd@BSA的T1弛豫率为18.615 L/(mmol·s),明显高于Gd-DTPA的3.404 L/(mmol·s);RGD-Gd@BSA探针呈类球形,平均水合动力学直径为(99.52±2.62)nm;Zeta电位为(-11.07±0.42)mV,在溶液中分散稳定。Gd 3+浓度为0.15、0.30、0.60、1.20和2.40μmol/L的RGD-Gd@BSA溶液中,人胚肾293T细胞的存活率分别为81.74%、86.80%、69.83%、78.41%和66.95%。共聚焦显微镜成像可见靶向组细胞具有比非靶向组更高的荧光强度;靶向组细胞悬液的T1WI相对信号强度高于非靶向组。结论 纳米分子探针RGD-Gd@BSA具备稳定的理化特性、较好的生物相容性、较高的T1弛豫率和对肺癌A549细胞的靶向性,具有作为用于非小细胞肺癌特异性诊断的纳米分子探针的价值。 展开更多
关键词 整合素ΑVΒ3 靶向性 磁共振成像 非小细胞肺
在线阅读 下载PDF
Effects of gadolinium addition on the microstructure and mechanical properties of Mg–9Al alloy 预览
19
作者 Lavish Kumar Singh Alok Bhadauria +2 位作者 Amirthalingam Srinivasan Uma Thanu Subramonia Pillai Bellambettu Chandrasekhara Pai 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2017年第8期901-908,共8页
This research aims to study the significance of Gd addition (0wt%-2wt%) on the microstructure and mechanical properties of Mg-9Al alloy. The effect of Gd addition on the microstructure was investigated via X-ray diffr... This research aims to study the significance of Gd addition (0wt%-2wt%) on the microstructure and mechanical properties of Mg-9Al alloy. The effect of Gd addition on the microstructure was investigated via X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The Mg-9Al alloy contained two phases, α-Mg and β-Mg17Al12. Alloying with Gd led to the emergence of a new rectangular-shaped phase, Al2Gd. The grain size also decreased marginally upon Gd addition.The ultimate tensile strength and microhardness of Mg-9Al alloy increased by 23% and 19%, respectively, upon 1.5wt% Gd addition. We observed that, although Mg-9Al-2.0Gd alloy exhibited the smallest grain size (181 μm) and the highest dislocation density (5.1 × 1010 m?2) among the investigated compositions, the Mg-9Al-1.5Gd alloy displayed the best mechanical properties. This anomalous behavior was observed because the Al2Gd phase was uniformly distributed and present in abundance in Mg-9Al-1.5Gd alloy, whereas it was coarsened and asymmetrically conglomerated in Mg-9Al-2.0Gd. 展开更多
关键词 MAGNESIUM RARE earth ALLOYING GADOLINIUM microstructure mechanical properties
在线阅读 下载PDF
锌-钆抗菌白炭黑粉体的改性及抗菌性能研究 预览
20
作者 张彬 胡艳玲 +3 位作者 李欢 唐晓宁 郭一婧 杨和山 《硅酸盐通报》 CSCD 北大核心 2017年第8期2714-2719,共6页
通过溶胶-凝胶法制备了锌-钆抗菌白炭黑。通过添加表面活性剂对材料进行改性,并探究了材料改性前后的粒径、比表面积和抗菌性能变化。采用粒度分析、BET、SEM和EDS等手段对样品进行表征。结果表明改性后材料的粒径减小,粒度分布相对集中... 通过溶胶-凝胶法制备了锌-钆抗菌白炭黑。通过添加表面活性剂对材料进行改性,并探究了材料改性前后的粒径、比表面积和抗菌性能变化。采用粒度分析、BET、SEM和EDS等手段对样品进行表征。结果表明改性后材料的粒径减小,粒度分布相对集中,比表面积增大至275.20209 m^2/g。并对材料进行抗菌性能检测,结果表明改性后材料的抗菌性能有一定的增强,锌-钆抗菌白炭黑的杀菌率可达90.29%。 展开更多
关键词 无机抗菌材料 白炭黑 改性
在线阅读 下载PDF
上一页 1 2 43 下一页 到第
使用帮助 返回顶部 意见反馈