肾内泌尿
词汇介绍
拓展阅读
解析
magnetic 英 [mægˈnetɪk] 美 [mægˈnetɪk]
释 义 adj. 地磁的;有磁性的;有吸引力的
例 句 But after getting the magnetic pulse, the volunteers tended to see nothing wrong with his actions - and judged his behaviour purely on whether his girlfriend survived.但在经受磁场刺激后,志愿者并不认为这种做法有任何不妥之处,而仅仅是根据他的女朋友是否幸存来评分。
resonance 英 [ˈrezənəns] 美 [ˈrezənəns]
释 义 n. [力]共振;共鸣;反响
例 句 Diagnosis was made via magnetic resonance imaging.是通过磁共振成像诊断的。
agent 英 [ˈeɪdʒənt] 美 [ˈeɪdʒənt]
释 义 n. 代理人,代理商;药剂;特工;动因
vt. 由…作中介;由…代理
adj. 代理的
例 句 This installs both the application and the agent.这会同时安装应用程序和代理。
概述
概述
以医学成像为目的将某种特定物质引入人体内,以改变机体局部组织的影像对比度,这种被引入的物质称为“造影剂”(contrast medium,CM),目前称之为“对比剂”(contrast media)。磁共振对比剂(MR contrast agent)能特异或非特异性地改变组织的弛豫时间和信号强度,将有助于病变的早期诊断、小病灶的检出和对疾病的定性诊断。
临床分类
(1)根据细胞内、外分布分类:①细胞外对比剂:细胞外对比剂应用最早,日前应用也最为广泛;②细胞内对比剂:以一些细胞作为目标靶来分布。
(2)根据磁敏感性的不同分类:①顺磁性对比剂;②超顺磁性对比剂;③铁磁性对比剂。
(3)根据对比剂特异性的不同分类:目前有肝特异性对比剂、血池对比剂、淋巴结对比剂和其他特异性对比剂四类。
磁共振对比剂的增强机制
(1)顺磁性对比剂缩短T1或2弛豫时间,与下列三种因素有关:①顺磁性物质的浓度;②顺磁性物质的磁矩;③顺磁性物质结合水的分子数;
(2)超顺磁性对比剂和铁磁性对比剂会造成磁场的不均匀性,而质子通过这种不均匀磁场时,改变了横向磁化相位,加速失相位过程,故形成T2,T2弛豫时间缩短,增强信号呈黑色低信号。这类对比剂对T1的效应较弱。
临床常用磁共振对比剂
传统对比剂:(1)Gd-DTPA(Gadoppentetate dieglumine, Magnevist,磁显葡胺,马根维显)作为第一种MRI对比剂也是目前应用最广泛的MRI造影剂,其主要成分钆为顺磁性很强的金属离子钆;(2)GD-DOTA(Gadoterate meglumine, Dotarem);(3)Omniscan(Gadodiamide, GD-DTPA-BMA);(4)Gd Hp-D03A(Gadoteridol, ProHance);(5)Gadobutrol(Gd D03A-butrol);(6)氧化铁胶体注射液(AMI25, Feridex IV, Ferumoxide, Endorem);(7)SHU-555A(Resovist);(8)Ami-227(Ferumoxtran, Sinerem. Combidex);(9)胃肠道磁共振对比剂:①AMI-121(Lumirem、Gastromark);②OMP(abdoscan);
新型造影剂:(1)低渗性钆螯合物对比剂;(2)顺磁性肝胆对比剂;(3)超顺磁性氧化铁对比剂;(4)病灶靶向性对比剂;(5)血池对比剂;(6)脂质体包裹对比剂;(7)其他细胞外液对比剂:目前除钆外,Dy螯合物研究较多,属于一种阴性造影剂,其适用于心肌梗死及脑梗死的检出。
Redox-Activated Manganese-Based MR Contrast Agent复制标题
氧化还原激活锰基MR造影剂
发表时间:2013-03-27
影响指数:14.7
作者: Galen S. Loving
期刊:J Am Chem Soc
Both intracellular and extracellular redox environments are tightly regulated in healthy tissues and are closely correlated with the physiological state of the cell.1,2 However, this regulation is often disrupted during periods of cellular stress, damage or cell death.3 While the dynamics of local redox status play an important role in mediating various biological processes such as cell-cycle progression, immune response and wound-healing,3,4 persistent dysregulation of the extracellular redox environment has been linked to a number of pathologies including chronic inflammation,3 neoplastic growth,4 and cancer cell aggressiveness.1,5,6 Indeed, the role of redox in tumor biology continues to be an area of active research and is the focus of many redox-activated prodrugs that are currently in devolpment.7,8 New imaging methods will certainly facilitate these endeavors while further advancing our basic understanding of redox dynamics in relation to disease.
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