血氧水平依赖磁共振成像在慢性肾病中的应用

背景:血氧水平依赖的磁共振成像是目前惟一能无创性地监测肾血氧含量的方法。目的:探讨血氧水平依赖的磁共振成像在评价慢性肾病患者肾血氧水平、反映肾功能状态方面的价值。方法:对20名健康志愿者和24名慢性肾病患者行肾脏血氧水平依赖的磁共振成像,测量各组肾皮质及髓质的R2*值,并进行统计学分析。结果与结论:正常肾髓质的R2*值高于皮质(P<0.05),双肾比较差异无显著性意义(P>0.05)。慢性肾病患者皮质及髓质的R2*值均高于正常人(P<0.05),均与血清肌酐水平呈正相关(r=0.564,P=0.004;r=0.588,P=0.003)。提示血氧水平依赖的磁共振成像可以反映肾脏血氧水平,在评价肾脏的功能状态方面有一定价值。     

磁共振血氧水平依赖成像在糖尿病肾病的研究进展

糖尿病肾脏疾病(diabetic kidney disease,DKD)是严重的糖尿病慢性微血管并发症,也是导致终末期肾病的主要原因。早发现、早预防、早治疗有助于延缓DKD的进展。血氧水平依赖磁共振成像(blood oxygen level dependent MRI,BOLD-MRI)通过监测糖尿病患者肾脏氧代谢变化,在DKD的早期诊断、功能评估、预后判断及监测药物对DKD的影响中具有重要研究应用价值。作者就BOLD-MRI在糖尿病肾病中的研究应用进展进行综述。     

肾脏血氧水平依赖磁共振成像研究进展

BOLD MRI最初只应用于神经系统.随着MR技术的进步,BOLD MRI越来越多地应用于肾脏不同研究领域,能无创评估肾实质氧合状态,具有一定临床应用价值,但仍存在一些不足.本文对肾脏BOLD MRI的基本原理及其临床应用价值进行综述.     

肾脏血氧水平依赖磁共振成像研究进展

血氧水平依赖磁共振成像是无创性评价肾内氧代谢功能技术.随着肾脏血氧水平依赖磁共振成像临床研究的持续发展,能监测慢性肾脏病、急性肾损伤、肾小球疾病、肾移植、肾血管疾病以及肾脏肿瘤等多种肾脏疾病的氧合水平变化.笔者综述了关于肾脏血氧水平依赖磁共振成像的基本原理与临床进展.     

血氧水平依赖磁共振成像技术在心血管疾病中的应用进展

传统的心脏磁共振检查需借助外源性对比剂才能评价心肌血供和代谢.血氧水平依赖磁共振成像技术(blood oxygen level dependent magnetic resonance,BOLD-MR)可不依赖对比剂,通过检测组织中脱氧血红蛋白水平高低即可反映局部血氧代谢情况.作为一种无创的功能磁共振成像技术,它在解释...     

血氧水平依赖功能磁共振成像在脑肿瘤诊治中的应用

血氧水平依赖功能磁共振成像(blood oxygen level dependent-functional magnetic resonance imaging,BOLD-fMRI)是功能磁共振成像技术的重要代表,其最大优势是能够显示大脑皮层功能区的活动,临床医师可通过该技术对脑肿瘤可能影响到的脑皮层功能区进行观察,这对于肿瘤治疗及预后评价均有极大帮助。本文就BOLD-fMRI在脑肿瘤中的应用展开综述。     

3.0T磁共振大鼠肾脏血氧水平依赖成像的初步研究

目的：评价用3．0TMR行大鼠肾脏功能成像的可行性，评价R2^＊值在观察者问和观察者内的可重复性。方法：12只健康雄性Wistar大鼠分别行肾脏T2WI及BOLD成像，两位医师分别对T2WI及BOLD图像按照5分法进行质量评价。在T2图像上由一位医师分别测量左右肾皮髓质信噪比。使用工作站进行BOLD图像重建，由两位医师分别独立测量肾皮髓质R2^＊值，其中一位医师2周后再次测量。然后对测量及评价结果进行统计学处理。结果：两观察者分别认为T2WI有91．7％（11／12）和83．3％（10／12）达到5分（Kappa值0．625，P=0．02）；BOLD图像两者判断分别有83．3％（10／12）和91．7％（11／12）达到4分及以上（Kappa值0．586，P=0．008）均达到测量要求。Bland—Altman分析显示观察者问和观察者自身测量皮髓质R2^＊值重复性较好，相关系数分别达到观察者问：0．96，0．98；观察者自身：0．97，0．98。R2^＊值的变异系数为皮质17．80％；髓质17．96％。结论：3．0TMR行大鼠肾脏BOLD成像所测数据在不同观察者问和同一观察者内的可重复性较好，能够用来进行肾脏功能成像的实验研究。     

肾脏血氧水平依赖磁共振成像的研究进展

肾脏的氧合状态在肾脏疾病的发生、发展中具有重要作用,近年来已引起了广泛关注。早期人们主要运用有创的微电极、缺氧探针等方法,在动物模型中获得肾脏内的缺氧情况;而血氧水平依赖磁共振成像(blood oxygenation leveldependent magnetic resonance imaging,BOLD-MRI)可利用内源性对比剂脱氧血红蛋白,无创地评价人体组织的氧代谢     

血氧水平依赖功能磁共振成像研究进展

血氧水平依赖功能磁共振成像（blood oxygenation level dependent-functional magnetic resonance imaging，BOLD-fMRI）是目前应用最广泛的脑功能成像方法，它使抽象的大脑活动得以用图像的方式显示。现就BOLD-fMRI的研究进展综述如下。     

磁共振扩散加权成像和血氧水平依赖脑功能成像在视路病变中的研究进展

视路是指从视网膜光感受器起,到大脑枕叶皮质视觉中枢为止的全部视觉神经冲动传递的路径,包括视网膜、视神经、视交叉、视束、视辐射、视皮质.由于视觉信号是通过神经纤维的传输和突触信号传递的,视路一部分出现问题可能会顺行性或逆行性影响其他神经功能.常规磁共振检查只能从形态学显示病变,不能探测微观结构的变化,神经眼科学检查也有一...     

磁共振成像技术在糖尿病肾脏疾病中的应用进展

糖尿病肾脏疾病是由糖尿病引起并对人体危害极大的慢性微血管并发症,存在着复杂的代谢紊乱,已成为导致终末期肾病的主要原因.早期发现、干预和治疗可以有效改善和延缓糖尿病肾脏疾病患者的肾功能损害.目前诊断糖尿病肾脏疾病的金标准是肾脏病理穿刺活检,但因其为有创检查,难以作为常规性检查方式.近年磁共振成像技术广泛应用于临床,在糖尿...     

3T magnetic resonance diffusion tensor imaging in chronic kidney disease

Objective

To investigate the relationship of apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values with renal function on 3T diffusion tensor imaging (DTI) in chronic kidney disease.

Materials and methods

Twenty healthy volunteers and 29 patients with CKD underwent DTI. The relationship among ADC, FA, and renal function was analyzed.

Results

Cortical and medullary ADC and FA values of patients with chronic kidney disease were lower than those of healthy volunteers (P = 0.000). Both the renal ADC and FA values correlated inversely with serum creatinine and blood urea nitrogen (P < 0.05).

Conclusion

DTI is a feasible and non-invasive means to reflect the severity of renal function damaged.     

烟雾病血氧水平依赖性功能磁共振成像研究进展

烟雾病患者脑内低灌注水平随着病程的不同而变化各异,临床医生常常需要根据患者的大脑灌注情况来制定相应的治疗策略。在临床工作中,评估大脑灌注状态的常用方法为CT灌注成像和磁共振灌注成像,但是这两种方法均存在诱发对比剂过敏的风险。近年来,随着以血氧水平依赖测量为原理的功能磁共振成像技术(blood oxygen level dependent-functional magnetic resonance imaging,BOLD-f MRI)的飞速发展,无创性研究烟雾病患者大脑灌注状态及神经重塑成为可能。本文通过综述BOLD-f MRI技术在烟雾病脑血管反应性方面的研究现状以及在无创性评估烟雾病血流延迟信息和神经重塑等方面的最新进展,为临床医生判断最佳手术时机以及评估临床预后提供一个崭新的视角。     

肾脏血氧水平依赖性成像研究进展

肾脏是机体保持内环境稳定、调节水和电解质平衡状态、排出体内代谢物的关键器官,肾实质氧合状态在其生理功能发挥、疾病发生发展中具有重要意义。血氧水平依赖性成像作为无创性评价肾内氧代谢功能技术,可实现生理研究从解剖展示向代谢、功能和分子水平迈进,对肾病诊断、鉴别与疗效评估发挥日益明显的作用,本文就近年血氧水平依赖磁共振成像对肾脏研究展开综述。     

Myocardial perfusion reserve assessed by t2-prepared steady-state free precession blood oxygen level-dependent magnetic resonance imaging in comparison to fractional flow reserve

Background- Blood oxygen level-dependent (BOLD) cardiac magnetic resonance imaging (CMR) has been shown to be able to detect myocardial perfusion differences. However, validation of BOLD CMR against fractional flow reserve (FFR) is lacking. The aim of our study was to analyze the potential diagnostic accuracy of BOLD CMR in comparison to invasively measured FFR, which served as gold standard for a hemodynamic significant coronary lesion. Methods and Results- BOLD image was performed at rest and during adenosine infusion in a 1.5-T CMR scanner. Thirty-six patients were analyzed for relative BOLD signal intensity increase according to the 16-segment model. Invasive FFR measurements were performed in the 3 major coronary arteries during adenosine infusion in all patients. An FFR≤0.8 was regarded to indicate a significant coronary lesion. Relative BOLD signal intensity increase was significantly lower in myocardial segments supplied by coronary arteries with an FFR≤0.8 compared with segments with an FFR>0.8 (1.1±0.2 versus 1.5±0.2; P<0.0001). Sensitivity and specificity yielded 88.2% and 89.5%, respectively. Conclusions- CMR BOLD imaging reliably detects hemodynamic significant coronary artery disease and is, thus, an alternative to contrast-enhanced perfusion studies.     

Assessment of cerebral hemodynamics and oxygen extraction using dynamic susceptibility contrast and spin echo blood oxygenation level-dependent magnetic resonance imaging: applications to carotid stenosis patients

Blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) has been recently used to quantify cerebral blood volume (CBV) and oxygen extraction ratio (OER). In the present study, we have exploited the intravascular BOLD model to assess gray matter (GM) OER at hemispheric level using parenchymal T(2) and CBV data at 1.5 T, obtained by single spin echo and dynamic susceptibility contrast (DSC) perfusion MRI, respectively. An OER of 0.40 +/- 0.07 was determined in gray matter for control subjects. A group of carotid stenosis (CS) patients (n = 22) was examined by multiparametric MRI. The degree of CS was determined by contrast agent-enhanced magnetic resonance angiography. Within the group, eight cases with <70% narrowing of a carotid lumen, nine cases with 70-99%, and five cases with complete occlusion of either carotid arteries were found. DSC MRI revealed abnormalities in 14 patients in dynamic parameters of perfusion images. These included four cases with elevated hemispheric gray matter CBV ipsilateral to the stenosis, above 2 SD of the level determined in control subjects. These four patients showed large variation in the degree of stenosis. We also found three cases with ipsilateral gray matter CBV below 2 SD of the control value, two of these with >70% stenosis. Gray matter OER ipsilateral to the stenosis was above 2 SD of the control range in eight CS patients, three of these showing also high CBV. Use of the present approach to determine OER for the assessment of hemodynamic adaptations in CS patients is discussed in the light of documented hemodynamic adaptations to carotid stenosis.     

Blood oxygen level-dependent MR imaging of the kidneys

Oxygenation status plays a major role in renal physiology and pathophysiology, and thus has attracted considerable attention in recent years. While much of the early work and a significant amount of present work is based on invasive methods or ex vivo analysis, and is therefore restricted to animal models, blood oxygen level-dependent (BOLD) MR imaging has been shown to extend these findings to human beings. BOLD MR imaging is most useful in monitoring effects of physiologic or pharmacologic maneuvers. Several teams around the world have demonstrated reproducible data and have illustrated several useful applications. Studies supporting the use of renal BOLD MR imaging in characterizing disease with prognostic value have also been reported. This article provides an overview of current state-of-the art of renal BOLD MR imaging.     

磁共振成像体积测量在阿尔茨海默病中的应用

阿尔茨海默病(Alzheimer's disease,AD)为最常见的老年性痴呆,占所有痴呆的60%～80%。我国初步流行病学调查结果表明,AD的患病率为1.75%～4.9%[1]。该病发病隐匿,且逐渐进展,临床上以失语、失用、失认、执行功能障碍等认知功能减退症状、社会生活功能减退症状和非认知性精神行为症状为主要表现。目前AD病因不明,临床诊断困难,确诊只能依靠尸检。AD患者生前诊断主要依赖临床检查结合神经心理学测试,由于缺乏客观的生物学标志,诊断准确率仅为74%～86%[2]。由于认知功能改变和脑功能异常在AD临床症状出现前许多年就出现了,只有早期诊断才能及早开始药物治疗。因此,如能有一种非侵入性的客观方法早期诊断该病将是很有应用价值的。