扩散成像技术在周围神经病变的应用进展

磁共振技术的发展和周围神经损伤机制研究的深入,提高了临床上对周围神经病变诊断的准确性.随着磁共振扩散加权成像、扩散张量成像及扩散张量示踪成像的临床应用,磁共振神经成像已经成为显示周围神经及其病变的客观、无创、无辐射、简便的成像方法.本文就最近几年磁共振扩散成像技术在周围神经疾病的应用进展予以综述.     

MRI扩散成像技术在阿尔兹海默病研究中的应用进展

【摘要】阿尔兹海默病(AD)是以进行性认知功能障碍和记忆损害为特征的神经系统退行性疾病,最常见于中老年人,其病因机制尚不十分明确。近年来随着MRI技术的不断发展,扩散成像在AD的早期诊断、鉴别诊断、治疗监测等方面起着重要作用,其中包括了扩散张量成像、神经突方向分散度和密度成像、扩散峰度成像、自由水扩散成像等技术。     

DTI在大脑髓质发育研究中的应用

脑白质纤维与大脑的发育和多种神经、精神疾病密切相关,磁共振扩散张量成像(DTI)作为一种无创性显示活体脑白质微观变化的MRI技术,被广泛地应用于脑白质发育及其相关疾病的研究。就其原理及在脑白质发育和临床应用方面的研究成果予以综述。     

前列腺癌的扩散成像研究新进展

近年来扩散成像已不再局限于神经、乳腺等组织的研究,前列腺癌(PCa)扩散成像的研究愈趋广泛,包括扩散加权成像(DWI)及扩散张量成像(DTI),其能够从分子水平对PCa无创性成像,为诊断提供了极大的帮助。就PCa扩散成像技术、临床诊疗、联合其他功能磁共振成像等方面的最新进展进行综述。     

磁共振扩散峰度成像在腹部肿瘤中的应用进展

【摘要】扩散峰度成像（DKI）是一种基于生物组织内水分子非高斯分布扩散运动状态的MRI新技术,是DWI、DTI技术的延伸,能够更加准确、真实地反映生物组织微观结构的微细变化。目前,DKI技术在中枢神经系统疾病（如脑肿瘤、脑梗死、神经变性疾病等）的应用较为广泛。近年来,该技术开始应用于腹部脏器（肝脏、肾脏、前列腺等）,并取得了一定的成果。该文对DKI的原理进行了介绍,并且对DKI在腹部肿瘤的应用进展进行综述。     

正常臂丛神经MRI技术:DWIBS与STIR-EPI的比较

目的 探讨MR背景信号抑制扩散加权成像(DWIBS)序列及短恢复时间反转恢复回波平面成像(STIR-EPI)序列对臂丛神经成像的可行性.资料与方法 利用3.0 T磁共振仪对27名自愿者行臂丛神经MRI,采用DWIBS及STIR-EPI序列.结果 在DWIBS及STIR-EPI图像上臂丛神经根、神经节、锁骨上神经及锁骨下神经均呈高信号;DWIBS对锁骨下神经显示效果较好,而STIR-EPI对于臂丛神经根显示较好,两者对于神经节及锁骨上神经都能很好显示.结论 结合两种序列能够准确显示臂丛神经解剖形态,对于臂丛神经病变的诊断和治疗可提供一定的帮助.     

扩散张量成像在神经系统疾病中的研究与应用

扩散张量成像以其特有的观察参数和指标,在神经系统生理功能和多种疾病的影像诊断和研究中得以广泛应用。本文综述了其在神经生理、脑梗死、脑肿瘤、多种脑组织变性性疾病、颞叶癫痫和血管性病变中的临床研究和实验进展情况。提出扩散张量成像的广泛应用必将引导对神经系统疾病的更准确的认识。     

慢性炎性脱髓鞘性多发性神经根神经病的 MRI研究进展

慢性炎性脱髓鞘性多发性神经根神经病（CIDP）是一类严重的免疫介导的周围神经病,累及范围广、病程复杂、临床表现多样。磁共振神经成像（MRN）在CIDP的诊断方面具有独特优势,可以从形态及功能学方面直接显示及评估周围神经病变。目前研究热点多集中于T2加权抑脂成像及基于扩散的MR成像。就CIDP的MRI研究进展做一综述。     

扩散张量成像在周围神经变性及再生中的研究进展

周围神经损伤后,其远端轴突和髓鞘发生沃勒变性,如何评估轴索再生、残端修复和神经支配区功能重建是临床研究的难题。目前,临床上主要通过神经电生理检查判断神经损伤程度,但对评估神经完全损伤及近端病变缺乏敏感性及特异性。MR扩散张量成像(DTI)能够无创性定量评估周围神经变性及再生过程,联合扩散张量纤维示踪技术(DTT)可追踪神经纤维束的方向、排列、髓鞘脱失等信息。就DTI技术评估周围神经损伤变性及再生的研究进展予以综述。     

脑的磁共振扩散张量成像及其临床应用

与传统扩散加权MR不同,扩散张量成像(DTI)可以采集6个或更多方向上的水分子的扩散情况,因此能更准确地显示脑白质水分子的各向异性扩散.它是目前惟一能够无创地显示活体白质纤维束的方法,为评价白质纤维束间的联系及其病变开拓了新的前景.从DTI的技术原理以及临床应用方面介绍其应用现状.     

Diffusion weighted imaging: Technique and applications

Diffusion weighted imaging (DWI) is a method of signal contrast generation based on the differences in Brownian motion. DWI is a method to evaluate the molecular function and micro-architecture of the human body. DWI signal contrast can be quantified by apparent diffusion coefficient maps and it acts as a tool for treatment response evaluation and assessment of disease progression. Ability to detect and quantify the anisotropy of diffusion leads to a new paradigm called diffusion tensor imaging (DTI). DTI is a tool for assessment of the organs with highly organised fibre structure. DWI forms an integral part of modern state-of-art magnetic resonance imaging and is indispensable in neuroimaging and oncology. DWI is a field that has been undergoing rapid technical evolution and its applications are increasing every day. This review article provides insights in to the evolution of DWI as a new imaging paradigm and provides a summary of current role of DWI in various disease processes.     

面神经MR成像技术及临床应用

面神经直径小,走行迂曲,难以完整显示。MRI具有高分辨力,对显示面神经及其病变具有重要作用。各种新序列的开发和应用提高了面神经MRI显示率。面神经功能障碍将导致面部肌肉瘫痪,严重影响病人的生活质量和容貌。面神经MR成像有助于明确面瘫原因、显示周围病变与面神经的关系,对术前评估、术中保护面神经具有重要临床应用价值。就近年来对面神经MR成像技术及其临床应用的研究予以综述。     

Diffusion Tensor Imaging: Exploring the Motor Networks and Clinical Applications

With the advances in diffusion magnetic resonance (MR) imaging techniques, diffusion tensor imaging (DTI) has been applied to a number of neurological conditions because DTI can demonstrate microstructures of the brain that are not assessable with conventional MR imaging. Tractography based on DTI offers gross visualization of the white matter fiber architecture in the human brain in vivo. Degradation of restrictive barriers and disruption of the cytoarchitecture result in changes in the diffusion of water molecules in various pathological conditions, and these conditions can also be assessed with DTI. Yet many factors may influence the ability to apply DTI clinically, so these techniques have to be used with a cautious hand.     

Various diffusion magnetic resonance imaging techniques for pancreatic cancer

Pancreatic cancer is one of the most common malignant tumors and remains a treatment-refractory cancer with a poor prognosis. Currently, the diagnosis of pancreatic neoplasm depends mainly on imaging and which methods are conducive to detecting small lesions. Compared to the other techniques, magnetic resonance imaging (MRI) has irreplaceable advantages and can provide valuable information unattainable with other noninvasive or minimally invasive imaging techniques. Advances in MR hardware and pulse sequence design have particularly improved the quality and robustness of MRI of the pancreas. Diffusion MR imaging serves as one of the common functional MRI techniques and is the only technique that can be used to reflect the diffusion movement of water molecules in vivo. It is generally known that diffusion properties depend on the characterization of intrinsic features of tissue microdynamics and microstructure. With the improvement of the diffusion models, diffusion MR imaging techniques are increasingly varied, from the simplest and most commonly used technique to the more complex. In this review, the various diffusion MRI techniques for pancreatic cancer are discussed, including conventional diffusion weighted imaging (DWI), multi-b DWI based on intra-voxel incoherent motion theory, diffusion tensor imaging and diffusion kurtosis imaging. The principles, main parameters, advantages and limitations of these techniques, as well as future directions for pancreatic diffusion imaging are also discussed.     

肌萎缩侧索硬化症MRI研究进展

肌萎缩侧索硬化(ALS)是一种以上、下运动神经元受累为主要特征的慢性进行性神经系统变性性疾病。下运动神经元功能障碍可经肌电图和肌肉活检证实,而上运动神经元受累尤其在早期难以检测。常规MRI和功能MRI技术如扩散张量成像（DTI）、磁共振波谱（MRS）和静息态功能MRI（rs-fMRI）等,可以检测ALS 运动区及非运动区变化,对疾病的早期诊断和监测有一定作用。就MRI技术及其在ALS中的应用进行综述。     

多模态MRI在颈椎间盘源性疼痛的研究进展

颈椎病是一种多病因、症状复杂的临床综合征,其中颈椎间盘退变是其重要病因之一。多模态MRI技术能够准确评估病人颈椎间盘形态和信号异常以及继发性脊髓和大脑结构与功能的细微改变,为深入理解颈椎间盘源性疼痛的发病机制及疗效评估提供重要影像学依据。就多模态MRI技术(常规MRI、基于体素的形态学分析、功能MRI、扩散张量成像、磁共振波谱等)对颈椎间盘源性疼痛的研究现状和进展予以综述。     

Diffusion-weighted and diffusion-tensor imaging of normal and diseased uterus

Owing to technical advances and improvement of the software, diffusion weighted imaging and diffusion tensor imaging (DWI and DTI) greatly improved the diagnostic value of magnetic resonance imaging (MRI) of the pelvic region. These imaging sequences can exhibit important tissue contrast on the basis of random diffusion (Brownian motion) of water molecules in tissues. Quantitative measurements can be done with DWI and DTI by apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values respectively. ADC and FA values may be changed by various physiological and pathological conditions providing additional information to conventional MRI. The quantitative DWI assists significantly in the differentiation of benign and malignant lesions. It can demonstrate the microstructural architecture and celluler density of the normal and diseased uterine zones. On the other hand, DWI and DTI are useful for monitoring the treatment outcome of the uterine lesions. In this review, we discussed advantages of DWI and DTI of the normal and diseased uterus.     

Evaluation of optimized b-value sampling schemas for diffusion kurtosis imaging with an application to stroke patient data

Diffusion kurtosis imaging (DKI) is a new method of magnetic resonance imaging (MRI) that provides non-Gaussian information that is not available in conventional diffusion tensor imaging (DTI). DKI requires data acquisition at multiple b-values for parameter estimation; this process is usually time-consuming. Therefore, fewer b-values are preferable to expedite acquisition. In this study, we carefully evaluated various acquisition schemas using different numbers and combinations of b-values. Acquisition schemas that sampled b-values that were distributed to two ends were optimized. Compared to conventional schemas using equally spaced b-values (ESB), optimized schemas require fewer b-values to minimize fitting errors in parameter estimation and may thus significantly reduce scanning time. Following a ranked list of optimized schemas resulted from the evaluation, we recommend the 3b schema based on its estimation accuracy and time efficiency, which needs data from only 3 b-values at 0, around 800 and around 2600 s/mm², respectively. Analyses using voxel-based analysis (VBA) and region-of-interest (ROI) analysis with human DKI datasets support the use of the optimized 3b (0, 1000, 2500 s/mm²) DKI schema in practical clinical applications.     

同时多层成像技术联合肝脏MR扩散成像的应用及展望

同时多层（SMS）成像技术与多种MRI序列联合应用可明显缩短成像时间。MR扩散成像,如常规扩散加权成像（DWI）、体素内不相干运动成像（IVIM）、扩散张量成像（DTI）和扩散峰度成像（DKI）能反映组织内水分子扩散、血流灌注、组织结构复杂性等微观特征,在肝脏病变检测和辅助定性中有重要价值。SMS与MR扩散成像联合后可明显缩短成像时间,利于各种MR扩散成像在肝脏中的广泛应用。综述SMS对肝脏扩散成像扫描速度的提升效率、对影像质量和定量参数的影响,以期推动SMS成像技术在临床中的广泛应用。