磁共振扩散加权成像在乳腺肿瘤中的临床应用

磁共振扩散加权成像（MRdiffusion-weightedimaging,DWI）依赖病理过程中水分子在不同环境中运动差异而成像,DWI成像速度快（平均时间-200s）、无创、没有电离辐射、不需要注射对比剂等优点使其成为乳腺肿瘤方面应用最广的一种功能成像,目前,DWI在应用中存在着诸多限制因素,如场强、b值、诊断的差异等。本文就DWI成像原理及目前在乳腺良恶性病变诊断中的临床应用进行综述。     

磁共振扩散加权成像在大肠癌中的诊断应用

磁共振扩散加权成像（DWI）是利用水分子扩散运动特性成像的新技术。它对人体的研究深入到细胞水平，反映着人体组织的微观结构和细胞内外水分子的转运等变化。随着MRI技术的发展，DWI在大肠肿瘤的应用逐渐引起人们的关注，就DWI的基本原理及在大肠癌诊断中的应用现状予以综述。     

磁共振DWI在肝癌中的应用

磁共振扩散加权成像（diffusion weighted magnetic resonance imaging,DWI）是目前唯一无创反映活体组织扩散的检查方法,在神经系统DWI作为MRI功能成像新技术,是唯一能在活体检测组织内水分子扩散运动的无创影像检查技术,能在宏观成像中反映活体组织中水分子微观扩散运动。以往DWI主要集中应用于神经放射学领域并且显示出巨大的临床应用价值。随着快速成像技术的迅速发展,DWI已逐步应用到全身其它系统和器官的疾病研究,并开始大量应用于肿瘤疾病,如肿瘤的分期、判断、鉴别诊断和预测肿瘤疗效等,本文着重对其在肝癌中的应用做简单总结。     

磁共振扩散加权成像在大肠癌中的诊断应用

磁共振扩散加权成像(DWI)是利用水分子扩散运动特性成像的新技术.它对人体的研究深入到细胞水平,反映着人体组织的微观结构和细胞内外水分子的转运等变化.随着MRI技术的发展,DWI在大肠肿瘤的应用逐渐引起人们的关注,就DWI的基本原理及在大肠癌诊断中的应用现状予以综述.     

DWI技术在肝外胆管细胞癌诊断、分期和 疗效评估中的研究进展

肝外胆管细胞癌（EHCC）是第二大原发性肝胆系统肿瘤,其恶性程度高,预后不良。扩散加权成像（DWI）是反映组织水分子扩散运动的常用无创性成像方法。近年来,DWI及体素内不相干运动（IVIM）、扩散张量成像（DTI）及扩散峰度成像（DKI）等衍生技术已广泛应用于EHCC的诊断、病理分期预测和监测以及疗效评估。就DWI及其衍生序列对EHCC应用的研究进展以及局限性和应用前景予以综述。     

颅内囊性病变的DWI信号形成机制和病理学基础

颅内囊性病变种类多样,其病理性质各异,在常规MRI上,部分病变表现类似,使得鉴别诊断困难。磁共振扩散加权成像(DWI)是一种新的功能成像方法,其通过检测活体组织中水分子的扩散运动,揭示病变的病理生理学特征,为此类病变的诊断提供了新的依据。DWI对颅内囊性病变(如囊肿、脓肿及囊性肿瘤等)具有较高的诊断及鉴别诊断价值。对颅内各类囊性病变的DWI信号特点及其影响因素、相关机制进行综述。     

颅内囊性病变的DWI信号形成机制和病理学基础

颅内囊性病变种类多样,其病理性质各异,在常规MRI上,部分病变表现类似,使得鉴别诊断困难.磁共振扩散加权成像(DWI)是一种新的功能成像方法,其通过检测活体组织中水分子的扩散运动,揭示病变的病理生理学特征,为此类病变的诊断提供了新的依据.DWI对颅内囊性病变(如囊肿、脓肿及囊性肿瘤等)具有较高的诊断及鉴别诊断价值.对颅内各类囊性病变的DWI信号特点及其影响因素、相关机制进行综述.     

DWI技术在中枢神经系统中的应用及研究进展

【摘要】扩散加权成像（DWI）是一种通过检测水分子微观运动反映组织结构的影像技术,主要用于中枢神经系统疾病的诊断。近年来,DWI新技术不断出现,如体素内不相干运动成像（IVIM）、水通道蛋白（AQP）、扩散频谱成像 (DSI）及扩散峰度成像（DKI）等,为中枢神经系统疾病的诊断提供了新的认识。本文对DWI新技术在中枢神经系统中的应用进展进行综述。     

磁共振扩散加权成像在子宫肿瘤诊断中的应用

扩散加权成像(diffusion-weighted imaging, DWI)通过不同组织间的水分子扩散差异所造成的图像信号衰减来反映组织的结构特性,是目前唯一能观察活体组织内水分子扩散运动的无创性成像方法,已广泛应用于神经系统方面的诊断。随着磁共振软硬件技术的进一步开发,尤其是平面回波成像(echo planar imaging,EPI)技术的成熟及完善、多通道线圈及并行采集等新技术的出现,使得 DWI 的应用范围逐步扩展到盆腹部,利用表观扩散系数(apparent diffusion co-efficient,ADC)值可以较客观地量化病变组织中水分子扩散运动的变化程度[1]。研究表明利用 DWI 图像和 ADC 值可用于妇科肿瘤的诊断以及分期和疗效的判定。现结合相关文献,对 DWI 在子宫肿瘤诊断中的应用综述如下。     

扩散加权成像在卵巢肿瘤中的应用

扩散加权成像(DWI)是目前唯一能够检测生物组织内水分子扩散运动的无创方法 ,该种扩散运动可以通过表观扩散系数(ADC)来量化分析。扩散峰度成像(DKI)、体素内不相干运动(IVIM)成像、背景抑制扩散加权全身成像(DWIBS)等DWI新技术用于卵巢肿瘤的评估提高了卵巢肿瘤影像诊断的准确性。综述DWI及其新技术在卵巢肿瘤定性诊断、分期、疗效评估、预后判断中的作用及其潜在缺陷。     

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.     

Diffusion-weighted imaging of pancreatic cancer

Magnetic resonance imaging (MRI) is a reliable and accurate imaging method for the evaluation of patients with pancreatic ductal adenocarcinoma (PDAC). Diffusion-weighted imaging (DWI) is a relatively recent technological improvement that expanded MRI capabilities, having brought functional aspects into conventional morphologic MRI evaluation. DWI can depict the random diffusion of water molecules within tissues (the so-called Brownian motions). Modifications of water diffusion induced by different factors acting on the extracellular and intracellular spaces, as increased cell density, edema, fibrosis, or altered functionality of cell membranes, can be detected using this MR sequence. The intravoxel incoherent motion (IVIM) model is an advanced DWI technique that consent a separate quantitative evaluation of all the microscopic random motions that contribute to DWI, which are essentially represented by molecular diffusion and blood microcirculation (perfusion). Technological improvements have made possible the routine use of DWI during abdominal MRI study. Several authors have reported that the addition of DWI sequence can be of value for the evaluation of patients with PDAC, especially improving the staging; nevertheless, it is still unclear whether and how DWI could be helpful for identification, characterization, prognostic stratification and follow-up during treatment. The aim of this paper is to review up-to-date literature data regarding the applications of DWI and IVIM to PDACs.     

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.     

肿瘤相关扩散加权成像模型在乳腺癌预后因素预测中的研究进展

乳腺癌的进展、治疗疗效及预后受多种预后因素的影响。扩散加权成像（DWI）无创,且能够定量显示组织水分子扩散受限情况,尤其随着多种DWI数学模型的提出,可以更准确地描述体内水分子的真实扩散情况,因此在乳腺癌分子生物标志物表达状态、分子分型、组织学分级及淋巴结状态等相关预后因素的预测中有重要应用价值。就不同肿瘤相关DWI模型在乳腺癌多种预后因素预测中的研究进展予以综述。     

乳腺磁共振扩散加权成像的应用

目的：探讨乳腺磁共振扩散加权成像（DWI）检查的可行性,并重点探讨影响DWI图像质量的技术参数。方法：使用GE1．5T磁共振扫描仪及阵列线圈对32例乳腺疾病患者行常规SE序列扫描,其中19例为良性肿瘤,5例炎性病变,6例恶性肿瘤．均经手术及病理证实;另硅胶置入2例。使用体线圈行DWI序列扫描,采用全方位扩散梯度及5个b值扫描。DWI总的扫描时间40s。结果：在DWI序列扫描中,良性和恶性肿瘤均为高信号,计算ADC值可鉴别良性和恶性肿瘤．通过各种扫描参数的合理匹配,可使图像质量的信噪比达到最佳,并减少图像的几何变形。结论：DWI对于检查乳腺病变是一种快速可行并行之有效的技术。     

扩散峰度成像在肝脏疾病中的应用进展

扩散峰度成像(DKI)序列作为扩散加权成像(DWI)的衍生序列能够显示复杂组织中水分子扩散受限程度,反映组织微观结构信息。其在肝脏主要应用于肝功能储备和肝脏纤维化程度评估、肝内良恶性肿块病变鉴别、及对肝癌经动脉化学栓塞术后复发评估等。就DKI的基本原理、主要技术参数及在肝脏疾病诊断和疗效评估中的研究进展予以综述。     

Benign neck masses showing restricted diffusion: Is there a histological basis for discordant behavior?

Diffusion weighted imaging (DWI) evolved as a complementary tool to morphologic imaging by offering additional functional information about lesions. Although the technique utilizes movement of water molecules to characterize biological tissues in terms of their cellularity, there are other factors related to the histological constitution of lesions which can have a significant bearing on DWI. Benign lesions with atypical histology including presence of lymphoid stroma, inherently increased cellularity or abundant extracellular collagen can impede movement of water molecules similar to malignant tissues and thereby, show restricted diffusion. Knowledge of these atypical entities while interpreting DWI in clinical practice can avoid potential misdiagnosis. This review aims to present an imaging spectrum of such benign neck masses which, owing to their distinct histology, can show discordant behavior on DWI.     

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.