A demonstration of the resolution of NMR imaging in biological systems.

A proton NMR imaging study of several fruit specimens demonstrates the integrity and resolution of this new imaging method.     

Genetic studies of diseases

Functional imaging techniques such as positron and single-photon emission tomography exploit the relationship between neural activity, energy demand and cerebral blood flow to functionally map the brain. Despite the fact that neurobiological processes are not completely understood, several results have revealed the signals that trigger the metabolic and vascular changes accompanying variations in neural activity. Advances in this field have demonstrated that release of the major excitatory neurotransmitter glutamate initiates diverse signaling processes between neurons, astrocytes and blood perfusion, and that this signaling is crucial for the occurrence of brain imaging signals. Better understanding of the neural sites of energy consumption and the temporal correlation between energy demand, energy consumption and associated cerebrovascular hemodynamics gives novel insight into the potential of these imaging tools in the study of metabolic neurodegenerative disorders.     

家蚕体内不同部位的同步辐射成像分析

以五龄熟蚕为研究对象，对其体内不同部位进行同步辐射成像（包括同轴位相衬度成像和显微断层成像）。研究结果表明，蚕体内中部丝腺的直径范围在3．74～4．21mm之间，其始端距离蚕头部约18mm。而吐丝管则被发现于距离蚕头部顶端1．43mm处，且直径相对较细，范围在7～52μm之间。     

In vivo imaging of therapy-induced anti-cancer immune responses in humans

Immunotherapy aims to re-engage and revitalize the immune system in the fight against cancer. Research over the past decades has shown that the relationship between the immune system and human cancer is complex, highly dynamic, and variable between individuals. Considering the complexity, enormous effort and costs involved in optimizing immunotherapeutic approaches, clinically applicable tools to monitor therapy-induced immune responses in vivo are most warranted. However, the development of such tools is complicated by the fact that a developing immune response encompasses several body compartments, e.g., peripheral tissues, lymph nodes, lymphatic and vascular systems, as well as the tumor site itself. Moreover, the cells that comprise the immune system are not static but constantly circulate through the vascular and lymphatic system. Molecular imaging is considered the favorite candidate to fulfill this task. The progress in imaging technologies and modalities has provided a versatile toolbox to address these issues. This review focuses on the detection of therapy-induced anticancer immune responses in vivo and provides a comprehensive overview of clinically available imaging techniques as well as perspectives on future developments. In the discussion, we will focus on issues that specifically relate to imaging of the immune system and we will discuss the strengths and limitations of the current clinical imaging techniques. The last section provides future directions that we envision to be crucial for further development.     

Prospects for NMR imaging in the study of biological morphogenesis

Small objects can be visualised with a spatial resolution that approaches microscopic dimensions using the technique of high resolution nuclear magnetic resonance (NMR) imaging. Some important features of the method are described and the prospects for using the technique to study morphogenesis are discussed. It is concluded that NMR imaging, in conjunction with the related method of localised spectroscopy, is capable of producing novel structural information.     

Prospects for NMR imaging in the study of biological morphogenesis

Summary Small objects can be visualised with a spatial resolution that approaches microscopic dimensions using the technique of high resolution nuclear magnetic resonance (NMR) imaging. Some important features of the method are described and the prospects for using the technique to study morphogenesis are discussed. It is concluded that NMR imaging, in conjunction with the related method of localised spectroscopy, is capable of producing novel structural information.     

基于压缩感知的多角度合成孔径雷达成像

多角度合成孔径雷达（syntheticapertureradar,SAR）成像是实现多SAR信息融合的重要方式．对提高成像分辨率．重构目标轮廓进而提高雷达目标检测或分类性能具有基础性价值．由于各传感器发射信号和测量位置的多样性,实现多角度SAR成像具有挑战性．如何在噪声干扰情况下快速实现多角度SAR成像是一个新问题．本文建立了基于压缩感知的多角度SAR测量模型．通过对测量矩阵的分析,证明多角度SAR测量角度范围、发射信号载频和空间采样位置是影响成像性能的关键因素,研究了目标空间离散间隔对成像质量和分辨率的影响．以上述分析为基础,本文对多角度SAR发射信号载频和测量位置进行设计,构建满足约束等距性的测量矩阵．针对测量矩阵阶次较高的问题,文章提出用分段正交匹配追踪（stagewiseorthogonalmatchingpursuit,STOMP）进行模型求解,在测量矩阵欠定严重的情况下,该算法可以迅速求得模型最优稀疏解．在实验环节．通过分析多角度SAR参数对成像性能的影响,进一步验证了本文结论．实验验证了模型和相应求解算法的有效性和鲁棒性．     

基于光学衍射的纳米尺度深度重建

传统的离焦深度恢复方法（depth from defocus,DFD）在计算离焦图像的模糊程度时,均是基于几何光学成像原理,并没有考虑光波衍射对图像模糊的影响.然而,衍射现象是波的基本特性,以针孔成像为基础的光学成像系统中必然存在光波衍射.本文基于光学衍射和图像模糊机理,提出了一种精确的单目视觉全局景物3D深度信息获取方法.首先,详细分析了光学成像系统中的菲涅耳衍射机理,建立了衍射模糊与景物深度之间的关系曲线;然后,采用曲线拟合的方式建立了衍射模糊的模糊程度（点扩散函数扩散程度）与景物深度的数学关系模型,结合热辐射和图像相对模糊原理,构建了衍射模糊热辐射方程组,并把衍射模糊深度获取问题转换成一个深度信息动态优化问题.最后,使用标准的纳米栅格模板验证了衍射模糊深度重建算法在纳米尺度相对深度和绝对深度重建中的有效性和精确性.     

Visualizing odor representation in the brain: a review of imaging techniques for the mapping of sensory activity in the olfactory glomeruli

The brain transforms clues from the external world, the sensory stimuli, into activities in neuroglial networks. These circuits are activated in specialized sensory cortices where specific functional modules are responsible for the spatiotemporal coding of the stimulus. A major challenge in the neuroscience field has been to image the spatial distribution and follow the temporal dynamics of the activation of such large populations in vivo. Functional imaging techniques developed in the last 30 years have enabled researchers to solve this critical issue, and are reviewed here. These techniques utilize sources of contrast of radioisotopic, magnetic and optical origins and exploit two major families of signals to image sensory activity: the first class uses sources linked to cellular energy metabolism and hemodynamics, while the second involves exogenous indicators of neuronal activity. The whole panel of imaging techniques has fostered the functional exploration of the olfactory bulb which is one of the most studied sensory structures. We summarize the major results obtained using these techniques that describe the spatial and temporal activity patterns in the olfactory glomeruli, the first relay of olfactory information processing in the main olfactory bulb. We conclude this review by describing promising technical developments in optical imaging and future directions in the study of olfactory spatiotemporal coding.     

基于压缩感知的宽孔径SAR成像

宽孔径SAR数据包含目标不同姿态角散射信息,实现宽孔径SAR成像对目标轮廓重构与解译识别具有重要价值.本文首先提出点模糊函数(point ambiguous function,PAF)研究影响压缩感知SAR成像的因素,然后用模型失配函数(model mismatch fucntion,MMF)分析宽孔径测量条件下点散射模型失配对成像性能的影响.最后根据上述结论,选择发射信号参数改善测量矩阵性能,利用广义似然比检验方法克服模型失配对成像性能的影响.实验结果验证了本文结论的正确性和成像算法的有效性.     

Dynamics of the nuclear envelope at mitosis and during apoptosis

The nuclear envelope is a highly dynamic structure that reversibly disassembles and reforms at mitosis. The nuclear envelope also breaks down--irreversibly--during apoptosis, a process essential for development and tissue homeostasis. Analyses of fixed cells, time-lapse, imaging studies of live cells and the development of powerful cell-free extracts derived from gametes or mammalian somatic cells have provided insights on the fate of nuclear envelope proteins during mitosis and apoptosis, and on the mechanisms behind nuclear envelope modifications in these processes. In this review, we discuss evidence leading to our understanding of the dynamics of the nuclear envelope alterations at mitosis and during apoptosis. We also present novel imaging and genetic approaches to the study of nuclear envelope dynamics and function.     

稀疏化的压缩传感超声图像重构特性研究

传统医学超声成像射频信息存储数据量大,传输耗时且成本高.基于稀疏化的压缩传感技术,研究超声图像的稀疏特性,利用离散余弦变换(DCT)对原始超声图像进行稀疏变换,在稀疏域内进行压缩采样获得降采样数据,然后通过求解L1范数重构原始图像.理论和实验表明,该方法可以很好地应用到超声图像的重构中,且随着稀疏度的减小和测量值的增加,重构图像的峰值信噪比(PSNR值)增加,重构图像的视觉效果较好.     

3.0T磁敏感加权成像在颅内胶质瘤中的应用价值

目的探讨3.0 T磁敏感加权成像在颅内胶质瘤诊断中的应用价值.方法经手术病理证实的20例高级别胶质瘤和12例低级别胶质瘤,均行MRI扫描和SWI,15例(10例高级别胶质瘤和5例低级别胶质瘤)于增强前后行SWI.将SWI与常规T1 FLAIR、T1 FLAIR增强图像作比较,并对SWI瘤内低信号形态及数量进行分级评分....     

New imaging probes to track cell fate: reporter genes in stem cell research

Cell fate is a concept used to describe the differentiation and development of a cell in its organismal context over time. It is important in the field of regenerative medicine, where stem cell therapy holds much promise but is limited by our ability to assess its efficacy, which is mainly due to the inability to monitor what happens to the cells upon engraftment to the damaged tissue. Currently, several imaging modalities can be used to track cells in the clinical setting; however, they do not satisfy many of the criteria necessary to accurately assess several aspects of cell fate. In recent years, reporter genes have become a popular option for tracking transplanted cells, via various imaging modalities in small mammalian animal models. This review article examines the reporter gene strategies used in imaging modalities such as MRI, SPECT/PET, Optoacoustic and Bioluminescence Imaging. Strengths and limitations of the use of reporter genes in each modality are discussed.     

One century of diagnostic imaging in medicine

The historical outline shows the development of radiologic diagnostics from the early Roentgen days up to this centenary. The roots of radiologic diagnostics go back to the European Renaissance. It is a history of medical pattern recognition and functional analysis by several methods including X-rays, ultrasound waves or strong magnetic fields. The difference between conventional radiographs and a picture reconstructed after digitalization, with several possibilities of postprocessing, is explained. Research and further technical revolutions, like the development of semiconductor elements and computers or tailored contrast media, sophisticated pictorial representations and perceptions, are among the cornerstones of imaging diagnostics. During this century many diseases have changed their manifestation and spread. This is illustrated by tuberculosis and cancer and highlights the growing importance of imaging diagnostics and interventional radiology. The thorny path to independence of radiology is also a history of the medical establishment's resistance.     

Labeling of endotoxin lipopolysaccharide with technetium-99m pertechnetate

Summry Bacterial endotoxin treated with technetium-99m can be visualized in living animals by gamma camera imaging.This work was supported in part by grant No. M4 305105-3100 from the Naval Research and Development Command.     

Magnetic resonance microscopy: in vivo sectioning of a developing insect

The utility of magnetic resonance imaging vis-a-vis insect morphology and development was investigated. MRI is a noninvasive technique that distinguishes between tissues based on proton content and proton 'environment'. At present a resolution of 100 micron is achievable. The technique avoids fixation artifacts and allows the detection of motion within the organism.     

光致发光稀土有机配合物在生物分析上的应用

稀土有机配合物因镧系元素独特的电子结构而成为一类具有重要理论和应用价值的发光材料.本文综述了稀土有机配合物的类型及其光致发光的基本原理,阐述了稀土有机配合物光致发光在生物分析方面的应用,并在荧光免疫分析及活细胞成像方面提出了良好的展望.     

Velocity gradient and contraction frequency of the pyeloureteral system.

An optical detection method, using video imaging, is used to quantitatively record the frequency and velocity profile of the renal pelvis of the rabbit. It is demonstrated that concentric waves originating at the periphery of the pelvis have an initial velocity of 3.2 cm/sec, accelerating toward the pelviureteral junction reaching a final velocity of 6.4 cm/sec.     

Systems microscopy approaches to understand cancer cell migration and metastasis

Cell migration is essential in a number of processes, including wound healing, angiogenesis and cancer metastasis. Especially, invasion of cancer cells in the surrounding tissue is a crucial step that requires increased cell motility. Cell migration is a well-orchestrated process that involves the continuous formation and disassembly of matrix adhesions. Those structural anchor points interact with the extra-cellular matrix and also participate in adhesion-dependent signalling. Although these processes are essential for cancer metastasis, little is known about the molecular mechanisms that regulate adhesion dynamics during tumour cell migration. In this review, we provide an overview of recent advanced imaging strategies together with quantitative image analysis that can be implemented to understand the dynamics of matrix adhesions and its molecular components in relation to tumour cell migration. This dynamic cell imaging together with multiparametric image analysis will help in understanding the molecular mechanisms that define cancer cell migration.