高光谱成像技术在生物医学中的应用

高光谱成像技术是传统成像与光谱技术相结合的一门新技术,其可同时获得被测物体的空间特征与光谱信息,以实现对物质特性的研究。本文介绍了高光谱成像技术的基本原理、系统的基本构成及特点,总结和阐述了近年来高光谱成像技术在生物医学领域的发展,以及其在疾病诊断中的应用。     

超声技术鉴别子宫肌瘤和子宫腺肌病

子宫肌瘤和腺肌病的准确鉴别在妇科临床诊治中有十分重要的意义,各种鉴别诊断技术中,超声技术因其无损性、简便性而成为常规的一种方法。超声成像技术是其中较为成熟的方法。在综述B型成像、彩色血流成像结合脉冲多普勒、彩色血流功率成像和三维彩色功率成像等四种超声成像技术鉴别子宫肌瘤和子宫腺肌病情况的基础上,介绍了两种新的超声鉴别方法：超声弹性检测技术、基于其他声学特征参数检测的组织定征技术。     

Imaging practices and radiation doses from imaging in radiotherapy

Modern radiotherapy treatments require frequent imaging for accurate patient positioning relative to the therapeutic radiation beam. Imaging practices in five Finnish radiotherapy clinics were assessed and discussed from the patient dose optimization point of view. The results show that imaging strategies are not jointly established and variations exist. The organ absorbed doses depend on imaging technique and imaging frequency. In particular, organ doses from the cone beam computed tomography can have very large variations (a factor of 10–50 in breast imaging and factor of 5 in prostate imaging). The cumulative imaging organ dose from the treatment can vary by a factor of ten or more for the same treatment, depending on the chosen technique and imaging frequency. Awareness and optimization of the imaging dose in image-guided radiotherapy should be strengthened.     

Approaching MALDI molecular imaging for clinical proteomic research: current state and fields of application

MALDI imaging mass spectrometry (‘MALDI imaging’) is an increasingly recognized technique for biomarker research. After years of method development in the scientific community, the technique is now increasingly applied in clinical research. In this article, we discuss the use of MALDI imaging in clinical proteomics and put it in context with classical proteomics techniques. We also highlight a number of upcoming challenges for personalized medicine, development of targeted therapies and diagnostic molecular pathology where MALDI imaging could help.     

Photon counting imaging: applications in biomedical research

Photon counting imaging, a technique capable of imaging at the single photon level, is finding applications in biological research and is providing unprecedented views of ultra-low light level phenomena. In combination with the optical microscope, this technique has provided a means of directly visualizing gene expression in single cells, imaging metabolites in tumor tissue and visualizing the chemiluminescence associated with oxidative metabolism in phagocytic cells. At the macroscopic level, it has greatly extended the sensitivity of detection in protein blots and has been applied as an image luminometer to assay microtiter plates. The technique holds great promise for use with fluorescence- and luminescence-based methods in many fields of research.     

Imaging in vivo redox status in high spatial resolution with OMRI

Redox-reactions are playing a significant role in regulation of homeostasis of organism. Disorder of the redox-status is related with the onset and/or propagation of oxidative diseases such as lifestyle-related diseases, including cancers and cardiac diseases, etc. In vivo imaging of redox-status is thereby important in the analysis of mechanisms of oxidative diseases and developments of new medicines for the diseases. Aminoxyl radicals are redox-sensitive reporter molecules, which lose their paramagnetic moiety by reactions of free radicals or reducing compounds. Electron spin resonance (ESR) technique has been used to measure the molecules in vivo. In vivo spatial resolution in ESR imaging is in the range of a few millimeters and is not sufficient for the detailed diagnosis of disease models. Overhauser enhanced MRI (OMRI) is an emerging free radical imaging technique, which utilised electron-proton coupling to image the distribution of free radicals. In vivo imaging of redox-status is applicable with OMRI/aminoxyl radical technique. The detailed imaging analysis was demonstrated in oxidative diseases, such as tumour-bearing, neurodegeneration or gastric ulcer models. The OMRI/aminoxyl radical technique has a large potential as a diagnostic system for biomedical applications in the future.     

Imaging of metabolites using secondary ion mass spectrometry

This article provides an overview of the technique of secondary ion mass spectrometry imaging and highlights some current and future areas of application relevant to the field of metabolomics. The approach benefits from label-free analysis of molecular species up to ~1500 Da with minimal sample preparation. Offering the highest spatial resolution of current mass spectrometry imaging methodologies, the technique is well-suited to metabolite imaging in both biological tissue and cells, in both 2D and 3D.     

Rapid MR imaging of cryoprotectant permeation in an engineered dermal replacement

Magnetic resonance (MR) imaging is a powerful technique for monitoring the permeation of cryoprotective agents (CPAs) inside tissues. However, the techniques published until now suffer from inherently long imaging times, limiting the application of these techniques to slow diffusion processes and large CPA concentrations. In this study, we present a rapid MR imaging technique based on a CHESS-FLASH scheme combined with Keyhole image acquisition. This technique can image the fast permeation of Me(2)SO solutions into freeze-dried artificial dermal replacements for concentrations down to 10% v/v. Special attention is given to evaluating the technique for quantitative analysis.     

Approaching MALDI molecular imaging for clinical proteomic research: current state and fields of application

MALDI imaging mass spectrometry ('MALDI imaging') is an increasingly recognized technique for biomarker research. After years of method development in the scientific community, the technique is now increasingly applied in clinical research. In this article, we discuss the use of MALDI imaging in clinical proteomics and put it in context with classical proteomics techniques. We also highlight a number of upcoming challenges for personalized medicine, development of targeted therapies and diagnostic molecular pathology where MALDI imaging could help.     

Cardiovascular applications of magnetic resonance imaging

Magnetic resonance (MR) imaging is a unique imaging modality that is gaining rapid acceptance for a variety of medical indications. Diagnostic information is obtained noninvasively, without the potential hazards of ionizing radiation. The spatial resolution and anatomic detail of MR imaging rival those of other currently available imaging methods. By gating to an electrocardiographic signal cardiac imaging is possible. Since March 1983 the authors have had experience with cardiac MR imaging in both animals and humans. Cardiac anatomy is well shown by this technique, which allows detection and characterization of intracardiac masses, congenital heart disease and anomalies of the great vessels. Myocardial infarction has been detected in both animals and humans without the use of contrast agents, and acute cardiac transplant rejection has been visualized in an animal model. Limitations of MR imaging primarily have been lengthy imaging times and the sensitivity of the images to motion. With further investigation and experience this technique may become useful for studying a wide variety of cardiovascular disorders.     

Imaging of metabolites using secondary ion mass spectrometry

This article provides an overview of the technique of secondary ion mass spectrometry imaging and highlights some current and future areas of application relevant to the field of metabolomics. The approach benefits from label-free analysis of molecular species up to ~1500 Da with minimal sample preparation. Offering the highest spatial resolution of current mass spectrometry imaging methodologies, the technique is well-suited to metabolite imaging in both biological tissue and cells, in both 2D and 3D.

     

活体动物体内光学成像技术的研究进展及其应用

活体动物体内光学成像是利用基因改构进行内源性成像试剂或外源性成像试剂标记细胞、蛋白或DNA，从而非侵入性地报告小动物体内的特定生物学事件的技术。活体成像可以直观灵敏地监测基因的表达模式、标记和示踪细胞、探讨蛋白间的相互作用，因而这一技术被广泛地用于分析基因的表达模式、评价基因治疗效果、评估肿瘤的发生和转移、监测移植器官等。简要综述了现有活体动物体内光学成像技术的基本原理、技术进展和相关应用。     

Cardiac magnetic resonance imaging in stable ischaemic heart disease

Cardiac magnetic resonance imaging (CMR) is a new robust versatile non-invasive imaging technique that can detect global and regional myocardial dysfunction, presence of myocardial ischaemia and myocardial scar tissue in one imaging session without radiation, with superb spatial and temporal resolution, inherited three-dimensional data collection and with relatively safe contrast material. The reproducibility of CMR is high which makes it possible to use this technique for serial assessment to evaluate the effect of revascularisation therapy in patients with ischaemic heart disease.     

应用基于内源信号的光学成像技术的视觉脑研究现状

基于脑内源信号的光学成像技术是近来国际上出现的一种脑功能成像方法。该技术既无毒,又具有较高的空间分辨率,因而被迅速应用于动物的视觉、听觉、体感皮层功能构筑的研究中。本文综述了这种光学脑功能成像在视觉脑研究方面所取得的重要进展,并分析了该方法与其他脑成像技术、微电极单细胞技术的关系。报道了国内自行研制第、套脑功能光学成像系统的研究工作,该系统已在猫初级视觉皮层不同深度获得了清晰的方位功能图,并已经和     

Imaging in vivo redox status in high spatial resolution with OMRI

Abstract

Redox-reactions are playing a significant role in regulation of homeostasis of organism. Disorder of the redox-status is related with the onset and/or propagation of oxidative diseases such as lifestyle-related diseases, including cancers and cardiac diseases, etc. In vivo imaging of redox-status is thereby important in the analysis of mechanisms of oxidative diseases and developments of new medicines for the diseases. Aminoxyl radicals are redox-sensitive reporter molecules, which lose their paramagnetic moiety by reactions of free radicals or reducing compounds. Electron spin resonance (ESR) technique has been used to measure the molecules in vivo. In vivo spatial resolution in ESR imaging is in the range of a few millimeters and is not sufficient for the detailed diagnosis of disease models. Overhauser enhanced MRI (OMRI) is an emerging free radical imaging technique, which utilised electron–proton coupling to image the distribution of free radicals. In vivo imaging of redox-status is applicable with OMRI/aminoxyl radical technique. The detailed imaging analysis was demonstrated in oxidative diseases, such as tumour-bearing, neurodegeneration or gastric ulcer models. The OMRI/aminoxyl radical technique has a large potential as a diagnostic system for biomedical applications in the future.     

Fluorescence molecular imaging of small animal tumor models

In vivo imaging of molecular events in small animals has great potential to impact basic science and drug development. For this reason, several imaging technologies have been adapted to small animal research, including X-ray, magnetic resonance, and radioisotope imaging. Despite this plethora of visualization techniques, fluorescence imaging is emerging as an important alternative because of its operational simplicity, safety, and cost-effectiveness. Fluorescence imaging has recently become particularly interesting because of advances in fluorescent probe technology, including targeted fluorochromes as well as fluorescent "switches" sensitive to specific biochemical events. While past biological investigations using fluorescence have focused on microscopic examination of ex vivo, in vitro, or intravital specimens, techniques for macroscopic fluorescence imaging are now emerging for in vivo molecular imaging applications. This review illuminates fluorescence imaging technologies that hold promise for small animal imaging. In particular we focus on planar illumination techniques, also known as Fluorescence Reflectance Imaging (FRI), and discuss its performance and current use. We then discuss fluorescence molecular tomography (FMT), an evolving technique for quantitative three-dimensional imaging of fluorescence in vivo. This technique offers the promise of non-invasively quantifying and visualizing specific molecular activity in living subjects in three dimensions.     

FTO and obesity: the missing link

The field of vascular molecular imaging is searching for the "holy grail" of an imaging technique that will quantitatively and reliably assess vulnerable coronary plaques. Fluorescence imaging with indocyanine green specifically identifies lipid-rich plaques in rabbits and in humans and represents a promising, though invasive, approach.     

Kidney pseudotumour diagnosed by emission computed tomography.

Emission computed tomography is a new, useful imaging technique; when a rotating gamma camera capable of such imaging is used multiple adjacent transverse sections may be obtained simultaneously, from which coronal and sagittal sections may be computed. The technique was used in a man undergoing urological investigation in whom excretion urography indicated a space-occupying lesion in the left kidney. Ultrasonography and radionuclide imaging showed nothing abnormal, but emission computed tomography using a rotating gamma camera showed that functioning cortical tissue extended across the middle of the left kidney. Radiographs were therefore reviewed and ultrasonography repeated, and it was concluded that the abnormality was a hypertrophied column of Bertin. Emission tomographic imaging of the kidney is a useful adjunct to other non-invasive studies.     

Application of Thinned-Skull Cranial Window to Mouse Cerebral Blood Flow Imaging Using Optical Microangiography

In vivo imaging of mouse brain vasculature typically requires applying skull window opening techniques: open-skull cranial window or thinned-skull cranial window. We report non-invasive 3D in vivo cerebral blood flow imaging of C57/BL mouse by the use of ultra-high sensitive optical microangiography (UHS-OMAG) and Doppler optical microangiography (DOMAG) techniques to evaluate two cranial window types based on their procedures and ability to visualize surface pial vessel dynamics. Application of the thinned-skull technique is found to be effective in achieving high quality images for pial vessels for short-term imaging, and has advantages over the open-skull technique in available imaging area, surgical efficiency, and cerebral environment preservation. In summary, thinned-skull cranial window serves as a promising tool in studying hemodynamics in pial microvasculature using OMAG or other OCT blood flow imaging modalities.     

Diffusion MRI of complex neural architecture

While functional brain imaging methods can locate the cortical regions subserving particular cognitive functions, the connectivity between the functional areas of the human brain remains poorly understood. Recently, investigators have proposed a method to image neural connectivity noninvasively using a magnetic resonance imaging method called diffusion tensor imaging (DTI). DTI measures the molecular diffusion of water along neural pathways. Accurate reconstruction of neural connectivity patterns from DTI has been hindered, however, by the inability of DTI to resolve more than a single axon direction within each imaging voxel. Here, we present a novel magnetic resonance imaging technique that can resolve multiple axon directions within a single voxel. The technique, called q-ball imaging, can resolve intravoxel white matter fiber crossing as well as white matter insertions into cortex. The ability of q-ball imaging to resolve complex intravoxel fiber architecture eliminates a key obstacle to mapping neural connectivity in the human brain noninvasively.