Contribution of high-resolution correlative imaging techniques in the study of the liver sieve in three-dimensions

2007 ◽  
Vol 70 (3) ◽  
pp. 230-242 ◽  
Author(s):  
Filip Braet ◽  
Eddie Wisse ◽  
Paul Bomans ◽  
Peter Frederik ◽  
Willie Geerts ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
Three Dimensions ◽  
Correlative Imaging

scholarly journals A new magnetic resonance-based technique for high-resolution quantification of amorphous and quasi-amorphous structures

2016 ◽  
Vol 13 (123) ◽  
pp. 20160589
Author(s):  
James Rafferty ◽  
Lance Farr ◽  
Tim James ◽  
David Chase ◽  
John Heinrich ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
High Resolution ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Three Dimensions ◽  
Small Scale ◽  
Micro Computed Tomography ◽  
Cross Sectional ◽  
Biological Structures ◽  
The One

We present a novel, high-resolution magnetic resonance technique, fine structure analysis (FSA) for the quantification and analysis of amorphous and quasi-amorphous biological structures. The one-dimensional technique is introduced mathematically and then applied to one simulated phantom, two physical phantoms and a set of ex vivo biological samples, scanned with interpoint spacings of 0.0038–0.195 mm and cross-sectional sizes of 3 × 3 or 5 × 5 mm. The simulated phantom and one of the physical phantoms consists of randomly arranged beads of known size in two and three dimensions, respectively. The second physical phantom was constructed by etching lines on Perspex. The ex vivo samples are human bone specimens. We show that for all three phantoms, the FSA technique is able to elucidate the average spacing of the structures present within each sample using structural spectroscopy, the smallest of which was 180 µm in size. We further show that in samples of trabecular bone, FSA is able to produce comparable results to micro-computed tomography, the current gold standard for measuring bone microstructure, but without the need for ionizing radiation. Many biological structures are too small to be captured by conventional, clinically deployed medical imaging techniques. FSA has the potential for use in the analysis of pathologies where such small-scale repeating structures are disrupted or their size, and spacing is otherwise altered.

High-resolution topographic SEM and radiation damage: The rationale for using low beam voltage

1992 ◽  
Vol 50 (2) ◽  
pp. 1278-1279
Author(s):  
James Pawley ◽  
David Joy
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
Morphological Structure ◽  
Radiation Sensitivity ◽  
Beam Specimen ◽  
Measured Signal ◽  
Practical Consideration ◽  
Interaction Volume ◽  
Impact Area ◽  
Signal Contrast

The scanning electron microscope (SEM) builds up an image by sampling contiguous sub-volumes near the surface of the specimen. A fine electron beam selectively excites each sub-volume and then the intensity of some resulting signal is measured and then plotted as a corresponding intensity in an image. The spatial resolution of such an image is limited by at least three factors. Two of these determine the size of the interaction volume: the size of the electron probe and the extent to which detectable signal is excited from locations remote from the beam impact area. A third limitation emerges from the fact that the probing beam is composed of a number of discrete particles and therefore that the accuracy with which any detectable signal can be measured is limited by Poisson statistics applied to this number (or to the number of events actually detected if this is smaller). As in all imaging techniques, the limiting signal contrast required to recognize a morphological structure is constrained by this statistical consideration. The only way to overcome this limit is to increase either the contrast of the measured signal or the number of beam/specimen interactions detected. Unfortunately, these interactions deposit ionizing radiation that may damage the very structure under investigation. As a result, any practical consideration of the high resolution performance of the SEM must consider not only the size of the interaction volume but also the contrast available from the signal producing the image and the radiation sensitivity of the specimen.

Recent applications of TEM to the study of interfaces

1990 ◽  
Vol 48 (4) ◽  
pp. 308-309
Author(s):  
C. Barry Carter
Keyword(s):  
High Resolution ◽  
Sample Preparation ◽  
Grain Boundaries ◽  
Diffuse Scattering ◽  
Imaging Techniques ◽  
Amorphous Material ◽  
Contrast Imaging ◽  
Current State ◽  
Actual Nature ◽  
High Resolution Images

This paper will review the current state of understanding of interface structure and highlight some of the future needs and problems which must be overcome. The study of this subject can be separated into three different topics: 1) the fundamental electron microscopy aspects, 2) material-specific features of the study and 3) the characteristics of the particular interfaces. The two topics which are relevant to most studies are the choice of imaging techniques and sample preparation. The techniques used to study interfaces in the TEM include high-resolution imaging, conventional diffraction-contrast imaging, and phase-contrast imaging (Fresnel fringe images, diffuse scattering). The material studied affects not only the characteristics of the interfaces (through changes in bonding, etc.) but also the method used for sample preparation which may in turn have a significant affect on the resulting image. Finally, the actual nature and geometry of the interface must be considered. For example, it has become increasingly clear that the plane of the interface is particularly important whenever at least one of the adjoining grains is crystalline.A particularly productive approach to the study of interfaces is to combine different imaging techniques as illustrated in the study of grain boundaries in alumina. In this case, the conventional imaging approach showed that most grain boundaries in ion-thinned samples are grooved at the grain boundary although the extent of this grooving clearly depends on the crystallography of the surface. The use of diffuse scattering (from amorphous regions) gives invaluable information here since it can be used to confirm directly that surface grooving does occur and that the grooves can fill with amorphous material during sample preparation (see Fig. 1). Extensive use of image simulation has shown that, although information concerning the interface can be obtained from Fresnel-fringe images, the introduction of artifacts through sample preparation cannot be lightly ignored. The Fresnel-fringe simulation has been carried out using a commercial multislice program (TEMPAS) which was intended for simulation of high-resolution images.

scholarly journals BIMG-04. MAPPING HETEROGENEITY OF HIGH-GRADE GLIOMA METABOLISM USING HIGH RESOLUTION 7T MRSI

2021 ◽  
Vol 3 (Supplement_1) ◽  
pp. i1-i1
Author(s):  
Gilbert Hangel ◽  
Cornelius Cadrien ◽  
Philipp Lazen ◽  
Sukrit Sharma ◽  
Julia Furtner ◽  
...  
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
Basis Set ◽  
Metabolic Imaging ◽  
Tumor Segmentation ◽  
Low Grade ◽  
High Grade ◽  
Isotropic Resolution ◽  
Contrast Enhanced ◽  
Definition Of

Abstract OBJECTIVES Neurosurgical resection in gliomas depends on the precise preoperative definition of the tumor and its margins to realize a safe maximum resection that translates into a better patient outcome. New metabolic imaging techniques could improve this delineation as well as designate targets for biopsies. We validated the performance of our fast high-resolution whole-brain 3D-magnetic resonance spectroscopic imaging (MRSI) method at 7T in high-grade gliomas (HGGs) as first step to this regard. METHODS We measured 23 patients with HGGs at 7T with MRSI covering the whole cerebrum with 3.4mm isotropic resolution in 15 min. Quantification used a basis-set of 17 neurochemical components. They were evaluated for their reliability/quality and compared to neuroradiologically segmented tumor regions-of-interest (necrosis, contrast-enhanced, non-contrast-enhanced+edema, peritumoral) and histopathology (e.g., grade, IDH-status). RESULTS We found 18/23 measurements to be usable and ten neurochemicals quantified with acceptable quality. The most common denominators were increases of glutamine, glycine, and total choline as well as decreases of N-acetyl-aspartate and total creatine over most tumor regions. Other metabolites like taurine and serine showed mixed behavior. We further found that heterogeneity in the metabolic images often continued into the peritumoral region. While 2-hydroxy-glutarate could not be satisfyingly quantified, we found a tendency for a decrease of glutamate in IDH1-mutant HGGs. DISCUSSION Our findings corresponded well to clinical tumor segmentation but were more heterogeneous and often extended into the peritumoral region. Our results corresponded to previous knowledge, but with previously not feasible resolution. Apart from glycine/glutamine and their role in glioma progression, more research on the connection of glutamate and others to specific mutations is necessary. The addition of low-grade gliomas and statistical ROI analysis in a larger cohort will be the next important steps to define the benefits of our 7T MRSI approach for the definition of spatial metabolic tumor profiles.

High-Resolution Magnetic Resonance Imaging of the Human Median Nerve

2004 ◽  
Vol 18 (2) ◽  
pp. 80-87 ◽  
Author(s):  
Archie Heddings ◽  
Mehmet Bilgen ◽  
Randolph Nudo ◽  
Bruce Toby ◽  
Terence McIff ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
High Resolution ◽  
Peripheral Nerve ◽  
Median Nerve ◽  
Ex Vivo ◽  
Imaging Techniques ◽  
Proton Density ◽  
Resonance Imaging ◽  
Imaging Protocols

Objectives. It is widely accepted that peripheral nerve repairs performed within 6 weeks of injury have much better outcomes than those performed at later dates. However, there is no diagnostic technique that can determine if a traumatic peripheral nerve injury requires surgical intervention in the early postinjury phase. The objective of this article was to determine whether novel, noninvasive magnetic resonance imaging techniques could demonstrate the microstructure of human peripheral nerves that is necessary for determining prognosis and determining if surgery is indicated following traumatic injury. Methods. Ex vivo magnetic resonance imaging protocols were developed on a 9.4-T research scanner using spin-echo proton density and gradient-echo imaging sequences and a specially designed, inductively coupled radio frequency coil. These imaging protocols were applied to in situ imaging of the human median nerve in 4 fresh-frozen cadaver arms. Results. Noninvasive high-resolution images of the human median nerve were obtained. Structures in the nerve that were observed included fascicles, interfascicular epineurium, perineurium, and intrafascicular septations. Conclusion. Application of these imaging techniques to clinical scanners could provide physicians with a tool that is capable of grading the severity of nerve injuries and providing indications for surgery in the early postinjury phase.

Confocal fluorescence microscopy with the tandem scanning light microscope

1989 ◽  
Vol 94 (4) ◽  
pp. 617-624
Author(s):  
S.J. Wright ◽  
J.S. Walker ◽  
H. Schatten ◽  
C. Simerly ◽  
J.J. McCarthy ◽  
...  
Keyword(s):  
High Resolution ◽  
Fluorescence Microscopy ◽  
Light Microscope ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Complex Structures ◽  
Charge Coupled Device ◽  
Confocal Fluorescence ◽  
Cooled Ccd ◽  
Cellular Components

Applications of the tandem scanning confocal microscope (TSM) to fluorescence microscopy and its ability to resolve fluorescent biological structures are described. The TSM, in conjunction with a cooled charge-coupled device (cooled CCD) and conventional epifluorescence light source and filter sets, provided high-resolution, confocal data, so that different fluorescent cellular components were distinguished in three dimensions within the same cell. One of the unique features of the TSM is the ability to image fluorochromes excited by ultraviolet light (e.g. Hoechst, DAPI) in addition to fluorescein and rhodamine. Since the illumination is dim, photobleaching is insignificant and prolonged viewing of living specimens is possible. Series of optical sections taken in the Z-axis with the TSM were reproduced as stereo images and three-dimensional reconstructions. These data show that the TSM is potentially a powerful tool in fluorescence microscopy for determining three-dimensional relationships of complex structures within cells labeled with multiple fluorochromes.

MO430MASS-SPECTROMETRIC IDENTIFICATION OF POST-TRANSLATIONAL GUANIDINYLATED PROTEINS IN THE CONTEXT OF SYSTEMIC LUPUS ERYTHEMATOSUS

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
Juliane Hermann ◽  
Ute Raffetseder ◽  
Michaela Lellig ◽  
Joachim Jankowski ◽  
Vera Jankowski
Keyword(s):  
Mass Spectrometry ◽  
Systemic Lupus Erythematosus ◽  
High Resolution ◽  
Lupus Erythematosus ◽  
Imaging Techniques ◽  
Mass Spectrometric ◽  
Mass Spectrometric Imaging ◽  
Systemic Lupus ◽  
Notch 3 ◽  
Resolution Mass

Abstract Background and Aims With continuous identification of post-translational modified isoforms of proteins, it is becoming increasingly clear that post-translational modifications limit or modify the biological functions of native proteins are majorly involved in development of various chronic disease. This is mostly due to technically advanced molecular identification and quantification methods, mainly based on mass spectrometry. Mass spectrometry has become one of the most powerful tools for the identification of lipids. Method In this study, we used sophisticated high-resolution mass-spectrometric methods to analyze the soluble ligand of receptor Notch-3, namely the Y-box protein (YB)-1, in serum from systemic lupus erythematosus (SLE) patients. In addition, kidneys of lupus-prone (MRL.lpr) mice were analyzed by mass-spectrometric imaging techniques to identify the underlying pathomechanisms. Serum YB-1 was isolated by chromatographic methods, afterwards digested by trypsin and analyzed by matrix assisted laser desorption/ionization mass spectrometry (MALDI-MS). The kidneys were fixed in paraffin, then kidney sections were deparaffinized, tryptic digested and analyzed by mass-spectrometric imaging techniques. Mass-spectrometry of extracellular YB-1 in SLE patient serum revealed post-translational guanidinylation of two lysine’s within the highly conserved cold shock domain (CSD) of the YB-1 protein (YB-1-2G). Patients with increased disease activity and those with active renal involvement (lupus nephritis, LN) had a higher degree of dual-guanidinylation within the CSD. Of note, at least one of these modifications was present in all analyzed LN patients, whereas single-guanidinylated YB-1 was present in only one and double modification in none of the control individuals. Mass-spectrometric imaging analyses specifically localized YB-1-2G and increases Notch-3 expression in kidney sections from MRL.lpr mice. Results The data from this study clearly demonstrate the high potential of high-resolution mass spectrometric methods as well as mass spectrometric imaging techniques to identify pathomechanisms of diseases like SLE/LN.

scholarly journals Fast Objective Coupled Planar Illumination Microscopy

2018 ◽  
Author(s):  
Cody Greer ◽  
Timothy E. Holy
Keyword(s):  
Fluorescence Microscopy ◽  
High Speed ◽  
Imaging Techniques ◽  
Light Sheet ◽  
Frame Rate ◽  
Three Dimensions ◽  
Two Photon Microscopy ◽  
Image Sharing ◽  
Scanning Rate ◽  
Fast Light

Among optical imaging techniques light sheet fluorescence microscopy stands out as one of the most attractive for capturing high-speed biological dynamics unfolding in three dimensions. The technique is potentially millions of times faster than point-scanning techniques such as two-photon microscopy. However current-generation light sheet microscopes are limited by volume scanning rate and/or camera frame rate. We present speed-optimized Objective Coupled Planar Illumination (OCPI) microscopy, a fast light sheet technique that avoids compromising image quality or photon efficiency. We increase volume scanning rate to 40 Hz for volumes up to 700 µm thick and introduce Multi-Camera Image Sharing (MCIS), a technique to scale imaging rate by parallelizing acquisition across cameras. Finally, we demonstrate fast calcium imaging of the larval zebrafish brain and find a heartbeat-induced artifact that can be removed by filtering when the imaging rate exceeds 15 Hz. These advances extend the reach of fluorescence microscopy for monitoring fast processes in large volumes.

Abstract 295: Magnetic Resonance Imaging Characterization of Peripheral Arterial Chronic Total Occlusions With MicroCT and Histologic Validation

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Trisha Roy ◽  
Garry Liu ◽  
Xiuling Qi ◽  
Andrew Dueck ◽  
Graham Wright
Keyword(s):  
High Resolution ◽  
Imaging Techniques ◽  
Calcium Sensitivity ◽  
7 Tesla ◽  
Chronic Total Occlusions ◽  
Difference Image ◽  
Surgical Bypass ◽  
Phase Map ◽  
Peripheral Arterial ◽  
Difference Images

Objectives: Guidelines recommend surgical bypass for peripheral chronic total occlusions (CTOs). Endovascular revascularization, however, offers improved morbidity and shorter length of hospitalization. Not all lesions are amenable to this technique but predicting crossability is difficult due to limitations in characterizing CTOs with current imaging techniques. This study demonstrates the ability of MRI to characterize peripheral CTO components with microCT and histologic validation. Methods: MRI was performed on 15 excised human peripheral arterial CTO segments from 4 patients. Each sample was imaged at 7 Tesla at high resolution (75μm3 voxels) to produce T2- and T2*-maps using ultrashort echo (UTE) sequences with echo times: {20μs, 500μs, 1ms}. A T2* difference image was produced by subtracting the UTE images and a phase map was constructed. The T2, UTE 20μs and T2* difference images were used together to differentiate CTO components. MicroCT and histology were used to validate regions of interest (ROIs). Results: 3 independent reviewers identified 47 ROIs. There was excellent agreement between MRI and microCT for calcium (sensitivity 87%, specificity 99%). There was also good agreement between MRI and histology for adipose tissue (100%, 100%), soft tissue (97%, 97%), thrombus (78%, 100%), collagen (83%, 94%) and open lumen (95%, 98%). Conclusions: These results demonstrate the potential of high-resolution T2 and T2* imaging using UTE, to characterize lesion components in human peripheral CTOs. Further work is required to better differentiate thrombus from collagen. This study provides the foundation for future studies in determining the lesion crossability in CTOs.

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