3D Affine Registration of Large Image Stack for High-Resolution Brain Imaging Techniques

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.

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Recent applications of TEM to the study of interfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100174679 ◽

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.

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

Neuro-Oncology Advances ◽

10.1093/noajnl/vdab024.003 ◽

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.

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Fast high-resolution brain imaging with balanced SSFP: Interpretation of quantitative magnetization transfer towards simple MTR

NeuroImage ◽

10.1016/j.neuroimage.2011.07.038 ◽

2012 ◽

Vol 59 (1) ◽

pp. 202-211 ◽

Cited By ~ 10

Author(s):

M. Garcia ◽

M. Gloor ◽

E.-W. Radue ◽

Ch. Stippich ◽

S.G. Wetzel ◽

...

Keyword(s):

High Resolution ◽

Brain Imaging ◽

Magnetization Transfer ◽

Balanced Ssfp

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High-Resolution Magnetic Resonance Imaging of the Human Median Nerve

Neurorehabilitation and Neural Repair ◽

10.1177/0888439004267074 ◽

2004 ◽

Vol 18 (2) ◽

pp. 80-87 ◽

Cited By ~ 11

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.

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

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfab088.003 ◽

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.

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