Mapping and Spectral Analysis of Acoustic Vibration in the Scanning Area of the Weak Field Magnetic Resonance Imager

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Jiří Přibil ◽  
Anna Přibilová ◽  
Ivan Frollo
Keyword(s):  
Magnetic Field ◽  
Spectral Analysis ◽  
Magnetic Resonance ◽  
Vibration Signal ◽  
Acoustic Vibration ◽  
Weak Field ◽  
Vibration Sensor ◽  
Gradient Coil ◽  
Propagation Time ◽  
Scanning Area

The paper describes measurement and calculation of 2D distribution of the vibration signal originated by the gradient coil system of the magnetic resonance imaging (MRI) equipment. The measurement experiments were performed at the bottom plastic holder of the scanning area of the open-air weak magnetic field MRI device. Selection of a usable type of a vibration sensor for measurement in a magnetic field with low B0 up to 0.2 T is also discussed. Realized calibration of the chosen sensor (sensitivity and frequency response) together with determination of the propagation time delay between the excitation impulses and the subsequently generated vibration signal is mentioned, too. The picked-up vibration signal exhibits harmonic character so it is suitable to describe it by determined spectral properties and features. Obtained statistical results of spectral analysis will be used to improve image sharpening and reduction of the motion effect in the MR pictures of thin layer samples and phantoms scanned by this MRI system.

scholarly journals Особенности регистрации спектра ядерного магнитного резонанса конденсированной среды при экспресс-контроле ее состояния

2020 ◽  
Vol 128 (10) ◽  
pp. 1554
Author(s):  
В.В. Давыдов ◽  
А.В. Мороз ◽  
Н.С. Мязин ◽  
С.С. Макеев ◽  
В.И. Дудкин
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Weak Magnetic Field ◽  
Experimental Studies ◽  
Condensed Medium ◽  
Weak Field ◽  
Nmr Spectrum ◽  
Nuclear Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The necessity of recording the spectrum of nuclear magnetic resonance in a weak field from a condensed medium during express control of its state is substantiated. The conditions are established that allow realizing the registration of nuclear magnetic resonance spectra in a weak field. A new design of a small-sized nuclear magnetic spectrometer has been developed for recording the NMR spectrum in a weak magnetic field from the volume of the condensed medium of the order of 3.0 ml. The results of experimental studies of various environments are presented.

scholarly journals О возможности использования спектрального анализа для исследования структуры линии сигнала ядерного магнитного резонанса

2021 ◽  
Vol 129 (5) ◽  
pp. 608
Author(s):  
В.В. Давыдов ◽  
В.Д. Купцов ◽  
В.И. Дудкин ◽  
А.В. Мороз ◽  
С.С. Макеев
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Weak Magnetic Field ◽  
Experimental Studies ◽  
Condensed Medium ◽  
Weak Field ◽  
Nmr Spectrum ◽  
Nuclear Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The necessity of recording the spectrum of nuclear magnetic resonance in a weak field from a condensed medium with express control of its state is substantiated. The conditions are established that allow the registration of nuclear magnetic resonance spectra in a weak field. A new design of a small-sized nuclear magnetic spectrometer for recording the NMR spectrum in a weak magnetic field from a volume of a condensed medium of about 3.0 ml has been developed. The results of experimental studies of various media are presented.

scholarly journals Determination of Spectral Characteristics in a Vibration Sensor Microcircuit

2020 ◽  
Vol 9 (3) ◽  
pp. 2044-2050
Keyword(s):  
Spectral Analysis ◽  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Integrated Circuit ◽  
Spectral Characteristics ◽  
Digital Signal ◽  
Vibration Signal ◽  
Vibration Sensor ◽  
Signal Processing Algorithms

This article discusses aspects of the implementation of digital signal processing algorithms in devices with multifunctional diagnostics of bearing assemblies in integrated-circuit form. The possibility of applying the effective implementation of spectral analysis algorithms on a defined basis is considered. The structural flow chart of the filter which performs Goertzel transformation and schemes for implementation of the fast Fourier transform unit is shown. To solve these problems in Matlab environment were developed mathematical models of Goertzel filter of fast Fourier transform unit was simulated operation of these units for specifying of parameters and evaluation of achieved characteristics. After the evaluation of simulation results, 2 types of spectral analysis units were developed: Goertzel transformation units for accurate calculations and fast Fourier transform units for analysis during the whole operating band. The created units of spectral analysis make it possible to efficiently solve the problems of bearing diagnostics, obtain information on the video spectrum of the vibration signal in the full frequency band and at the same time to determine the exact value or vibration levels at the characteristic frequencies.

Spectroscopic imaging of human disease

1996 ◽  
Vol 54 ◽  
pp. 884-885
Author(s):  
D.J. Meyerhoff
Keyword(s):  
Magnetic Field ◽  
Magnetic Resonance ◽  
Field Gradient ◽  
Human Disease ◽  
Morphological Changes ◽  
Magnetic Field Gradient ◽  
Spectroscopic Imaging ◽  
Resonance Spectroscopy ◽  
Tissue Water

Magnetic Resonance Imaging (MRI) observes tissue water in the presence of a magnetic field gradient to study morphological changes such as tissue volume loss and signal hyperintensities in human disease. These changes are mostly non-specific and do not appear to be correlated with the range of severity of a certain disease. In contrast, Magnetic Resonance Spectroscopy (MRS), which measures many different chemicals and tissue metabolites in the millimolar concentration range in the absence of a magnetic field gradient, has been shown to reveal characteristic metabolite patterns which are often correlated with the severity of a disease. In-vivo MRS studies are performed on widely available MRI scanners without any “sample preparation” or invasive procedures and are therefore widely used in clinical research. Hydrogen (H) MRS and MR Spectroscopic Imaging (MRSI, conceptionally a combination of MRI and MRS) measure N-acetylaspartate (a putative marker of neurons), creatine-containing metabolites (involved in energy processes in the cell), choline-containing metabolites (involved in membrane metabolism and, possibly, inflammatory processes),

Nuclear magnetic resonance microscopy

1989 ◽  
Vol 47 ◽  
pp. 828-829
Author(s):  
Paul C. Lauterbur
Keyword(s):  
Magnetic Field ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Magnetic Fields ◽  
Signal To Noise ◽  
Field Gradients ◽  
Useful Signal ◽  
Magnetic Field Gradients ◽  
Observation Times ◽  
Nuclear Magnetic

Nuclear magnetic resonance imaging can reach microscopic resolution, as was noted many years ago, but the first serious attempt to explore the limits of the possibilities was made by Hedges. Resolution is ultimately limited under most circumstances by the signal-to-noise ratio, which is greater for small radio receiver coils, high magnetic fields and long observation times. The strongest signals in biological applications are obtained from water protons; for the usual magnetic fields used in NMR experiments (2-14 tesla), receiver coils of one to several millimeters in diameter, and observation times of a number of minutes, the volume resolution will be limited to a few hundred or thousand cubic micrometers. The proportions of voxels may be freely chosen within wide limits by varying the details of the imaging procedure. For isotropic resolution, therefore, objects of the order of (10μm) may be distinguished.Because the spatial coordinates are encoded by magnetic field gradients, the NMR resonance frequency differences, which determine the potential spatial resolution, may be made very large. As noted above, however, the corresponding volumes may become too small to give useful signal-to-noise ratios. In the presence of magnetic field gradients there will also be a loss of signal strength and resolution because molecular diffusion causes the coherence of the NMR signal to decay more rapidly than it otherwise would. This phenomenon is especially important in microscopic imaging.

scholarly journals SYNTHESIS, CHARACTERIZATION, AND ANTHELMINTIC ACTIVITY OF NOVEL BENZOTHIAZOLE DERIVATIVES CONTAINING INDOLE MOIETIES

2019 ◽  
pp. 321-325
Author(s):  
ALETI RAJAREDDY ◽  
SRINIVAS MURTHY M
Keyword(s):  
Spectral Analysis ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Fourier Transform Infrared Spectroscopy ◽  
Anthelmintic Activity ◽  
Mass Spectral Analysis ◽  
Standard Drug ◽  
Mass Spectral ◽  
Benzothiazole Derivatives

Objective: The objective of this study was to synthesize and evaluate the anthelmintic activity (AA) of novel benzothiazole derivatives containing indole moieties (BDIM). Methods: The present works which involve the substituted isatin Schiff bases undergo acetylating and reacting with 2-aminobenzothiazole to give novel BDIM. Results: All the newly synthesized molecules (5a-5o) were characterized by Fourier-transform infrared spectroscopy, H_nuclear magnetic resonance, and mass spectral analysis along with physical data. The biological potentials of the newly synthesized compounds are evaluated for their AA using an Indian earthworm (Pheretima posthuma), and albendazole was used as standard drug. Conclusion: The synthesized compound 5f, 5n, and 5o showed good AA, whereas others exhibited significant activities.

Magnetic resonance imaging: effects of magnetic field strength.

Radiology ◽  
1984 ◽  
Vol 151 (1) ◽  
pp. 127-133 ◽  
Author(s):  
L E Crooks ◽  
M Arakawa ◽  
J Hoenninger ◽  
B McCarten ◽  
J Watts ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Magnetic Resonance ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Resonance Imaging

MRI Susceptibility Artefacts Related to Scaphoid Screws: the Effect of Screw Type, Screw Orientation and Imaging Parameters

2002 ◽  
Vol 27 (2) ◽  
pp. 165-170 ◽  
Author(s):  
M. GANAPATHI ◽  
G. JOSEPH ◽  
R. SAVAGE ◽  
A. R. JONES ◽  
B. TIMMS ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Field ◽  
Titanium Alloy ◽  
Magnetic Resonance ◽  
Main Magnetic Field ◽  
Resonance Imaging ◽  
Metal Implants ◽  
Imaging Parameters ◽  
Susceptibility Artefact

Metal implants produce susceptibility artefacts in magnetic resonance imaging. We have explored the effects of scaphoid screw characteristics and orientation on MR susceptibility artefact. Titanium alloy, smallness and longitudinal alignment with the z-axis of the main magnetic field reduce the size of the susceptibility artefact.

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