A method for in-plane imaging of large objects as compared to the RF coil is proposed based on the use of a single specially designed surface coil, without using B(0) gradients. A constant B(1) gradient was generated along the main axis of a ladder-shaped coil, and RF-encoding along the direction of the gradient made it possible to obtain spin-density profiles. Successive acquisitions of profiles obtained by translation of the NMR coil resulted in distorted images-due to the presence of non-zero gradients perpendicular to the constant gradient-that were successfully processed using a mathematical treatment based on linear combinations of calculated altered images from single-pixel objects. Copyright 2000 Academic Press.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1006/jmre.2000.2130 | DOI Listing |
NMR Biomed
August 2023
Center for Magnetic Resonance Research (CMRR), Department of Radiology, University of Minnesota, Minnesota, USA.
Low-γ X-nuclear MRS and imaging have played a key role in studying metabolism and physiopathology, especially at ultrahigh fields. We design and demonstrate a novel and simple dual-frequency RF resonant coil that can operate at both low-γ X-nuclear and proton frequencies. The dual-frequency resonant coil comprises an LC coil loop and a tuning-matching circuit bridged by two short wires of the desired length to generate two resonant modes: one for proton MRI and the other for low-γ X-nuclear MRS imaging with a large difference in their Larmor frequencies at ultrahigh fields.
View Article and Find Full Text PDFSensors (Basel)
December 2022
Samara Federal Research Scientific Center RAS, Institute for the Control of Complex Systems RAS, 443020 Samara, Russia.
Single-coil eddy current sensors (SCECS) form a separate and independent branch among the existing eddy current probes. Such sensors are often used for aviation and aerospace applications where the conditions accompanying the measuring process are harsh and even extreme. High temperatures (up to +600 °C in the compressor and over +1000 °C in the turbine of gas turbine engines), the complex shape surfaces of the monitored parts, the multidimensional movement of the power plants' structural elements, restrictions on the probes number and their placement in the measuring zone are the main factors affecting the reliability and accuracy of the measurement results obtained by the sensors.
View Article and Find Full Text PDFMagn Reson Imaging
May 2020
Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA. Electronic address:
MR Imaging the spinal cord of non-human primates (NHP), such as squirrel monkey, is important since the injuries in NHP resemble those that afflict human spinal cords. Our previous studies have reported a multi-parametric MRI protocol, including functional MRI, diffusion tensor imaging, quantitative magnetization transfer and chemical exchange saturation transfer, which allows non-invasive detection and monitoring of injury-associated structural, functional and molecular changes over time. High signal-to-noise ratio (SNR) is critical for obtaining high-resolution images and robust estimates of MRI parameters.
View Article and Find Full Text PDFMAGMA
June 2018
Center for Advanced Imaging Innovation and Research and the Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, 660 First Ave, Fourth Floor, New York, NY, 10016, USA.
Objective: To use high-permittivity materials (HPM) positioned near radiofrequency (RF) surface coils to manipulate transmit/receive field patterns.
Materials And Methods: A large HPM pad was placed below the RF coil to extend the field of view (FOV). The resulting signal-to-noise ratio (SNR) was compared with that of other coil configurations covering the same FOV in simulations and experiments at 7 T.
Rev Sci Instrum
February 2017
GE Healthcare, 1515 Danner Drive, Aurora, Ohio 44202, USA.
Surface coils are widely used in magnetic resonance imaging and spectroscopy. While smaller diameter coils produce higher signal to noise ratio (SNR) closer to the coil, imaging larger fields of view or greater distance into the sample requires a larger overall size array or, in the case of a channel count limited system, larger diameter coils. In this work, we consider reconfiguring the geometry of coils and coil arrays such that the same coil or coil array may be used in multiple field of view imaging.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!