Investigation of a whole-body receiver coil operating at liquid nitrogen temperatures.

abstract：:For protons diffusing among a system of magnetic particles, the process by which initial phase coherence is lost depends substantially on particle size. In this article, evidence for three dephasing mechanisms is presented: an incremental process at small particle sizes (motional averaging regime), a discrete process ...

journal_title：Magnetic resonance in medicine

authors： de Haan HW

更新日期：2011-12-01 00:00:00

abstract：:This report describes a noninvasive 1H-NMR method for measuring absolute temperatures (+/- 0.2 degrees C) in biological samples and, in particular, in cell culture perfusion systems, utilizing the linear temperature dependence of the water chemical shift relative to the temperature-independent shift of one of the comp...

journal_title：Magnetic resonance in medicine

authors： Lutz NW,Kuesel AC,Hull WE

更新日期：1993-01-01 00:00:00

abstract：:Rapid flow imaging was achieved with a partial field of view (pFOV) spiral motion-encoded technique. The FOV and the acquisition time were reduced by a factor of 2 by undersampling k-space. The pFOV spiral k-space trajectory aliased signals from outside a circular ring whose radius was inversely proportional to the di...

journal_title：Magnetic resonance in medicine

authors： Nezafat R,Thompson RB,Derbyshire JA,McVeigh ER

更新日期：2006-09-01 00:00:00

abstract：:A new strategy for a quantitative measurement of regional pulmonary ventilation using hyperpolarized helium-3 (3He) MRI has been developed. The method employs the build-up of the signal intensity after a variable number of (3)He breaths. A mathematical model of the signal dynamics is presented, from which the local ve...

journal_title：Magnetic resonance in medicine

authors： Deninger AJ,Månsson S,Petersson JS,Pettersson G,Magnusson P,Svensson J,Fridlund B,Hansson G,Erjefeldt I,Wollmer P,Golman K

更新日期：2002-08-01 00:00:00

abstract：:Phase contrast flow velocity measurements were performed in six healthy volunteers and 30 patients with arteriosclerotic disease. The iliac arteries were investigated in 8 cases and the femoral arteries in 28 cases. In the first 24 patients, 16 evenly distributed data sets were acquired during one cardiac cycle. In th...

journal_title：Magnetic resonance in medicine

authors： Krug B,Kugel H,Harnischmacher U,Heindel W,Schmidt R,Krings F

更新日期：1995-11-01 00:00:00

abstract：:The suppression of water signals in in vivo proton spectra by means of multiple-quantum filtering can be brought about in several ways. This communication exposes the shortcomings of using purely subtractive filtering techniques to observe signals from metabolites that contain proton couplings of the form AX3. ...

journal_title：Magnetic resonance in medicine

authors： Nosel W,Trimble LA,Shen JF,Allen PS

更新日期：1989-09-01 00:00:00

abstract：:The chemical shift of water and fat resonances in proton MRI allows separation of water and fat signal from chemical shift encoded data. This work describes an automatic method that produces separate water and fat images as well as quantitative maps of fat signal fraction and T2* from complex multiecho gradient-recall...

journal_title：Magnetic resonance in medicine

authors： Berglund J,Kullberg J

更新日期：2012-06-01 00:00:00

abstract：:A high frequency solution of the electromagnetic field produced by a circular surface coil adjacent to a homogeneous conducting, dielectric sphere is used to predict the attainable signal to noise ratio (S/N) and specific absorption rate (SAR) for in vivo 1H NMR spectroscopy experiments from 200 to 430 MHz (4.7-10 T)....

journal_title：Magnetic resonance in medicine

authors： Keltner JR,Carlson JW,Roos MS,Wong ST,Wong TL,Budinger TF

更新日期：1991-12-01 00:00:00

abstract：:It is demonstrated that a high-resolution (1)H NMR spectrum of excised rat liver can be obtained using the technique of magic angle turning (MAT) at a sample spinning rate of 1 Hz. A variant of the phase-corrected MAT (PHORMAT) pulse sequence that includes a water suppression segment was developed for the investigatio...

journal_title：Magnetic resonance in medicine

authors： Hu JZ,Rommereim DN,Wind RA

更新日期：2002-05-01 00:00:00

abstract：:This note considers the anomolous contrast in inversion recovery images produced by NMR scanners if a map of [My] is reconstructed, rather than a map of My'. ...

journal_title：Magnetic resonance in medicine

authors： Young IR,Bailes DR,Bydder GM

更新日期：1985-02-01 00:00:00

abstract：:Patient-specific radiofrequency shimming in high-field MRI strengthens the need for online, patient-specific specific absorption rate (SAR) monitoring. Numerical simulation is currently most effective for this purpose but may require a patient-specific dielectric model. To investigate whether a generic model may be co...

journal_title：Magnetic resonance in medicine

authors： de Greef M,Ipek O,Raaijmakers AJ,Crezee J,van den Berg CA

更新日期：2013-05-01 00:00:00

abstract：:A double-tuned single coil probe for high field metabolic NMR studies has been designed and tested. The resonant coil is a single-turn of copper foil wound on a quartz cylinder. It is fed by a short length of parallel strip line made of the same material; the feeder is also used as a tuning capacitance. Electrical par...

journal_title：Magnetic resonance in medicine

authors： Najim E,Grivet JP

更新日期：1992-02-01 00:00:00

abstract：:A single breath-hold 3D cardiac phase resolved steady-state free precession (SSFP) sequence was developed, allowing 3D visualization of the moving coronary arteries. A 3D stack of spirals was acquired continuously throughout the cardiac cycle, and a sliding window reconstruction was used to achieve high temporal resol...

journal_title：Magnetic resonance in medicine

authors： Kressler B,Spincemaille P,Nguyen TD,Cheng L,Xi Hai Z,Prince MR,Wang Y

更新日期：2007-09-01 00:00:00

abstract：:Of the various techniques employed to quantify temperature changes by MR, proton resonance frequency (PRF) shift-based phase-difference imaging (PDI) is the most accurate and widely used. However, PDI is associated with various artifacts. Motivated by these limitations, we developed a new method to monitor temperature...

journal_title：Magnetic resonance in medicine

authors： Paliwal V,El-Sharkawy AM,Du X,Yang X,Atalar E

更新日期：2004-10-01 00:00:00

abstract：:The dependence of 1/T1 on the magnetic field strength (the relaxation dispersion) has been measured at 37 degrees C on autopsy samples of human brain gray and white matter at field strengths corresponding to proton Larmor frequencies between 10 kHz and 50 MHz (0.0002-1.2 T). Additional measurements of 1/T1 and 1/T2 ha...

journal_title：Magnetic resonance in medicine

authors： Fischer HW,Rinck PA,Van Haverbeke Y,Muller RN

更新日期：1990-11-01 00:00:00

abstract：PURPOSE:Diffusion magnetic resonance imaging (MRI) microstructure imaging provides a unique noninvasive probe into tissue microstructure. The technique relies on biophysically motivated mathematical models, relating microscopic tissue features to the magnetic resonance (MR) signal. This work aims to determine which com...

journal_title：Magnetic resonance in medicine

authors： Ferizi U,Schneider T,Panagiotaki E,Nedjati-Gilani G,Zhang H,Wheeler-Kingshott CA,Alexander DC

更新日期：2014-12-01 00:00:00

abstract：PURPOSE:We describe a 2 × 6 channel sodium/proton array for knee MRI at 3T. Multielement coil arrays are desirable because of well-known signal-to-noise ratio advantages over volume and single-element coils. However, low tissue-coil coupling that is characteristic of coils operating at low frequency can make the potent...

journal_title：Magnetic resonance in medicine

authors： Brown R,Lakshmanan K,Madelin G,Alon L,Chang G,Sodickson DK,Regatte RR,Wiggins GC

更新日期：2016-10-01 00:00:00

abstract：:Half k-space gradient-recalled echo-planar imaging (GR-EPI) is discussed in detail. T2* decay during full k-space GR-EPI gives rise to unequal weighting of the lines of k-space, loss of signal intensity at the center of k-space, and a point-spread function that limits resolution. In addition, the long readout time for...

journal_title：Magnetic resonance in medicine

authors： Jesmanowicz A,Bandettini PA,Hyde JS

更新日期：1998-11-01 00:00:00

abstract：PURPOSE:To develop and evaluate a method for volumetric contrast-enhanced MRI of the liver, with high spatial and temporal resolutions, for combined dynamic imaging and MR angiography (MRA) using a single injection of contrast agent. METHODS:An interleaved variable density (IVD) undersampling pattern was implemented i...

journal_title：Magnetic resonance in medicine

authors： Salmani Rahimi M,Korosec FR,Wang K,Holmes JH,Motosugi U,Bannas P,Reeder SB

更新日期：2015-03-01 00:00:00

abstract：:High-signal artifacts produced by cerebrospinal fluid (CSF) flow can adversely affect fluid-attenuated inversion recovery (FLAIR) imaging of the brain and spinal cord. This study explores the use of a nonslice-selective inversion pulse to eliminate CSF flow artifacts together with a technique called "K-space Reordered...

journal_title：Magnetic resonance in medicine

authors： Herlihy AH,Oatridge A,Curati WL,Puri BK,Bydder GM,Hajnal JV

更新日期：2001-08-01 00:00:00

abstract：:An array of 33 prototype polypeptides was examined as putative contrast agents that can be distinguished from each other based on the chemical exchange saturation transfer (CEST) mechanism. These peptides were chosen based on predictions of the chemical exchange rates of exchangeable amide, amine, and hydroxyl protons...

journal_title：Magnetic resonance in medicine

authors： McMahon MT,Gilad AA,DeLiso MA,Berman SM,Bulte JW,van Zijl PC

更新日期：2008-10-01 00:00:00

abstract：PURPOSE:We report a series of techniques to reliably eliminate artifacts in interleaved echo-planar imaging (EPI) based diffusion-weighted imaging (DWI). METHODS:First, we integrate the previously reported multiplexed sensitivity encoding (MUSE) algorithm with a new adaptive Homodyne partial-Fourier reconstruction alg...

journal_title：Magnetic resonance in medicine

authors： Chang HC,Guhaniyogi S,Chen NK

更新日期：2015-05-01 00:00:00

abstract：:The objective of this study is to evaluate the effect of MR image resolution on trabecular bone parameters and to determine the acceptable resolution that can be accurately analyzed to assess structural parameters. Ten distal femoral condyle specimens of 1 × 1 × 1 cm(3) were scanned with a 4.7-T Bruker BioSpec MRI sca...

journal_title：Magnetic resonance in medicine

authors： Kim N,Lee JG,Song Y,Kim HJ,S Yeom J,Cho G

更新日期：2012-01-01 00:00:00

abstract：:An electron paramagnetic resonance image was measured for the first time from in vivo field gradient spectra of a living murine tumor (Cloudman S-91 melanoma in the tail of a DBA-2J mouse) using the paramagnetic nitroxide imaging agent 3-carboxamido-2,2,5,5-tetramethylpyrroline-1-oxyl injected into the tail vein. The ...

journal_title：Magnetic resonance in medicine

authors： Berliner LJ,Fujii H,Wan XM,Lukiewicz SJ

更新日期：1987-04-01 00:00:00

abstract：:A novel method for detecting neural activity in functional magnetic resonance imaging (fMRI) data is introduced. It is based on canonical correlation analysis (CCA), which is a multivariate extension of the univariate correlation analysis widely used in fMRI. To detect homogeneous regions of activity, the method combi...

journal_title：Magnetic resonance in medicine

authors： Friman O,Cedefamn J,Lundberg P,Borga M,Knutsson H

更新日期：2001-02-01 00:00:00

abstract：:Deuterium (2H) double-quantum filtered (DQF) NMR spectroscopy of nucleus pulposus (NP) tissues from human intervertebral discs is reported. The DQF spectral intensities, DQ build-up rates, and DQF-detected rotating-frame spin-lattice relaxation times are sensitive to the degree of hydration of the NP tissue, and displ...

journal_title：Magnetic resonance in medicine

authors： Perea W,Cannella M,Yang J,Vega AJ,Polenova T,Marcolongo M

更新日期：2007-06-01 00:00:00

abstract：:Magnetization transfer experiments using an off-resonance irradiation technique were performed on bovine serum albumin solutions by varying the irradiation frequency and the concentration. A transition of the magnetization transfer spectrum from Lorentzian to Gaussian line shape was observed around the critical concen...

journal_title：Magnetic resonance in medicine

authors： Iino M

更新日期：1994-10-01 00:00:00

abstract：:Single-slab 3D turbo/fast spin echo (SE) imaging with very long echo trains was recently introduced with slab selection using a highly selective excitation pulse and short, nonselective refocusing pulses with variable flip angles for high imaging efficiency. This technique, however, is vulnerable to image degradation ...

journal_title：Magnetic resonance in medicine

authors： Park J,Mugler JP 3rd,Hughes T

更新日期：2009-10-01 00:00:00

abstract：:Optimal control theory has been applied in the past for the design of RF pulses for selective excitation. This was the outcome of having established the controllability of the MR spin system for the selective excitation problem. "Minimum distance" was the main formulation used for the solution. Because of their robust...

journal_title：Magnetic resonance in medicine

authors： Rosenfeld D,Zur Y

更新日期：1996-09-01 00:00:00

abstract：:Radiofrequency induced pacemaker lead tip heating is one of the main reasons magnetic resonance imaging (MRI) is contraindicated for patients with pacemakers. The objective of this work was to evaluate the dependence of pacemaker lead tip heating during MRI scanning on the electrical conductivity of the medium surroun...

journal_title：Magnetic resonance in medicine

authors： Langman DA,Goldberg IB,Judy J,Paul Finn J,Ennis DB

更新日期：2012-08-01 00:00:00