Early changes in water diffusion, perfusion, T1, and T2 during focal cerebral ischemia in the rat studied at 8.5 T.

abstract：:Experiments have been performed to demonstrate and quantify cross-relaxation between water and methylene resonances in a simple model system. Inversion recovery experiments on aqueous solutions of polyethylene glycol produce a transient nuclear Overhauser effect that alters the recovery of the methylene resonance. The...

journal_title：Magnetic resonance in medicine

authors： Gore JC,Brown MS,Armitage IM

更新日期：1989-03-01 00:00:00

abstract：:Time-dependent changes of T1 in the rotating frame (T1rho), diffusion, T2, and magnetization transfer contrast on cardiac arrest-induced global ischemia in rat were investigated. T1rho, as acquired with spin lock amplitudes >0.6 G, started to increase 10-20 sec after cardiac arrest followed by an increase within 3-4 m...

journal_title：Magnetic resonance in medicine

authors： Kettunen MI,Gröhn OH,Penttonen M,Kauppinen RA

更新日期：2001-09-01 00:00:00

abstract：PURPOSE:Quantitative susceptibility mapping can be performed through the minimization of a function consisting of data fidelity and regularization terms. For data consistency, a Gaussian-phase noise distribution is often assumed, which breaks down when the signal-to-noise ratio is low. A previously proposed alternative...

journal_title：Magnetic resonance in medicine

authors： Milovic C,Bilgic B,Zhao B,Acosta-Cabronero J,Tejos C

更新日期：2018-08-01 00:00:00

abstract：:Introduction of a Gaussian weighting function into the phase encoding of the spin-echo imaging method via variable tip angle excitation, with concomitant optimization of the recycle delay, is shown to increase the sensitivity of T2-weighted imaging by up to 40%. In addition, the Gibbs artifact associated with sharp bo...

journal_title：Magnetic resonance in medicine

authors： Webb AG,Clarkson RB

更新日期：1991-10-01 00:00:00

abstract：PURPOSE:The aim of this study was to compare prospective head motion correction and motion tracking abilities of two tracking systems: Active NMR field probes and a Moiré phase tracking camera system using an optical marker. METHODS:Both tracking systems were used simultaneously on human subjects. The prospective head...

journal_title：Magnetic resonance in medicine

authors： Eschelbach M,Aghaeifar A,Bause J,Handwerker J,Anders J,Engel EM,Thielscher A,Scheffler K

更新日期：2019-01-01 00:00:00

abstract：:The purpose of this study is to examine the usefulness of histogram analysis combined with vessel size index (VSI) magnetic resonance imaging for the specific characterization of brain tumor microvasculature in a panel of six volume-matched glioma xenografts. Using a simple descriptive histogram analysis, significant ...

journal_title：Magnetic resonance in medicine

authors： Just N

更新日期：2011-03-01 00:00:00

abstract：PURPOSE:Transverse relaxation time (T2 ) mapping with MRI has a plethora of clinical and research applications. Current T2 mapping techniques are based primarily on spin-echo (SE) relaxometry strategies that rely on the signal magnitude, and often suffer from lengthy acquisition times. In this work, we propose a phase-...

journal_title：Magnetic resonance in medicine

authors： Wang X,Hernando D,Reeder SB

更新日期：2020-08-01 00:00:00

abstract：:This work presents a method applied to the design of short self-shielded gradient coils of cylindrical geometry. The method uses a hybrid technique that combines the simulated annealing and target field methods to optimize the standard stream functions. The optimized stream functions were parameterized using a few deg...

journal_title：Magnetic resonance in medicine

authors： Tomasi D

更新日期：2001-03-01 00:00:00

abstract：:A novel method based on selective detection of rapidly changing DeltaB(0) magnetic fields and suppression of slowly changing DeltaB(0) fields is presented. The ultimate goal of this work is to present a method that may allow detection of transient and subtle changes in B(0) in cortical tissue associated with electrica...

journal_title：Magnetic resonance in medicine

authors： Bodurka J,Bandettini PA

更新日期：2002-06-01 00:00:00

abstract：:A novel linear parameterization for the variable flip angle method for longitudinal relaxation time T(1) quantification from spoiled steady state MRI is derived from the half angle tangent transform, τ, of the flip angle. Plotting the signal S at coordinates x=Sτ and y=S/τ, respectively, establishes a line that render...

journal_title：Magnetic resonance in medicine

authors： Helms G,Dathe H,Weiskopf N,Dechent P

更新日期：2011-09-01 00:00:00

abstract：:The focal underdetermined system solver (FOCUSS) was originally designed to obtain sparse solutions by successively solving quadratic optimization problems. This article adapts FOCUSS for a projection reconstruction MR imaging problem to obtain high resolution reconstructions from angular under-sampled radial k-space ...

journal_title：Magnetic resonance in medicine

authors： Ye JC,Tak S,Han Y,Park HW

更新日期：2007-04-01 00:00:00

abstract：:In this article, we determined the relative accuracy of semiautomated spleen volumetry with diffusion-weighted (DW) MR images compared to standard manual volumetry with DW-MR or CT images. Semiautomated spleen volumetry using simple thresholding followed by 3D and 2D connected component analysis was performed with DW-...

journal_title：Magnetic resonance in medicine

authors： Lee J,Kim KW,Lee H,Lee SJ,Choi S,Jeong WK,Kye H,Song GW,Hwang S,Lee SG

更新日期：2012-07-01 00:00:00

abstract：:A multiple quantum filter strategy is presented for spectrally discriminating metabolites with strongly coupled spins from those whose spins are either uncoupled or weakly coupled. The strategy also includes a means for selectively suppressing the background multiplets of metabolites that also have strongly coupled sp...

journal_title：Magnetic resonance in medicine

authors： Kim H,Wild JM,Allen PS

更新日期：2004-02-01 00:00:00

abstract：:Longitudinal and transverse relaxation rates for the 11B resonances in sodium borocaptate (BSH) at varying concentrations were measured in undiluted horse serum in a 4.7 Tesla field. The results could be fit by a model that assumes fast exchange of the BSH molecule between a free and a bound state, using values of 0.7...

journal_title：Magnetic resonance in medicine

authors： Bendel P,Frantz A,Zilberstein J,Kabalka GW,Salomon Y

更新日期：1998-03-01 00:00:00

abstract：:19F NMR imaging of the perfluorocarbon emulsion Fluosol has been used to study regional variations in oxygen tension in rat liver and spleen. We have used the linear dependence of spin lattice relaxation rate (1/T1) on the partial oxygen pressure (pO2) of Fluosol to determine the oxygen tension in the reticuloendothel...

journal_title：Magnetic resonance in medicine

authors： Holland SK,Kennan RP,Schaub MM,D'Angelo MJ,Gore JC

更新日期：1993-04-01 00:00:00

abstract：PURPOSE:Cross-relaxation of protons with (14) N nuclei in proteins enhances relaxivity in the quadrupolar dip range of typically 2-3 MHz Larmor frequency. The magnitude of these dips was suggested as a means of assessing the degeneracy of articular cartilage during osteoarthritis (OA). However, so far only proteoglycan...

journal_title：Magnetic resonance in medicine

authors： Rössler E,Mattea C,Stapf S

更新日期：2015-05-01 00:00:00

abstract：PURPOSE:The oxygen extraction fraction (OEF) is an important biomarker for tissue-viability. MRI enables noninvasive estimation of the OEF based on the blood-oxygenation-level-dependent (BOLD) effect. Quantitative OEF-mapping is commonly applied using least-squares regression (LSR) to an analytical tissue model. Howeve...

journal_title：Magnetic resonance in medicine

authors： Domsch S,Mürle B,Weingärtner S,Zapp J,Wenz F,Schad LR

更新日期：2018-02-01 00:00:00

abstract：:The utility of a noninvasive steady state susceptibility-contrast MRI technique for continuous measurement of relative cerebral blood volume (rCBV) during global transient ischemia and subsequent hyperemia in a feline ischemia model is demonstrated. The measurements were obtained during a 10-min period of occlusion an...

journal_title：Magnetic resonance in medicine

authors： Hamberg LM,Boccalini P,Stranjalis G,Hunter GJ,Huang Z,Halpern E,Weisskoff RM,Moskowitz MA,Rosen BR

更新日期：1996-02-01 00:00:00

abstract：:With the advent of breath-hold MR cardiac imaging techniques, the minimization of TR and TE for oblique planes has become a critical issue. The slew rates and maximum currents of gradient amplifiers limit the minimum possible TR and TE by adding dead-periods to the pulse sequences. We propose a method of designing gra...

journal_title：Magnetic resonance in medicine

authors： Atalar E,McVeigh ER

更新日期：1994-12-01 00:00:00

abstract：PURPOSE:Previous studies have associated low pH in intervertebral discs (IVDs) with discogenic back pain. The purpose of this study was to determine whether quantitative CEST (qCEST) MRI can be used to detect pH changes in IVDs in vivo. METHODS:The exchange rate ksw between glycosaminoglycan (GAG) protons and water pr...

journal_title：Magnetic resonance in medicine

authors： Zhou Z,Bez M,Tawackoli W,Giaconi J,Sheyn D,de Mel S,Maya MM,Pressman BD,Gazit Z,Pelled G,Gazit D,Li D

更新日期：2016-12-01 00:00:00

abstract：:The incorporation of RF coils into the tips of intravascular devices has been shown to enable the localization of catheters and guidewires under MR guidance. Furthermore, such coils can be used for endoluminal imaging. The long cable required to connect the coil with the scanner input inadvertently acts as a dipole an...

journal_title：Magnetic resonance in medicine

authors： Ladd ME,Quick HH

更新日期：2000-04-01 00:00:00

abstract：:Hydrogen, sodium, and fluorine (added F-) NMR spectra of venous and oxygenated blood were measured. The fluorine resonance was seen as a single peak in both samples, and all three resonances exhibited the same deoxy-oxy shift. Because F- exchanges slowly across the red cell membrane, and because sodium is 95% extracel...

journal_title：Magnetic resonance in medicine

authors： Brooks RA,Brunetti A,Alger JR,Di Chiro G

更新日期：1989-11-01 00:00:00

abstract：PURPOSE:Recent MRI studies have suggested that the magnetic susceptibility of white matter (WM) in the human brain is anisotropic, providing a new contrast mechanism for the visualization of fiber bundles and allowing the extraction of cellular compartment-specific information. This study provides an independent confir...

journal_title：Magnetic resonance in medicine

authors： van Gelderen P,Mandelkow H,de Zwart JA,Duyn JH

更新日期：2015-11-01 00:00:00

abstract：:The purpose of this study was the simulation and measurement of balanced steady-state free precession (bSSFP) slice profiles for a detailed analysis of the influence of off-resonance effects on slice profile shape and bSSFP signal intensity. Due to the frequency response function of the bSSFP sequence, measurements th...

journal_title：Magnetic resonance in medicine

authors： Staehle F,Leupold J,Hennig J,Markl M

更新日期：2008-05-01 00:00:00

abstract：PURPOSE:Breath-holding is an established strategy for reducing motion artifacts in abdominal imaging. However, the breath-holding capabilities of patients are often overstrained by scans with large coverage and high resolution. In this work, a new strategy for coping with resulting incomplete breath-holds in abdominal ...

journal_title：Magnetic resonance in medicine

authors： Gdaniec N,Eggers H,Börnert P,Doneva M,Mertins A

更新日期：2014-05-01 00:00:00

abstract：:A stimulated echo sequence was used to obtain 19F NMR spectra from within a 4-ml voxel in a cat brain. The time dependence of the 19F NMR signal from an inert gas (CHF3) was used to calculate the blood flow in the voxel. The position of the voxel was selected using a 1H MR image. ...

journal_title：Magnetic resonance in medicine

authors： van Zijl PC,Ligeti L,Sinnwell T,Alger JR,Chesnick AS,Moonen CT,McLaughlin AC

更新日期：1990-12-01 00:00:00

abstract：PURPOSE:The aim of this work was to quantify the extent of lipid-rich necrotic core (LRNC) and intraplaque hemorrhage (IPH) in atherosclerotic plaques. METHODS:Patients scheduled for carotid endarterectomy underwent four-point Dixon and T1-weighted magnetic resonance imaging (MRI) at 3 Tesla. Fat and R2* maps were gen...

journal_title：Magnetic resonance in medicine

authors： Koppal S,Warntjes M,Swann J,Dyverfeldt P,Kihlberg J,Moreno R,Magee D,Roberts N,Zachrisson H,Forssell C,Länne T,Treanor D,de Muinck ED

更新日期：2017-07-01 00:00:00

abstract：:This contribution reports the first direct and noninvasive observation of cerebral glucose in normal anesthetized rats (n = 16) using short-echo-time localized proton NMR spectroscopy (2.35 T, STEAM, TR = 6000 ms, TE = 20 ms, 125 microliters). In addition to resonances from N-acetyl aspartate (NAA), glutamate, total c...

journal_title：Magnetic resonance in medicine

authors： Gyngell ML,Michaelis T,Hörstermann D,Bruhn H,Hänicke W,Merboldt KD,Frahm J

更新日期：1991-06-01 00:00:00

abstract：:We have noninvasively produced low-resolution, quantitative nuclear magnetic resonance images of cerebral blood flow in 2-ml voxels in eight cats. Typical signal-to-noise of 4 to 1 was obtained in cerebral voxels in 16.5-s epochs. Mean flow during normocapnia (paCO2 = 39 +/- 4 mm Hg) and hypercapnia (paCO2 = 62 +/- 4 ...

journal_title：Magnetic resonance in medicine

authors： Branch CA,Ewing JR,Helpern JA,Ordidge RJ,Butt S,Welch KM

更新日期：1992-11-01 00:00:00

abstract：:To increase image acquisition efficiency, we develop alternative gradient encoding strategies designed to provide spatial encoding complementary to the spatial encoding provided by the multiple receiver coil elements in parallel image acquisitions. Intuitively, complementary encoding is achieved when the magnetic fiel...

journal_title：Magnetic resonance in medicine

authors： Tam LK,Stockmann JP,Galiana G,Constable RT

更新日期：2012-10-01 00:00:00