abstract：:In order to obtain proton magnetic resonance spectra from the normal human kidney in vivo, we employed a STEAM sequence with delay times TE = 10 ms and TM = 30 ms. Signals are attenuated during STEAM sequences by J-coupling effects and by macroscopic movement of the sample. The combination of short echo times and resp...

journal_title：Magnetic resonance in medicine

authors： Dixon RM,Frahm J

更新日期：1994-05-01 00:00:00

abstract：:Longitudinal P-31 relaxation rate enhancements of phosphate groups have been measured at pH 7-7.2 and 310 degrees K on aqueous solutions containing adenosine triphosphate (ATP), phosphocreatine (PCr), inorganic phosphate (Pi) and some lanthanide complexes (Gd-DOTA, Gd-HPDO3A, Gd-DO3A, Gd-DTPA, Gd-DTPA-BMA). The macroc...

journal_title：Magnetic resonance in medicine

authors： Vander Elst L,Van Haverbeke Y,Goudemant JF,Muller RN

更新日期：1994-04-01 00:00:00

abstract：:A new 3D acquisition regimen that enables the collection of conventional, water-suppressed, and fat-suppressed images with no increase in scan times compared with currently implemented 3D sequences is presented. The method is based on conventional 3D steady state with interleaved selective excitation of the fat resona...

journal_title：Magnetic resonance in medicine

authors： Sun L,Aletras AH,Schmalbrock P,Skinner TE,Chakeres D,Irsik R,Robitaille PM

更新日期：1994-04-01 00:00:00

abstract：:A partial saturation method is described for obtaining rapid images of tissue 1H spin-lattice relaxation rates following administration of the paramagnetic contrast agent gadolinium-diethylenetriaminepentaacetate. The paramagnetic contribution to the relaxation rates is proportional to the concentration of contrast ag...

journal_title：Magnetic resonance in medicine

authors： Kennedy SD,Szczepaniak LS,Gibson SL,Hilf R,Foster TH,Bryant RG

更新日期：1994-03-01 00:00:00

abstract：:Using a material that already is in widespread use in humans, India ink, the first EPR measurements in a human have been made, using the India ink in a pre-existing tattoo. The EPR spectra of India ink are very sensitive to the partial pressure of oxygen (pO2), thereby making it feasible to use this approach to measur...

journal_title：Magnetic resonance in medicine

authors： Swartz HM,Liu KJ,Goda F,Walczak T

更新日期：1994-02-01 00:00:00

abstract：:Detre et al. (Magn. Reson. Med. 23, 37-45 (1992)) and Zhang et al., (Magn. Reson. Med. 25, 362 (1992)) have recently demonstrated a technique for the measurement of regional cerebral blood flow (rCBF) based on the continuous saturation (or inversion) of the arterial blood supply to the brain in rats at 4.7 T. In the w...

journal_title：Magnetic resonance in medicine

authors： Walsh EG,Minematsu K,Leppo J,Moore SC

更新日期：1994-02-01 00:00:00

abstract：:The commercial synthetic homopolypeptide polyaspartate (average MW = 30,000, approximately 220 monomers) in solution quantitatively binds up to 40 mol Gd3+ ions per mole of polyaspartate. The water proton relaxivity of the solutions is far higher than that of clinically used or commonly investigated gadolinium(III) co...

journal_title：Magnetic resonance in medicine

authors： Cavagna F,Luchinat C,Scozzafava A,Xia Z

更新日期：1994-01-01 00:00:00

abstract：:Recent in vivo 1H MRS studies of muscle oxygen levels by means of myoglobin (Mb) oxygenation have necessitated an investigation of the possible contamination from deoxy-hemoglobin (Hb). To determine the contribution of Hb in these NMR measurements, we studied the NMR visibility of histidyl N-delta proton of Hb in lyse...

journal_title：Magnetic resonance in medicine

authors： Wang DJ,Nioka S,Wang Z,Leigh JS,Chance B

更新日期：1993-12-01 00:00:00

abstract：:Homogeneous soft tissue, as regards its magnetic relaxation properties, is well-modeled by solutions of cross-linked protein (see Koenig and Brown, Prog. NMR Spectr. 22, 487 (1991)). Interactions at the solute-solvent interface alter the hydrodynamics of solvent water, and also couple the solute and solvent proton Zee...

journal_title：Magnetic resonance in medicine

authors： Koenig SH,Brown RD 3rd

更新日期：1993-12-01 00:00:00

abstract：:Generating flow-specific images (arteriograms, venograms) with optimal signal-to-noise ratios for time-resolved MR angiography is a conditional maximum problem, and its solutions are generalized matched filters. We have investigated six matched filters, corresponding to all possible combinations of three flow suppress...

journal_title：Magnetic resonance in medicine

authors： Wang Y,Weber DM,Korosec FR,Mistretta CA,Grist TM,Swan JS,Turski PA

更新日期：1993-11-01 00:00:00

abstract：:A method is suggested whereby the shifted extracellular triple quantum filtered 23Na signal of an isolated organ is completely eliminated. The method is based on the long relaxation time of the triple quantum coherence and on its fast evolution rate. When the carrier frequency is set on top of the intracellular sodium...

journal_title：Magnetic resonance in medicine

authors： Navon G

更新日期：1993-10-01 00:00:00

abstract：:Cerebral metabolite concentrations and water content were measured by means of localized proton magnetic resonance spectroscopy in 50 children, while metabolite peak ratios in short echo time spectra were evaluated in 173 examinations. Normative curves for normal development were established for two cerebral locations...

journal_title：Magnetic resonance in medicine

authors： Kreis R,Ernst T,Ross BD

更新日期：1993-10-01 00:00:00

abstract：:We present preliminary results for a 3D finite element calculation to evaluate RF penetration in conducting dielectric materials at high field strengths. A tetrahedral mesh is used along with a Coulomb gauge constraint in a finite element method that yields excellent numerical stability at high frequencies. Accuracy i...

journal_title：Magnetic resonance in medicine

authors： Petropoulos LS,Haacke EM,Brown RW,Boerner E

更新日期：1993-09-01 00:00:00

abstract：:Some of the important features of how pulsatile flow generates artifacts in three-dimensional magnetic resonance imaging are analyzed and demonstrated. Time variations in the magnetic resonance signal during the heart cycle lead to more complex patterns of artifacts in 3D imaging than in 2D imaging. The appearance and...

journal_title：Magnetic resonance in medicine

authors： Frank LR,Buxton RB,Kerber CW

更新日期：1993-09-01 00:00:00

abstract：:We propose a new magnetic resonance imaging (MRI) technique that is sensitive to myocardial tissue perfusion that obviates the use of an extrinsic contrast agent. Significant advantages of such a technique are that it avoids accumulation of contrast agent when repeated studies are performed on the same subject and tha...

journal_title：Magnetic resonance in medicine

authors： Prasad PV,Burstein D,Edelman RR

更新日期：1993-08-01 00:00:00

abstract：:Myocardial tagging is a new noninvasive MRI method that allows the study of myocardial motion with high accuracy. However, with conventional tagging techniques tagging contrast is impaired at later heart phases due to longitudinal relaxation. An improved method, called Complementary SPAtial Modulation of Magnetization...

journal_title：Magnetic resonance in medicine

authors： Fischer SE,McKinnon GC,Maier SE,Boesiger P

更新日期：1993-08-01 00:00:00

abstract：:A gradient technique to measure electron paramagnetic resonance spectra simultaneously at several different locations is described. The technique is based on the use of point probes containing paramagnetic centers. The value of the magnetic field gradient is chosen to be sufficient to separate the EPR signals from the...

journal_title：Magnetic resonance in medicine

authors： Smirnov AI,Norby SW,Clarkson RB,Walczak T,Swartz HM

更新日期：1993-08-01 00:00:00

abstract：:A demonstration of MR guided thermal surgery involved experiments with imaging of focused ultrasound in an MRI system, measurements of the thermal transients and a thermal analysis of the resulting images. Both the heat distribution and the creation of focused ultrasound lesions in gel phantoms, in vitro bovine muscle...

journal_title：Magnetic resonance in medicine

authors： Cline HE,Schenck JF,Watkins RD,Hynynen K,Jolesz FA

更新日期：1993-07-01 00:00:00

abstract：:In vivo 1H MRS can be used to detect and quantify the lactate resonance at 1.3 ppm provided that overlapping lipid resonances are eliminated. A homonuclear spectral editing method was developed to acquire uncontaminated 1H spectra of lactate with adiabatic pulses. An advantage of the adiabatic pulse sequence is the ab...

journal_title：Magnetic resonance in medicine

authors： Schupp DG,Merkle H,Ellermann JM,Ke Y,Garwood M

更新日期：1993-07-01 00:00:00

abstract：:T2 measurements of 31P NMR signals of ATP using the Hahn 90 degrees-180 degrees spin-echo sequence imply difficulties whenever the 180 degrees pulse angle is not completely perfect. The reason for this finding is the crucial influence of the J-couplings of the ATP signals which result in intensity modulations and cons...

journal_title：Magnetic resonance in medicine

authors： Jung WI,Straubinger K,Bunse M,Widmaier S,Schick F,Küper K,Dietze G,Lutz O

更新日期：1993-07-01 00:00:00

abstract：:Diffusion-weighted MRI is a clinically useful technique, but its utility is compromised by high sensitivity to patient motion. Use of radial-scan data acquisition and projection reconstruction, rather than the conventional Fourier imaging method, can substantially reduce the sensitivity to global translational motion ...

journal_title：Magnetic resonance in medicine

authors： Gmitro AF,Alexander AL

更新日期：1993-06-01 00:00:00

abstract：:The echo-planar k-space trajectory can be used as the basis for any two-dimensional selective pulse. The main application is spectral-spatial pulses, which must be based on the echo-planar trajectory. In this paper we show how echo-planar spin-echo (EPSE) pulses may be designed. ...

journal_title：Magnetic resonance in medicine

authors： Pauly J,Spielman D,Macovski A

更新日期：1993-06-01 00:00:00

abstract：:A new method is presented for the quantitative determination of regional blood volumes in vivo. It is based on rapid quantitative T1 mapping by Snapshot FLASH MRI combined with the injection of an intravascular MR contrast agent. Regional blood volumes in four different tissues of the rat (skeletal muscle, heart, live...

journal_title：Magnetic resonance in medicine

authors： Schwarzbauer C,Syha J,Haase A

更新日期：1993-05-01 00:00:00

abstract：:Traditionally, the method of nonlinear least squares (NLLS) analysis has been used to estimate the parameters obtained from exponential decay data. In this study, we evaluated the use of Bayesian probability theory to analyze such data; specifically, that resulting from intravoxel incoherent motion NMR experiments. An...

journal_title：Magnetic resonance in medicine

authors： Neil JJ,Bretthorst GL

更新日期：1993-05-01 00:00:00

abstract：:Noninvasive investigation of aldose reductase activities in rat testis was performed using 3-fluoro-3-deoxy-D-glucose (3-FDG) and nuclear magnetic resonance (NMR) spectroscopy/imaging. Quantitative determination of testis aldose reductase activities, expressed as the sorbitol index, showed a value similar to that of b...

journal_title：Magnetic resonance in medicine

authors： Nakada T,Kwee IL

更新日期：1993-04-01 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：:Electron Spin Echo Envelope Modulation (ESEEM) data are reported for three gadolinium (III) chelates, Gd-EDTA, Gd-DTPA, and Gd-TTHA, in frozen D2O/CH3OD glasses. This series includes Gd-DTPA, an MRI contrast agent that is in clinical use. Three-pulse electron spin echo modulation patterns can be modeled to yield geome...

journal_title：Magnetic resonance in medicine

authors： Clarkson RB,Hwang JH,Belford RL

更新日期：1993-04-01 00:00:00

abstract：:A 3.0 Tesla, 0.80-m bore magnet replaced our previous 1.9 Tesla, 0.76-m magnet. The 3.0 Tesla replacement magnet had a dipole moment of 1.7 with respect to that of the 1.9 Tesla magnet. The pre-existing cylindrically symmetric passive steel shielding was modified to confine the fringe fields of the replacement magnet ...

journal_title：Magnetic resonance in medicine

authors： Ewing JR,Warner R,Helpern JA

更新日期：1993-03-01 00:00:00

abstract：:Using NMR spectroscopy, we studied purified, human T lymphocytes in a serum-free medium. Purified cells were entrapped inside agarose beads and induced to proliferate by the mitogens phorbol-12-myristate-13-acetate and ionomycin. T lymphocytes in standard culture and inside agarose beads exhibit comparable viability, ...

journal_title：Magnetic resonance in medicine

authors： Bental M,Deutsch C

更新日期：1993-03-01 00:00:00

abstract：:A lactate editing sequence based on the use of spin-locking pulses with surface coils is described. The sequence retains more than 90% of the available lactate magnetization and suppresses at least 95% of the lipid signal in a single scan and ca. 99.5% after a simple two step cycle. The technique allows simultaneous o...

journal_title：Magnetic resonance in medicine

authors： Bourgeois D,Kozlowski P

更新日期：1993-03-01 00:00:00

abstract：:Chemical shifts were extracted from in vivo 3-dimensional 31P NMR CSI data and pH images were constructed. The images could spatially resolve tissue pH ranging from 5.8 to 7.2 (with uncertainty of 0.11-0.17 pH unit) in an ischemia-reperfusion model of diabetic rat calf muscles. ...

journal_title：Magnetic resonance in medicine

authors： Morikawa S,Inubushi T,Kito K,Kido C

更新日期：1993-02-01 00:00:00

abstract：:We have obtained high-field (11.7 Tesla), high-resolution carbon-13 solid-state "magic-angle" sample-spinning nuclear magnetic resonance (NMR) spectra of a variety of phospholipids, sphingolipids, myelin and white matter samples, resolving and assigning over 40 resonances in the spectra of human and bovine myelin. The...

journal_title：Magnetic resonance in medicine

authors： Husted C,Montez B,Le C,Moscarello MA,Oldfield E

更新日期：1993-02-01 00:00:00

abstract：:Strong, extensive magnetic fringe fields are a significant problem with magnetic resonance imaging magnets. This is particularly acute with 4-T, whole-body research magnets. To date this problem has been addressed by restricting an extensive zone around the unshielded magnet or by placing external unsaturated iron shi...

journal_title：Magnetic resonance in medicine

authors： Huson FR,Bryan RN,MacKay WW,Herrick RC,Colvin J,Ford JJ,Pissanetzky S,Plishker GA,Rocha R,Schmidt W

更新日期：1993-01-01 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：:The concentration of oxygen within cells is important in many physiological and pathological processes, but such oxygen-dependent phenomena are generally studied as a function of the concentration of extracellular oxygen, due to a lack of suitable methods. Electron parmamagnetic resonance (EPR) oximetric techniques of...

journal_title：Magnetic resonance in medicine

authors： Glockner JF,Norby SW,Swartz HM

更新日期：1993-01-01 00:00:00

abstract：:A method is presented for measuring myocardial deformation in a breath-hold with tagged cine MRI. Tagged cine images of human hearts are obtained in arbitrary oblique planes on a standard imager with as few as four heartbeats. The scan time has been reduced 16- to 64-fold from previous techniques. ...

journal_title：Magnetic resonance in medicine

authors： McVeigh ER,Atalar E

更新日期：1992-12-01 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：:Gradient-recalled echo-planar (T2*-weighted) imaging was used to noninvasively monitor regional blood oxygenation state changes in real time during transient episodes of focal ischemia in cat brain. Varying ischemic intervals (12 s to 30 min) were caused by middle cerebral artery occlusion. A rapid signal drop was not...

journal_title：Magnetic resonance in medicine

authors： De Crespigny AJ,Wendland MF,Derugin N,Kozniewska E,Moseley ME

更新日期：1992-10-01 00:00:00

abstract：:This study investigates the potential of in vivo 31P magnetic resonance spectroscopy (MRS) to characterize musculoskeletal tumors and to determine preoperative levels of histological necrosis, which is an important clinical indicator of patient response. Pretherapy MRS was performed on 28 patients with large musculosk...

journal_title：Magnetic resonance in medicine

authors： Redmond OM,Bell E,Stack JP,Dervan PA,Carney DN,Hurson B,Ennis JT

更新日期：1992-10-01 00:00:00

abstract：:A magnetic resonance imaging (MRI) method is presented to detect, localize, and quantify myocardial kinematics by measuring the material rate-of-strain tensor at each pixel in gated NMR images of the heart. The immediate, local effect of muscular activity is self-deformation, and the strain tensor is the basic mathema...

journal_title：Magnetic resonance in medicine

authors： Wedeen VJ

更新日期：1992-09-01 00:00:00