bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unified multiple‐feature color display for MR images
Authors: Kamman R. L. , Stomp G. P. , Berendsen H. J. C. 
Published: March 2007

AbstractA display method is proposed in which the spin‐lattice relaxation time T1, the spinspin relaxation time T2, and the proton density ρ of each pixel in a MR image are simultaneously expressed in color features in a unified way that allows international standardization. MR images were made from a phantom, a healthy volunteer, and patients in such a way that T1 and T2 and proton density images could be derived. T1 and T2 data were compared with accurate relaxation time measurements of the phantom content. Color images were computed from the acquired T1 and T2 images using matrix multiplication on a pixel base. In this way the color combination in each pixel represents the properties of that particular pixel by a unique mixing of the elementary colors red, green, and blue. Color resolution could be modified using different choices of the reference triangle in which the color combinations were defined. This method of representation offers a means for displaying multiple features as T1, and T2 in one directly interpretable image, independent of instrumental settings. © 1989 Academic Press, Inc.
A fuse for magnetic resonance imaging probes
Authors: Hedges L. Kyle 
Published: March 2007

AbstractIn a research environment, a magnetic resonance imaging system's manufacturer‐supplied protection against excessive rf power deposition in the sample is often compromised. This paper presents a widely applicable scheme, based on a commonly available fuse, that simply and effectively limits the average rf power into a magnetic resonance imaging probe. © 1989 Academic Press, Inc.
31P NMR bayesian spectral analysis of rat brain in vivo
Authors: Bretthorst G. Larry , Kotyk John J. , Ackerman Joseph J. H. 
Published: March 2007

AbstractBayesian spectrum analysis for parameter estimation is a rigorous statistical (non‐ Fourier‐based) method. Herein the Bayesian quadrature NMR model is introduced and applied to analysis of 31P NMR time domain data from in vivo rat brain. Immunity to both the brain spectrum “baseline hump” and the phase twist is demonstrated. © 1989 Academic Press, Inc.
Computer simulation of MRS localization techniques: An analysis of ISIS
Authors: Lawry T. J. , Karczmar G. S. , Weiner M. W. , Matson G. B. 
Published: March 2007

AbstractComputer simulations were used to evaluate the ISIS localization technique as implemented with both head and surface coils. The effects ofchemical shift, B1 inhomogeneity, repetition time, T2 relaxation, a postacquisition saturation pulse, and a B1 insensitive observation pulse were examined. Integrals of ISIS signals over the sample volume showed that significant signal loss from the volume of interest (VOI) and contamination from outside the VOI can occur for both head and surface coil ISIS experiments. The results showed that the saturation pulse, order of the various ISIS acquisitions, and repetition time affect contamination but not signal loss. In addition, short T2 and high RF power can combine synergistically to degrade the selective inversion pulses, causing further contamination and signal loss. © 1989 Academic Press, Inc.
The use of band‐selectable digital filtering in magnetic resonance image enhancement
Authors: Mitchell D. K. , Nichols S. T. , Smith M. R. , Scott K. 
Published: March 2007

AbstractManipulation of the data describing two‐dimensional magnetic resonance (MR) images can be used to zoom an image, decrease image noise and artifacts by modeling, or emphasize object edges in the field of view. In this paper, a two‐dimensional band‐selectable digital filtering (2D‐BSDF) technique is detailed. This can be used to decrease the computational burden and increase algorithm stability associated with such data manipulation. Many display devices have the ability of expanding an image by pixel or linear interpolation. Application of the efficient zooming fast Fourier transformation algorithms provides a superior quality sinc‐function interpolated image. In 2D‐BSDF, the ideal rectangular windows used in sinc‐function interpolation are replaced by windows with a more gradual roll‐off. This gradual roll‐off results in a slight degradation of the image edges but substantially reduces the computation time. Modeling of MRI data has been attempted to remove noise and artifacts from the image. These algorithms are computationally expensive and frequently unstable because of the high model orders required. The 2D‐BSDF can be used to prepare a reduced data set, without loss ofinformation. A lower order model may be applied to the subset and computation times approaching that required for normal fast Fourier transform algorithms result. The absence of noise and signal from objects outside the region of interest can considerably enhance the stability of the modeling algorithms. The use of BSDF is equally applicable when used in association with the modeling of 2D NMR spectroscopy data or with edge enhancement or any other data manipulation of magnetic resonance imaging images. In this paper an explanation of ID‐BSDF is provided and an algorithm for 2D‐BSDF is developed. A comparison of filter designs and computational times is given when applying the technique to zooming and modeling of MR images. Images from medical MRI data are provided. © 1989 Academic Press, Inc.
Magnetic resonance imaging using a ribbonator: Hand and wrist
Authors: Marshall Eric A. , Listinsky Jay J. , Ceckler Toni L. , Szumowski Jerzy , Bryant Robert G. , Hornak Joseph P. 
Published: March 2007

AbstractA modified version of a single‐turn solenoid with rectangular symmetry, which we call a ribbonator, provides excellent magnetic resonance images of the hand and wrist when used as both the transmitter and the receiver in a 1.5‐T clinical imaging system. The very high RF efficiency provides excellent signal‐to‐noise and anatomical resolution. Design equations and RF properties of the resonator are discussed. © 1989 Academic Press, Inc.
Hybrid methods of chemical‐shift imaging
Authors: Szumowski Jerzy , Eisen Jane K. , Vinitski Simon , Haake Peter W. , Plewes Donald B. 
Published: March 2007

AbstractWe propose a family of hybrid chemical‐shift sequences which combines two physical principles for water/lipid separation to minimize artifacts introduced by B0 and B1 inho‐mogeneities. Hybrid sequences provide improved species discrimination over earlier methods without resorting to postprocessing while maintaining a multislice/multiecho capability. © 1989 Academic Press, Inc.
Variable excitation angle AFP pulses
Authors: Norris David G. , Haase Axel 
Published: March 2007

AbstractRF pulses employing the principle of adiabatic fast passage are finding increasing application with surface coils. A small modification to existing AFP pulses that allows the excitation angle to be chosen largely independently of B1 strength is described here. Rapid 3D imaging applications of such pulses are presented. © 1989 Academic Press, Inc.
Interleaved 31P NMR with transcutaneous nerve stimulation (tns): a method of monitoring compliance‐independent skeletal muscle metabolic response to exercise
Authors: Helpern J. A. , Kao W. , Gross B. , Kensora T. G. , Welch K. M. A. 
Published: March 2007

Abstract31P NMR spectroscopy was used to monitor the metabolic response of the tibialis anterior muscle group to transcutaneous nerve stimulation of the peroneal nerve at a rate of 4 Hz for 5 min in human volunteers (n = 8). It is demonstrated that this technique can be used as a method of investigating effort‐free and compensation‐independent skeletal muscle exercise. © 1989 Academic Press, Inc.
A perfusion system developed for 31p NMR study of melanoma cells at tissue‐like density
Authors: Minichiello Margaret M. , Albert Daniel M. , Kolodny Nancy H. , Lee Moon‐Soo , Craft Joseph L. 
Published: March 2007

AbstractA perfusion culture system has been developed for 31P NMR study of human uveal melanoma metabolism by adapting the Vitafiber I cartridge system (Amicon). 31P NMR spectra collected weekly during periods of up to 10 weeks demonstrated increasing levels of phosphorus metabolites as the anchorage‐dependent cells grew to tissue‐like density. © 1989 Academic Press, Inc.
The influence of pulse sequence on the relaxation effects of superparamagnetic iron oxide contrast agents
Authors: Majumdar S. , Zoghbi S. S. , Gore J. C. 
Published: March 2007

AbstractThe effects of different pulse sequences and timing parameters on the increase in transverse relaxation rate produced by superparamagnetic iron oxide particles have been studied. Gradient‐echo, single spin‐echo, and multiple‐echo images recorded at 2.0 T were used to evaluate the reduction in signal intensity per unit concentration of iron oxide for different echo times and in different media. For the same echo time, gradient‐echo sequences were found to be more than twice as sensitive to the effects of the agent as single spin‐echo imaging sequences, while multiple‐echo sequences were much less affected than either. Using measurements of the relative effects on different sequences, the contributions of different relaxation mechanisms have been quantified. © 1989 Academic Press, Inc.
Bone marrow uptake of liposome‐entrapped spin label after liver blockade with empty liposomes
Authors: Federico Massimo , Iannone Anna , Chan Hsiao C. , Magin Richard L. 
Published: March 2007

AbstractUsing an ESR spectrometer, we studied the time course of the uptake of the liposomeentrapped spin label 2,2,6,6‐tetramethylpipendine‐N‐oxyl‐4‐tnmethylammonium in liver, spleen, and bone marrow following reticuloendothelial liver blockade. Our results show that suppression of the phagocytic activity of the liver increases the delivery of liposomes to the spleen and bone marrow without substantially altering uptake by the liver. © 1989 Academic PITS, Inc. © 1989 Academic Press, Inc.
Evaluation of a newly discovered water suppression pulse sequence for high‐field in vivo1H surface coil NMR spectroscopy
Authors: Alger J. R. , Brunetti A. , Nagashima G. , Hossmann K.‐A. 
Published: March 2007

AbstractThe use of a water‐suppressing spin‐echo pulse sequence reported recently (V. Sklenar and A. Bax, J. Magn. Reson. 74, 469 (1987); M. von Kienlin, M. DeCorps, J. P. Albrand, M. F. Foray, and P. Blondet, J. Magn. Reson. 76, 169 (1987)) was evaluated for in vivo brain proton surface coil NMR spectroscopy. The studies were performed on cat brain using surface coils at 4.7 T. The sequence produced brain spectra with adequate water suppression, and a broader excitation profile than sequences which form spin echoes using 1331 pulses (P. J. Hore, J. Magn. Reson. 54, 539 (1983); H. P. Hetherington, M. J. Avison, and R. G. Shulman, Proc. Natl. Acad. Sci. USA 82, 3115 (1985)). The phase artifacts were smaller than those produced in 1331 methods, but theoretical analysis showed they should not be completely absent. The effectiveness of lengthening the spin‐echo delay in the new sequence for suppression of unwanted lipid resonances was demon‐strated. The sequence was shown to be capable of detecting lactate formation and clearance in a global cerebral ischemia experiment. © 1989 Academic WSS, Inc.
Androgen sensitivity of rat prostate carcinoma studied by 31P NMR spectroscopy, 1H MR imaging, and 23Na MR imaging
Authors: Vigneron D. B. , Hricak H. , James T. L. , Jajodia P. B. , Nunes L. , Narayans P. 
Published: March 2007

Abstract31P NMR spectroscopy, 1H magnetic resonance (MR) imaging, and 23Na MR imaging were used to study the biochemical difference between nine hormone‐sensitive and six hormone‐resistant rat prostate cancers and to follow bioenergetic and morphologic changes subsequent to androgen deprivation in the hormone‐sensitive model. Neither 1H nor 23Na MR image characteristics were useful in distinguishing androgen‐sensitive from androgen‐resistant prostate cancer nor in identifying androgen deprivation. 31P NMR spectroscopy did detect bioenergetic differences between the hormone‐sensitive and hormone‐resistant tumors. Baseline spectra showed a significantly higher PCr/ATP ratio (mean 0.86 ± 0.09 SEM) for hormone‐sensitive tumors than for hormone‐resistant tumors (mean 0.26 ± 0.07 SEM). By 3 days after androgen deprivation (orchiectomy (castration)), PCr/ATP ratios had decreased noticeably; by 1 week, the decrease was statistically significant and remained so for the rest of the study (3 weeks). It appears that 31P NMR spectroscopy is useful in detecting androgen sensitivity of prostatic carcinoma. © 1989 Academic Press, Inc.
1H NMR studies of urine from premature and sick babies
Authors: Brown Judith C. C. , Mills Graham A. , Sadler Peter J. , Walker Valerie 
Published: March 2007

AbstractHigh‐frequency proton nuclear magnetic resonance (1H NMR) has been applied to a study of urine from premature and sick newborn babies with a variety of clinical disorders. These included severe birth asphyxia, necrotizing enterocolitis, ketosis, and drug treatment. Abnormal levels of metabolites such as lactate, ketone bodies, betaine, dicarboxylic acids, and 4‐hydroxyphenolic acids were detected, as was the antibiotic metronidazole and one of its metabolites. The assignment of betaine was confirmed by two dimensional 1H NMR studies of urine obtained from two adults with homocystinuria receiving treatment with oral betaine. High‐resolution 1H NMR spectroscopy of urine is a potentially useful research technique for monitoring metabolism during early life.
Transrectal probe for 1H MRI and 31P MR spectroscopy of the prostate gland
Authors: Narayan Perinchery , Vigneron Daniel B. , Jajodia Prahalad , Anderson Charles M. , Hedgcock Marcus W. , Tanagho Emil A. , James Thomas L. 
Published: March 2007

AbstractA transrectal probe for 1H imaging and 31P MR spectroscopy of the prostate gland is described. The probe is covered with plastic and consists of an insertional portion containing an rf coil and a handle containing a tuning and matching circuit. Using this transrectal probe, 1H MR images and the first 31P MR spectra of the in situ canine prostate were obtained. Serial alterations in prostate size and changes in the ratio of phosphomonoesters to ATP ratio following orchiectomy were observed. Transrectal images of the prostate appear to be superior to conventional whole body coil images in the canine. For the first time a device to obtain high signal‐to‐noise 1H images and 31P spectra of the in situ prostate has been constructed. This will allow the assessment oftransrectal imaging and spctroscopy as tools for medical studies of prostate pathophysiology.
Imaging tumors with respect to a grid coordinate system by proton magnetic resonance using lipid suppression and T2 weighting
Authors: Block Ronald E. , Parekh Barbara C. 
Published: March 2007

AbstractExperimental tumors can be located with respect to a grid coordinate system by using lipid‐suppressed T2‐weighted proton imaging with thick coronal slices and a plexiglass grid containing a solution of paramagnetic ions. Most normal tissues except the brain. eyes, and CNS are essentially transparent under these conditions, allowing thick sections to be rapidly searched for tumors. Use of this approach to monitor tumor growth is demonstrated.
1H image‐guided localized 31P MR spectroscopy of human brain: Quantitative analysis of 31P MR spectra measured on volunteers and on intracranial tumor patients
Authors: Segebarth Christoph M. , Balériaux Danielle F. , De Beer Ron , Van Ormondt Dirk , Mariën Ad , Luyten Peter R. , Den Hollanders Jan A. 
Published: March 2007

Abstract1H image‐guided 31P MR spectra of normal human brain and of intracranial tumors have been analyzed quantitatively. Tumor types examined include prolactinoma, lymphoma, and various grade gliomas. The experimental signals were processed by means of a time‐domain least‐square fitting procedure, which yields the spectral parameters, as well as a prediction of the standard deviations. Significant spectral variations are observed within both populations of normal brain and of intracranial tumor 31P MR spectra. The metabolic ratios derived from the glioma 31P MR spectra and from corresponding unin‐filtrated brain tissue do not differ significantly. Significant differences are, however, observed between the metabolic ratios of prolactinoma and uninfiltrated tissue 31P MR spectra. Alkaline pH values are found for the prolactinoma and the high‐grade gliomas. Furthermore. spectral differences are observed between the patient' uninfiltrated tissue 31P MR spectra and those of an unmatched population of volunteers. This underscores the necessity for control measurements on the uninfiltrated tissue of the patient and for controls from a matched population of healthy individuals.
Localized volume selection technique using an additional radial gradient coil
Authors: Lee S. Y. , Cho Z. H. 
Published: March 2007

AbstractA volume selection technique for the localized NMR imaging using an additional radial gradient is proposed. This volume selection gradient is the fourth gradient in addition to the usual 3‐dimensional imaging gradients, i.e., x‐, y‐, and z‐directional gradients, and is of the radial form. The principle of the proposed method is the use of the radial gradient in conjunction with the selective RF pulse thereby selecting a small cylindrical volume which can be used for the 3‐dimensional volume imaging with fewer encoding steps than those of the conventional full 3‐dimensional volume imaging. The present technique combined with the fast steady state free precession gradient echo imaging sequence allows us to reduce the total scan time to several minutes for the 3‐dimensional volume imaging with the spatial resolution of 1 X 1 X 1 mm or to spend the same scan time for the 3‐dimensional imaging with improved spatial resolution. The basic principle of the radial gradient coil consisting of a main circular loop coil and an offset compensating Helmholtz coil is discussed and the construction details are presented. Some experimental results of the proposed volume selection imaging technique as well as computer simulation results are also given. © 1989 Academic Press, Inc.
Multiple‐output chemical shift imaging (MOCSI): A practical technique for rapid spectroscopic imaging
Authors: Twieg D. B. 
Published: March 2007

AbstractA new technique for rapid multiple‐frame chemical shift imaging and localized spectroscopy is reported. Unlike phase‐encoding techniques and multiple‐delay chemical shift imaging techniques, this technique permits spectroscopic imaging at high spatial resolution and moderately high spectral resolution with acquisition times as short as 10 min or less. Unlike other rapid spectroscopic imaging techniques which have been reported, it uses cyclic trapezoidal gradient waveforms achievable in standard clinical magnetic resonance imaging systems. Multiple‐output chemical shift imaging images and spectra from a human study are shown. © 1989 Academic Press, Inc.
Monoclonal antibody‐coated magnetite particles as contrast agents in magnetic resonance imaging of tumors
Authors: Cerdan Sebastian , Lötscher Hans Ruedi , Künnecke Basil , Seelig Joachim 
Published: March 2007

AbstractA highly specific and powerful magnetic resonance imaging contrast agent has been prepared by coating magnetite (Fe3 O4) particles with monoclonal antibodies directed against a tumor antigen. The preparation maintains both the immunoreactivity of the monoclonal antibody and the full relaxing capability of the magnetite particle. MRI image contrast by spin‐echo methods can be easily induced in a concentration range of 1–10 nM of the antibody‐coated magnetite particles. © 1989 Academic Press, Inc.
Erythrocyte Na+/K+ ATPase activity measured with 23Na NMR
Authors: Ouwerkerk Ronald , Echteld Cees J. A. Van , Staal Gerard E. J. , Rijksen Gert 
Published: March 2007

AbstractA 23Na NMR assay for measurement of erythrocyte Na+/K+ ATPase activity is presented. Using the nonpermeant shift reagent dysprosium tripolyphosphate the signals of intra‐ and extracellular sodium are separated, enabling measurement of sodium fluxes nondestructively, without the need to physically separate the cells from their environment. By increasing membrane permeability with nystatin we have shown that the assay allows the detection of differences in membrane permeability. With low doses of nystatin the ouabain‐sensitive sodium flux increased more than twofold. With high doses of nystatin the Na+/K+ pump could not prevent an almost total equilibration of intra‐ and extracellular sodium. All sodium that entered the cells remained NMR visible, proving that sodium influx can be measured quantitatively. 31P NMR spectra taken before and after the assay revealed a slight acidification of the cells and no significant change in ATP concentration. No evidence of Dy3+ entering the cell was observed. © 1989 Academic Press, Inc.
The use of an improved inversion pulse with the Spin‐Echo/ inversion‐recovery sequence to give increased accuracy and reduced imaging time for T1 measurements
Authors: Gowland P. A. , Leach M. O. , Sharp J. C. 
Published: March 2007

AbstractThe hyperbolic secant inversion pulse has been incorporated into the interleaved saturation‐recovery/inversion‐recovery sequence to provide T1 measurements combining high precision with a significantly reduced imaging time (a mean accuracy of 2% over a T1 range of 300 to 1650 ms for standard gel phantoms, with Tr1 = Tr2 = 2.0 s, Ti = 0.67 s). © 1989 Academic Press, Inc.
An incubation system for the NMR study of kidney tubules
Authors: Ammann H. , Boulanger Y. , Legault P. , Vinay P. 
Published: March 2007

AbstractIsolated kidney cortical tubules require a very rapid oxygen supply and mechanical agitation to be optimally functional. A sample chamber in which a tubule suspension is oxygenated by recirculating oxygen gas inside a coil of dialysis fibers to avoid cell loss through bubbling and in which the tubules are agitated by a gas‐driven turbine has been designed. In such a system, dog cortical tubules (35‐45 mg/ml) were found to be metabolically stable for more than 3 h as indicated by linear lactate consumption and glucose production. Small pH variations resulting from carbon dioxide and bicarbonate productions were measured. Good‐quality 23Na NMR spectra of dog kidney cortical tubules were recorded with such a system, allowing a I‐min time resolution.The authors are particularly grateful to Mr. Michel Brunette, Groupe de Recherche en Transport Membranaire, for the construction of the NMR chamber. The technical assistance of Mrs. Pierrette Fournel, Mr. Jacques Sénécal, and Mrs. Josette Noël is gratefully acknowledged. This project was supported by the Kidney Foundation of Canada and the Medical Research Council of Canada. H.A. is the recipient of a Medical Research Council studentship. Y.B. is chercheur‐boursier of the Fonds de la Recherche en Santé du Québec. © 1989 Academic Press, Inc.
A comparison of three radiofrequency coils for NMR studies of conductive samples
Authors: Murphy Marilee K. , Frnandez Erik J. , Clark Douglas S. 
Published: March 2007

AbstractThree rf coil designs of equal volume (approximately 15 ml) were compared using conductive samples. Magnetic loss into the sample was the dominant noise source. At physiological conductivity the sensitivity of the horizontally aligned solenoid and loop‐gap resonator was only 1.3 ± 0.2 times that of the vertically aligned slotted tube resonator. © 1989 Academic Press, Inc.
Extraction of cardiac and respiratory motion cycles by use of projection data and its applications to nmr imaging
Authors: Kim W. S. , Mun C. W. , Kim D. J. , Cho Z. H. 
Published: March 2007

AbstractA technique of extracting cardiac and respiratory motion cycles by use of projection data is proposed and studied. These extracted cardiac and respiratory motion cycles are applied to the cine imaging of heart and motion artifact reduction in abdominal imaging instead of the conventional ECG gating devices. The basic concepts and their applications are discussed, Experimental results on human volunteers obtained with the KAIS 2.0‐T whole‐body NMR imaging system together with the pulse sequences used for the experiments are presented.