The dependence of radiofrequency induced pacemaker lead tip heating on the electrical conductivity of the medium at the lead tip.

abstract：:In order to determine if an increase in myocardial oxygen consumption is accompanied by changes in high energy phosphates in normal subjects and patients with dilated cardiomyopathy, phosphorus-31 spectra were acquired under resting conditions and during dobutamine infusion. In seven normal subjects, dobutamine raised...

journal_title：Magnetic resonance in medicine

authors： Schaefer S,Schwartz GG,Steinman SK,Meyerhoff DJ,Massie BM,Weiner MW

更新日期：1992-06-01 00:00:00

abstract：:Cell death by apoptosis is critical in myocardial diseases, and noninvasive detection of early, reversible apoptosis might be useful clinically. Exogenous Annexin-V (ANX) protein binds membrane phosphatidylserine, which is externalized in early apoptosis. A molecular MRI probe was constructed with superparamagnetic ir...

journal_title：Magnetic resonance in medicine

authors： Dash R,Chung J,Chan T,Yamada M,Barral J,Nishimura D,Yang PC,Simpson PC

更新日期：2011-10-01 00:00:00

abstract：:IVIM MR imaging is a method which generates images of diffusion and perfusion in vivo. Until now, intravoxel incoherent motion (IVIM) images have been obtained using spin-echo sequences with extragradient pulses, resulting in long acquisition times (typically 2 x 8 min 32 s). A new method is proposed here, using stead...

journal_title：Magnetic resonance in medicine

authors： Le Bihan D

更新日期：1988-07-01 00:00:00

abstract：:Prospective motion correction methods using an optical system, diffusion-weighted prospective acquisition correction, or a free induction decay navigator have recently been applied to correct for motion in diffusion tensor imaging. These methods have some limitations and drawbacks. This article describes a novel techn...

journal_title：Magnetic resonance in medicine

authors： Alhamud A,Tisdall MD,Hess AT,Hasan KM,Meintjes EM,van der Kouwe AJ

更新日期：2012-10-01 00:00:00

abstract：PURPOSE:To facilitate assessment of RF power deposition and temperature rise within the breast, we present a method to seamlessly join heterogeneous breast models with standard whole-body models and demonstrate simulations at 7 T. METHODS:Finite-difference time-domain electromagnetic and bioheat simulations are perfor...

journal_title：Magnetic resonance in medicine

authors： Li X,Rispoli JV

更新日期：2019-02-01 00:00:00

abstract：:Magnetic resonance imaging allows numerous k-space sampling schemes such as cartesian, polar, spherical, and other non-rectilinear trajectories. Non-rectilinear MR acquisitions permit fast scan times and can suppress motion artifacts. Still, these sampling schemes may adversely affect the image characteristics due to ...

journal_title：Magnetic resonance in medicine

authors： Lauzon ML,Rutt BK

更新日期：1996-12-01 00:00:00

abstract：PURPOSE:To develop and evaluate a novel 2D phase-unwrapping method that works robustly in the presence of severe noise, rapid phase changes, and disconnected regions. THEORY AND METHODS:The MR phase map usually varies rapidly in regions adjacent to wraps. In contrast, the phasors can vary slowly, especially in regions...

journal_title：Magnetic resonance in medicine

authors： Cheng J,Mei Y,Liu B,Guan J,Liu X,Wu EX,Feng Q,Chen W,Feng Y

更新日期：2018-01-01 00:00:00

abstract：:Function and morphology of the cerebral vasculature were studied in the amyloid (Abeta) plaque-containing double-transgenic (TG) B6.PS2APP Alzheimer's disease (AD) mouse model with MRI at an age range of 10 to 17 months. Perfusion, blood volume, and average vessel geometry were assessed in the brain and compared to ag...

journal_title：Magnetic resonance in medicine

authors： Weidensteiner C,Metzger F,Bruns A,Bohrmann B,Kuennecke B,von Kienlin M

更新日期：2009-07-01 00:00:00

abstract：:Comparative NMR studies of normal and pathologically altered human stomach tissues were performed on the basis of proton T1 relaxation time measurements in the presence of high external concentrations of relaxation (contrast) agents manganese ethylenediaminetetraacetic acid (Mn-EDTA) and gadolinium diethylenetriaminep...

journal_title：Magnetic resonance in medicine

authors： Srejić R,Popov DV,Boricić I,Zuvela M

更新日期：1990-09-01 00:00:00

abstract：PURPOSE:To use quantitative susceptibility mapping (QSM) to investigate changes in cartilage canals in the distal femur of juvenile goats after their surgical transection. METHODS:Chondronecrosis was surgically induced in the right medial femoral condyles of four 4-day-old goats. Both the operated and control knees we...

journal_title：Magnetic resonance in medicine

authors： Wang L,Nissi MJ,Toth F,Johnson CP,Garwood M,Carlson CS,Ellermann J

更新日期：2017-03-01 00:00:00

abstract：PURPOSE:Single-scan two-dimensional MRI has been generally constrained to acquisitions in high quality magnets. This study introduces a methodology, cross-term spatiotemporal encoding (xSPEN), that delivers such images under much poorer external field conditions. METHODS:xSPEN departs from conventional k-space scannin...

journal_title：Magnetic resonance in medicine

authors： Zhang Z,Seginer A,Frydman L

更新日期：2017-02-01 00:00:00

abstract：:In this work, a new double quantum filter for glutathione (GSH) editing is introduced, combined with the point-resolved spectroscopy localization sequence (PRESS), and demonstrated in vivo. Compared to the conventional double quantum coherence filter, the new filter has two major advantages. First, it eliminates the n...

journal_title：Magnetic resonance in medicine

authors： Zhao T,Heberlein K,Jonas C,Jones DP,Hu X

更新日期：2006-03-01 00:00:00

abstract：:A radiofrequency (RF) time-domain electron paramagnetic resonance (EPR) instrument operating at 300, 600, and 750 MHz was used to image tumor hypoxia with high spatial and temporal resolution. A high-speed signal-averaging Peripheral Component Interconnect (PCI) board with flexibility in the input signal level and the...

journal_title：Magnetic resonance in medicine

authors： Devasahayam N,Subramanian S,Murugesan R,Hyodo F,Matsumoto K,Mitchell JB,Krishna MC

更新日期：2007-04-01 00:00:00

abstract：:The proton T(1) was measured at 132 μT in ex vivo prostate tissue specimens from radical prostatectomies of 35 patients with prostate cancer. Each patient provided two specimens. The NMR and MRI measurements involved proton repolarization, a field of typically 150 mT and detection of the 5.6-kHz signal with a supercon...

journal_title：Magnetic resonance in medicine

authors： Busch S,Hatridge M,Mößle M,Myers W,Wong T,Mück M,Chew K,Kuchinsky K,Simko J,Clarke J

更新日期：2012-04-01 00:00:00

abstract：:Stejskal and Tanner's ingenious pulsed field gradient design from 1965 has made diffusion NMR and MRI the mainstay of most studies seeking to resolve microstructural information in porous systems in general and biological systems in particular. Methods extending beyond Stejskal and Tanner's design, such as double diff...

journal_title：Magnetic resonance in medicine

authors： Shemesh N,Jespersen SN,Alexander DC,Cohen Y,Drobnjak I,Dyrby TB,Finsterbusch J,Koch MA,Kuder T,Laun F,Lawrenz M,Lundell H,Mitra PP,Nilsson M,Özarslan E,Topgaard D,Westin CF

更新日期：2016-01-01 00:00:00

abstract：PURPOSE:This study evaluates biochemical imbalances in a rat model that reflects dysfunctional pathways in migraine. The high sensitivity and spectral dispersion available to 1 H MRS at 21.1 T expands metabolic profiling in this migraine model to include lactate (Lac), taurine (Tau), aspartate, and Gly-a mixture of gly...

journal_title：Magnetic resonance in medicine

authors： Abad N,Rosenberg JT,Roussel T,Grice DC,Harrington MG,Grant SC

更新日期：2018-03-01 00:00:00

abstract：:A simple iterative algorithm, termed deconvolution-interpolation gridding (DING), is presented to address the problem of reconstructing images from arbitrarily-sampled k-space. The new algorithm solves a sparse system of linear equations that is equivalent to a deconvolution of the k-space with a small window. The dec...

journal_title：Magnetic resonance in medicine

authors： Gabr RE,Aksit P,Bottomley PA,Youssef AB,Kadah YM

更新日期：2006-12-01 00:00:00

abstract：:Time-resolved three-dimensional phase-contrast MRI is an important tool for physiological as well as clinical studies of blood flow in the heart and vessels. The application of the technique is, however, limited by the long scan times required. In this work, we investigate the feasibility of using spiral readouts to r...

journal_title：Magnetic resonance in medicine

authors： Sigfridsson A,Petersson S,Carlhäll CJ,Ebbers T

更新日期：2012-10-01 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：PURPOSE:To present a time-efficient technique for banding reduction in balanced steady-state free precession (bSSFP) imaging using phase-cycled simultaneous multislice (SMS) acquisition with CAIPIRINHA (controlled aliasing in parallel imaging results in higher acceleration). THEORY:The proposed technique exploits the ...

journal_title：Magnetic resonance in medicine

authors： Wang Y,Shao X,Martin T,Moeller S,Yacoub E,Wang DJ

更新日期：2016-12-01 00:00:00

abstract：:The shells trajectory is a 3D data acquisition method with improved efficiency compared to Cartesian sampling. It is a true center-out trajectory that does not repeatedly resample the center of k-space, and also offers advantages for motion correction. This work demonstrates that k-space undersampling can be combined ...

journal_title：Magnetic resonance in medicine

authors： Shu Y,Riederer SJ,Bernstein MA

更新日期：2006-09-01 00:00:00

abstract：:In vivo measurements of gadodiamide (Gd-DTPA-BMA) T(1) relaxivity were performed at 4.7 T in injured and normal rat brains. Cerebral lesions were induced in nine rats by a localized freezing method. T(1) maps of the lesions were generated before and after injection of Gd-DTPA-BMA (0.1-0.6 mmol/kg). Samples of normal a...

journal_title：Magnetic resonance in medicine

authors： Pickup S,Wood AK,Kundel HL

更新日期：2005-01-01 00:00:00

abstract：:Elastase-induced changes in lung morphology and function were detected in spontaneously breathing rats using conventional proton MRI at 4.7 T. A single dose of porcine pancreatic elastase (75 U/100 g body weight) or vehicle (saline) was administered intratracheally (i.t.) to male Brown Norway (BN) rats. MRI fluid sign...

journal_title：Magnetic resonance in medicine

authors： Quintana HK,Cannet C,Zurbruegg S,Blé FX,Fozard JR,Page CP,Beckmann N

更新日期：2006-12-01 00:00:00

abstract：PURPOSE:To separate the spectrally overlapped lactate and lipid signals at 1.3 ppm using diffusion-weighted magnetic resonance spectroscopy (DW-MRS) based on their large diffusivity difference. METHODS:DW-MRS was applied to the gel phantoms containing lactate and lipid droplets, and to the rat brain tumors. Lactate an...

journal_title：Magnetic resonance in medicine

authors： Wang AM,Leung GK,Kiang KM,Chan D,Cao P,Wu EX

更新日期：2017-02-01 00:00:00

abstract：:Calibration of the spatial sensitivity functions of coil arrays is a crucial element in parallel magnetic resonance imaging (PMRI). The most common approach has been to measure coil sensitivities directly using one or more low-resolution images acquired before or after accelerated data acquisition. However, since it i...

journal_title：Magnetic resonance in medicine

authors： McKenzie CA,Yeh EN,Ohliger MA,Price MD,Sodickson DK

更新日期：2002-03-01 00:00:00

abstract：PURPOSE:A method for the quantification of perfusion in murine myocardium is demonstrated. The method allows for the reconstruction of perfusion maps on arbitrary time points in the heart cycle while addressing problems that arise due to the irregular heart beat of mice. METHODS:A flow-sensitive alternating inversion ...

journal_title：Magnetic resonance in medicine

authors： Gutjahr FT,Kampf T,Winter P,Meyer CB,Williams T,Jakob PM,Bauer WR,Ziener CH,Helluy X

更新日期：2015-12-01 00:00:00

abstract：PURPOSE:MUSSELS is a one-step iterative reconstruction method for multishot diffusion weighted (msDW) imaging. The current work presents an efficient implementation, termed IRLS MUSSELS, that enables faster reconstruction to enhance its utility for high-resolution diffusion MRI studies. METHODS:The recently proposed M...

journal_title：Magnetic resonance in medicine

authors： Mani M,Aggarwal HK,Magnotta V,Jacob M

更新日期：2020-06-01 00:00:00

abstract：PURPOSE:Magnetic resonance imaging of humans at high magnetic field strengths is strongly influenced by the interference of the radiofrequency (RF) electromagnetic field and the body. To minimize this effect, multiple RF sources could be used. A novel setup (called multimode, coaxial waveguide) is proposed that facilit...

journal_title：Magnetic resonance in medicine

authors： Andreychenko A,Kroeze H,Boer VO,Lagendijk JJ,Luijten PR,van den Berg CA

更新日期：2014-04-01 00:00:00

abstract：:In in vivo (1)H spectroscopy, the signal at 1.32 ppm is usually assigned to lactate. This resonance position is shared with threonine at physiological pH. The similarity of spectral patterns of lactate and threonine renders the separate measurement of either threonine or lactate without and even with editing technical...

journal_title：Magnetic resonance in medicine

authors： Marjanska M,Henry PG,Uğurbil K,Gruetter R

更新日期：2008-02-01 00:00:00

abstract：PURPOSE:The optic nerve (ON) represents the sole pathway between the eyes and brain; consequently, diseases of the ON can have dramatic effects on vision. However, quantitative magnetization transfer (qMT) applications in the ON have been limited to ex vivo studies, in part because of the fatty connective tissue that s...

journal_title：Magnetic resonance in medicine

authors： Smith AK,Dortch RD,Dethrage LM,Lyttle BD,Kang H,Welch EB,Smith SA

更新日期：2017-02-01 00:00:00