Abstract:
PURPOSE:To introduce a new outer volume suppression (OVS) technique that uses a single pulse and rotating gradients to accomplish frequency-swept excitation. This new technique, which is called gradient rotating outer volume excitation (GROOVE), produces a circular or elliptical suppression band rather than suppressing the entire outer volume. METHODS:Theoretical and k-space descriptions of GROOVE are provided. The properties of GROOVE were investigated with simulations, phantom, and human experiments performed using a 4T horizontal bore magnet equipped with a TEM coil. RESULTS:Similar suppression performance was obtained in phantom and human brain using GROOVE with circular and elliptical shapes. Simulations indicate that GROOVE requires less SAR and time than traditional OVS schemes, but traditional schemes provide a sharper transition zone and less residual signal. CONCLUSION:GROOVE represents a new way of performing OVS in which spins are excited temporally in space on a trajectory that can be tailored to fit the shape of the suppression region. In addition, GROOVE is capable of suppressing tailored regions of space with more flexibility and in a shorter period of time than conventional methods. GROOVE provides a fast, low SAR alternative to conventional OVS methods in some applications (e.g., scalp suppression).
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Powell NJ,Jang A,Park JY,Valette J,Garwood M,Marjańska Mdoi
10.1002/mrm.25101subject
Has Abstractpub_date
2015-01-01 00:00:00pages
139-49issue
1eissn
0740-3194issn
1522-2594journal_volume
73pub_type
杂志文章abstract:PURPOSE:To develop the simultaneous acquisition of multiple voxels in localized MR spectroscopy (MRS) using sensitivity encoding, allowing reduced total scan time compared to conventional sequential single voxel (SV) acquisition methods. METHODS:Dual volume localization was used to simultaneously excite voxels in both...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25718
更新日期:2015-09-01 00:00:00
abstract::A novel radio-frequency (RF) pulse design algorithm is presented that generates fast slice-selective excitation pulses that mitigate B+1 inhomogeneity present in the human brain at high field. The method is provided an estimate of the B+1 field in an axial slice of the brain and then optimizes the placement of sinc-li...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21585
更新日期:2008-06-01 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
pub_type: 杂志文章
doi:10.1002/mrm.25318
更新日期:2015-05-01 00:00:00
abstract:PURPOSE:Blood flow causes induced voltages via the magnetohydrodynamic (MHD) effect distorting electrograms (EGMs) made during magnetic resonance imaging. To investigate the MHD effect in this context MHD voltages occurring inside the human heart were simulated in an in vitro model system inside a 1.5 T MR system. MET...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25456
更新日期:2015-09-01 00:00:00
abstract::Susceptibility artifacts and transmission radio frequency (RF) field (B(1) +) inhomogeneity are major limitations in high-field gradient echo MRI. Previously proposed numerical 2D spectral-spatial RF pulses have been shown to be promising for reducing the through-plane signal loss susceptibility artifact by incorporat...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22725
更新日期:2011-02-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25653
更新日期:2016-01-01 00:00:00
abstract::In this study we utilized manganese-enhanced MRI (MEMRI) to evaluate the in vivo transneuronal efficiency of manganese ion (Mn(2+)) movement as a means to assess overall changes in neuronal function. We designated this extension the manganese transfer index (MTI) value. To evaluate the MTI value as an index of transne...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.21648
更新日期:2008-07-01 00:00:00
abstract:PURPOSE:The aim of this study was to develop a technique for rapid collection of chemical exchange saturation transfer images with the saturation varied to modulate signal loss transfer and enhance contrast. METHODS:Multi-echo Length and Offset VARied Saturation (MeLOVARS) divides the saturation pulse of length Tsat i...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25567
更新日期:2015-02-01 00:00:00
abstract::In echo-planar-based diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI), the evaluation of diffusion parameters such as apparent diffusion coefficients and anisotropy indices is affected by image distortions that arise from residual eddy currents produced by the diffusion-sensitizing gradients. Correc...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10690
更新日期:2004-01-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.23041
更新日期:2012-03-01 00:00:00
abstract::The success in utilizing in vivo NMR to identify and/or monitor metabolic abnormalities will be determined in large part on the reliability with which the spectral parameters of the metabolites present can be measured. For these reasons it is clear that there is a need for the development of algorithms with which to o...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910100306
更新日期:1989-06-01 00:00:00
abstract::Parallel excitation is being studied intensively for applications in MR imaging and in particular for selecting arbitrary shapes as regions of interest. In this work, parallel excitation was applied to arbitrarily shaped voxel selection in spectroscopy and investigated for different excitation k-space trajectories (ra...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.23018
更新日期:2012-02-01 00:00:00
abstract::The fate of the 13C label arising from [U-13C]succinate in rabbit renal proximal convoluted tubular (PCT) cells, incubated with [U-13C]succinate, was investigated by 13C NMR spectroscopy of the perchloric acid extracts of the cell pellets. The 13C label of [U-13C]succinate was predominantly metabolized into glutamate,...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910140114
更新日期:1990-04-01 00:00:00
abstract::A proton NMR relaxation and pulsed field gradient self-diffusion study of water in fibrin gels, plasma, and blood clots has been performed with special emphasis on the effect of the sol-gel and shrinkage transitions. Deuteron NMR in fibrin gels was also studied to supplement the proton data. It is shown that a measure...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910140111
更新日期:1990-04-01 00:00:00
abstract:PURPOSE:The purpose of this study was to develop a three-dimensional black blood imaging method for simultaneously evaluating the carotid and intracranial arterial vessel walls with high spatial resolution and excellent blood suppression with and without contrast enhancement. METHODS:The delay alternating with nutatio...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25785
更新日期:2016-06-01 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
pub_type: 杂志文章
doi:10.1002/mrm.25524
更新日期:2015-11-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24401
更新日期:2013-06-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910180204
更新日期:1991-04-01 00:00:00
abstract::The mechanics of the macrocirculation are examined as a basis for imaging blood flow within the system. The macrocirculation is defined as that part of the circulation in which inertial forces are not negligible compared to viscous forces and as such in human subjects comprises the heart and large blood vessels. Becau...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910140204
更新日期:1990-05-01 00:00:00
abstract:PURPOSE:To exploit the improved comparability and hardware independency of quantitative MRI, databases of MR physical parameters in healthy tissue are required, to which tissue properties of patients can be compared. In this work, normative values for longitudinal and transverse relaxation times in the brain were estab...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27927
更新日期:2020-01-01 00:00:00
abstract::Human cardiac 31P nuclear magnetic resonance (NMR) spectra are usually quantified in relative terms, i.e., the ratio of metabolite signals is calculated. If 31P NMR spectroscopy of the heart is to emerge as a clinically relevant diagnostic modality, reliable quantification of absolute concentrations of 31P metabolites...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199904)41:4<657::aid-mrm3>
更新日期:1999-04-01 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
pub_type: 杂志文章
doi:10.1002/mrm.1910120210
更新日期:1989-11-01 00:00:00
abstract::Coronal proton and sodium images of control rats and rats with either increased permeability edema produced by intravenous alloxan (300 mg/kg) or increased pressure edema produced by saline infusion (2 ml/min) were obtained. Axial chest CT images were used to monitor the development of pulmonary edema. Immediately aft...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910060403
更新日期:1988-04-01 00:00:00
abstract::Recently, a technique based on arterial spin labeling, called dynamic arterial spin labeling (DASL (Magn Reson Med 1999;41:299-308)), has been introduced to measure simultaneously the transit time of the labeled blood from the labeling plane to the exchange site, the longitudinal relaxation time of the tissue, and the...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1136
更新日期:2001-06-01 00:00:00
abstract::Fast proton magnetic resonance spectroscopic imaging (MRSI) using a multi-element head-coil array is examined with respect to three aspects: the coil design, the use of an appropriate signal combination method, and the design of the MRSI pulse sequence itself. An eight-element head-coil array has been developed to inc...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910400204
更新日期:1998-08-01 00:00:00
abstract:PURPOSE:To investigate and compare several quantification methods of myocardial perfusion measurements, paying special attention to the relation between the techniques and the required measurement duration. METHODS:Seven patients underwent contrast-enhanced rest and stress cardiac perfusion measurements at 3T. Three s...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章,随机对照试验
doi:10.1002/mrm.25212
更新日期:2015-03-01 00:00:00
abstract::Flow-sensitive dephasing (FSD) magnetization preparation has been developed for black-blood vessel wall MRI and noncontrast MR angiography. The first-order gradient moment, m(1) , is a measure of the flow-sensitization imparted by an FSD preparative module. Determination of the optimal m(1) for each individual is high...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22847
更新日期:2011-04-01 00:00:00
abstract::A 3-T study is presented, comparing the ability of two (1) H spectroscopy pulse sequences, Carr-Purcell point resolved spectroscopy (CPRESS; TE = 45 msec), and conventional PRESS (TE = 35 msec), to separate between groups of 20 normal control (NC) and 20 mild cognitive impairment (MCI) subjects. Both sequences showed ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.22749
更新日期:2011-06-01 00:00:00
abstract::A novel and automated technique is described for removing fMRI image artifacts resulting from motion outside of the imaging field of view. The technique is based on the Stockwell transform (ST), a mathematical operation that provides the frequency content at each time point within a time-varying signal. Using this tec...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.10681
更新日期:2004-01-01 00:00:00
abstract:PURPOSE:To develop a novel technique for voxel-based mapping of lung microstructural parameters using hyperpolarized 129 Xe dissolved-phase MR imaging during saturation recovery. METHODS:A pulse sequence using a highly undersampled stack-of-stars trajectory was developed, and low-rank plus sparse matrix decomposition ...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27559
更新日期:2019-04-01 00:00:00