Abstract:
:Image contrast with gradient-recalled echo sequences (GRE) used for fMRI can have both blood oxygen level-dependent (BOLD) and inflow components, and the latter is often undesirable. A dual-echo technique can be used to differentiate these mechanisms, because modulation of signal from inflow is common to both echoes, whereas susceptibility and diffusion-related signal losses are larger in the second echo. An efficient dual-echo interleaved spiral sequence was developed for use with a conventional scanner. It uses a k-space trajectory that spirals out from the origin while the first echo is collected, then spirals back in while collecting the second echo. Decomposition of the data provides separate images of the inflow and T2-weighted components. Results demonstrate the decomposition with phantom experiments and with photic stimulation in normal volunteers.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Glover GH,Lemieux SK,Drangova M,Pauly JMdoi
10.1002/mrm.1910350306subject
Has Abstractpub_date
1996-03-01 00:00:00pages
299-308issue
3eissn
0740-3194issn
1522-2594journal_volume
35pub_type
杂志文章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
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journal_title:Magnetic resonance in medicine
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更新日期:1999-06-01 00:00:00
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
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更新日期:2014-12-01 00:00:00
abstract:PURPOSE:Magnetic resonance-guided high-intensity focused ultrasound is considered to be a promising treatment for localized cancer in abdominal organs such as liver, pancreas, or kidney. Abdominal motion, anatomical arrangement, and required sustained sonication are the main challenges. METHODS:MR acquisition consiste...
journal_title:Magnetic resonance in medicine
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更新日期:2014-10-01 00:00:00
abstract::A simple theoretical model was developed to compare the sensitivities (i.e., signal-to-noise ratios per unit imaging time) of two-dimensional (2D) multislice and 3D imaging sequences. The model shows that the sensitivities of 3D and 2D multislice MRI sequences are usually similar. Sensitivities are identical in T2-wei...
journal_title:Magnetic resonance in medicine
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doi:10.1002/(sici)1522-2594(199904)41:4<824::aid-mrm23
更新日期:1999-04-01 00:00:00
abstract::The acquisition of complete three-dimensional (3D), segmented gradient-echo data sets to visualize the coronary arteries can be both time consuming and sensitive to motion, even with use of multiple breath-holding or respiratory gating. An alternate hybrid approach is demonstrated here, in which real-time interactive ...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.1910400115
更新日期:1998-07-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.28247
更新日期:2020-07-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.1910140114
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doi:10.1002/mrm.1198
更新日期:2001-08-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.25653
更新日期:2016-01-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20508
更新日期:2005-06-01 00:00:00
abstract::A novel multislice B₁-mapping method dubbed dual refocusing echo acquisition mode is proposed, able to cover the whole transmit coil volume in only one second, which is more than an order of magnitude faster than established approaches. The dual refocusing echo acquisition mode technique employs a stimulated echo acqu...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.24158
更新日期:2012-11-01 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
abstract::Applications of fMRI in functional brain imaging are mainly confined to single subject designs, prohibiting the assessment of subject or group by condition interactions (i.e., differential activations) or areas of conjoint activation. In this paper a framework for fMRI group designs, using statistical parametric mappi...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910380502
更新日期:1997-11-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.24186
更新日期:2012-12-01 00:00:00
abstract::Certain kinds of artifacts have been reported when projection reconstruction (PR) techniques are used in magnetic resonance imaging (MRI). These will occur if the spacing between samples in k-space is too large. It has been suggested that PR requires finer k-space sampling than does two-dimensional Fourier reconstruct...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910400317
更新日期:1998-09-01 00:00:00
abstract::Assuming that the SSFP magnetization response maintains a steady state which is periodic in the presence of diffusion, we can solve for the diffusion effect in such sequences. Formulating a Fourier series decomposition solution to the Bloch-Torrey equation and imposing the steady-state condition, analytical expression...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910190209
更新日期:1991-06-01 00:00:00
abstract::T1 is often ill-determined. This means that an Ernst angle excitation often cannot be precisely defined for the simple pulse and acquire experiment. Here, published 31P T1 values of metabolites in human muscle, liver, heart, and brain are archived, some new data on heart and brain added, and overall confidence interva...
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pub_type: 杂志文章
doi:10.1002/mrm.1910320120
更新日期:1994-07-01 00:00:00
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更新日期:2001-06-01 00:00:00
abstract::Artery wall motion and strain play important roles in vascular remodeling and may be important in the pathogenesis of vascular disease. In vivo observations of circumferentially nonuniform wall motion in the human aorta suggest that nonuniform strain may contribute to the localization of vascular pathology. A velocity...
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更新日期:2004-08-01 00:00:00
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更新日期:2004-10-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:2004-05-01 00:00:00
abstract::Two-dimensional 1H-31P correlation spectroscopy and relaxation time measurements of intact diseased pancreas were performed in order to identify an unknown peak appearing at -0.18 +/- 0.04 ppm in a 31P NMR spectrum of taurocholate-induced experimental acute pancreatitis in rats. The signal was identified as a solubili...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910100111
更新日期:1989-04-01 00:00:00
abstract:PURPOSE:To characterize the q-space truncation and sampling on the spin-displacement probability density function (PDF) in diffusion spectrum imaging (DSI). METHODS:DSI data were acquired using the MGH-USC connectome scanner (Gmax = 300 mT/m) with bmax = 30,000 s/mm2 , 17 × 17 × 17, 15 × 15 × 15 and 11 × 11 × 11 gri...
journal_title:Magnetic resonance in medicine
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更新日期:2016-12-01 00:00:00
abstract:PURPOSE:Nicotinamide adenine dinucleotide (NAD), in oxidized (NAD(+) ) or reduced (NADH) form, plays key roles in cellular metabolism. Intracellular NAD(+) /NADH ratio represents the cellular redox state; however, it is difficult to measure in vivo. We report here a novel in vivo (31) P MRS method for noninvasive measu...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.24859
更新日期:2014-06-01 00:00:00
abstract:PURPOSE:Diffusion-weighted magnetic resonance imaging suffers from physiological noise, such as artifacts caused by motion or system instabilities. Therefore, there is a need for robust diffusion parameter estimation techniques. In the past, several techniques have been proposed, including RESTORE and iRESTORE (Chang e...
journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.25351
更新日期:2015-06-01 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:PURPOSE:The T(1) of tissue has a strong dependence on the measurement magnetic field strength. T(1) -dispersion could be a useful contrast parameter, but is unavailable to clinical MR systems which operate at fixed magnetic field strength. The purpose of this work was to implement a removable insert magnet coil for fie...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25040
更新日期:2014-11-01 00:00:00
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doi:10.1002/mrm.1910130202
更新日期:1990-02-01 00:00:00