Abstract:
:In the pulsed arterial spin labeling (ASL) techniques EPISTAR, PICORE, and FAIR, subtraction of two images in which inflowing blood is first tagged and then not tagged yields a qualitative map of perfusion. An important reason this map is not quantitative is that there is a spatially varying delay in the transit of blood from the tagging region to the imaging slice that cannot be measured from a single subtraction. We introduce here two modifications of pulsed ASL (QUIPSS and QUIPSS II) that avoid this problem by applying additional saturation pulses to control the time duration of the tagged bolus, rendering the technique relatively insensitive to transit delays and improving the quantitation of perfusion.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Wong EC,Buxton RB,Frank LRdoi
10.1002/mrm.1910390506subject
Has Abstractpub_date
1998-05-01 00:00:00pages
702-8issue
5eissn
0740-3194issn
1522-2594journal_volume
39pub_type
杂志文章abstract::We exploit the intrinsic difference in magnetic resonance spin-spin relaxation time, T2, between water associated with myelin sheaths and water in other central nervous system tissue in order to measure myelin water content within any region of an image or to generate indirectly a myelin map of the brain. In normal vo...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910310614
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910290107
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abstract:PURPOSE:To develop and evaluate a method for volumetric contrast-enhanced MRI of the liver, with high spatial and temporal resolutions, for combined dynamic imaging and MR angiography (MRA) using a single injection of contrast agent. METHODS:An interleaved variable density (IVD) undersampling pattern was implemented i...
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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:2013-12-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:1996-09-01 00:00:00
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更新日期:1998-03-01 00:00:00
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更新日期:2005-12-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.28004
更新日期:2020-04-01 00:00:00
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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::Fitting a model to an experimental spectrum is a difficult nonlinear estimation problem. The solution presented here is to start an iterative search procedure sufficiently close to the optimal model parameter set. This is achieved by providing tissue-dependent a priori peak information and by a novel correlation metho...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910210206
更新日期:1991-10-01 00:00:00
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.25797
更新日期:2016-05-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910400416
更新日期:1998-10-01 00:00:00
abstract::In vivo echo-planar MR imaging was used to measure apparent diffusion coefficients (ADC) of cerebral tissues in a comprehensive noninvasive evaluation of early ischemic brain damage induced by occlusion of the middle cerebral artery (MCA) in a cat model of acute regional stroke. Within 10 min after arterial occlusion,...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.1910190220
更新日期:1991-06-01 00:00:00
abstract::NMRD profiles, the magnetic field dependence of the water proton longitudinal relaxation rates, have been acquired for two new diphosphonate-modified GdDTPA complexes currently under evaluation as relaxation agents for the MRI detection of soft-tissue calcifications. Fresh dilute solutions show profiles identical to t...
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更新日期:2005-07-01 00:00:00
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更新日期:1989-09-01 00:00:00
abstract::MRI of myocardial perfusion observed with an extracellular contrast agent has proven valuable for the detection of coronary artery disease. During contrast enhancement transient dark rim artifacts are sometimes visible, complicating diagnosis and quantification. In this work a quantification of the frequency offsets c...
journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
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更新日期:2008-10-01 00:00:00
abstract::The regional cerebral blood flow (rCBF) values determined using continuous arterial spin labeling (CASL) are subject to several sources of variability, including natural physiologic variations, sensitivity to the input parameters, and the use of different quantification models. To date, a thorough analysis of the impa...
journal_title:Magnetic resonance in medicine
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更新日期:2005-04-01 00:00:00
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更新日期:2005-03-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:2009-10-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/(sici)1522-2594(199906)41:6<1093::aid-mrm4
更新日期:1999-06-01 00:00:00
abstract:PURPOSE:To design hyperbolic secant (HS) excitation pulses to reduce signal dropout in the orbitofrontal and inferior temporal regions in gradient-echo echo-planar imaging (GE-EPI) for functional MRI (fMRI) applications. METHODS:An algorithm based on Bloch simulations optimizes the HS pulse parameters needed to give t...
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更新日期:2015-09-01 00:00:00
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更新日期:1998-06-01 00:00:00