Abstract:
:The remarkable success of magnetic resonance imaging of adult brain relates to the unusually large ratio of the longitudinal relaxation rates 1/T1 of white and gray matter, approximately 2:1 at physiological temperature and traditional imaging fields. Several investigators have conjectured that myelin is the source of the greater 1/T1 of white matter without, however, suggesting details of the molecular mechanisms responsible. From measurements of the magnetic field dependence of 1/T1 (NMRD profiles) of adult and neonatal gray and white matter at 5 and 35 degrees C, we find a thermally activated contribution to the NMRD profile of adult white matter that is not present in the profiles of either adult gray or neonatal gray and white matter. We attribute this contribution to myelin and develop a quantitative model that accounts for the unique relaxation behavior of myelinated white matter. We find that myelin water, 15% of the total, has a relatively short T1 that arises from an unexpectedly large interaction with myelin lipid; when cast in terms of an interaction over the entire myelin bilipid-water interface, it is sevenfold greater than the analogous protein-water interfacial interaction. Its magnitude remains to be accounted for, but cholesterol, known to alter the relaxation rates of lipid protons, may play an important role. The contribution of myelin to 1/T1 at physiological temperatures is attributed to thermally activated transmembrane diffusion of water and, hence, more rapid mixing of axonal and the rapidly relaxing myelin water molecules.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Koenig SH,Brown RD 3rd,Spiller M,Lundbom Ndoi
10.1002/mrm.1910140306subject
Has Abstractpub_date
1990-06-01 00:00:00pages
482-95issue
3eissn
0740-3194issn
1522-2594journal_volume
14pub_type
杂志文章abstract:PURPOSE:To obtain multicontrast images including fat-suppressed contrast image, a novel multicontrast imaging method using an SSFP sequence with alternating RF flip angles is proposed. METHODS:The proposed method uses the balanced SSFP sequence with 2 flip angles. In general, the conventional balanced SSFP sequence ha...
journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.27342
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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
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journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
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更新日期:1996-11-01 00:00:00
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journal_title:Magnetic resonance in medicine
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abstract::We applied MRI to the in vivo detection of spontaneous colorectal tumors in a unique mouse model, the Fox Chase Cancer Center (FCCC) ApcMIN mouse. Unlike other Min (multiple intestinal neoplasia) strains, FCCC ApcMIN animals develop an appreciable number of tumors in the large intestine, which makes them an appropriat...
journal_title:Magnetic resonance in medicine
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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:2014-10-01 00:00:00
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journal_title:Magnetic resonance in medicine
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journal_title:Magnetic resonance in medicine
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更新日期:2011-04-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
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更新日期:1998-03-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 临床试验,杂志文章
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更新日期:2000-01-01 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
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更新日期:1999-01-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:2012-07-01 00:00:00
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journal_title:Magnetic resonance in medicine
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doi:10.1002/mrm.1910370317
更新日期:1997-03-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:2010-01-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
doi:10.1002/mrm.20031
更新日期:2004-04-01 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
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journal_title:Magnetic resonance in medicine
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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:1993-11-01 00:00:00
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journal_title:Magnetic resonance in medicine
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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
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更新日期:1992-12-01 00:00:00
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journal_title:Magnetic resonance in medicine
pub_type: 杂志文章
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更新日期:2016-04-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:2017-06-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:2003-08-01 00:00:00
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journal_title:Magnetic resonance in medicine
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更新日期:2010-02-01 00:00:00
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更新日期:2010-07-01 00:00:00
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journal_title:Magnetic resonance in medicine
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