Linked Life Data

9771576

Source:http://linkedlifedata.com/resource/pubmed/id/9771576

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1998-12-21
pubmed:abstractText
A method is presented for the accurate extraction of relative spin-density (rho0) and spin-lattice relaxation time (T1) in the presence of RF-field inhomogeneities and flip-angle miscalibration. The method requires collecting images at several flip-angles with a three-dimensional, spoiled steady-state, gradient-echo imaging sequence. Results show that the predominant effect of an overestimated flip-angle is to shift the T1 estimate to a higher value, whereas reductions in the normalized RF-field from unity cause rho0 and T1 distributions to be skewed toward lower values. Phantom and in vivo results demonstrate that the proposed method overcomes both of these systematic errors. The method was shown to be valid for up to a 50% reduction in RF sensitivity. A self-consistency argument was used to validate the absence of systematic errors in the extracted rho0 and T1 values over a large number of voxels. This made it possible to obtain a very precise estimate of muscle T1 at 1.5 T, yielding a 95% confidence interval of (1077.7 +/- 3.5) ms.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0740-3194
pubmed:author
pubmed:issnType
Print
pubmed:volume
40
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
592-602
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Accurate determination of spin-density and T1 in the presence of RF-field inhomogeneities and flip-angle miscalibration.
pubmed:affiliation
Mallinckrodt Institute of Radiology, Washington University, St Louis, Missouri, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.