Linked Life Data

8139453

Source:http://linkedlifedata.com/resource/pubmed/id/8139453

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1994-4-25
pubmed:abstractText
An echo planar linewidth mapping technique, Shufflebutt, has allowed temporal measurements of changes in linewidth caused by static inhomogeneities (delta LWSI) and transverse relaxation rate (delta R2) in models of hypoxia and hypercapnia. We demonstrate these changes are due to intravascular susceptibility differences/(delta chi) between the blood and tissue. Contrast agent injections at a delta chi equivalent to that of deoxygenated blood showed a twofold difference between the contrast agent and physiological anoxia values. Hypercapnia decreased both delta LWSI and delta R2 consistent with an increase in blood oxygenation. We attribute these findings to constant oxygen extraction during an increase in blood flow, resulting in less deoxygenated venous blood and thus reduced delta chi. For in vivo perturbations we found that delta R2/delta R2' approximately 0.33, a ratio much different from that measured in whole blood phantoms (delta R2/delta R2' approximately 2). This demonstrates that signal changes in these studies are produced predominantly by dephasing of extravascular protons due to field inhomogeneities produced by intravascular deoxygenated hemoglobin (deoxyHb).
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0740-3194
pubmed:author
pubmed:issnType
Print
pubmed:volume
30
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
715-23
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Measurement of regional blood oxygenation and cerebral hemodynamics.
pubmed:affiliation
Department of Radiology, Massachusetts General Hospital, Boston.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.