Linked Life Data

16292741

Source:http://linkedlifedata.com/resource/pubmed/id/16292741

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2006-2-7
pubmed:abstractText
In the context of quantitative functional MRI (fMRI), deoxyhemoglobin (dHb) content is the essential physiological parameter for calibrating the blood oxygenation level-dependent (BOLD) signal. In studies on humans, the baseline dHb content or its equivalent has been evaluated indirectly by means of carbon dioxide breathing as a physiological reference condition. In this study with normal volunteers, quantitative mapping of baseline dHb content was performed in a direct manner by measuring the reversible contribution of the effective transverse relaxation rate. The BOLD signal change in the visual cortex during 8 Hz flicker visual stimulation was calibrated based on the quantitative map of baseline dHb content. The calibrated relaxation rate change that represents the stimulation-induced fractional change of dHb content decreased by 14% within the activated visual cortex. Simultaneous measurement of cerebral blood flow (CBF) with BOLD showed an increase of 59%. From the calibrated relaxation rate and CBF changes, the cerebral metabolic rate of oxygen (CMRO2) was calculated to increase by 19-28% within the activated visual cortex. The ratio of the CBF increase to the CMRO2 increase was 2-3:1, which agreed well with results of similar quantitative fMRI studies for humans. The method proposed here for quantitative evaluation of the BOLD signal may be applicable not only to fMRI for normal human subjects, but also to physiologically altered or diseased states, because it requires no physiological perturbation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0952-3480
pubmed:author
pubmed:copyrightInfo
2006 John Wiley & Sons, Ltd.
pubmed:issnType
Print
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
60-8
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Quantitative study of changes in oxidative metabolism during visual stimulation using absolute relaxation rates.
pubmed:affiliation
Department of Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. nofujita@radiol.med.osaka-u.ac.jp
pubmed:publicationType
Journal Article, Clinical Trial