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Echo-Time and Field Strength Dependence of BOLD Reactivity in Veins and Parenchyma Using Flow-Normalized Hypercapnic Manipulation

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dc.contributor.author Hoge, Richard D.
dc.contributor.author Triantafyllou, Christina
dc.contributor.author Wald, Lawrence
dc.date.accessioned 2012-02-15T18:05:01Z
dc.date.available 2012-02-15T18:05:01Z
dc.date.issued 2011-09
dc.date.submitted 2011-04
dc.identifier.issn 1932-6203
dc.identifier.uri http://hdl.handle.net/1721.1/69111
dc.description.abstract While the BOLD (Blood Oxygenation Level Dependent) contrast mechanism has demonstrated excellent sensitivity to neuronal activation, its specificity with regards to differentiating vascular and parenchymal responses has been an area of ongoing concern. By inducing a global increase in Cerebral Blood Flow (CBF), we examined the effect of magnetic field strength and echo-time (TE) on the gradient-echo BOLD response in areas of cortical gray matter and in resolvable veins. In order to define a quantitative index of BOLD reactivity, we measured the percent BOLD response per unit fractional change in global gray matter CBF induced by inhaling carbon dioxide (CO[scubript 2]). By normalizing the BOLD response to the underlying CBF change and determining the BOLD response as a function of TE, we calculated the change in R[scubript 2]* (ΔR[scubript 2]*) per unit fractional flow change; the Flow Relaxation Coefficient, (FRC) for 3T and 1.5T in parenchymal and large vein compartments. The FRC in parenchymal voxels was 1.76±0.54 fold higher at 3T than at 1.5T and was 2.96±0.66 and 3.12±0.76 fold higher for veins than parenchyma at 1.5T and 3T respectively, showing a quantitative measure of the increase in specificity to parenchymal sources at 3T compared to 1.5T. Additionally, the results allow optimization of the TE to prioritize either maximum parenchymal BOLD response or maximum parenchymal specificity. Parenchymal signals peaked at TE values of 62.0±11.5 ms and 41.5±7.5 ms for 1.5T and 3T, respectively, while the response in the major veins peaked at shorter TE values; 41.0±6.9 ms and 21.5±1.0 ms for 1.5T and 3T. These experiments showed that at 3T, the BOLD CNR in parenchymal voxels exceeded that of 1.5T by a factor of 1.9±0.4 at the optimal TE for each field. en_US
dc.description.sponsorship National Institutes of Health (U.S.) en_US
dc.description.sponsorship National Center for Research Resources (U.S.) en_US
dc.description.sponsorship National Institutes of Health (U.S.) (P41 Regional Resource Grant P41RR14075) en_US
dc.description.sponsorship National Institutes of Health (U.S.) (P41 Regional Resource Grant RO1RR1453A01) en_US
dc.description.sponsorship Mental Illness and Neuroscience Discovery (MIND) Institute en_US
dc.description.sponsorship Natural Sciences and Engineering Research Council of Canada (NSERC) (355583-2010) en_US
dc.description.sponsorship Canadian Institutes of Health Research (MOP 84378) en_US
dc.language.iso en_US
dc.publisher Public Library of Science en_US
dc.relation.isversionof http://dx.doi.org/10.1371/journal.pone.0024519 en_US
dc.rights Creative Commons Attribution en_US
dc.rights.uri http://creativecommons.org/licenses/by/2.5/ en_US
dc.source PLoS en_US
dc.title Echo-Time and Field Strength Dependence of BOLD Reactivity in Veins and Parenchyma Using Flow-Normalized Hypercapnic Manipulation en_US
dc.type Article en_US
dc.identifier.citation Triantafyllou, Christina, Lawrence L. Wald, and Richard D. Hoge. “Echo-Time and Field Strength Dependence of BOLD Reactivity in Veins and Parenchyma Using Flow-Normalized Hypercapnic Manipulation.” Ed. Chris I. Baker. PLoS ONE 6.9 (2011): e24519. Web. 15 Feb. 2012. en_US
dc.contributor.department Martinos Imaging Center at MIT en_US
dc.contributor.department McGovern Institute for Brain Research at MIT en_US
dc.contributor.department Harvard University--MIT Division of Health Sciences and Technology en_US
dc.contributor.approver Wald, Lawrence L.
dc.contributor.mitauthor Hoge, Richard D.
dc.contributor.mitauthor Triantafyllou, Christina
dc.contributor.mitauthor Wald, Lawrence
dc.relation.journal PLoS ONE en_US
dc.identifier.mitlicense PUBLISHER_CC en_US
dc.eprint.version Final published version en_US
dc.type.uri http://purl.org/eprint/type/JournalArticle en_US
eprint.status http://purl.org/eprint/status/PeerReviewed en_US
dspace.orderedauthors Triantafyllou, Christina; Wald, Lawrence L.; Hoge, Richard D. en


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