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Article: In vivo study of myocardial elastography under graded ischemia conditions

TitleIn vivo study of myocardial elastography under graded ischemia conditions
Authors
Issue Date2011
PublisherInstitute of Physics Publishing. The Journal's web site is located at http://www.iop.org/journals/pmb
Citation
Physics In Medicine And Biology, 2011, v. 56 n. 4, p. 1155-1172 How to Cite?
AbstractThe capability of currently available echocardiography-based strain estimation techniques to fully map myocardial abnormality at early stages of myocardial ischemia is yet to be investigated. In this study, myocardial elastography (ME), a radio-frequency (RF)-based strain imaging technique that maps the full 2D transmural angle-independent strain tensor in standard echocardiographic views at both high spatial and temporal resolution is presented. The objectives were to (1) evaluate the performance of ME on mapping the onset, extent and progression of myocardial ischemia at graded coronary constriction levels (from partial to complete coronary flow reduction), and (2) validate the accuracy of the strain estimates against sonomicrometry (SM) measurements. A non-survival canine ischemic model (n = 5) was performed by gradually constricting the left anterior descending (LAD) coronary blood flow from 0% (baseline blood flow) to 100% (zero blood flow) at 20% increments. An open-architecture ultrasound system was used to acquire RF echocardiograms in a standard full short-axis view at the frame rate of 211 fps, at least twice higher than what is typically used in conventional echocardiographic systems, using a previously developed, fully automated composite technique. Myocardial deformation was estimated by ME and validated against sonomicrometry. ME estimates and maps transmural (1) 2D displacements using RF cross-correlation and recorrelation; and (2) 2D polar (radial and circumferential) strains, derived from 2D (i.e. both lateral and axial) displacement components, at high accuracy. Full-view strain images were shown and found to reliably depict decreased myocardial function in the region at risk at increased levels of coronary flow reduction. The ME radial strain was deemed to be a more sensitive, quantitative, regional measure of myocardial ischemia as a result of coronary flow reduction when compared to the conventional wall motion score index and ejection fraction. Good agreement (0.22% strain bias, 95% limits of agreement) using Bland-Altman analysis and good correlation (r = 0.84) were found between the ME and SM measurements. These findings demonstrate for the first time that ME could map angle-independent strains to non-invasively detect, localize and characterize the early onset of myocardial ischemia, i.e. at 40%, and possibly as low as 20%, LAD flow reduction, which could be further associated with the severity of coronary stenosis. © 2011 Institute of Physics and Engineering in Medicine.
Persistent Identifierhttp://hdl.handle.net/10722/167061
ISSN
2015 Impact Factor: 2.811
2015 SCImago Journal Rankings: 1.577
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLee, WNen_US
dc.contributor.authorProvost, Jen_US
dc.contributor.authorFujikura, Ken_US
dc.contributor.authorWang, Jen_US
dc.contributor.authorKonofagou, EEen_US
dc.date.accessioned2012-09-28T04:02:26Z-
dc.date.available2012-09-28T04:02:26Z-
dc.date.issued2011en_US
dc.identifier.citationPhysics In Medicine And Biology, 2011, v. 56 n. 4, p. 1155-1172en_US
dc.identifier.issn0031-9155en_US
dc.identifier.urihttp://hdl.handle.net/10722/167061-
dc.description.abstractThe capability of currently available echocardiography-based strain estimation techniques to fully map myocardial abnormality at early stages of myocardial ischemia is yet to be investigated. In this study, myocardial elastography (ME), a radio-frequency (RF)-based strain imaging technique that maps the full 2D transmural angle-independent strain tensor in standard echocardiographic views at both high spatial and temporal resolution is presented. The objectives were to (1) evaluate the performance of ME on mapping the onset, extent and progression of myocardial ischemia at graded coronary constriction levels (from partial to complete coronary flow reduction), and (2) validate the accuracy of the strain estimates against sonomicrometry (SM) measurements. A non-survival canine ischemic model (n = 5) was performed by gradually constricting the left anterior descending (LAD) coronary blood flow from 0% (baseline blood flow) to 100% (zero blood flow) at 20% increments. An open-architecture ultrasound system was used to acquire RF echocardiograms in a standard full short-axis view at the frame rate of 211 fps, at least twice higher than what is typically used in conventional echocardiographic systems, using a previously developed, fully automated composite technique. Myocardial deformation was estimated by ME and validated against sonomicrometry. ME estimates and maps transmural (1) 2D displacements using RF cross-correlation and recorrelation; and (2) 2D polar (radial and circumferential) strains, derived from 2D (i.e. both lateral and axial) displacement components, at high accuracy. Full-view strain images were shown and found to reliably depict decreased myocardial function in the region at risk at increased levels of coronary flow reduction. The ME radial strain was deemed to be a more sensitive, quantitative, regional measure of myocardial ischemia as a result of coronary flow reduction when compared to the conventional wall motion score index and ejection fraction. Good agreement (0.22% strain bias, 95% limits of agreement) using Bland-Altman analysis and good correlation (r = 0.84) were found between the ME and SM measurements. These findings demonstrate for the first time that ME could map angle-independent strains to non-invasively detect, localize and characterize the early onset of myocardial ischemia, i.e. at 40%, and possibly as low as 20%, LAD flow reduction, which could be further associated with the severity of coronary stenosis. © 2011 Institute of Physics and Engineering in Medicine.en_US
dc.languageengen_US
dc.publisherInstitute of Physics Publishing. The Journal's web site is located at http://www.iop.org/journals/pmben_US
dc.relation.ispartofPhysics in Medicine and Biologyen_US
dc.titleIn vivo study of myocardial elastography under graded ischemia conditionsen_US
dc.typeArticleen_US
dc.identifier.emailLee, WN: wnlee@hku.hken_US
dc.identifier.authorityLee, WN=rp01663en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1088/0031-9155/56/4/017en_US
dc.identifier.pmid21285479-
dc.identifier.scopuseid_2-s2.0-79551703929en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-79551703929&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume56en_US
dc.identifier.issue4en_US
dc.identifier.spage1155en_US
dc.identifier.epage1172en_US
dc.identifier.isiWOS:000286800800017-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridLee, WN=22634980600en_US
dc.identifier.scopusauthoridProvost, J=7103236841en_US
dc.identifier.scopusauthoridFujikura, K=7004375160en_US
dc.identifier.scopusauthoridWang, J=36070765500en_US
dc.identifier.scopusauthoridKonofagou, EE=7005877325en_US

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