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Article: Electromechanical wave imaging of normal and ischemic hearts in vivo

TitleElectromechanical wave imaging of normal and ischemic hearts in vivo
Authors
Issue Date2010
Citation
Ieee Transactions On Medical Imaging, 2010, v. 29 n. 3, p. 625-635 How to Cite?
AbstractElectromechanical wave imaging (EWI) has recently been introduced as a noninvasive, ultrasound-based imaging modality, which could map the electrical activation of the heart in various echocardiographic planes in mice, dogs, and humans in vivo. By acquiring radio-frequency (RF) frames at very high frame rates (390520 Hz), the onset of small, localized, transient deformations resulting from the electrical activation of the heart, i.e., generating the electromechanical wave (EMW), can be mapped. The correlation between the EMW and the electrical activation speed and pacing scheme has previously been reported. In this study, we pursue the development of EWI using both displacements and strains and analysis of the EMW properties in dogs in vivo for early detection of ischemia. EWI was performed in normal and ischemic open-chest dogs during sinus rhythm. Ischemia of increasing severity was obtained by gradually obstructing the left-anterior descending (LAD) coronary artery flow. We also introduce the novel method of motion-matching that achieves the reconstruction of the full EWI cin-loop at very high frame rates even when the ECG may be irregular or unavailable. Incremental displacements were previously used by our group to map the EMW. This paper focuses on the associated incremental strains, which facilitate the interpretation of the EMW by relating it directly to contraction. Moreover, we define the onset of the EMW as the time, at which the incremental strains change sign after the onset of the QRS complex of the ECG. Based on this definition, isochronal representations of the EMW were generated using a semi-automated method. The isochronal representation of the EMW during sinus rhythm was reproducible and shown similar to electrical activation maps previously reported in the literature. After segmentation using a contour-tracking method, the two-and four-chamber views were imaged and displayed in bi-plane views, allowing a 3-D interpretation of the EMW. EWI was shown to be sensitive to the presence of intermediate ischemia. EWI localized the ischemic region when the LAD flow was obstructed at 60% and beyond and was capable of mapping the increase of the ischemic region size as the LAD occlusion level increased. In conclusion, the activation maps and wave patterns obtained with EWI were similar to the electrical equivalents previously reported in the literature. Moreover, EWI was found to be sensitive enough to detect and map intermediate ischemia. Those results indicate that EWI could be used to assess the conduction properties of the myocardium, and detect its ischemic onset and disease progression entirely noninvasively. © 2010 IEEE.
Persistent Identifierhttp://hdl.handle.net/10722/167060
ISSN
2015 Impact Factor: 3.756
2015 SCImago Journal Rankings: 1.941
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorProvost, Jen_US
dc.contributor.authorLee, WNen_US
dc.contributor.authorFujikura, Ken_US
dc.contributor.authorKonofagou, EEen_US
dc.date.accessioned2012-09-28T04:02:26Z-
dc.date.available2012-09-28T04:02:26Z-
dc.date.issued2010en_US
dc.identifier.citationIeee Transactions On Medical Imaging, 2010, v. 29 n. 3, p. 625-635en_US
dc.identifier.issn0278-0062en_US
dc.identifier.urihttp://hdl.handle.net/10722/167060-
dc.description.abstractElectromechanical wave imaging (EWI) has recently been introduced as a noninvasive, ultrasound-based imaging modality, which could map the electrical activation of the heart in various echocardiographic planes in mice, dogs, and humans in vivo. By acquiring radio-frequency (RF) frames at very high frame rates (390520 Hz), the onset of small, localized, transient deformations resulting from the electrical activation of the heart, i.e., generating the electromechanical wave (EMW), can be mapped. The correlation between the EMW and the electrical activation speed and pacing scheme has previously been reported. In this study, we pursue the development of EWI using both displacements and strains and analysis of the EMW properties in dogs in vivo for early detection of ischemia. EWI was performed in normal and ischemic open-chest dogs during sinus rhythm. Ischemia of increasing severity was obtained by gradually obstructing the left-anterior descending (LAD) coronary artery flow. We also introduce the novel method of motion-matching that achieves the reconstruction of the full EWI cin-loop at very high frame rates even when the ECG may be irregular or unavailable. Incremental displacements were previously used by our group to map the EMW. This paper focuses on the associated incremental strains, which facilitate the interpretation of the EMW by relating it directly to contraction. Moreover, we define the onset of the EMW as the time, at which the incremental strains change sign after the onset of the QRS complex of the ECG. Based on this definition, isochronal representations of the EMW were generated using a semi-automated method. The isochronal representation of the EMW during sinus rhythm was reproducible and shown similar to electrical activation maps previously reported in the literature. After segmentation using a contour-tracking method, the two-and four-chamber views were imaged and displayed in bi-plane views, allowing a 3-D interpretation of the EMW. EWI was shown to be sensitive to the presence of intermediate ischemia. EWI localized the ischemic region when the LAD flow was obstructed at 60% and beyond and was capable of mapping the increase of the ischemic region size as the LAD occlusion level increased. In conclusion, the activation maps and wave patterns obtained with EWI were similar to the electrical equivalents previously reported in the literature. Moreover, EWI was found to be sensitive enough to detect and map intermediate ischemia. Those results indicate that EWI could be used to assess the conduction properties of the myocardium, and detect its ischemic onset and disease progression entirely noninvasively. © 2010 IEEE.en_US
dc.languageengen_US
dc.relation.ispartofIEEE Transactions on Medical Imagingen_US
dc.subject.meshAlgorithmsen_US
dc.subject.meshAnimalsen_US
dc.subject.meshDogsen_US
dc.subject.meshEchocardiography - Methodsen_US
dc.subject.meshHeart Conduction System - Physiology - Ultrasonographyen_US
dc.subject.meshHumansen_US
dc.subject.meshIschemia - Physiopathology - Ultrasonographyen_US
dc.subject.meshMaleen_US
dc.subject.meshMyocardial Contraction - Physiologyen_US
dc.subject.meshSignal Processing, Computer-Assisteden_US
dc.titleElectromechanical wave imaging of normal and ischemic hearts in vivoen_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.doi10.1109/TMI.2009.2030186en_US
dc.identifier.pmid19709966-
dc.identifier.scopuseid_2-s2.0-77749254598en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-77749254598&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume29en_US
dc.identifier.issue3en_US
dc.identifier.spage625en_US
dc.identifier.epage635en_US
dc.identifier.isiWOS:000276308800005-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridProvost, J=7103236841en_US
dc.identifier.scopusauthoridLee, WN=22634980600en_US
dc.identifier.scopusauthoridFujikura, K=7004375160en_US
dc.identifier.scopusauthoridKonofagou, EE=7005877325en_US

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