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Conference Paper: Experimental assessment of angle-independent myocardial elastography performance using a left-ventricular phantom undergoing physiologic motion

TitleExperimental assessment of angle-independent myocardial elastography performance using a left-ventricular phantom undergoing physiologic motion
Authors
KeywordsAngle-Independent
Axial
Circumferential
Cross-Correlation
Echocardiography
Elastography
Left Ventricle
Myocardial
Phantom
Polyacrylamide
Strain
Issue Date2007
Citation
Proceedings - Ieee Ultrasonics Symposium, 2007, p. 741-744 How to Cite?
AbstractEchocardiography is the most prevalent imaging modalities in clinical cardiology. However, current diagnostic techniques rely on qualitative image analysis, ignoring the quantitative data inherent to this modality. We seek to develop a quantitative system for analyzing echocardiographic images. In this study, the performance of Myocardial Elastography was tested under motion-induced decorrelation noise using a tissue-mimicking phantom of the human left ventricle (LV) that underwent physiologic, cardiac motion configurations. A Terason system (Teratech Corp., Burlington, MA, USA.) with a phased array transducer (128 elements, 3.5 MHz) was utilized to acquire radiofrequency (RF) data in a short-axis view of a cylindrical Polyacrylamide phantom with geometric (R0 = 28mm, Ri = 15mm, L = 15cm) and mechanical properties (Ewall = 50 kPa + agar scatterers; Ecore = 10 kPa) similar to those of an adult, healthy LV. The phantom underwent two motion configurations - either pure rotation, with the non-rotating end of the phantom being free, or torsion with the non-rotating end being fixed; the latter in order to simulate the "wringing" action of the LV This provided a realistic motion pattern for decorrelation noise and rotational motion analysis. RF data were acquired at multiple slices to assess differential displacements under these motion configurations. In-plane (lateral and axial) displacements were iteratively estimated using a 1D cross-correlation and recorrelation technique in a 2D search (4.10 mm window with 75% overlap) and then radial, circumferential, and angular displacements were calculated via a coordinate transformation. Second, in-plane strains were calculated using a least-squares strain estimator. Radial and circumferential strains were then computed based on a similar coordinate transformation. The observed displacement estimates were in accordance with the theoretically predicted results. During pure rotation, all regions of the phantom exhibited similar displacements and minute strains. In the case of torsion, in-plane strains were again insignificant, but analysis of multiple slices revealed differential motion resulting from the imposed constraint on rotation. Ongoing studies aim at investigating the reproducibility of the measurements as well as studying more complex motion configurations, including simultaneous radial deformation and flow. © 2007 IEEE.
Persistent Identifierhttp://hdl.handle.net/10722/167107
ISSN
References

 

DC FieldValueLanguage
dc.contributor.authorGamarnik, Ven_US
dc.contributor.authorLuo, Jen_US
dc.contributor.authorLee, WNen_US
dc.contributor.authorKonofagou, Een_US
dc.date.accessioned2012-09-28T04:04:12Z-
dc.date.available2012-09-28T04:04:12Z-
dc.date.issued2007en_US
dc.identifier.citationProceedings - Ieee Ultrasonics Symposium, 2007, p. 741-744en_US
dc.identifier.issn1051-0117en_US
dc.identifier.urihttp://hdl.handle.net/10722/167107-
dc.description.abstractEchocardiography is the most prevalent imaging modalities in clinical cardiology. However, current diagnostic techniques rely on qualitative image analysis, ignoring the quantitative data inherent to this modality. We seek to develop a quantitative system for analyzing echocardiographic images. In this study, the performance of Myocardial Elastography was tested under motion-induced decorrelation noise using a tissue-mimicking phantom of the human left ventricle (LV) that underwent physiologic, cardiac motion configurations. A Terason system (Teratech Corp., Burlington, MA, USA.) with a phased array transducer (128 elements, 3.5 MHz) was utilized to acquire radiofrequency (RF) data in a short-axis view of a cylindrical Polyacrylamide phantom with geometric (R0 = 28mm, Ri = 15mm, L = 15cm) and mechanical properties (Ewall = 50 kPa + agar scatterers; Ecore = 10 kPa) similar to those of an adult, healthy LV. The phantom underwent two motion configurations - either pure rotation, with the non-rotating end of the phantom being free, or torsion with the non-rotating end being fixed; the latter in order to simulate the "wringing" action of the LV This provided a realistic motion pattern for decorrelation noise and rotational motion analysis. RF data were acquired at multiple slices to assess differential displacements under these motion configurations. In-plane (lateral and axial) displacements were iteratively estimated using a 1D cross-correlation and recorrelation technique in a 2D search (4.10 mm window with 75% overlap) and then radial, circumferential, and angular displacements were calculated via a coordinate transformation. Second, in-plane strains were calculated using a least-squares strain estimator. Radial and circumferential strains were then computed based on a similar coordinate transformation. The observed displacement estimates were in accordance with the theoretically predicted results. During pure rotation, all regions of the phantom exhibited similar displacements and minute strains. In the case of torsion, in-plane strains were again insignificant, but analysis of multiple slices revealed differential motion resulting from the imposed constraint on rotation. Ongoing studies aim at investigating the reproducibility of the measurements as well as studying more complex motion configurations, including simultaneous radial deformation and flow. © 2007 IEEE.en_US
dc.languageengen_US
dc.relation.ispartofProceedings - IEEE Ultrasonics Symposiumen_US
dc.subjectAngle-Independenten_US
dc.subjectAxialen_US
dc.subjectCircumferentialen_US
dc.subjectCross-Correlationen_US
dc.subjectEchocardiographyen_US
dc.subjectElastographyen_US
dc.subjectLeft Ventricleen_US
dc.subjectMyocardialen_US
dc.subjectPhantomen_US
dc.subjectPolyacrylamideen_US
dc.subjectStrainen_US
dc.titleExperimental assessment of angle-independent myocardial elastography performance using a left-ventricular phantom undergoing physiologic motionen_US
dc.typeConference_Paperen_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/ULTSYM.2007.190en_US
dc.identifier.scopuseid_2-s2.0-48149083453en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-48149083453&selection=ref&src=s&origin=recordpageen_US
dc.identifier.spage741en_US
dc.identifier.epage744en_US
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridGamarnik, V=35760868400en_US
dc.identifier.scopusauthoridLuo, J=7404182785en_US
dc.identifier.scopusauthoridLee, WN=22634980600en_US
dc.identifier.scopusauthoridKonofagou, E=7005877325en_US

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