The ultimate objective of the proposed research is to elucidate the physical principles underlying the use of ultrasound fore the definitive quantification of acoustic properties of heart muscle needed for optimal diagnosis and assessment of function. In clinical echocardiography, scans are made with the direction of propagation of ultrasound at varying angles relative to the local fiber orientation of the myocardium and throughout the contraction-relaxation cycle. We have demonstrated that the magnitudes of backscatter and attenuation vary substantially with the angle of insonification relative to the arrangement of myofibers in the ventricular walls. Anisotropy is responsible for the drop out of the lateral and septal wall echoes in parasternal short-axis echocardiographic views and is especially pertinent for quantitative tissue characterization which has as its goal assessment of the properties of the tissue itself, as opposed to assessment of dimensions or motion. We propose to continue and extend our systematic investigations of the extent of angular variation of the ultrasonic properties of the heart and their relationship to conventional echocardiography, automatic echocardiographic detection of tissue-blood interfaces, myocardial tissue characterization, and ultimately to ultrasonic assessment of myocardial elastic properties. Research during the current grant period has focused on anisotropic properties averaged over the entire thickness of the ventricular wall. In this competitive renewal proposal, we outline studies designed to delineate the transmural variation of elastic properties that parallel significant transmural variations in the three-dimensional architecture of normal and diseased myocardium by measuring the transmural variations of the anisotropy of backscatter, attenuation, and velocity of myocardium and comparing with appropriate experimental and mathematical models. We further propose strategies for overcoming potential stumbling blocks arising from anisotropy for echocardiographic imaging, automatic detection of cardiac chamber dimensions, and myocardial tissue characterization. The proposed research is designed to lay the groundwork for exploiting the anisotropy of myocardial elastic properties to achieve improved understanding of cardiac mechanical properties (elasticity and compliance) in normal and diseases hearts. Our goal is to provide definitive answers to a series of explicit questions posed in the text of the proposal and thus to provide a basis for improving the diagnostic power of ultrasonics.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
2R01HL040302-06
Application #
3357388
Study Section
Diagnostic Radiology Study Section (RNM)
Project Start
1988-04-01
Project End
1998-03-31
Budget Start
1993-04-01
Budget End
1994-03-31
Support Year
6
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Washington University
Department
Type
Schools of Arts and Sciences
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Milne, Michelle L; Singh, Gautam K; Miller, James G et al. (2016) Toward 3-D Echocardiographic Determination of Regional Myofiber Structure. Ultrasound Med Biol 42:607-18
Groopman, Amber M; Katz, Jonathan I; Holland, Mark R et al. (2015) Conventional, Bayesian, and Modified Prony's methods for characterizing fast and slow waves in equine cancellous bone. J Acoust Soc Am 138:594-604
Milne, Michelle L; Singh, Gautam K; Miller, James G et al. (2012) Echocardiographic-based assessment of myocardial fiber structure in individual, excised hearts. Ultrason Imaging 34:129-41
Lloyd, Christopher W; Shmuylovich, Leonid; Holland, Mark R et al. (2011) The diastolic function to cyclic variation of myocardial ultrasonic backscatter relation: the influence of parameterized diastolic filling (PDF) formalism determined chamber properties. Ultrasound Med Biol 37:1185-95
Anderson, Christian C; Gibson, Allyson A; Schaffer, Jean E et al. (2011) Bayesian parameter estimation for characterizing the cyclic variation of echocardiographic backscatter to assess the hearts of asymptomatic type 2 diabetes mellitus subjects. Ultrasound Med Biol 37:805-12
Hoffman, Joseph J; Johnson, Benjamin L; Holland, Mark R et al. (2011) Layer-dependent variation in the anisotropy of apparent integrated backscatter from human coronary arteries. Ultrasound Med Biol 37:632-41
Holland, Mark R; Gibson, Allyson A; Bauer, Adam Q et al. (2010) Echocardiographic tissue characterization demonstrates differences in the left and right sides of the ventricular septum. Ultrasound Med Biol 36:1653-61
Holland, Mark R; Gibson, Allyson A; Kirschner, Carol A et al. (2009) Intrinsic myoarchitectural differences between the left and right ventricles of fetal human hearts: an ultrasonic backscatter feasibility study. J Am Soc Echocardiogr 22:170-6
Gibson, Allyson A; Schaffer, Jean E; Peterson, Linda R et al. (2009) Quantitative analysis of the magnitude and time delay of cyclic variation of myocardial backscatter from asymptomatic type 2 diabetes mellitus subjects. Ultrasound Med Biol 35:1458-67
Bauer, Adam Q; Anderson, Christian C; Holland, Mark R et al. (2009) Bone sonometry: reducing phase aberration to improve estimates of broadband ultrasonic attenuation. J Acoust Soc Am 125:522-9

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