Exploring the Complexity of Cardiac Motion by Multiscale Motion Mapping, a Novel Quantitative Echocardiograpic Technique
M. Sühling, M. Unser, C. Jansen, M. Arigovindan, P. Buser, S. Marsch, P.R. Hunziker
Proceedings of the Twenty-Fifth Annual Congress of the European Society of Cardiology (ESC'03), Wien, Republic of Austria, August 30-September 2, 2003, European Heart Journal, vol. 24, abstr. supp. 1, pp. 376, August-September 2003.
Background: Measuring motion is fundamental for echo. Conventionally, this is done by “eyeballing”, i.e. visual inspection, with strong intraobserver variability. More recently, tissue Doppler echo and border detection algorithms have been introduced, but their limited impact on routine echo reflects some of their weaknesses, including a limitation to strict 1D motion vectors, the angle dependence of Doppler, and the inability to directly measure wall thickening.
Methods and Results: Multiscale Motion Mapping is a novel echocardiographic technique for measuring motion. This technique is able to assess cardiac motion at arbitrary locations in the echocardiogram, based on exhaustive mathematical analysis of the images using so-called “optical flow” techniques, spline-based imaging, and hierarchical image decomposition. In contrast to conventional techniques, it allows quantitative assessment of true 2D motion, and quantitative measurement of thickening independent of translation. After successful testing of this new technique in synthetic echocardiograms constructed to contain defined motion patterns, and in a physical phantom of heart motion, we explored its potential in clinical echocardiograms. The ability to display motion independent of the ultrasound beam angle was assessed in the short axis views of the left ventricle. We found that the resulting color motion map showed systolic inward- and diastolic outward motion at all locations of the short axis view, in strong contrast to tissue Doppler that failed to show motion at 90 and 270 degrees of the short axis circle.
The ability of Multiscale Motion Mapping to analyze complex 2D motion was tested in short axis views using a novel vector motion display: in this case, apical rotation/twisting could clearly be shown, a phenomenon difficult to observe in echocardiograms.
To validate quantification of wall thickening, synthetic echocardiograms containing predefined wall thickening were constructed digitally; in this model, multiscale motion mapping was able to detect direction and extent of instantaneous wall thickening (true 2D strain rate) reliably.
Conclusion: Multiscale Motion Mapping, a novel method for objective and quantitative determination of myocardial motion, has been validated in vitro and is applicable to clinical echocardiograms. Its unprecedented ability to measure full 2D motion including wall thickening at arbitrary locations in the echo opens a new window to the complexity of cardiac motion in health and disease, and highlights the limitations of current quantitative methods.
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AUTHOR="S{\"{u}}hling, M. and Unser, M. and Jansen, C. and Arigovindan,
M. and Buser, P. and Marsch, S. and Hunziker, P.R.",
TITLE="Exploring the Complexity of Cardiac Motion by Multiscale Motion
Mapping, a Novel Quantitative Echocardiograpic Technique",
BOOKTITLE="Twenty-Fifth Annual Congress of the European Society of
Cardiology ({ESC'03})",
YEAR="2003",
editor="",
volume="24, abstr. supp. 1, August/September 2003",
series="European Heart Journal",
pages="376",
address="Wien, Republic of Austria",
month="August 30-September 2,",
organization="",
publisher="",
note="")