High Frame Rate Myocardial Integrated Backscatter. Does this Change our Understanding of this Acoustic Parameter?

J. D'Hooge, B. Bijnens, F. Jamal, C. Pislaru, S. Pislaru, J. Thoen, P. Suetens, F. Van De Werf, C. Angermann, F. E. Rademakers, M. C. Herregods, G. R. Sutherland

Research output: Contribution to journalArticle

43 Scopus citations

Abstract

Aims: Integrated backscatter (IB) and its cyclic variation (CV) derived from radio-frequency (RF) data have been used as parameters to attempt myocardial tissue characterization. Prior imaging systems used to measure IB and its CV typically acquired data at frame rates of 20-30Hz and at a resolution of 6-8bits. If changes in IB levels are in part related to specific short-lived events, occurring within the cardiac cycle, this frame rate and resolution could have been too low to resolve adequately what might be a more complex data set. Methods and Results: To investigate this possibility, we acquired real time two-dimensional (2D) myocardial IQ data (the 'in-phase quadrature' sampled RF data) at high frame rate (7gt;100Hz), high dynamic resolution (theoretical 19-bit) and a sector angle of 20°. Several consecutive heart cycles of myocardial data were acquired from individual cardiac walls in five closed chest dogs and 10 healthy, young volunteers at normal heart rates. On the reconstructed RF data regions of interest were indicated, and IB and its CV were calculated. The extracted high frame rate curves showed that the CV of IB is not a smooth sinusoidal-like curve, but is made up of multiple reproducible peaks and troughs with local minima and maxima which are temporally related to active or passive mechanical events, i.e. systolic contraction, early ventricular relaxation and ventricular filling due to atrial contraction. Conclusions: This study shows that increasing the rate of real-time RF data acquisition results in a more complex, reproducible IB curve. The resolved maxima and minima in IB levels are related to specific phases of the myocardial contraction. Furthermore, spectral analysis showed that IB curves acquired at normal heart rates contain information up to 40Hz. Hence, cardiac imaging data sets used to analyse regional myocardial function obtained at frequencies lower than 80 frames per second can contain aliased information.

Original languageEnglish (US)
Pages (from-to)32-41
Number of pages10
JournalEuropean Journal of Echocardiography
Volume1
Issue number1
DOIs
StatePublished - Mar 1 2000

Keywords

  • Cyclic variation; Integrated backscatter; Temporal resolution; Tissue characterization

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine

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    D'Hooge, J., Bijnens, B., Jamal, F., Pislaru, C., Pislaru, S., Thoen, J., Suetens, P., Van De Werf, F., Angermann, C., Rademakers, F. E., Herregods, M. C., & Sutherland, G. R. (2000). High Frame Rate Myocardial Integrated Backscatter. Does this Change our Understanding of this Acoustic Parameter? European Journal of Echocardiography, 1(1), 32-41. https://doi.org/10.1053/euje.2000.0004