Use of myocardial backscatter as a quantitative tool for dobutamine echocardiography: feasibility, response to ischemia and accuracy compared with coronary angiography

Dart, Jared, Yuda, Satoshi, Cain, Peter, Case, Colin and Marwick, Thomas H. (2002) Use of myocardial backscatter as a quantitative tool for dobutamine echocardiography: feasibility, response to ischemia and accuracy compared with coronary angiography. International Journal of Cardiovascular Imaging, 18 5: 325-336. doi:10.1023/A:1016083006528


Author Dart, Jared
Yuda, Satoshi
Cain, Peter
Case, Colin
Marwick, Thomas H.
Title Use of myocardial backscatter as a quantitative tool for dobutamine echocardiography: feasibility, response to ischemia and accuracy compared with coronary angiography
Journal name International Journal of Cardiovascular Imaging   Check publisher's open access policy
ISSN 1569-5794
1573-0743
Publication date 2002-10-01
Sub-type Article (original research)
DOI 10.1023/A:1016083006528
Open Access Status Not yet assessed
Volume 18
Issue 5
Start page 325
End page 336
Total pages 12
Editor Johan Reiber
Place of publication Dordrecht
Publisher Kluwer Academic Publ
Language eng
Subject C1
321003 Cardiology (incl. Cardiovascular Diseases)
730106 Cardiovascular system and diseases
Abstract Integrated backscatter (IB) changes with ischemia, but most prior studies have involved parasternal imaging, which limited the number of evaluable segments. We sought to assess the efficacy and feasibility of IB from the apical views, and compare this to myocardial Doppler findings and wall motion analysis during dobutamine echocardiography.

Forty-one patients undergoing dobutamine echocardiography had gray scale images and color myocardial Doppler acquired in three apical views. Cyclic variation IB (CVIB), time to peak IB (tIB, corrected for QT interval) and Doppler peak velocity (PV) in the same segment at rest and peak stress were assessed offline from digital cineloops at 80-120 frames/s. Significant coronary disease was defined by quantitative angiography as > 50% stenosis. Analysis of the waveform in the apical views was feasible in 82% of segments. The backscatter curve was shown to be biphasic, with correlation of the first peak with peak tissue velocity, and significant regional variation. However, the response to normal segments was different with tissue Doppler (increased velocity) and backscatter (no change). Ischemia was associated with a lower peak tissue velocity and lower CVIB. Only resting tissue velocity and tIB (not CVIB) distinguished scar from ischemic segments. Using an optimal cutoff of < 5.3 dB at rest achieved a sensitivity of 55%, a specificity of 76% and an accuracy of 75% when compared to angiography. The same cutoff at peak achieved a sensitivity of 58%, a specificity of 80% and an accuracy of 76%.

CVIB and tissue velocity responses to stress are different, but both may be used to identify abnormal segments in patients with CAD. However, while measurement of CVIB is feasible in the apical views, the variability caused by anisotropy limits the accuracy of a single cutoff.
Formatted abstract
Background:
Integrated backscatter (IB) changes with ischemia, but most prior studies have involved parasternal imaging, which limited the number of evaluable segments. We sought to assess the efficacy and feasibility of IB from the apical views, and compare this to myocardial Doppler findings and wall motion analysis during dobutamine echocardiography.

Methods and results:
Forty-one patients undergoing dobutamine echocardiography had gray scale images and color myocardial Doppler acquired in three apical views. Cyclic variation OB (CVIB), time to peak IB (tIB, corrected for QT interval) and Doppler peak velocity (PV) in the same segment at rest and peak stress were assessed offline from digital cineloops at 80-120 frames/s. Significant coronary disease was defined by quantitative angiography as >50% stenosis. Analysis of the waveform in the apical views was feasible in 82% of segments. The backscatter curve was shown to be biphasic, with correlation of the first peak with peak tissue velocity, and significant regional variation. However, the response to normal segments was different with tissue Doppler (increased velocity) and backscatter (no change). Ischemia was associated with a lower peak tissue velocity and lower CVIB. Only resting tissue velocity and tIB (not CVIB) distinguished scar from ischemic segments. Using an optimal cutoff of <5.3 dB at rest achieved a sensitivity of 55%, a specificity of 76% and an accuracy of 75% when compared to angiography. The same cutoff at peak achieved a sensitivity of 58%, a specificity of 80% and an accuracy of 76%.

Conclusions:
CVIB and tissue velocity responses to stress are different, but both may be used to identify abnormal segments in patients with CAD. However, while measurement of CVIB is feasible in the apical views, the variability caused by anisotropy limits the accuracy of a single cutoff.
Keyword Cardiac & Cardiovascular Systems
Radiology, Nuclear Medicine & Medical Imaging
dobutamine echocardiography
integrated backscatter
ischemia
tissue Doppler
Ultrasonic Tissue Characterization
Ventricular Wall-motion
Integrated Backscatter
Stress Echocardiography
Artery Disease
Stunned Myocardium
Doppler Velocity
Cyclic Variation
Color Kinesis
Exercise
Q-Index Code C1
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Medicine Publications
 
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Created: Wed, 17 Oct 2007, 21:28:37 EST