Quantification by Speckle Tracking at Rest and During Stress

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Abstract

Abstract
The introduction of speckle tracking imaging and the opportunity to objectify regional myocardial function in an angle-independent fashion has opened a wide array of opportunities. Quantitative echocardiography is likely to reduce intra-observer variability and shorten learning curves and this will allow broader use of these new imaging modalities in clinical routine and for research purposes. Tissue Doppler is used for deformation imaging, but has disadvantages that can be overcome with 2D speckle tracking. This article briefly summarises the technical details of 2D speckle tracking (strain and strain rate) and gives an overview on current and potential future applications of this new technique at rest and during stress.

Keywords
Left ventricular systolic function, deformation imaging, strain analysis, speckle tracking, stress test, echocardiography

Disclosure: The authors have no conflicts of interest to declare.
Received: 8 October 2010 Accepted: 24 October 2010 Citation: European Cardiology, 2010;6(4):16├óÔé¼ÔÇ£20
Correspondence: Paul Erne, Department of Cardiology, Kantonsspital Luzern, 6000 Luzern 16, Switzerland. E: paul.erne@ksl.ch

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The introduction of tissue Doppler imaging (TDI) strain was a great achievement in echocardiography and for the first time allowed true quantification of regional myocardial function. The central problem with this technique was the angle dependence and the unfavourable signal-to-noise ratio, which has been partially overcome with 2D speckle tracking. Figures 1 and 2 demonstrate application of speckle tracking at rest and during dobutamine stress echocardiography (DSE) in a normal subject.

Assessing Patients with Suspected Coronary Artery Disease
Given the fact that survival from revascularisation has only been demonstrated for patients with inducible ischaemia,1 the role of stress echocardiography, myocardial perfusion scintigraphy and perfusion magnetic resonance imaging (MRI) is likely to remain important in the future.

DSE has excellent rates of sensitivity and specificity2 and has been widely used for clinical and research purposes in the past. However, DSE has a long learning curve, is relatively subjective and the poor temporal resolution of the human eye is a limitation for the accurate visual assessment of the complex myocardial motion.3 Initial studies using quantitative longitudinal strain rate analysis with TDI during DSE showed high specificity and sensitivity in detecting coronary artery disease.4├óÔé¼ÔÇ£6

2D speckle tracking is site specific and angle independent and allows quantitative assessment of longitudinal, transversal, radial and circumferential strain, which cannot be completely appreciated visually.7 This opens new opportunities and even further increases the accuracy of this method in ischaemia assessment.8 Figure 3 demonstrates the example of a patient with a circumflex stenosis and ischaemia during DSE with post-systolic contraction of the lateral wall in the recovery period in 2D speckle tracking. In the recovery period, displacement imaging depicts post-systolic contraction of the lateral wall in red.