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Analysis of myocardial deformation based on pixel tracking in two dimensional echocardiographic images enables quantitative assessment of regional left ventricular function
  1. M Becker1,
  2. E Bilke1,
  3. H Kühl1,
  4. M Katoh2,
  5. R Kramann1,
  6. A Franke1,
  7. A Bücker2,
  8. P Hanrath1,
  9. R Hoffmann1
  1. 1Medical Clinic I, University Hospital RWTH Aachen, Aachen, Germany
  2. 2Department of Radiology, University Hospital RWTH Aachen, Aachen, Germany
  1. Correspondence to:
    Dr Rainer Hoffmann
    Medical Clinic I, University RWTH Aachen, Pauwelsstraße 30, 52057 Aachen, Germany; RHoffmann{at}UKAACHEN.de

Abstract

Objective: To evaluate whether myocardial strain and strain rate calculated from two dimensional echocardiography by automatic frame-by-frame tracking of natural acoustic markers enables objective description of regional left ventricular (LV) function.

Methods: In 64 patients parasternal two dimensional echocardiographic views at the apical, mid-ventricular and basal levels were obtained. An automatic frame-by-frame tracking system of natural acoustic echocardiographic markers was used to calculate radial strain, circumferential strain, radial strain rate and circumferential strain rate for each LV segment in a 16 segment model. Cardiac magnetic resonance imaging (cMRI) was performed to define segmental LV function as normokinetic, hypokinetic or akinetic.

Results: Image quality was sufficient for adequate strain and strain-rate analysis from two dimensional echocardiographic images obtained from parasternal views in 88% of segments. Obtained radial strain data were highly reproducible and analysis was affected by only small intraobserver (mean 4.4 (SD 1.6)%) and interobserver variabilities (7.3 (2.5)%). Each of the analysed strain and strain-rate parameters was significantly different between segments defined as normokinetic, hypokinetic or akinetic by cMRI (radial strain 36.8 (10.5)%, 24.1 (7.5)% and 13.4 (4.8)%, respectively, p < 0.001). Peak systolic radial strain enabled detection of hypokinesis or akinesis with a sensitivity of 83.5% and a specificity of 83.5% (cut off value 29.1%, receiver operating characteristic (ROC) curve area 0.905, 95% CI 0.883 to 0.923). Peak systolic radial strain analysis also enabled detection of akinesis versus hypokinesis with a sensitivity of 82.7% and a specificity of 94.5% (cut off value 21.0%, ROC curve area 0.946). Peak systolic radial strain-rate analysis was less accurate than peak systolic radial strain analysis to detect cMRI-defined segmental function abnormalities. The accuracy of peak systolic circumferential strain and strain rate was similar to that of corresponding radial parameters.

Conclusions: Frame-by-frame tracking of acoustic markers in two dimensional echocardiographic images enables accurate analysis of regional systolic LV function.

  • cMRI, cardiac magnetic resonance imaging
  • LV, left ventricular
  • ROC, receiver operating characteristic
  • echocardiography
  • magnetic resonance imaging
  • strain imaging
  • left ventricular function

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Footnotes

  • Published Online First 30 December 2005

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